Chapter I. and II.--Elevation of the land: equability on E. coast as

Produced by Sue Asscher

MORE LETTERS OF CHARLES DARWIN

By Charles Darwin

A RECORD OF HIS WORK IN A SERIES OF HITHERTO UNPUBLISHED LETTERS

EDITED BY FRANCIS DARWIN, FELLOW OF CHRIST'S COLLEGE, AND A.C. SEWARD,

FELLOW OF EMMANUEL COLLEGE, CAMBRIDGE

IN TWO VOLUMES

Transcriber's Notes:

All biographical footnotes of both volumes appear at the end of Volume

II.

All other notes by Charles Darwin's editors appear in the text, in

brackets () with a Chapter/Note or Letter/Note number.

VOLUME II.

DEDICATED WITH AFFECTION AND RESPECT, TO

SIR JOSEPH HOOKER

IN REMEMBRANCE OF HIS LIFELONG FRIENDSHIP WITH CHARLES DARWIN

"You will never know how much I owe to you for your constant kindness

and encouragement"

CHARLES DARWIN TO SIR JOSEPH HOOKER, SEPTEMBER 14, 1862

MORE LETTERS OF CHARLES DARWIN

VOLUME II

CHAPTER 2.VII.--GEOGRAPHICAL DISTRIBUTION.

1843-1882 (Continued) (1867-1882.)

LETTER 378. J.D. HOOKER TO CHARLES DARWIN. Kew, January 20th, 1867.

Prof. Miquel, of Utrecht, begs me to ask you for your carte, and offers

his in return. I grieve to bother you on such a subject. I am sick and

tired of this carte correspondence. I cannot conceive what Humboldt's

Pyrenean violet is: no such is mentioned in Webb, and no alpine one at

all. I am sorry I forgot to mention the stronger African affinity of

the eastern Canary Islands. Thank you for mentioning it. I cannot admit,

without further analysis, that most of the peculiar Atlantic Islands

genera were derived from Europe, and have since become extinct there.

I have rather thought that many are only altered forms of existing

European genera; but this is a very difficult point, and would require

a careful study of such genera and allies with this object in view. The

subject has often presented itself to me as a grand one for analytic

botany. No doubt its establishment would account for the community of

the peculiar genera on the several groups and islets, but whilst so

many species are common we must allow for a good deal of migration of

peculiar genera too.

By Jove! I will write out next mail to the Governor of St. Helena for

boxes of earth, and you shall have them to grow. Thanks for telling me

of having suggested to me the working out of proportions of plants with

irregular flowers in islands. I thought it was a deuced deal too good

an idea to have arisen spontaneously in my block, though I did not

recollect your having done so. No doubt your suggestion was crystallised

in some corner of my sensorium. I should like to work out the point.

Have you Kerguelen Land amongst your volcanic islands? I have a curious

book of a sealer who was wrecked on the island, and who mentions a

volcanic mountain and hot springs at the S.W. end; it is called the

"Wreck of the Favourite." (378/1. "Narrative of the Wreck of the

'Favourite' on the Island of Desolation; detailing the Adventures,

Sufferings and Privations of John Munn; an Historical Account of the

Island and its Whale and Sea Fisheries." Edited by W.B. Clarke: London,

1850.)

LETTER 379. TO J.D. HOOKER. Down, March 17th, 1867.

It is a long time since I have written, but I cannot boast that I have

refrained from charity towards you, but from having lots of work...You

ask what I have been doing. Nothing but blackening proofs with

corrections. I do not believe any man in England naturally writes so

vile a style as I do...

In your paper on "Insular Floras" (page 9) there is what I must think an

error, which I before pointed out to you: viz., you say that the plants

which are wholly distinct from those of nearest continent are often

very common instead of very rare. (379/1. "Insular Floras," pamphlet

reprinted from the "Gardeners' Chronicle," page 9: "As a general

rule the species of the mother continent are proportionally the most

abundant, and cover the greatest surface of the islands. The peculiar

species are rarer, the peculiar genera of continental affinity are rarer

still; whilst the plants having no affinity with those of the mother

continent are often very common." In a letter of March 20th, 1867,

Sir Joseph explains that in the case of the Atlantic islands it is the

"peculiar genera of EUROPEAN AFFINITY that are so rare," while Clethra,

Dracaena and the Laurels, which have no European affinity, are common.)

Etty (379/2. Mr. Darwin's daughter, now Mrs. Litchfield.), who has read

your paper with great interest, was confounded by this sentence. By the

way, I have stumbled on two old notes: one, that twenty-two species of

European birds occasionally arrive as chance wanderers to the Azores;

and, secondly, that trunks of American trees have been known to be

washed on the shores of the Canary Islands by the Gulf-stream, which

returns southward from the Azores. What poor papers those of A. Murray

are in "Gardeners' Chronicle." What conclusions he draws from a single

Carabus (379/3. "Dr. Hooker on Insular Floras" ("Gardeners' Chronicle,"

1867, pages 152, 181). The reference to the Carabidous beetle

(Aplothorax) is at page 181.), and that a widely ranging genus! He seems

to me conceited; you and I are fair game geologically, but he refers to

Lyell, as if his opinion on a geological point was worth no more than

his own. I have just bought, but not read a sentence of, Murray's

big book (379/4. "Geographical Distribution of Mammals," 1866.),

second-hand, for 30s., new, so I do not envy the publishers. It is clear

to me that the man cannot reason. I have had a very nice letter from

Scott at Calcutta (379/5. See Letter 150.): he has been making some

good observations on the acclimatisation of seeds from plants of same

species, grown in different countries, and likewise on how far European

plants will stand the climate of Calcutta. He says he is astonished

how well some flourish, and he maintains, if the land were unoccupied,

several could easily cross, spreading by seed, the Tropics from north to

south, so he knows how to please me; but I have told him to be cautious,

else he will have dragons down on him...

As the Azores are only about two-and-a-half times more distant from

America (in the same latitude) than from Europe, on the occasional

migration view (especially as oceanic currents come directly from

West Indies and Florida, and heavy gales of wind blow from the same

direction), a large percentage of the flora ought to be American; as it

is, we have only the Sanicula, and at present we have no explanation of

this apparent anomaly, or only a feeble indication of an explanation in

the birds of the Azores being all European.

LETTER 380. TO J.D. HOOKER. Down, March 21st [1867].

Many thanks for your pleasant and very amusing letter. You have been

treated shamefully by Etty and me, but now that I know the facts,

the sentence seems to me quite clear. Nevertheless, as we have both

blundered, it would be well to modify the sentence something as follows:

"whilst, on the other hand, the plants which are related to those

of distant continents, but have no affinity with those of the mother

continent, are often very common." I forget whether you explain this

circumstance, but it seems to me very mysterious (380/1. Sir Joseph

Hooker wrote (March 23rd, 1867): "I see you 'smell a rat' in the matter

of insular plants that are related to those of [a] distant continent

being common. Yes, my beloved friend, let me make a clean breast of

it. I only found it out after the lecture was in print!...I have

been waiting ever since to 'think it out,' and write to you about it,

coherently. I thought it best to squeeze it in, anyhow or anywhere,

rather than leave so curious a fact unnoticed.")...Do always remember

that nothing in the world gives us so much pleasure as seeing you here

whenever you can come. I chuckle over what you say of And. Murray, but I

must grapple with his book some day.

LETTER 381. TO C. LYELL. Down, October 31st [1867].

Mr. [J.P. Mansel] Weale sent to me from Natal a small packet of dry

locust dung, under 1/2 oz., with the statement that it is believed that

they introduce new plants into a district. (381/1. See Volume I., Letter

221.) This statement, however, must be very doubtful. From this packet

seven plants have germinated, belonging to at least two kinds of

grasses. There is no error, for I dissected some of the seeds out of

the middle of the pellets. It deserves notice that locusts are sometimes

blown far out to sea. I caught one 370 miles from Africa, and I have

heard of much greater distances. You might like to hear the following

case, as it relates to a migratory bird belonging to the most wandering

of all orders--viz. the woodcock. (381/2. "Origin," Edition VI., page

328.) The tarsus was firmly coated with mud, weighing when dry 9 grains,

and from this the Juncus bufonius, or toad rush, germinated. By the way,

the locust case verifies what I said in the "Origin," that many possible

means of distribution would be hereafter discovered. I quite agree about

the extreme difficulty of the distribution of land mollusca. You will

have seen in the last edition of "Origin" (381/3. "Origin," Edition IV.,

page 429. The reference is to MM. Marten's (381/4. For Marten's read

Martins' [the name is wrongly spelt in the "Origin of Species."])

experiments on seeds "in a box in the actual sea.") that my observations

on the effects of sea-water have been confirmed. I still suspect that

the legs of birds which roost on the ground may be an efficient means;

but I was interrupted when going to make trials on this subject, and

have never resumed it.

We shall be in London in the middle of latter part of November, when I

shall much enjoy seeing you. Emma sends her love, and many thanks for

Lady Lyell's note.

LETTER 382. TO J.D. HOOKER. Down, Wednesday [1867].

I daresay there is a great deal of truth in your remarks on the glacial

affair, but we are in a muddle, and shall never agree. I am bigoted to

the last inch, and will not yield. I cannot think how you can attach so

much weight to the physicists, seeing how Hopkins, Hennessey, Haughton,

and Thomson have enormously disagreed about the rate of cooling of the

crust; remembering Herschel's speculations about cold space (382/1.

The reader will find some account of Herschel's views in Lyell's

"Principles," 1872, Edition XI., Volume I., page 283.), and bearing in

mind all the recent speculations on change of axis, I will maintain to

the death that your case of Fernando Po and Abyssinia is worth ten

times more than the belief of a dozen physicists. (382/2. See "Origin,"

Edition VI., page 337: "Dr. Hooker has also lately shown that several of

the plants living on the upper parts of the lofty island of Fernando Po

and on the neighbouring Cameroon mountains, in the Gulf of Guinea, are

closely related to those in the mountains of Abyssinia, and likewise to

those of temperate Europe." Darwin evidently means that such facts as

these are better evidence of the gigantic periods of time occupied by

evolutionary changes than the discordant conclusions of the physicists.

See "Linn. Soc. Journ." Volume VII., page 180, for Hooker's general

conclusions; also Hooker and Ball's "Marocco," Appendix F, page 421. For

the case of Fernando Po see Hooker ("Linn. Soc. Journ." VI., 1861, page

3, where he sums up: "Hence the result of comparing Clarence Peak flora

[Fernando Po] with that of the African continent is--(1) the intimate

relationship with Abyssinia, of whose flora it is a member, and from

which it is separated by 1800 miles of absolutely unexplored country;

(2) the curious relationship with the East African islands, which are

still farther off; (3) the almost total dissimilarity from the Cape

flora." For Sir J.D. Hooker's general conclusions on the Cameroon plants

see "Linn. Soc. Journ." VII., page 180. More recently equally striking

cases have come to light: for instance, the existence of a Mediterranean

genus, Adenocarpus, in the Cameroons and on Kilima Njaro, and nowhere

else in Africa; and the probable migration of South African forms along

the highlands from the Natal District to Abysinnia. See Hooker, "Linn.

Soc. Journ." XIV., 1874, pages 144-5.) Your remarks on my regarding

temperate plants and disregarding the tropical plants made me at first

uncomfortable, but I soon recovered. You say that all botanists would

agree that many tropical plants could not withstand a somewhat cooler

climate. But I have come not to care at all for general beliefs without

the special facts. I have suffered too often from this: thus I found in

every book the general statement that a host of flowers were fertilised

in the bud, that seeds could not withstand salt water, etc., etc. I

would far more trust such graphic accounts as that by you of the mixed

vegetation on the Himalayas and other such accounts. And with respect to

tropical plants withstanding the slowly coming on cool period, I trust

to such facts as yours (and others) about seeds of the same species

from mountains and plains having acquired a slightly different climatal

constitution. I know all that I have said will excite in you savage

contempt towards me. Do not answer this rigmarole, but attack me to your

heart's content, and to that of mine, whenever you can come here, and

may it be soon.

LETTER 383. J.D. HOOKER TO CHARLES DARWIN. Kew, 1870.

(383/1. The following extract from a letter of Sir J.D. Hooker shows the

tables reversed between the correspondents.)

Grove is disgusted at your being disquieted about W. Thomson. Tell

George from me not to sit upon you with his mathematics. When I

threatened your tropical cooling views with the facts of the physicists,

you snubbed me and the facts sweetly, over and over again; and now,

because a scarecrow of x+y has been raised on the selfsame facts, you

boo-boo. Take another dose of Huxley's penultimate G. S. Address, and

send George back to college. (383/2. Huxley's Anniversary Address to the

Geological Society, 1869 ("Collected Essays," VIII., page 305). This is

a criticism of Lord Kelvin's paper "On Geological Time" ("Trans. Geolog.

Soc. Glasgow," III.). At page 336 Mr. Huxley deals with Lord Kelvin's

"third line of argument, based on the temperature of the interior of the

earth." This was no doubt the point most disturbing to Mr. Darwin, since

it led Lord Kelvin to ask (as quoted by Huxley), "Are modern geologists

prepared to say that all life was killed off the earth 50,000, 100,000,

or 200,000 years ago?" Mr. Huxley, after criticising Lord Kelvin's data

and conclusion, gives his conviction that the case against Geology has

broken down. With regard to evolution, Huxley (page 328) ingeniously

points out a case of circular reasoning. "But it may be said that it

is biology, and not geology, which asks for so much time--that the

succession of life demands vast intervals; but this appears to me to

be reasoning in a circle. Biology takes her time from geology. The only

reason we have for believing in the slow rate of the change in living

forms is the fact that they persist through a series of deposits which,

geology informs us, have taken a long while to make. If the geological

clock is wrong, all the naturalist will have to do is to modify his

notions of the rapidity of change accordingly.")

LETTER 384. TO J.D. HOOKER. February 3rd [1868].

I am now reading Miquel on "Flora of Japan" (384/1. Miquel, "Flore du

Japon": "Archives Neerlandaises" ii., 1867.), and like it: it is rather

a relief to me (though, of course, not new to you) to find so very

much in common with Asia. I wonder if A. Murray's (384/2. "Geographical

Distribution of Mammals," by Andrew Murray, 1866. See Chapter V., page

47. See Letter 379.) notion can be correct, that a [profound] arm of

the sea penetrated the west coast of N. America, and prevented the

Asiatico-Japan element colonising that side of the continent so much

as the eastern side; or will climate suffice? I shall to the day of my

death keep up my full interest in Geographical Distribution, but I doubt

whether I shall ever have strength to come in any fuller detail than in

the "Origin" to this grand subject. In fact, I do not suppose any man

could master so comprehensive a subject as it now has become, if all

kingdoms of nature are included. I have read Murray's book, and am

disappointed--though, as you said, here and there clever thoughts occur.

How strange it is, that his view not affording the least explanation of

the innumerable adaptations everywhere to be seen apparently does not

in the least trouble his mind. One of the most curious cases which he

adduces seems to me to be the two allied fresh-water, highly peculiar

porpoises in the Ganges and Indus; and the more distantly allied form

of the Amazons. Do you remember his explanation of an arm of the sea

becoming cut off, like the Caspian, converted into fresh-water, and then

divided into two lakes (by upheaval), giving rise to two great rivers.

But no light is thus thrown on the affinity of the Amazon form. I now

find from Flower's paper (384/3. "Zoolog. Trans." VI., 1869, page 115.

The toothed whales are divided into the Physeteridae, the Delphinidae,

and the Platanistidae, which latter is placed between the two

other families, and is divided into the sub-families Iniinae and

Platanistinae.) that these fresh-water porpoises form two sub-families,

making an extremely isolated and intermediate, very small family. Hence

to us they are clearly remnants of a large group; and I cannot doubt

we here have a good instance precisely like that of ganoid fishes, of a

large ancient marine group, preserved exclusively in fresh-water, where

there has been less competition, and consequently little modification.

(384/4. See Volume I., Letter 95.) What a grand fact that is which

Miquel gives of the beech not extending beyond the Caucasus, and then

reappearing in Japan, like your Himalayan Pinus, and the cedar of

Lebanon. (384/5. For Pinus read Deodar. The essential identity of the

deodar and the cedar of Lebanon was pointed out in Hooker's "Himalayan

Journals" in 1854 (Volume I., page 257.n). In the "Nat. History Review,"

January, 1862, the question is more fully dealt with by him, and the

distribution discussed. The nearest point at which cedars occur is the

Bulgar-dagh chain of Taurus--250 miles from Lebanon. Under the name of

Cedrus atlantica the tree occurs in mass on the borders of Tunis, and as

Deodar it first appears to the east in the cedar forests of Afghanistan.

Sir J.D. Hooker supposes that, during a period of greater cold, the

cedars on the Taurus and on Lebanon lived many thousand feet nearer the

sea-level, and spread much farther to the east, meeting similar belts

of trees descending and spreading westward from Afghanistan along the

Persian mountains.) I know of nothing that gives one such an idea of the

recent mutations in the surface of the land as these living "outlyers."

In the geological sense we must, I suppose, admit that every yard of

land has been successively covered with a beech forest between the

Caucasus and Japan!

I have not yet seen (for I have not sent to the station) Falconer's

works. When you say that you sigh to think how poor your reprinted

memoirs would appear, on my soul I should like to shake you till your

bones rattled for talking such nonsense. Do you sigh over the "Insular

Floras," the Introduction to New Zealand Flora, to Australia, your

Arctic Flora, and dear Galapagos, etc., etc., etc.? In imagination I am

grinding my teeth and choking you till I put sense into you. Farewell. I

have amused myself by writing an audaciously long letter. By the way, we

heard yesterday that George has won the second Smith's Prize, which I am

excessively glad of, as the Second Wrangler by no means always succeeds.

The examination consists exclusively of [the] most difficult subjects,

which such men as Stokes, Cayley, and Adams can set.

LETTER 385. A.R. WALLACE TO CHARLES DARWIN. March 8th, 1868.

...While writing a few pages on the northern alpine forms of plants

on the Java mountains I wanted a few cases to refer to like Teneriffe,

where there are no northern forms and scarcely any alpine. I expected

the volcanoes of Hawaii would be a good case, and asked Dr. Seemann

about them. It seems a man has lately published a list of Hawaiian

plants, and the mountains swarm with European alpine genera and

some species! (385/1. "This turns out to be inaccurate, or greatly

exaggerated. There are no true alpines, and the European genera are

comparatively few. See my 'Island Life,' page 323."--A.R.W.) Is not this

most extraordinary, and a puzzler? They are, I believe, truly oceanic

islands, in the absence of mammals and the extreme poverty of birds and

insects, and they are within the Tropics.

Will not that be a hard nut for you when you come to treat in detail on

geographical distribution? I enclose Seemann's note, which please return

when you have copied the list, if of any use to you.

LETTER 386. TO J.D. HOOKER. Down, February 21st [1870].

I read yesterday the notes on Round Island (386/1. In Wallace's "Island

Life," page 410, Round Island is described as an islet "only about a

mile across, and situated about fourteen miles north-east of Mauritius."

Wallace mentions a snake, a python belonging to the peculiar and

distinct genus Casarea, as found on Round Island, and nowhere else in

the world. The palm Latania Loddigesii is quoted by Wallace as "confined

to Round Island and two other adjacent islets." See Baker's "Flora of

the Mauritius and the Seychelles." Mr. Wallace says that, judging from

the soundings, Round Island was connected with Mauritius, and that when

it was "first separated [it] would have been both much larger and much

nearer the main island.") which I owe to you. Was there ever such an

enigma? If, in the course of a week or two, you can find time to let me

hear what you think, I should very much like to hear: or we hope to be

at Erasmus' on March 4th for a week. Would there be any chance of your

coming to luncheon then? What a case it is. Palms, screw-pines, four

snakes--not one being in main island--lizards, insects, and not one

land bird. But, above everything, such a proportion of individual

monocotyledons! The conditions do not seem very different from the Tuff

Galapagos Island, but, as far as I remember, very few monocotyledons

there. Then, again, the island seems to have been elevated. I wonder

much whether it stands out in the line of any oceanic current, which

does not so forcibly strike the main island? But why, oh, why should so

many monocotyledons have come there? or why should they have survived

there more than on the main island, if once connected? So, again, I

cannot conceive that four snakes should have become extinct in Mauritius

and survived on Round Island. For a moment I thought that Mauritius

might be the newer island, but the enormous degradation which the outer

ring of rocks has undergone flatly contradicts this, and the marine

remains on the summit of Round Island indicate the island to be

comparatively new--unless, indeed, they are fossil and extinct marine

remains. Do tell me what you think. There never was such an enigma.

I rather lean to separate immigration, with, of course, subsequent

modification; some forms, of course, also coming from Mauritius.

Speaking of Mauritius reminds me that I was so much pleased the day

before yesterday by reading a review of a book on the geology of St.

Helena, by an officer who knew nothing of my hurried observations, but

confirms nearly all that I have said on the general structure of the

island, and on its marvellous denudation. The geology of that island was

like a novel.

LETTER 387. TO A. BLYTT. Down, March 28th, 1876.

(387/1. The following refers to Blytt's "Essay on the Immigration of the

Norwegian Flora during Alternating Rainy and Dry Periods," Christiania,

1876.)

I thank you sincerely for your kindness in having sent me your work on

the "Immigration of the Norwegian Flora," which has interested me in the

highest degree. Your view, supported as it is by various facts, appears

to me the most important contribution towards understanding the present

distribution of plants, which has appeared since Forbes' essay on the

effects of the Glacial Period.

LETTER 388. TO AUG. FOREL. Down, June 19th, 1876.

I hope you will allow me to suggest an observation, should any

opportunity occur, on a point which has interested me for many

years--viz., how do the coleoptera which inhabit the nests of ants

colonise a new nest? Mr. Wallace, in reference to the presence of such

coleoptera in Madeira, suggests that their ova may be attached to the

winged female ants, and that these are occasionally blown across the

ocean to the island. It would be very interesting to discover whether

the ova are adhesive, and whether the female coleoptera are guided by

instinct to attach them to the female ants (388/1. Dr. Sharp is good

enough to tell us that he is not aware of any such adaptation. Broadly

speaking, the distribution of the nest-inhabiting beetles is due to

co-migration with the ants, though in some cases the ants transport the

beetles. Sitaris and Meloe are beetles which live "at the expense of

bees of the genus Anthophora." The eggs are laid not in but near the

bees' nest; in the early stage the larva is active and has the instinct

to seize any hairy object near it, and in this way they are carried by

the Anthophora to the nest. Dr. Sharp states that no such preliminary

stage is known in the ant's-nest beetles. For an account of Sitaris and

Meloe, see Sharp's "Insects," II., page 272.); or whether the larvae

pass through an early stage, as with Sitaris or Meloe, or cling to the

bodies of the females. This note obviously requires no answer. I trust

that you continue your most interesting investigations on ants.

(PLATE: MR. A.R. WALLACE, 1878. From a photograph by Maull & Fox.)

LETTER 389. TO A.R. WALLACE.

(389/1. Published in "Life and Letters," III., page 230.)

(389/2. The following five letters refer to Mr. Wallace's "Geographical

Distribution of Animals," 1876.)

[Hopedene] (389/3. Mr. Hensleigh Wedgwood's house in Surrey.), June 5th,

1876.

I must have the pleasure of expressing to you my unbounded admiration

of your book (389/4. "Geographical Distribution," 1876.), though I have

read only to page 184--my object having been to do as little as

possible while resting. I feel sure that you have laid a broad and safe

foundation for all future work on Distribution. How interesting it will

be to see hereafter plants treated in strict relation to your views; and

then all insects, pulmonate molluscs and fresh-water fishes, in greater

detail than I suppose you have given to these lower animals. The point

which has interested me most, but I do not say the most valuable point,

is your protest against sinking imaginary continents in a quite

reckless manner, as was stated by Forbes, followed, alas, by Hooker,

and caricatured by Wollaston and [Andrew] Murray! By the way, the main

impression that the latter author has left on my mind is his utter want

of all scientific judgment. I have lifted up my voice against the above

view with no avail, but I have no doubt that you will succeed, owing

to your new arguments and the coloured chart. Of a special value, as it

seems to me, is the conclusion that we must determine the areas, chiefly

by the nature of the mammals. When I worked many years ago on this

subject, I doubted much whether the now-called Palaearctic and Nearctic

regions ought to be separated; and I determined if I made another region

that it should be Madagascar. I have, therefore, been able to appreciate

your evidence on these points. What progress Palaeontology has made

during the last twenty years! but if it advances at the same rate in the

future, our views on the migration and birthplace of the various groups

will, I fear, be greatly altered. I cannot feel quite easy about the

Glacial period, and the extinction of large mammals, but I must hope

that you are right. I think you will have to modify your belief about

the difficulty of dispersal of land molluscs; I was interrupted when

beginning to experimentise on the just hatched young adhering to the

feet of ground-roosting birds. I differ on one other point--viz. in the

belief that there must have existed a Tertiary Antarctic continent, from

which various forms radiated to the southern extremities of our present

continents. But I could go on scribbling forever. You have written, as

I believe, a grand and memorable work, which will last for years as the

foundation for all future treatises on Geographical Distribution.

P.S.--You have paid me the highest conceivable compliment, by what

you say of your work in relation to my chapters on distribution in the

"Origin," and I heartily thank you for it.

LETTER 390. FROM A.R. WALLACE TO CHARLES DARWIN. The Dell, Grays, Essex,

June 7th, 1876.

Many thanks for your very kind letter. So few people will read my book

at all regularly, that a criticism from one who does so will be very

welcome. If, as I suppose, it is only to page 184 of Volume I. that you

have read, you cannot yet quite see my conclusions on the points you

refer to (land molluscs and Antarctic continent). My own conclusion

fluctuated during the progress of the book, and I have, I know,

occasionally used expressions (the relics of earlier ideas) which are

not quite consistent with what I say further on. I am positively against

any Southern continent as uniting South America with Australia or New

Zealand, as you will see at Volume I., pages 398-403, and 459-66. My

general conclusions as to distribution of land mollusca are at Volume

II., pages 522-9. (390/1. "Geographical Distribution" II., pages 524,

525. Mr. Wallace points out that "hardly a small island on the globe but

has some land-shells peculiar to it"--and he goes so far as to say that

probably air-breathing mollusca have been chiefly distributed by air-

or water-carriage, rather than by voluntary dispersal on the land.) When

you have read these passages, and looked at the general facts which lead

to them, I shall be glad to hear if you still differ from me.

Though, of course, present results as to the origin and migrations of

genera of mammals will have to be modified owing to new discoveries, I

cannot help thinking that much will remain unaffected, because in all

geographical and geological discoveries the great outlines are soon

reached, the details alone remain to be modified. I also think much of

the geological evidence is now so accordant with, and explanatory of,

Geographical Distribution, that it is prima facie correct in outline.

Nevertheless, such vast masses of new facts will come out in the next

few years that I quite dread the labour of incorporating them in a new

edition.

I hope your health is improved; and when, quite at your leisure, you

have waded through my book, I trust you will again let me have a few

lines of friendly criticism and advice.

LETTER 391. TO A.R. WALLACE. Down, June 17th, 1876.

I have now finished the whole of Volume I., with the same interest and

admiration as before; and I am convinced that my judgment was right

and that it is a memorable book, the basis of all future work on the

subject. I have nothing particular to say, but perhaps you would like to

hear my impressions on two or three points. Nothing has struck me more

than the admirable and convincing manner in which you treat Java. To

allude to a very trifling point, it is capital about the unadorned head

of the Argus-pheasant. (391/1. See "Descent of Man," Edition I., pages

90 and 143, for drawings of the Argus pheasant and its markings. The

ocelli on the wing feathers were favourite objects of Mr. Darwin,

and sometimes formed the subject of the little lectures which on rare

occasions he would give to a visitor interested in Natural History. In

Mr. Wallace's book the meaning of the ocelli comes in by the way, in the

explanation of Plate IX., "A Malayan Forest with some of its peculiar

Birds." Mr. Wallace (volume i., page 340) points out that the head of

the Argus pheasant is, during the display of the wings, concealed from

the view of a spectator in front, and this accounts for the absence of

bright colour on the head--a most unusual point in a pheasant. The case

is described as a "remarkable confirmation of Mr. Darwin's views, that

gaily coloured plumes are developed in the male bird for the purpose

of attractive display." For the difference of opinion between the two

naturalists on the broad question of coloration see "Life and Letters,"

III., page 123. See Letters 440-453.) How plain a thing is, when it is

once pointed out! What a wonderful case is that of Celebes: I am glad

that you have slightly modified your views with respect to Africa.

(391/2. "I think this must refer to the following passage in 'Geog.

Dist. of Animals,' Volume I., pages 286-7. 'At this period (Miocene)

Madagascar was no doubt united with Africa, and helped to form a great

southern continent which must at one time have extended eastward as far

as Southern India and Ceylon; and over the whole of this the lemurine

type no doubt prevailed.' At the time this was written I had not paid

so much attention to islands, and in my "Island Life" I have given ample

reasons for my belief that the evidence of extinct animals does not

require any direct connection between Southern India and Africa."--Note

by Mr. Wallace.) And this leads me to say that I cannot swallow the

so-called continent of Lemuria--i.e., the direct connection of Africa

and Ceylon. (391/3. See "Geographical Distribution," I., page 76. The

name Lemuria was proposed by Mr. Sclater for an imaginary submerged

continent extending from Madagascar to Ceylon and Sumatra. Mr. Wallace

points out that if we confine ourselves to facts Lemuria is reduced to

Madagascar, which he makes a subdivision of the Ethiopian Region.) The

facts do not seem to me many and strong enough to justify so immense a

change of level. Moreover, Mauritius and the other islands appear to

me oceanic in character. But do not suppose that I place my judgment

on this subject on a level with yours. A wonderfully good paper was

published about a year ago on India, in the "Geological Journal," I

think by Blanford. (391/4. H.F. Blanford "On the Age and Correlations

of the Plant-bearing Series of India and the Former Existence of an

Indo-Oceanic Continent" ("Quart. Journ. Geol. Soc." XXXI., 1875, page

519). The name Gondwana-Land was subsequently suggested by Professor

Suess for this Indo-Oceanic continent. Since the publication of

Blanford's paper, much literature has appeared dealing with the evidence

furnished by fossil plants, etc., in favour of the existence of a vast

southern continent.) Ramsay agreed with me that it was one of the

best published for a long time. The author shows that India has been a

continent with enormous fresh-water lakes, from the Permian period to

the present day. If I remember right, he believes in a former connection

with S. Africa.

I am sure that I read, some twenty to thirty years ago in a French

journal, an account of teeth of Mastodon found in Timor; but the

statement may have been an error. (391/5. In a letter to Falconer

(Letter 155), January 5th, 1863, Darwin refers to the supposed

occurrence of Mastodon as having been "smashed" by Falconer.)

With respect to what you say about the colonising of New Zealand,

I somewhere have an account of a frog frozen in the ice of a Swiss

glacier, and which revived when thawed. I may add that there is an

Indian toad which can resist salt-water and haunts the seaside. Nothing

ever astonished me more than the case of the Galaxias; but it does

not seem known whether it may not be a migratory fish like the salmon.

(391/6. The only genus of the Galaxidae, a family of fresh-water fishes

occurring in New Zealand, Tasmania, and Tierra del Fuego, ranging north

as far as Queensland and Chile (Wallace's "Geographical Distribution,"

II., page 448).)

LETTER 392. TO A.R. WALLACE. Down, June 25th, 1876.

I have been able to read rather more quickly of late, and have finished

your book. I have not much to say. Your careful account of the temperate

parts of South America interested me much, and all the more from knowing

something of the country. I like also much the general remarks towards

the end of the volume on the land molluscs. Now for a few criticisms.

Page 122. (392/1. The pages refer to Volume II. of Wallace's

"Geographical Distribution.")--I am surprised at your saying that

"during the whole Tertiary period North America was zoologically far

more strongly contrasted with South America than it is now." But we know

hardly anything of the latter except during the Pliocene period; and

then the mastodon, horse, several great edentata, etc., etc., were

common to the north and south. If you are right, I erred greatly in my

"Journal," where I insisted on the former close connection between the

two.

Page 252 and elsewhere.--I agree thoroughly with the general principle

that a great area with many competing forms is necessary for much and

high development; but do you not extend this principle too far--I should

say much too far, considering how often several species of the same

genus have been developed on very small islands?

Page 265.--You say that the Sittidae extend to Madagascar, but there

is no number in the tabular heading. [The number (4) was erroneously

omitted.--A.R.W.]

Page 359.--Rhinochetus is entered in the tabular heading under No. 3

of the neotropical subregions. [An error: should have been the

Australian.--A.R.W.]

Reviewers think it necessary to find some fault; and if I were to

review you, the sole point which I should blame is your not giving very

numerous references. These would save whoever follows you great

labour. Occasionally I wished myself to know the authority for certain

statements, and whether you or somebody else had originated certain

subordinate views. Take the case of a man who had collected largely on

some island, for instance St. Helena, and who wished to work out the

geographical relations of his collections: he would, I think, feel very

blank at not finding in your work precise references to all that had

been written on St. Helena. I hope you will not think me a confoundedly

disagreeable fellow.

I may mention a capital essay which I received a few months ago

from Axel Blytt (392/2. Axel Blytt, "Essay on the Immigration of

the Norwegian Flora." Christiania, 1876. See Letter 387.) on the

distribution of the plants of Scandinavia; showing the high probability

of there having been secular periods alternately wet and dry, and of the

important part which they have played in distribution.

I wrote to Forel (392/3. See Letter 388.), who is always at work

on ants, and told him your views about the dispersal of the blind

coleoptera, and asked him to observe.

I spoke to Hooker about your book, and feel sure that he would like

nothing better than to consider the distribution of plants in relation

to your views; but he seemed to doubt whether he should ever have time.

And now I have done my jottings, and once again congratulate you on

having brought out so grand a work. I have been a little disappointed at

the review in "Nature." (392/4. June 22nd, 1876, pages 165 et seq.)

LETTER 393. A.R. WALLACE TO CHARLES DARWIN. Rosehill, Dorking, July

23rd, 1876.

I should have replied sooner to your last kind and interesting letters,

but they reached me in the midst of my packing previous to removal here,

and I have only just now got my books and papers in a get-at-able state.

And first, many thanks for your close observation in detecting the two

absurd mistakes in the tabular headings.

As to the former greater distinction of the North and South American

faunas, I think I am right. The edentata being proved (as I hold)

to have been mere temporary migrants into North America in the

post-Pliocene epoch, form no part of its Tertiary fauna. Yet in South

America they were so enormously developed in the Pliocene epoch that

we know, if there is any such thing as evolution, etc., that strange

ancestral forms must have preceded them in Miocene times.

Mastodon, on the other hand, represented by one or two species only,

appears to have been a late immigrant into South America from the north.

The immense development of ungulates (in varied families, genera, and

species) in North America during the whole Tertiary epoch is, however,

the great feature which assimilates it to Europe, and contrasts it

with South America. True camels, hosts of hog-like animals, true

rhinoceroses, and hosts of ancestral horses, all bring the North

American [fauna] much nearer to the Old World than it is now. Even the

horse, represented in all South America by Equus only, was probably a

temporary immigrant from the north.

As to extending too far the principle (yours) of the necessity of

comparatively large areas for the development of varied faunas, I may

have done so, but I think not. There is, I think, every probability that

most islands, etc., where a varied fauna now exists, have been once more

extensive--eg., New Zealand, Madagascar: where there is no such evidence

(e.g., Galapagos), the fauna is very restricted.

Lastly, as to want of references: I confess the justice of your

criticism; but I am dreadfully unsystematic. It is my first large work

involving much of the labour of others. I began with the intention of

writing a comparatively short sketch, enlarged it, and added to it bit

by bit; remodelled the tables, the headings, and almost everything else,

more than once, and got my materials in such confusion that it is a

wonder it has not turned out far more crooked and confused than it is.

I, no doubt, ought to have given references; but in many cases I found

the information so small and scattered, and so much had to be combined

and condensed from conflicting authorities, that I hardly knew how

to refer to them or where to leave off. Had I referred to all authors

consulted for every fact, I should have greatly increased the bulk of

the book, while a large portion of the references would be valueless

in a few years, owing to later and better authorities. My experience

of referring to references has generally been most unsatisfactory. One

finds, nine times out of ten, the fact is stated, and nothing more; or a

reference to some third work not at hand!

I wish I could get into the habit of giving chapter and verse for every

fact and extract; but I am too lazy, and generally in a hurry, having to

consult books against time, when in London for a day.

However, I will try to do something to mend this matter, should I have

to prepare another edition.

I return you Forel's letter. It does not advance the question much;

neither do I think it likely that even the complete observation he

thinks necessary would be of much use, because it may well be that the

ova, or larvae, or imagos of the beetles are not carried systematically

by the ants, but only occasionally, owing to some exceptional

circumstances. This might produce a great effect in distribution, yet be

so rare as never to come under observation.

Several of your remarks in previous letters I shall carefully consider.

I know that, compared with the extent of the subject, my book is in

many parts crude and ill-considered; but I thought, and still think, it

better to make some generalisations wherever possible, as I am not at

all afraid of having to alter my views in many points of detail. I was

so overwhelmed with zoological details, that I never went through the

Geological Society's "Journal" as I ought to have done, and as I mean to

do before writing more on the subject.

LETTER 394. TO F. BUCHANAN WHITE.

(394/1. "Written in acknowledgment of a copy of a paper (published by me

in the "Proceedings of the Zoological Society") on the Hemiptera of St.

Helena, but discussing the origin of the whole fauna and flora of that

island."--F.B.W.)

Down, September 23rd. [1878].

I have now read your paper, and I hope that you will not think me

presumptuous in writing another line to say how excellent it seems to

me. I believe that you have largely solved the problem of the affinities

of the inhabitants of this most interesting little island, and this is a

delightful triumph.

LETTER 395. TO J.D. HOOKER. Down, July 22nd [1879].

I have just read Ball's Essay. (395/1. The late John Ball's lecture

"On the Origin of the Flora of the Alps" in the "Proceedings of the R.

Geogr. Soc." 1879. Ball argues (page 18) that "during ancient Palaeozoic

times, before the deposition of the Coal-measures, the atmosphere

contained twenty times as much carbonic acid gas and considerably less

oxygen than it does at present." He further assumes that in such an

atmosphere the percentage of CO2 in the higher mountains would be

excessively different from that at the sea-level, and appends the result

of calculations which gives the amount of CO2 at the sea-level as 100

per 10,000 by weight, at a height of 10,000 feet as 12.5 per 10,000.

Darwin understands him to mean that the Vascular Cryptogams and

Gymnosperms could stand the sea-level atmosphere, whereas the

Angiosperms would only be able to exist in the higher regions where the

percentage of CO2 was small. It is not clear to us that Ball relies so

largely on the condition of the atmosphere as regards CO2. If he does

he is clearly in error, for everything we know of assimilation points

to the conclusion that 100 per 10,000 (1 per cent.) is by no means a

hurtful amount of CO2, and that it would lead to an especially vigorous

assimilation. Mountain plants would be more likely to descend to the

plains to share in the rich feast than ascend to higher regions to avoid

it. Ball draws attention to the imperfection of our plant records as

regards the floras of mountain regions. It is, he thinks, conceivable

that there existed a vegetation on the Carboniferous mountains of which

no traces have been preserved in the rocks. See "Fossil Plants as Tests

of Climate," page 40, A.C. Seward, 1892.

Since the first part of this note was written, a paper has been read

(May 29th, 1902) by Dr. H.T. Brown and Mr. F. Escombe, before the Royal

Society on "The Influence of varying amounts of Carbon Dioxide in the

Air on the Photosynthetic Process of Leaves, and on the Mode of Growth

of Plants." The author's experiments included the cultivation of several

dicotyledonous plants in an atmosphere containing in one case 180 to 200

times the normal amount of CO2, and in another between three and four

times the normal amount. The general results were practically identical

in the two sets of experiments. "All the species of flowering plants,

which have been the subject of experiment, appear to be accurately

'tuned' to an atmospheric environment of three parts of CO2 per 10,000,

and the response which they make to slight increases in this amount

are in a direction altogether unfavourable to their growth and

reproduction." The assimilation of carbon increases with the increase in

the partial pressure of the CO2. But there seems to be a disturbance

in metabolism, and the plants fail to take advantage of the increased

supply of CO2. The authors say:--"All we are justified in concluding is,

that if such atmospheric variations have occurred since the advent

of flowering plants, they must have taken place so slowly as never

to outrun the possible adaptation of the plants to their changing

conditions."

Prof. Farmer and Mr. S.E. Chandler gave an account, at the same meeting

of the Royal Society, of their work "On the Influence of an Excess of

Carbon Dioxide in the Air on the Form and Internal Structure of Plants."

The results obtained were described as differing in a remarkable way

from those previously recorded by Teodoresco ("Rev. Gen. Botanique,"

II., 1899

It is hoped that Dr. Horace Brown and Mr. Escombe will extend their

experiments to Vascular Cryptogams, and thus obtain evidence bearing

more directly upon the question of an increased amount of CO2 in the

atmosphere of the Coal-period forests.) It is pretty bold. The rapid

development as far as we can judge of all the higher plants within

recent geological times is an abominable mystery. Certainly it would be

a great step if we could believe that the higher plants at first could

live only at a high level; but until it is experimentally [proved] that

Cycadeae, ferns, etc., can withstand much more carbonic acid than the

higher plants, the hypothesis seems to me far too rash. Saporta believes

that there was an astonishingly rapid development of the high plants,

as soon [as] flower-frequenting insects were developed and favoured

intercrossing. I should like to see this whole problem solved. I

have fancied that perhaps there was during long ages a small isolated

continent in the S. Hemisphere which served as the birthplace of the

higher plants--but this is a wretchedly poor conjecture. It is odd

that Ball does not allude to the obvious fact that there must have

been alpine plants before the Glacial period, many of which would have

returned to the mountains after the Glacial period, when the climate

again became warm. I always accounted to myself in this manner for the

gentians, etc.

Ball ought also to have considered the alpine insects common to the

Arctic regions. I do not know how it may be with you, but my faith in

the glacial migration is not at all shaken.

LETTER 396. A.R. WALLACE TO CHARLES DARWIN.

(396/1. This letter is in reply to Mr. Darwin's criticisms on Mr.

Wallace's "Island Life," 1880.)

Pen-y-Bryn, St. Peter's Road, Croydon, November 8th, 1880.

Many thanks for your kind remarks and notes on my book. Several of the

latter will be of use to me if I have to prepare a second edition, which

I am not so sure of as you seem to be.

1. In your remark as to the doubtfulness of paucity of fossils being due

to coldness of water, I think you overlook that I am speaking only of

water in the latitude of the Alps, in Miocene and Eocene times, when

icebergs and glaciers temporarily descended into an otherwise warm sea;

my theory being that there was no Glacial epoch at that time, but merely

a local and temporary descent of the snow-line and glaciers owing to

high excentricity and winter in aphelion.

2. I cannot see the difficulty about the cessation of the Glacial

period.

Between the Miocene and the Pleistocene periods geographical changes

occurred which rendered a true Glacial period possible with high

excentricity. When the high excentricity passed away the Glacial epoch

also passed away in the temperate zone; but it persists in the arctic

zone, where, during the Miocene, there were mild climates, and this

is due to the persistence of the changed geographical conditions. The

present arctic climate is itself a comparatively new and abnormal state

of things, due to geographical modification.

As to "epoch" and "period," I use them as synonyms to avoid repeating

the same word.

3. Rate of deposition and geological time. Here no doubt I may have

gone to an extreme, but my "28 million years" may be anything under 100

millions, as I state. There is an enormous difference between mean and

maximum denudation and deposition. In the case of the great faults

the upheaval along a given line would itself facilitate the denudation

(whether sub-aerial or marine) of the upheaved portion at a rate perhaps

a hundred times above the average, just as valleys have been denuded

perhaps a hundred times faster than plains and plateaux. So local

subsidence might itself lead to very rapid deposition. Suppose a portion

of the Gulf of Mexico, near the mouths of the Mississippi, were to

subside for a few thousand years, it might receive the greater portion

of the sediment from the whole Mississippi valley, and thus form strata

at a very rapid rate.

4. You quote the Pampas thistles, etc., against my statement of the

importance of preoccupation. But I am referring especially to St.

Helena, and to plants naturally introduced from the adjacent continents.

Surely if a certain number of African plants reached the island, and

became modified into a complete adaptation to its climatic conditions,

they would hardly be expelled by other African plants arriving

subsequently. They might be so, conceivably, but it does not seem

probable. The cases of the Pampas, New Zealand, Tahiti, etc., are

very different, where highly developed aggressive plants have been

artificially introduced. Under nature it is these very aggressive

species that would first reach any island in their vicinity, and, being

adapted to the island and colonising it thoroughly, would then hold

their own against other plants from the same country, mostly less

aggressive in character.

I have not explained this so fully as I should have done in the book.

Your criticism is therefore useful.

5. My Chapter XXIII. is no doubt very speculative, and I cannot wonder

at your hesitating at accepting my views. To me, however, your theory of

hosts of existing species migrating over the tropical lowlands from the

N. temperate to the S. temperate zone appears more speculative and

more improbable. For where could the rich lowland equatorial flora have

existed during a period of general refrigeration sufficient for this?

and what became of the wonderfully rich Cape flora, which, if the

temperature of tropical Africa had been so recently lowered, would

certainly have spread northwards, and on the return of the heat

could hardly have been driven back into the sharply defined and very

restricted area in which it now exists.

As to the migration of plants from mountain to mountain not being so

probable as to remote islands, I think that is fully counterbalanced by

two considerations:--

a. The area and abundance of the mountain stations along such a range

as the Andes are immensely greater than those of the islands in the N.

Atlantic, for example.

b. The temporary occupation of mountain stations by migrating plants

(which I think I have shown to be probable) renders time a much more

important element in increasing the number and variety of the plants so

dispersed than in the case of islands, where the flora soon acquires

a fixed and endemic character, and where the number of species is

necessarily limited.

No doubt direct evidence of seeds being carried great distances through

the air is wanted, but I am afraid can hardly be obtained. Yet I feel

the greatest confidence that they are so carried. Take, for instance,

the two peculiar orchids of the Azores (Habenaria sp.) What other mode

of transit is conceivable? The whole subject is one of great difficulty,

but I hope my chapter may call attention to a hitherto neglected factor

in the distribution of plants.

Your references to the Mauritius literature are very interesting, and

will be useful to me; and I again thank you for your valuable remarks.

LETTER 397. TO J.D. HOOKER.

(397/1. The following letters were written to Sir J.D. Hooker when he

was preparing his Address as President of the Geographical Section of

the British Association at its fiftieth meeting, at York. The second

letter (August 12th) refers to an earlier letter of August 6th,

published in "Life and Letters," III., page 246.)

4, Bryanston Street, W., Saturday, 26th [February, 1881].

I should think that you might make a very interesting address on

Geographical Distribution. Could you give a little history of the

subject. I, for one, should like to read such history in petto; but I

can see one very great difficulty--that you yourself ought to figure

most prominently in it; and this you would not do, for you are just the

man to treat yourself in a dishonourable manner. I should very much like

to see you discuss some of Wallace's views, especially his ignoring

the all-powerful effects of the Glacial period with respect to alpine

plants. (397/2. "Having been kindly permitted by Mr. Francis Darwin to

read this letter, I wish to explain that the above statement applies

only to my rejection of Darwin's view that the presence of arctic and

north temperate plants in the SOUTHERN HEMISPHERE was brought about

by the lowering of the temperature of the tropical regions during the

Glacial period, so that even 'the lowlands of these great continents

were everywhere tenanted under the equator by a considerable number of

temperate forms ("Origin of Species," Edition VI., page 338). My

own views are fully explained in Chapter XXIII. of my "Island Life,"

published in 1880. I quite accept all that Darwin, Hooker, and Asa Gray

have written about the effect of the Glacial epoch in bringing about

the present distribution of alpine and arctic plants in the NORTHERN

HEMISPHERE."--Note by Mr. Wallace.) I do not know what you think, but it

appears to me that he exaggerates enormously the influence of debacles

or slips and new surface of soil being exposed for the reception of

wind-blown seeds. What kinds of seeds have the plants which are common

to the distant mountain-summits in Africa? Wallace lately wrote to me

about the mountain plants of Madagascar being the same with those on

mountains in Africa, and seemed to think it proved dispersal by the

wind, without apparently having inquired what sorts of seeds the plants

bore. (397/3. The affinity with the flora of the Eastern African islands

was long ago pointed out by Sir J.D. Hooker, "Linn. Soc. Journal," VI.,

1861, page 3. Speaking of the plants of Clarence Peak in Fernando Po, he

says, "The next affinity is with Mauritius, Bourbon, and Madagascar:

of the whole 76 species, 16 inhabit these places and 8 more are closely

allied to plants from there. Three temperate species are peculiar to

Clarence Peak and the East African islands..." The facts to which

Mr. Wallace called Darwin's attention are given by Mr. J.G. Baker in

"Nature," December 9th, 1880, page 125. He mentions the Madagascar

Viola, which occurs elsewhere only at 7,000 feet in the Cameroons, at

10,000 feet in Fernando Po and in the Abyssinian mountains; and the same

thing is true of the Madagascar Geranium. In Mr. Wallace's letter

to Darwin, dated January 1st, 1881, he evidently uses the expression

"passing through the air" in contradistinction to the migration of a

species by gradual extension of its area on land. "Through the air"

would moreover include occasional modes of transport other than simple

carriage by wind: e.g., the seeds might be carried by birds, either

attached to the feathers or to the mud on their feet, or in their crops

or intestines.)

I suppose it would be travelling too far (though for the geographical

section the discussion ought to be far-reaching), but I should like

to see the European or northern element in the Cape of Good Hope

flora discussed. I cannot swallow Wallace's view that European plants

travelled down the Andes, tenanted the hypothetical Antarctic continent

(in which I quite believe), and thence spread to South Australia and the

Cape of Good Hope.

Moseley told me not long ago that he proposed to search at Kerguelen

Land the coal beds most carefully, and was absolutely forbidden to do

so by Sir W. Thomson, who said that he would undertake the work, and he

never once visited them. This puts me in a passion. I hope that you will

keep to your intention and make an address on distribution. Though I

differ so much from Wallace, his "Island Life" seems to me a wonderful

book.

Farewell. I do hope that you may have a most prosperous journey. Give my

kindest remembrances to Asa Gray.

LETTER 398. TO J.D. HOOKER. Down, August 12th, 1881.

...I think that I must have expressed myself badly about Humboldt.

I should have said that he was more remarkable for his astounding

knowledge than for originality. I have always looked at him as, in fact,

the founder of the geographical distribution of organisms. I thought

that I had read that extinct fossil plants belonging to Australian forms

had lately been found in Australia, and all such cases seem to me very

interesting, as bearing on development.

I have been so astonished at the apparently sudden coming in of the

higher phanerogams, that I have sometimes fancied that development might

have slowly gone on for an immense period in some isolated continent or

large island, perhaps near the South Pole. I poured out my idle thoughts

in writing, as if I had been talking with you.

No fact has so interested me for a heap of years as your case of the

plants on the equatorial mountains of Africa; and Wallace tells me that

some one (Baker?) has described analogous cases on the mountains of

Madagascar (398/1. See Letter 397, note.)...I think that you ought to

allude to these cases.

I most fully agree that no problem is more interesting than that of

the temperate forms in the southern hemisphere, common to the north. I

remember writing about this after Wallace's book appeared, and hoping

that you would take it up. The frequency with which the drainage from

the land passes through mountain-chains seems to indicate some general

law--viz., the successive formation of cracks and lines of elevation

between the nearest ocean and the already upraised land; but that is too

big a subject for a note.

I doubt whether any insects can be shown with any probability to have

been flower feeders before the middle of the Secondary period. Several

of the asserted cases have broken down.

Your long letter has stirred many pleasant memories of long past days,

when we had many a discussion and many a good fight.

LETTER 399. TO J.D. HOOKER. Down, August 21st, 1881.

I cannot aid you much, or at all. I should think that no one could

have thought on the modification of species without thinking of

representative species. But I feel sure that no discussion of any

importance had been published on this subject before the "Origin,"

for if I had known of it I should assuredly have alluded to it in the

"Origin," as I wished to gain support from all quarters. I did not then

know of Von Buch's view (alluded to in my Historical Introduction in all

the later editions). Von Buch published his "Isles Canaries" in 1836,

and he here briefly argues that plants spread over a continent and

vary, and the varieties in time come to be species. He also argues that

closely allied species have been thus formed in the SEPARATE valleys of

the Canary Islands, but not on the upper and open parts. I could lend

you Von Buch's book, if you like. I have just consulted the passage.

I have not Baer's papers; but, as far as I remember, the subject is not

fully discussed by him.

I quite agree about Wallace's position on the ocean and continent

question.

To return to geographical distribution: As far as I know, no one ever

discussed the meaning of the relation between representative species

before I did, and, as I suppose, Wallace did in his paper before the

Linnean Society. Von Buch's is the nearest approach to such discussion

known to me.

LETTER 400. TO W.D. CRICK.

(400/1. The following letters are interesting not only for their own

sake, but because they tell the history of the last of Mr. Darwin's

publications--his letter to "Nature" on the "Dispersal of Freshwater

Bivalves," April 6th, 1882.)

Down, February 21st, 1882.

Your fact is an interesting one, and I am very much obliged to you for

communicating it to me. You speak a little doubtfully about the name of

the shell, and it would be indispensable to have this ascertained with

certainty. Do you know any good conchologist in Northampton who could

name it? If so I should be obliged if you would inform me of the result.

Also the length and breadth of the shell, and how much of leg (which

leg?) of the Dytiscus [a large water-beetle] has been caught. If you

cannot get the shell named I could take it to the British Museum when I

next go to London; but this probably will not occur for about six weeks,

and you may object to lend the specimen for so long a time.

I am inclined to think that the case would be worth communicating to

"Nature."

P.S.--I suppose that the animal in the shell must have been alive when

the Dytiscus was captured, otherwise the adductor muscle of the shell

would have relaxed and the shell dropped off.

LETTER 401. TO W.D. CRICK. Down, February 25th, 1882.

I am much obliged for your clear and distinct answers to my questions.

I am sorry to trouble you, but there is one point which I do not fully

understand. Did the shell remain attached to the beetle's leg from the

18th to the 23rd, and was the beetle kept during this time in the air?

Do I understand rightly that after the shell had dropped off, both being

in water, that the beetle's antenna was again temporarily caught by the

shell?

I presume that I may keep the specimen till I go to London, which will

be about the middle of next month.

I have placed the shell in fresh-water, to see if the valve will open,

and whether it is still alive, for this seems to me a very interesting

point. As the wretched beetle was still feebly alive, I have put it in

a bottle with chopped laurel leaves, that it may die an easy and quicker

death. I hope that I shall meet with your approval in doing so.

One of my sons tells me that on the coast of N. Wales the bare fishing

hooks often bring up young mussels which have seized hold of the points;

but I must make further enquiries on this head.

LETTER 402. TO W.D. CRICK. Down, March 23rd, 1882.

I have had a most unfortunate and extraordinary accident with your

shell. I sent it by post in a strong box to Mr. Gwyn Jeffreys to be

named, and heard two days afterwards that he had started for Italy.

I then wrote to the servant in charge of his house to open the parcel

(within which was a cover stamped and directed to myself) and return

it to me. This servant, I suppose, opened the box and dropped the glass

tube on a stone floor, and perhaps put his foot on it, for the tube and

shell were broken into quite small fragments. These were returned to me

with no explanation, the box being quite uninjured. I suppose you would

not care for the fragments to be returned or the Dytiscus; but if you

wish for them they shall be returned. I am very sorry, but it has not

been my fault.

It seems to me almost useless to send the fragments of the shell to the

British Museum to be named, more especially as the umbo has been lost.

It is many years since I have looked at a fresh-water shell, but I

should have said that the shell was Cyclas cornea. (402/1. It was Cyclas

cornea.) Is Sphaenium corneum a synonym of Cyclas? Perhaps you could

tell by looking to Mr. G. Jeffreys' book. If so, may we venture to call

it so, or shall I put an (?) to the name?

As soon as I hear from you I will send my letter to "Nature." Do you

take in "Nature," or shall I send you a copy?

CHAPTER 2.VIII.--MAN.

I. Descent of Man.--II. Sexual Selection.--III. Expression of the

Emotions.

2.VIII.I. DESCENT OF MAN, 1860-1882.

LETTER 403. TO C. LYELL. Down, April 27th [1860].

I cannot explain why, but to me it would be an infinite satisfaction to

believe that mankind will progress to such a pitch that we should [look]

back at [ourselves] as mere Barbarians. I have received proof-sheets

(with a wonderfully nice letter) of very hostile review by Andrew

Murray, read before the Royal Society of Edinburgh. (403/1. "On Mr.

Darwin's Theory of the Origin of Species," by Andrew Murray. "Proc. Roy.

Soc., Edinb." Volume IV., pages 274-91, 1862. The review concludes with

the following sentence: "I have come to be of opinion that Mr. Darwin's

theory is unsound, and that I am to be spared any collision between my

inclination and my convictions" (referring to the writer's belief in

Design).) But I am tired with answering it. Indeed I have done nothing

the whole day but answer letters.

LETTER 404. TO L. HORNER.

(404/1. The following letter occurs in the "Memoir of Leonard Horner,

edited by his daughter Katherine M. Lyell," Volume II., page 300

(privately printed, 1890).)

Down, March 20th [1861].

I am very much obliged for your Address (404/2. Mr. Horner's Anniversary

Address to the Geological Society ("Proc. Geol. Soc." XVII., 1861).)

which has interested me much...I thought that I had read up pretty well

on the antiquity of man; but you bring all the facts so well together in

a condensed focus, that the case seems much clearer to me. How curious

about the Bible! (404/3. At page lxviii. Mr. Horner points out that the

"chronology, given in the margin of our Bibles," i.e., the statement

that the world was created 4004 B.C., is the work of Archbishop Usher,

and is in no way binding on those who believe in the inspiration of

Scripture. Mr. Horner goes on (page lxx): "The retention of the marginal

note in question is by no means a matter of indifference; it is untrue,

and therefore it is mischievous." It is interesting that Archbishop

Sumner and Dr. Dawes, Dean of Hereford, wrote with approbation of Mr.

Horner's views on Man. The Archbishop says: "I have always considered

the first verse of Genesis as indicating, rather than denying, a

PREADAMITE world" ("Memoir of Leonard Horner, II.", page 303).) I declare

I had fancied that the date was somehow in the Bible. You are coming out

in a new light as a Biblical critic. I must thank you for some remarks

on the "Origin of Species" (404/4. Mr. Horner (page xxxix) begins by

disclaiming the qualifications of a competent critic, and confines

himself to general remarks on the philosophic candour and freedom from

dogmatism of the "Origin": he does, however, give an opinion on the

geological chapters IX. and X. As a general criticism he quotes Mr.

Huxley's article in the "Westminster Review," which may now be read in

"Collected Essays," II., page 22.) (though I suppose it is almost as

incorrect to do so as to thank a judge for a favourable verdict): what

you have said has pleased me extremely. I am the more pleased, as I

would rather have been well attacked than have been handled in the

namby-pamby, old-woman style of the cautious Oxford Professor. (404/5.

This no doubt refers to Professor Phillips' "Life on the Earth," 1860, a

book founded on the author's "Rede Lecture," given before the University

of Cambridge. Reference to this work will be found in "Life and

Letters," II., pages 309, 358, 373.)

LETTER 405. TO J.D. HOOKER.

(405/1. Mr. Wallace was, we believe, the first to treat the evolution of

Man in any detail from the point of view of Natural Selection,

namely, in a paper in the "Anthropological Review and Journal of the

Anthropological Society," May 1864, page clviii. The deep interest with

which Mr. Darwin read his copy is graphically recorded in the continuous

series of pencil-marks along the margins of the pages. His views are

fully given in Letter 406. The phrase, "in this case it is too far,"

refers to Mr. Wallace's habit of speaking of the theory of Natural

Selection as due entirely to Darwin.)

May 22nd 1864.

I have now read Wallace's paper on Man, and think it MOST striking and

original and forcible. I wish he had written Lyell's chapters on Man.

(405/2. See "Life and Letters," III., page 11 et seq. for Darwin's

disappointment over Lyell's treatment of the evolutionary question in

his "Antiquity of Man"; see also page 29 for Lyell's almost pathetic

words about his own position between the discarded faith of many years

and the new one not yet assimilated. See also Letters 132, 164, 170.) I

quite agree about his high-mindedness, and have long thought so; but in

this case it is too far, and I shall tell him so. I am not sure that

I fully agree with his views about Man, but there is no doubt, in my

opinion, on the remarkable genius shown by the paper. I agree, however,

to the main new leading idea.

LETTER 406. TO A.R. WALLACE.

(406/1. This letter was published in "Life and Letters," III., page 89.)

Down, [May] 28th [1864].

I am so much better that I have just finished a paper for the Linnean

Society (406/2. On the three forms, etc., of Lythrum.); but I am not yet

at all strong, I felt much disinclination to write, and therefore you

must forgive me for not having sooner thanked you for your paper on

Man (406/3. "Anthropological Review," May 1864.) received on the 11th.

(406/4. Mr. Wallace wrote, May 10th, 1864: "I send you now my little

contribution to the theory of the origin of man. I hope you will be able

to agree with me. If you are able [to write] I shall be glad to have

your criticisms. I was led to the subject by the necessity of explaining

the vast mental and cranial differences between man and the apes

combined with such small structural differences in other parts of the

body,--and also by an endeavour to account for the diversity of human

races combined with man's almost perfect stability of form during all

historical epochs." But first let me say that I have hardly ever in my

life been more struck by any paper than that on "Variation," etc., etc.,

in the "Reader." (406/5. "Reader," April 16th, 1864, an abstract of Mr.

Wallace: "On the Phenomena of Variation and Geographical Distribution

as illustrated by the Papilionidae of the Malayan Region." "Linn.

Soc. Trans." XXV.) I feel sure that such papers will do more for the

spreading of our views on the modification of species than any separate

treatises on the simple subject itself. It is really admirable; but you

ought not in the Man paper to speak of the theory as mine; it is just

as much yours as mine. One correspondent has already noticed to me your

"high-minded" conduct on this head.

But now for your Man paper, about which I should like to write more than

I can. The great leading idea is quite new to me--viz. that during late

ages the mind will have been modified more than the body; yet I had got

as far as to see with you, that the struggle between the races of man

depended entirely on intellectual and moral qualities. The latter part

of the paper I can designate only as grand and most eloquently done. I

have shown your paper to two or three persons who have been here, and

they have been equally struck with it. I am not sure that I go with you

on all minor points: when reading Sir G. Grey's account of the constant

battles of Australian savages, I remember thinking that Natural

Selection would come in, and likewise with the Esquimaux, with whom the

art of fishing and managing canoes is said to be hereditary. I rather

differ on the rank, under a classificatory point of view, which you

assign to man; I do not think any character simply in excess ought ever

to be used for the higher divisions. Ants would not be separated from

other hymenopterous insects, however high the instinct of the one, and

however low the instincts of the other. With respect to the differences

of race, a conjecture has occurred to me that much may be due to the

correlation of complexion (and consequently hair) with constitution.

Assume that a dusky individual best escaped miasma, and you will

readily see what I mean. I persuaded the Director-General of the Medical

Department of the Army to send printed forms to the surgeons of all

regiments in tropical countries to ascertain this point, but I daresay

I shall never get any returns. Secondly, I suspect that a sort of sexual

selection has been the most powerful means of changing the races of man.

I can show that the different races have a widely different standard of

beauty. Among savages the most powerful men will have the pick of

the women, and they will generally leave the most descendants. I have

collected a few notes on man, but I do not suppose I shall ever use

them. Do you intend to follow out your views? and if so, would you like

at some future time to have my few references and notes? I am sure I

hardly know whether they are of any value, and they are at present in a

state of chaos.

There is much more that I should like to write, but I have not strength.

P.S. Our aristocracy is handsomer (more hideous according to a Chinese

or Negro) than the middle classes, from [having the] pick of the women;

but oh, what a scheme is primogeniture for destroying Natural Selection!

I fear my letter will be barely intelligible to you.

LETTER 406* A.R. WALLACE TO CHARLES DARWIN. 5, Westbourne Grove Terrace,

W., May 29th [1864].

You are always so ready to appreciate what others do, and especially to

overestimate my desultory efforts, that I cannot be surprised at your

very kind and flattering remarks on my papers. I am glad, however, that

you have made a few critical observations (and am only sorry that you

were not well enough to make more), as that enables me to say a few

words in explanation.

My great fault is haste. An idea strikes me, I think over it for a few

days, and then write away with such illustrations as occur to me while

going on. I therefore look at the subject almost solely from one

point of view. Thus, in my paper on Man (406*/1. Published in the

"Anthropological Review," 1864.), I aim solely at showing that brutes

are modified in a great variety of ways by Natural Selection, but that

in none of these particular ways can Man be modified, because of the

superiority of his intellect. I therefore no doubt overlook a few

smaller points in which Natural Selection may still act on men and

brutes alike. Colour is one of them, and I have alluded to this in

correlation to constitution, in an abstract I have made at Sclater's

request for the "Natural History Review." (406*/2. "Nat. Hist. Review,"

1864, page 328.) At the same time, there is so much evidence of

migrations and displacements of races of man, and so many cases of

peoples of distinct physical characters inhabiting the same or similar

regions, and also of races of uniform physical characters inhabiting

widely dissimilar regions,--that the external characteristics of the

chief races of man must, I think, be older than his present geographical

distribution, and the modifications produced by correlation to

favourable variations of constitution be only a secondary cause of

external modification. I hope you may get the returns from the Army.

(406*/3. Measurements taken of more than one million soldiers in the

United States showed that "local influences of some kind act directly

on structure."--"Descent of Man," 1901, page 45.) They would be very

interesting, but I do not expect the results would be favourable to your

view.

With regard to the constant battles of savages leading to selection of

physical superiority, I think it would be very imperfect and subject to

so many exceptions and irregularities that it would produce no definite

result. For instance: the strongest and bravest men would lead, and

expose themselves most, and would therefore be most subject to wounds

and death. And the physical energy which led to any one tribe delighting

in war, might lead to its extermination, by inducing quarrels with

all surrounding tribes and leading them to combine against it. Again,

superior cunning, stealth, and swiftness of foot, or even better

weapons, would often lead to victory as well as mere physical strength.

Moreover, this kind of more or less perpetual war goes on amongst savage

peoples. It could lead, therefore, to no differential characters, but

merely to the keeping up of a certain average standard of bodily and

mental health and vigour.

So with selection of variations adapted to special habits of life as

fishing, paddling, riding, climbing, etc., etc., in different races,

no doubt it must act to some extent, but will it be ever so rigid as to

induce a definite physical modification, and can we imagine it to have

had any part in producing the distinct races that now exist?

The sexual selection you allude to will also, I think, have been equally

uncertain in its results. In the very lowest tribes there is rarely much

polygamy, and women are more or less a matter of purchase. There is also

little difference of social condition, and I think it rarely happens

that any healthy and undeformed man remains without wife and children.

I very much doubt the often-repeated assertion that our aristocracy

are more beautiful than the middle classes. I allow that they present

specimens of the highest kind of beauty, but I doubt the average. I have

noticed in country places a greater average amount of good looks among

the middle classes, and besides we unavoidably combine in our idea of

beauty, intellectual expression, and refinement of manner, which often

makes the less appear the more beautiful. Mere physical beauty--i.e. a

healthy and regular development of the body and features approaching to

the mean and type of European man, I believe is quite as frequent in one

class of society as the other, and much more frequent in rural districts

than in cities.

With regard to the rank of man in zoological classification, I fear I

have not made myself intelligible. I never meant to adopt Owen's or any

other such views, but only to point out that from one point of view he

was right. I hold that a distinct family for Man, as Huxley allows, is

all that can possibly be given him zoologically. But at the same time,

if my theory is true, that while the animals which surrounded him have

been undergoing modification in all parts of their bodies to a generic

or even family degree of difference, he has been changing almost wholly

in the brain and head--then in geological antiquity the SPECIES man may

be as old as many mammalian families, and the origin of the FAMILY man

may date back to a period when some of the ORDERS first originated.

As to the theory of Natural Selection itself, I shall always maintain it

to be actually yours and yours only. You had worked it out in details I

had never thought of, years before I had a ray of light on the subject,

and my paper would never have convinced anybody or been noticed as more

than an ingenious speculation, whereas your book has revolutionised the

study of Natural History, and carried away captive the best men of

the present age. All the merit I claim is the having been the means of

inducing you to write and publish at once. I may possibly some day go a

little more into this subject (of Man), and if I do will accept the kind

offer of your notes.

I am now, however, beginning to write the "Narrative of my Travels,"

which will occupy me a long time, as I hate writing narrative, and after

Bates' brilliant success rather fear to fail.

I shall introduce a few chapters on Geographical Distribution and other

such topics. Sir C. Lyell, while agreeing with my main argument on Man,

thinks I am wrong in wanting to put him back into Miocene times, and

thinks I do not appreciate the immense interval even to the later

Pliocene. But I still maintain my view, which in fact is a logical

result of my theory; for if man originated in later Pliocene, when

almost all mammalia were of closely allied species to those now living,

and many even identical, then man has not been stationary in bodily

structure while animals have been varying, and my theory will be proved

to be all wrong.

In Murchison's address to the Geographical Society, just delivered, he

points out Africa as being the oldest existing land. He says there is

no evidence of its having been ever submerged during the Tertiary epoch.

Here then is evidently the place to find early man. I hope something

good may be found in Borneo, and that the means may be found to explore

the still more promising regions of tropical Africa, for we can expect

nothing of man very early in Europe.

It has given me great pleasure to find that there are symptoms of

improvement in your health. I hope you will not exert yourself too soon

or write more than is quite agreeable to you. I think I made out every

word of your letter, though it was not always easy.

(406*/4. For Wallace's later views see Letter 408, note.)

LETTER 407. TO W. TURNER.

(407/1. Sir William Turner is frequently referred to in the "Descent of

Man" as having supplied Mr. Darwin with information.)

Down, December 14th [1866].

Your kindness when I met you at the Royal Society makes me think that

you would grant me the favour of a little information, if in your power.

I am preparing a book on Domestic Animals, and as there has been so much

discussion on the bearing of such views as I hold on Man, I have some

thoughts of adding a chapter on this subject. The point on which I

want information is in regard to any part which may be fairly called

rudimentary in comparison with the same part in the Quadrumana or any

other mammal. Now the os coccyx is rudimentary as a tail, and I am

anxious to hear about its muscles. Mr. Flower found for me in some work

that its one muscle (with striae) was supposed only to bring this bone

back to its proper position after parturition. This seems to me hardly

credible. He said he had never particularly examined this part, and when

I mentioned your name, he said you were the most likely man to give me

information.

Are there any traces of other muscles? It seems strange if there are

none. Do you know how the muscles are in this part in the anthropoid

apes? The muscles of the ear in man may, I suppose, in most cases be

considered as rudimentary; and so they seem to be in the anthropoids;

at least, I am assured in the Zoological Gardens they do not erect their

ears. I gather there are a good many muscles in various parts of the

body which are in this same state: could you specify any of the best

cases? The mammae in man are rudimentary. Are there any other glands or

other organs which you can think of? I know I have no right whatever to

ask all these questions, and can only say that I should be grateful for

any information. If you tell me anything about the os coccyx or other

structures, I hope that you will permit me to quote the statement on

your authority, as that would add so greatly to its value.

Pray excuse me for troubling you, and do not hurry yourself in the least

in answering me.

I do not know whether you would care to possess a copy, but I told my

publisher to send you a copy of the new edition of the "Origin" last

month.

LETTER 408. TO W. TURNER. Down, February 1st [1867].

I thank you cordially for all your full information, and I regret much

that I have given you such great trouble at a period when your time is

so much occupied. But the facts were so valuable to me that I cannot

pretend that I am sorry that I did trouble you; and I am the less so,

as from what you say I hope you may be induced some time to write a full

account of all rudimentary structures in Man: it would be a very curious

and interesting memoir. I shall at present give only a brief abstract

of the chief facts which you have so very kindly communicated to me, and

will not touch on some of the doubtful points. I have received far more

information than I ventured to anticipate. There is one point which has

occurred to me, but I suspect there is nothing in it. If, however, there

should be, perhaps you will let me have a brief note from you, and if

I do not hear I will understand there is nothing in the notion. I have

included the down on the human body and the lanugo on the foetus as a

rudimentary representation of a hairy coat. (408/1. "Descent of Man"

I., page 25; II., page 375.) I do not know whether there is any direct

functional connection between the presence of hair and the panniculus

carnosus (408/2. Professor Macalister draws our attention to the fact

that Mr. Darwin uses the term panniculus in the generalised sense of any

sheet of muscle acting on the skin.) (to put the question under

another point of view, is it the primary or aboriginal function of the

panniculus to move the dermal appendages or the skin itself?); but both

are superficial, and would perhaps together become rudimentary. I was

led to think of this by the places (as far as my ignorance of anatomy

has allowed me to judge) of the rudimentary muscular fasciculi which you

specify. Now, some persons can move the skin of their hairy heads; and

is this not effected by the panniculus? How is it with the eyebrows? You

specify the axillae and the front region of the chest and lower part of

scapulae: now, these are all hairy spots in man. On the other hand,

the neck, and as I suppose the covering of the gluteus medius, are not

hairy; so, as I said, I presume there is nothing in this notion. If

there were, the rudiments of the panniculus ought perhaps to occur more

plainly in man than in woman...

P.S.--If the skin on the head is moved by the panniculus, I think I

ought just to allude to it, as some men alone having power to move the

skin shows that the apparatus is generally rudimentary.

(408/3. In March 1869 Darwin wrote to Mr. Wallace: "I shall be intensely

curious to read the "Quarterly." I hope you have not murdered too

completely your own and my child." The reference is to Mr. Wallace's

review, in the April number of the "Quarterly," of Lyell's "Principles

of Geology" (tenth edition), and of the sixth edition of the "Elements

of Geology." Mr. Wallace points out that here for the first time Sir C.

Lyell gave up his opposition to evolution; and this leads Mr. Wallace to

give a short account of the views set forth in the "Origin of Species."

In this article Mr. Wallace makes a definite statement as to his views

on the evolution of man, which were opposed to those of Mr. Darwin. He

upholds the view that the brain of man, as well as the organs of speech,

the hand and the external form, could not have been evolved by Natural

Selection (the child he is supposed to murder). At page 391 he writes:

"In the brain of the lowest savages, and, as far as we know, of the

prehistoric races, we have an organ...little inferior in size and

complexity to that of the highest types...But the mental requirements

of the lowest savages, such as the Australians or the Andaman Islanders,

are very little above those of many animals...How, then, was an organ

developed so far beyond the needs of its possessor? Natural Selection

could only have endowed the savage with a brain a little superior

to that of an ape, whereas he actually possesses one but very little

inferior to that of the average members of our learned societies." This

passage is marked in Mr. Darwin's copy with a triply underlined "No,"

and with a shower of notes of exclamation. It was probably the first

occasion on which he realised the extent of this great and striking

divergence in opinion between himself and his colleague.

He had, however, some indication of it in Wallace's paper on Man,

"Anthropological Review," 1864. (See Letter 406). He wrote to Lyell,

May 4th, 1869, "I was dreadfully disappointed about Man; it seems to me

incredibly strange." And to Mr. Wallace, April 14th, 1869, "If you had

not told me, I should have thought that [your remarks on Man] had been

added by some one else. As you expected, I differ grievously from you,

and I am very sorry for it."

LETTER 409. TO T.H. HUXLEY. Down, Thursday, February 21st [1868-70?].

I received the Jermyn Street programme, but have hardly yet considered

it, for I was all day on the sofa on Tuesday and Wednesday. Bad though

I was, I thought with constant pleasure of your very great kindness in

offering to read the proofs of my essay on man. I do not know whether

I said anything which might have appeared like a hint, but I assure you

that such a thought had never even momentarily passed through my mind.

Your offer has just made all the difference, that I can now write,

whether or no my essay is ever printed, with a feeling of satisfaction

instead of vague dread.

Beg my colleague, Mrs. Huxley, not to forget the corrugator supercilii:

it will not be easy to catch the exact moment when the child is on the

point of crying, and is struggling against the wrinkling up [of] its

little eyes; for then I should expect the corrugator, from being little

under the command of the will, would come into play in checking or

stopping the wrinkling. An explosion of tears would tell nothing.

LETTER 410. TO FRANCIS GALTON. Down, December 23rd [1870?].

I have only read about fifty pages of your book (to the Judges) (410/1.

"Hereditary Genius: an Inquiry into its Laws and Consequences," by

Francis Galton, London, 1869. "The Judges of England between 1660 and

1865" is the heading of a section of this work (page 55). See "Descent

of Man" (1901), page 41.), but I must exhale myself, else something

will go wrong in my inside. I do not think I ever in all my life read

anything more interesting and original. And how well and clearly you

put every point! George, who has finished the book, and who expressed

himself just in the same terms, tells me the earlier chapters are

nothing in interest to the later ones! It will take me some time to get

to these later chapters, as it is read aloud to me by my wife, who is

also much interested. You have made a convert of an opponent in one

sense, for I have always maintained that, excepting fools, men did not

differ much in intellect, only in zeal and hard work; and I still think

[this] is an eminently important difference. I congratulate you on

producing what I am convinced will prove a memorable work. I look

forward with intense interest to each reading, but it sets me thinking

so much that I find it very hard work; but that is wholly the fault of

my brain, and not of your beautifully clear style.

LETTER 411. TO W.R. GREG. March 21st [1871?].

Many thanks for your note. I am very glad indeed to read remarks made by

a man who possesses such varied and odd knowledge as you do, and who is

so acute a reasoner. I have no doubt that you will detect blunders of

many kinds in my book. (411/1. "The Descent of Man.") Your MS. on the

proportion of the sexes at birth seems to me extremely curious, and I

hope that some day you will publish it. It certainly appears that the

males are decreasing in the London districts, and a most strange fact

it is. Mr. Graham, however, I observe in a note enclosed, does not seem

inclined to admit your conclusion. I have never much considered the

subject of the causes of the proportion. When I reflected on queen

bees producing only males when not impregnated, whilst some other

parthenogenetic insects produced, as far as known, only females, the

subject seemed to me hopelessly obscure. It is, however, pretty clear

that you have taken the one path for its solution. I wished only to

ascertain how far with various animals the males exceeded the females,

and I have given all the facts which I could collect. As far as I

know, no other data have been published. The equality of the sexes with

race-horses is surprising. My remarks on mankind are quite superficial,

and given merely as some sort of standard for comparison with the lower

animals. M. Thury is the writer who makes the sex depend on the period

of impregnation. His pamphlet was sent me from Geneva. (411/2. "Memoire

sur la loi de Production des Sexes," 2nd edition, 1863 (a pamphlet

published by Cherbuliez, Geneva).) I can lend it you if you like. I

subsequently read an account of experiments which convinced me that

M. Thury was in error; but I cannot remember what they were, only the

impression that I might safely banish this view from my mind. Your

remarks on the less ratio of males in illegitimate births strikes me

as the most doubtful point in your MS.--requiring two assumptions, viz.

that the fathers in such cases are relatively too young, and that the

result is the same as when the father is relatively too old.

My son, George, who is a mathematician, and who read your MS. with much

interest, has suggested, as telling in the right direction, but whether

sufficient is another question, that many more illegitimate children

are murdered and concealed shortly after birth, than in the case of

legitimate children; and as many more males than females die during the

first few days of life, the census of illegitimate children practically

applies to an older age than with legitimate children, and would thus

slightly reduce the excess of males. This might possibly be worth

consideration. By a strange coincidence a stranger writes to me this

day, making the very same suggestion.

I am quite delighted to hear that my book interests you enough to lead

you to read it with some care.

LETTER 412. TO FRANCIS GALTON. Down, January 4th, 1873.

Very many thanks for "Fraser" (412/1. "Hereditary Improvement," by

Francis Galton, "Fraser's Magazine," January 1873, page 116.): I have

been greatly interested by your article. The idea of castes being

spontaneously formed and leading to intermarriage (412/2. "My object is

to build up, by the mere process of extensive enquiry and publication of

results, a sentiment of caste among those who are naturally gifted,

and to procure for them, before the system has fairly taken root, such

moderate social favours and preference, no more no less, as would seem

reasonable to those who were justly informed of the precise measure of

their importance to the nation" (loc. cit., page 123).) is quite new

to me, and I should suppose to others. I am not, however, so hopeful

as you. Your proposed Society (412/3. Mr. Galton proposes that "Some

society should undertake three scientific services: the first, by

means of a moderate number of influential local agencies, to institute

continuous enquiries into the facts of human heredity; the second to be

a centre of information on heredity for breeders of animals and plants;

and the third to discuss and classify the facts that were collected"

(loc. cit., page 124).) would have awfully laborious work, and I doubt

whether you could ever get efficient workers. As it is, there is much

concealment of insanity and wickedness in families; and there would

be more if there was a register. But the greatest difficulty, I think,

would be in deciding who deserved to be on the register. How few are

above mediocrity in health, strength, morals and intellect; and how

difficult to judge on these latter heads. As far as I see, within the

same large superior family, only a few of the children would deserve

to be on the register; and these would naturally stick to their own

families, so that the superior children of distinct families would have

no good chance of associating much and forming a caste. Though I see so

much difficulty, the object seems a grand one; and you have pointed out

the sole feasible, yet I fear utopian, plan of procedure in improving

the human race. I should be inclined to trust more (and this is part

of your plan) to disseminating and insisting on the importance of the

all-important principle of inheritance. I will make one or two minor

criticisms. Is it not possible that the inhabitants of malarious

countries owe their degraded and miserable appearance to the bad

atmosphere, though this does not kill them, rather than to "economy of

structure"? I do not see that an orthognathous face would cost more

than a prognathous face; or a good morale than a bad one. That is a fine

simile (page 119) about the chip of a statue (412/4. "...The life of the

individual is treated as of absolutely no importance, while the race is

as everything; Nature being wholly careless of the former except as a

contributor to the maintenance and evolution of the latter. Myriads

of inchoate lives are produced in what, to our best judgment, seems a

wasteful and reckless manner, in order that a few selected specimens

may survive, and be the parents of the next generation. It is as though

individual lives were of no more consideration than are the senseless

chips which fall from the chisel of the artist who is elaborating some

ideal form from a rude block" (loc. cit., page 119).); but surely Nature

does not more carefully regard races than individuals, as (I believe I

have misunderstood what you mean) evidenced by the multitude of races

and species which have become extinct. Would it not be truer to say that

Nature cares only for the superior individuals and then makes her new

and better races? But we ought both to shudder in using so freely the

word "Nature" (412/5. See Letter 190, Volume I.) after what De Candolle

has said. Again let me thank you for the interest received in reading

your essay.

Many thanks about the rabbits; your letter has been sent to Balfour:

he is a very clever young man, and I believe owes his cleverness to

Salisbury blood. This letter will not be worth your deciphering. I have

almost finished Greg's "Enigmas." (412/6. "The Enigmas of Life," 1872.)

It is grand poetry--but too Utopian and too full of faith for me; so

that I have been rather disappointed. What do you think about it? He

must be a delightful man.

I doubt whether you have made clear how the families on the Register are

to be kept pure or superior, and how they are to be in course of time

still further improved.

LETTER 413. TO MAX MULLER. Down, July 3rd, 1873.

(413/1. In June, 1873, Professor Max Muller sent to Mr. Darwin a copy of

the sixth edition of his "Lectures on the Science of Language" (413/2.

A reference to the first edition occurs in "Life and Letters," II., page

390.), with a letter concluding with these words: "I venture to send

you my three lectures, trusting that, though I differ from some of your

conclusions, you will believe me to be one of your diligent readers and

sincere admirers.")

I am much obliged for your kind note and present of your lectures. I

am extremely glad to have received them from you, and I had intended

ordering them.

I feel quite sure from what I have read in your works that you would

never say anything of an honest adversary to which he would have any

just right to object; and as for myself, you have often spoken highly of

me--perhaps more highly than I deserve.

As far as language is concerned I am not worthy to be your adversary, as

I know extremely little about it, and that little learnt from very few

books. I should have been glad to have avoided the whole subject,

but was compelled to take it up as well as I could. He who is fully

convinced, as I am, that man is descended from some lower animal, is

almost forced to believe a priori that articulate language has been

developed from inarticulate cries (413/3. "Descent of Man" (1901), page

133.); and he is therefore hardly a fair judge of the arguments opposed

to this belief.

(413/4. In October, 1875, Mr. Darwin again wrote cordially to Professor

Max Muller on receipt of a pamphlet entitled "In Self-Defence" (413/5.

Printed in "Chips from a German Workshop," Volume IV., 1875, page 473.),

which is a reply to Professor Whitney's "Darwinism and Language" in the

"North American Review," July 1874. This essay had been brought before

the "general reader" in England by an article of Mr. G. Darwin's in the

"Contemporary Review," November, 1874, page 894, entitled, "Professor

Whitney on the Origin of Language." The article was followed by

"My reply to Mr. Darwin," contributed by Professor Muller to the

"Contemporary Review," January, 1875, page 305.)

LETTER 414. G. ROLLESTON TO CHARLES DARWIN. British Association,

Bristol, August 30th, 1875.

(414/1. In the first edition of the "Descent of Man" Mr. Darwin wrote:

"It is a more curious fact that savages did not formerly waste away, as

Mr. Bagehot has remarked, before the classical nations, as they now

do before modern civilised nations..."(414/2. Bagehot, "Physics and

Politics," "Fortnightly Review," April, 1868, page 455.) In the second

edition (page 183) the statement remains, but a mass of evidence

(pages 183-92) is added, to which reference occurs in the reply to the

following letter.)

At pages 4-5 of the enclosed Address (414/3. "British Association

Reports," 1875, page 142.) you will find that I have controverted Mr.

Bagehot's view as to the extinction of the barbarians in the times of

classical antiquity, as also the view of Poppig as to there being

some occult influence exercised by civilisation to the disadvantage of

savagery when the two come into contact.

I write to say that I took up this subject without any wish to impugn

any views of yours as such, but with the desire of having my say upon

certain anti-sanitarian transactions and malfeasance of which I had had

a painful experience.

On reading however what I said, and had written somewhat hastily, it has

struck me that what I have said might bear the former interpretation in

the eyes of persons who might not read other papers of mine, and indeed

other parts of the same Address, in which my adhesion, whatever it

is worth, to your views in general is plainly enough implied. I have

ventured to write this explanation to you for several reasons.

LETTER 415. TO G. ROLLESTON. Bassett, Southampton, September 2nd [1875].

I am much obliged to you for having sent me your Address, which has

interested me greatly. I quite subscribe to what you say about Mr.

Bagehot's striking remark, and wish I had not quoted it. I can perceive

no sort of reflection or blame on anything which I have written, and I

know well that I deserve many a good slap on the face. The decrease of

savage populations interests me much, and I should like you some time

to look at a discussion on this subject which I have introduced in the

second edition of the "Descent of Man," and which you can find (for I

have no copy here) in the list of additions. The facts have convinced me

that lessened fertility and the poor constitution of the children is one

chief cause of such decrease; and that the case is strictly parallel to

the sterility of many wild animals when made captive, the civilisation

of savages and the captivity of wild animals leading to the same result.

LETTER 416. TO ERNST KRAUSE. Down, June 30th, 1877.

I have been much interested by your able argument against the belief

that the sense of colour has been recently acquired by man. (416/1.

See "Kosmos," June 1877, page 264, a review of Dr. Hugo Magnus' "Die

Geschichtliche Entwickelung des Farbensinnes," 1877. The first part is

chiefly an account of the author's views; Dr. Krause's argument begins

at page 269. The interest felt by Mr. Darwin is recorded by the numerous

pencil-marks on the margin of his copy.) The following observation bears

on this subject.

I attended carefully to the mental development of my young children, and

with two, or as I believe three of them, soon after they had come to the

age when they knew the names of all common objects, I was startled by

observing that they seemed quite incapable of affixing the right names

to the colours in coloured engravings, although I tried repeatedly to

teach them. I distinctly remember declaring that they were colour-blind,

but this afterwards proved a groundless fear.

On communicating this fact to another person he told me that he had

observed a nearly similar case. Therefore the difficulty which young

children experience either in distinguishing, or more probably in naming

colours, seems to deserve further investigation. I will add that it

formerly appeared to me that the gustatory sense, at least in the

case of my own infants, and very young children, differed from that of

grown-up persons. This was shown by their not disliking rhubarb mixed

with a little sugar and milk, which is to us abominably nauseous; and

in their strong taste for the sourest and most austere fruits, such as

unripe gooseberries and crabapples.

(PLATE: G.J. ROMANES, 1891. Elliott & Fry, photo. Walker and Cockerell,

ph. sc.)

LETTER 417. TO G.J. ROMANES. [Barlaston], August 20th, 1878.

(417/1. Part of this letter (here omitted) is published in "Life and

Letters," III., page 225, and the whole in the "Life and Letters of G.J.

Romanes," page 74. The lecture referred to was on animal intelligence,

and was given at the Dublin meeting of the British Association.)

...The sole fault which I find with your lecture is that it is too

short, and this is a rare fault. It strikes me as admirably clear and

interesting. I meant to have remonstrated that you had not discussed

sufficiently the necessity of signs for the formation of abstract ideas

of any complexity, and then I came on the discussion on deaf mutes. This

latter seems to me one of the richest of all the mines, and is worth

working carefully for years, and very deeply. I should like to read

whole chapters on this one head, and others on the minds of the higher

idiots. Nothing can be better, as it seems to me, than your several

lines or sources of evidence, and the manner in which you have arranged

the whole subject. Your book will assuredly be worth years of hard

labour; and stick to your subject. By the way, I was pleased at your

discussing the selection of varying instincts or mental tendencies;

for I have often been disappointed by no one having ever noticed this

notion.

I have just finished "La Psychologie, son Present et son Avenir,"

1876, by Delboeuf (a mathematician and physicist of Belgium) in about a

hundred pages. It has interested me a good deal, but why I hardly know;

it is rather like Herbert Spencer. If you do not know it, and would care

to see it, send me a postcard.

Thank Heaven, we return home on Thursday, and I shall be able to go on

with my humdrum work, and that makes me forget my daily discomfort.

Have you ever thought of keeping a young monkey, so as to observe its

mind? At a house where we have been staying there were Sir A. and Lady

Hobhouse, not long ago returned from India, and she and he kept [a]

young monkey and told me some curious particulars. One was that her

monkey was very fond of looking through her eyeglass at objects, and

moved the glass nearer and further so as to vary the focus. This struck

me, as Frank's son, nearly two years old (and we think much of his

intellect!!) is very fond of looking through my pocket lens, and I have

quite in vain endeavoured to teach him not to put the glass close down

on the object, but he always will do so. Therefore I conclude that a

child under two years is inferior in intellect to a monkey.

Once again I heartily congratulate you on your well-earned present, and

I feel assured, grand future success.

(417/2. Later in the year Mr. Darwin wrote: "I am delighted to hear that

you mean to work the comparative Psychology well. I thought your letter

to the "Times" very good indeed. (417/3. Romanes wrote to the "Times"

August 28th, 1878, expressing his views regarding the distinction

between man and the lower animals, in reply to criticisms contained in

a leading article in the "Times" of August 23rd on his lecture at the

Dublin meeting of the British Association.) Bartlett, at the Zoological

Gardens, I feel sure, would advise you infinitely better about

hardiness, intellect, price, etc., of monkey than F. Buckland; but with

him it must be viva voce.

"Frank says you ought to keep a idiot, a deaf mute, a monkey, and a baby

in your house.")

LETTER 418. TO G.A. GASKELL. Down, November 15th, 1878.

(418/1. This letter has been published in Clapperton's "Scientific

Meliorism," 1885, page 340, together with Mr. Gaskell's letter of

November 13th (page 337). Mr. Gaskell's laws are given in his letter of

November 13th, 1878. They are:--

I. The Organological Law:

Natural Selection, or the Survival of the Fittest.

II. The Sociological Law:

Sympathetic Selection, or Indiscriminate Survival.

III. The Moral Law:

Social Selection, or the Birth of the Fittest.)

Your letter seems to me very interesting and clearly expressed, and I

hope that you are in the right. Your second law appears to be largely

acted on in all civilised countries, and I just alluded to it in my

remarks to the effect (as far as I remember) that the evil which would

follow by checking benevolence and sympathy in not fostering the weak

and diseased would be greater than by allowing them to survive and then

to procreate.

With regard to your third law, I do not know whether you have read an

article (I forget when published) by F. Galton, in which he proposes

certificates of health, etc., for marriage, and that the best should be

matched. I have lately been led to reflect a little, (for, now that I

am growing old, my work has become [word indecipherable] special) on the

artificial checks, but doubt greatly whether such would be advantageous

to the world at large at present, however it may be in the distant

future. Suppose that such checks had been in action during the last

two or three centuries, or even for a shorter time in Britain, what a

difference it would have made in the world, when we consider America,

Australia, New Zealand, and S. Africa! No words can exaggerate the

importance, in my opinion, of our colonisation for the future history of

the world.

If it were universally known that the birth of children could be

prevented, and this were not thought immoral by married persons, would

there not be great danger of extreme profligacy amongst unmarried women,

and might we not become like the "arreoi" societies in the Pacific? In

the course of a century France will tell us the result in many ways, and

we can already see that the French nation does not spread or increase

much.

I am glad that you intend to continue your investigations, and I hope

ultimately may publish on the subject.

LETTER 419. TO K. HOCHBERG. Down, January 13th, 1879.

I am much obliged for your note and for the essay which you have sent

me. I am a poor german scholar, and your german is difficult; but I

think that I understand your meaning, and hope at some future time, when

more at leisure, to recur to your essay. As far as I can judge, you have

made a great advance in many ways in the subject; and I will send your

paper to Mr. Edmund Gurney (The late Edmund Gurney, author of "The Power

of Sound," 1880.), who has written on and is much interested in the

origin of the taste for music. In reading your essay, it occurred to me

that facility in the utterance of prolonged sounds (I do not think that

you allude to this point) may possibly come into play in rendering them

musical; for I have heard it stated that those who vary their voices

much, and use cadences in long continued speaking, feel less fatigued

than those who speak on the same note.

LETTER 420. TO G.J. ROMANES. Down, February 5th, 1880.

(420/1. Romanes was at work on what ultimately came to be a book on

animal intelligence. Romanes's reply to this letter is given in his

"Life," page 95. The table referred to is published as a frontispiece to

his "Mental Evolution in Animals," 1885.)

As I feared, I cannot be of the least use to you. I could not venture to

say anything about babies without reading my Expression book and paper

on Infants, or about animals without reading the "Descent of Man" and

referring to my notes; and it is a great wrench to my mind to change

from one subject to another.

I will, however, hazard one or two remarks. Firstly, I should have

thought that the word "love" (not sexual passion), as shown very low in

the scale, to offspring and apparently to comrades, ought to have come

in more prominently in your table than appears to be the case. Secondly,

if you give any instance of the appreciation of different stimulants by

plants, there is a much better case than that given by you--namely,

that of the glands of Drosera, which can be touched roughly two or three

times and do not transmit any effect, but do so if pressed by a weight

of 1/78000 grain ("Insectivorous Plants" 263). On the other hand, the

filament of Dionoea may be quietly loaded with a much greater weight,

while a touch by a hair causes the lobes to close instantly. This has

always seemed to me a marvellous fact. Thirdly, I have been accustomed

to look at the coming in of the sense of pleasure and pain as one of the

most important steps in the development of mind, and I should think it

ought to be prominent in your table. The sort of progress which I have

imagined is that a stimulus produced some effect at the point affected,

and that the effect radiated at first in all directions, and then that

certain definite advantageous lines of transmission were acquired,

inducing definite reaction in certain lines. Such transmission

afterwards became associated in some unknown way with pleasure or pain.

These sensations led at first to all sorts of violent action, such as

the wriggling of a worm, which was of some use. All the organs of sense

would be at the same time excited. Afterwards definite lines of action

would be found to be the most useful, and so would be practised. But it

is of no use my giving you my crude notions.

LETTER 421. TO S. TOLVER PRESTON. Down, May 22nd, 1880.

(421/1. Mr. Preston wrote (May 20th, 1880) to the effect that

"self-interest as a motive for conduct is a thing to be commended--and

it certainly [is] I think...the only conceivable rational motive of

conduct: and always is the tacitly recognised motive in all rational

actions." Mr. Preston does not, of course, commend selfishness, which is

not true self-interest.

There seem to be two ways of looking at the case given by Darwin. The

man who knows that he is risking his life,--realising that the personal

satisfaction that may follow is not worth the risk--is surely admirable

from the strength of character that leads him to follow the social

instinct against his purely personal inclination. But the man who

blindly obeys the social instinct is a more useful member of a social

community. He will act with courage where even the strong man will

fail.)

Your letter appears to me an interesting and valuable one; but I have

now been working for some years exclusively on the physiology of plants,

and all other subjects have gone out of my head, and it fatigues me

much to try and bring them back again into my head. I am, moreover,

at present very busy, as I leave home for a fortnight's rest at the

beginning of next week. My conviction as yet remains unchanged, that

a man who (for instance) jumps into a river to save a life without a

second's reflection (either from an innate tendency or from one gained

by habit) is deservedly more honoured than a man who acts deliberately

and is conscious, for however short a time, that the risk and sacrifice

give him some inward satisfaction.

You are of course familiar with Herbert Spencer's writings on Ethics.

(422/1. The observations to which the following letters refer were

continued by Mr. Wallis, who gave an account of his work in an

interesting paper in the "Proceedings of the Zoological Society," March

2nd, 1897. The results on the whole confirm the belief that traces of an

ancestral pointed ear exist in man.)

LETTER 422. TO H.M. WALLIS. Down, March 22nd, 1881.

I am very much obliged for your courteous and kind note. The fact which

you communicate is quite new to me, and as I was laughed at about the

tips to human ears, I should like to publish in "Nature" some time your

fact. But I must first consult Eschricht, and see whether he notices

this fact in his curious paper on the lanugo on human embryos; and

secondly I ought to look to monkeys and other animals which have tufted

ears, and observe how the hair grows. This I shall not be able to do for

some months, as I shall not be in London until the autumn so as to go to

the Zoological Gardens. But in order that I may not hereafter throw away

time, will you be so kind as to inform me whether I may publish your

observation if on further search it seems desirable?

LETTER 423. TO H.M. WALLIS. Down, March 31st, 1881.

I am much obliged for your interesting letter. I am glad to hear that

you are looking to other ears, and will visit the Zoological Gardens.

Under these circumstances it would be incomparably better (as more

authentic) if you would publish a notice of your observations in

"Nature" or some scientific journal. Would it not be well to confine

your attention to infants, as more likely to retain any primordial

character, and offering less difficulty in observing. I think, though,

it would be worth while to observe whether there is any relation (though

probably none) between much hairiness on the ears of an infant and

the presence of the "tip" on the folded margin. Could you not get an

accurate sketch of the direction of the hair of the tip of an ear?

The fact which you communicate about the goat-sucker is very curious.

About the difference in the power of flight in Dorkings, etc., may it

not be due merely to greater weight of body in the adults?

I am so old that I am not likely ever again to write on general and

difficult points in the theory of Evolution.

I shall use what little strength is left me for more confined and easy

subjects.

LETTER 424. TO MRS. TALBOT.

(Mrs. Emily Talbot was secretary of the Education Department of the

American Social Science Association, Boston, Mass. A circular and

register was issued by the Department, and answers to various questions

were asked for. See "Nature," April 28th, page 617, 1881. The above

letter was published in "The Field Naturalist," Manchester, 1883, page

5, edited by Mr. W.E. Axon, to whom we are indebted for a copy.)

Down, July 19th [1881?]

In response to your wish, I have much pleasure in expressing the

interest which I feel in your proposed investigation on the mental and

bodily development of infants. Very little is at present accurately

known on this subject, and I believe that isolated observations will add

but little to our knowledge, whereas tabulated results from a very large

number of observations, systematically made, would probably throw

much light on the sequence and period of development of the several

faculties. This knowledge would probably give a foundation for some

improvement in our education of young children, and would show us

whether the system ought to be followed in all cases.

I will venture to specify a few points of inquiry which, as it seems to

me, possess some scientific interest. For instance, does the education

of the parents influence the mental powers of their children at any

age, either at a very early or somewhat more advanced stage? This could

perhaps be learned by schoolmasters and mistresses if a large number

of children were first classed according to age and their mental

attainments, and afterwards in accordance with the education of their

parents, as far as this could be discovered. As observation is one of

the earliest faculties developed in young children, and as this power

would probably be exercised in an equal degree by the children of

educated and uneducated persons, it seems not impossible that any

transmitted effect from education could be displayed only at a somewhat

advanced age. It would be desirable to test statistically, in a similar

manner, the truth of the oft-repeated statement that coloured children

at first learn as quickly as white children, but that they afterwards

fall off in progress. If it could be proved that education acts not only

on the individual, but, by transmission, on the race, this would be a

great encouragement to all working on this all-important subject. It is

well known that children sometimes exhibit, at a very early age,

strong special tastes, for which no cause can be assigned, although

occasionally they may be accounted for by reversion to the taste or

occupation of some progenitor; and it would be interesting to learn how

far such early tastes are persistent and influence the future career

of the individual. In some instances such tastes die away without

apparently leaving any after effect, but it would be desirable to know

how far this is commonly the case, as we should then know whether it

were important to direct as far as this is possible the early tastes

of our children. It may be more beneficial that a child should follow

energetically some pursuit, of however trifling a nature, and thus

acquire perseverance, than that he should be turned from it because

of no future advantage to him. I will mention one other small point of

inquiry in relation to very young children, which may possibly prove

important with respect to the origin of language; but it could be

investigated only by persons possessing an accurate musical ear.

Children, even before they can articulate, express some of their

feelings and desires by noises uttered in different notes. For instance,

they make an interrogative noise, and others of assent and dissent,

in different tones; and it would, I think, be worth while to ascertain

whether there is any uniformity in different children in the pitch of

their voices under various frames of mind.

I fear that this letter can be of no use to you, but it will serve to

show my sympathy and good wishes in your researches.

2.VIII.II. SEXUAL SELECTION, 1866-1872.

LETTER 425. TO JAMES SHAW. Down, February 11th [1866].

I am much obliged to you for your kindness in sending me an abstract of

your paper on beauty. (425/1. A newspaper report of a communication to

the "Dumfries Antiquarian and Natural History Society.") In my opinion

you take quite a correct view of the subject. It is clear that Dr.

Dickson has either never seen my book, or overlooked the discussion

on sexual selection. If you have any precise facts on birds' "courtesy

towards their own image in mirror or picture," I should very much like

to hear them. Butterflies offer an excellent instance of beauty being

displayed in conspicuous parts; for those kinds which habitually display

the underside of the wing have this side gaudily coloured, and this is

not so in the reverse case. I daresay you will know that the males of

many foreign butterflies are much more brilliantly coloured than the

females, as in the case of birds. I can adduce good evidence from two

large classes of facts (too large to specify) that flowers have become

beautiful to make them conspicuous to insects. (425/2. This letter is

published in "A Country Schoolmaster, James Shaw." Edited by Robert

Wallace, Edinburgh, 1899.)

(425/3. Mr. Darwin wrote again to Mr. Shaw in April, 1866:--)

I am much obliged for your kind letter and all the great trouble which

you have taken in sending to all the various and interesting facts on

birds admiring themselves. I am very glad to hear of these facts. I have

just finished writing and adding to a new edition of the "Origin," and

in this I have given, without going into details (so that I shall not be

able to use your facts), some remarks on the subject of beauty.

LETTER 426. TO A.D. BARTLETT. Down, February 16th [1867?]

I want to beg two favours of you. I wish to ascertain whether the

Bower-Bird discriminates colours. (426/1. Mr. Bartlett does not seem to

have supplied any information on the point in question. The evidence for

the Bower-Bird's taste in colour is in "Descent of Man," II., page 112.)

Will you have all the coloured worsted removed from the cage and bower,

and then put all in a row, at some distance from bower, the enclosed

coloured worsted, and mark whether the bird AT FIRST makes any

selection. Each packet contains an equal quantity; the packets had

better be separate, and each thread put separate, but close

together; perhaps it would be fairest if the several colours were put

alternately--one thread of bright scarlet, one thread of brown, etc.,

etc. There are six colours. Will you have the kindness to tell me

whether the birds prefer one colour to another?

Secondly, I very much want several heads of the fancy and

long-domesticated rabbits, to measure the capacity of skull. I want

only small kinds, such as Himalaya, small Angora, Silver Grey, or any

small-sized rabbit which has long been domesticated. The Silver Grey

from warrens would be of little use. The animals must be adult, and the

smaller the breed the better. Now when any one dies would you send me

the carcase named; if the skin is of any value it might be skinned, but

it would be rather better with skin, and I could make a present to

any keeper to whom the skin is a perquisite. This would be of great

assistance to me, if you would have the kindness thus to aid me.

LETTER 427. TO W.B. TEGETMEIER.

(427/1. We are not aware that the experiment here suggested has ever

been carried out.)

Down, March 5th [1867].

I write on the bare and very improbable chance of your being able

to try, or get some trustworthy person to try, the following little

experiment. But I may first state, as showing what I want, that it has

been stated that if two long feathers in the tail of the male Widow-Bird

at the Cape of Good Hope are pulled out, no female will pair with him.

Now, where two or three common cocks are kept, I want to know, if the

tail sickle-feathers and saddle-feathers of one which had succeeded in

getting wives were cut and mutilated and his beauty spoiled, whether he

would continue to be successful in getting wives. This might be tried

with drakes or peacocks, but no one would be willing to spoil for a

season his peacocks. I have no strength or opportunity of watching my

own poultry, otherwise I would try it. I would very gladly repay all

expenses of loss of value of the poultry, etc. But, as I said, I have

written on the most improbable chance of your interesting any one to

make the trial, or having time and inclination yourself to make it.

Another, and perhaps better, mode of making the trial would be to turn

down to some hens two or three cocks, one being injured in its plumage.

I am glad to say that I have begun correcting proofs. (427/2. "The

Variation of Animals and Plants.") I hope that you received safely the

skulls which you so kindly lent me.

LETTER 428. TO W.B. TEGETMEIER. Down, March 30th [1867].

I am much obliged for your note, and shall be truly obliged if you will

insert any question on the subject. That is a capital remark of yours

about the trimmed game cocks, and shall be quoted by me. (428/1.

"Descent of Man," Edition I., Volume II., page 117. "Mr. Tegetmeier is

convinced that a game cock, though disfigured by being dubbed with his

hackles trimmed, would be accepted as readily as a male retaining all

his natural ornaments.") Nevertheless I am still inclined from many

facts strongly to believe that the beauty of the male bird determines

the choice of the female with wild birds, however it may be under

domestication. Sir R. Heron has described how one pied peacock was extra

attentive to the hens. This is a subject which I must take up as soon as

my present book is done.

I shall be most particularly obliged to you if you will dye with magenta

a pigeon or two. (428/2. "Mr. Tegetmeier, at my request, stained some

of his birds with magenta, but they were not much noticed by the

others."--"Descent of Man" (1901), page 637.) Would it not be better

to dye the tail alone and crown of head, so as not to make too great

difference? I shall be very curious to hear how an entirely crimson

pigeon will be received by the others as well as his mate.

P.S.--Perhaps the best experiment, for my purpose, would be to colour a

young unpaired male and turn him with other pigeons, and observe whether

he was longer or quicker than usual in mating.

LETTER 429. TO A.R. WALLACE. Down, April 29th [1867].

I have been greatly interested by your letter, but your view is not new

to me. (429/1. We have not been able to find Mr. Wallace's letter to

which this is a reply. It evidently refers to Mr. Wallace's belief in

the paramount importance of protection in the evolution of colour. This

is clear from the P.S. to the present letter and from the passages in

the "Origin" referred to. The first reference, Edition IV., page 240,

is as follows: "We can sometimes plainly see the proximate cause of the

transmission of ornaments to the males alone; for a pea-hen with the

long tail of the male bird would be badly fitted to sit on her eggs, and

a coal-black female capercailzie would be far more conspicuous on her

nest, and more exposed to danger, than in her present modest attire."

The passages in Edition I. (pages 89, 101) do not directly bear on the

question of protection.) If you will look at page 240 of the fourth

edition of the "Origin" you will find it very briefly given with

two extreme examples of the peacock and black grouse. A more general

statement is given at page 101, or at page 89 of the first edition,

for I have long entertained this view, though I have never had space to

develop it. But I had not sufficient knowledge to generalise as far as

you do about colouring and nesting. In your paper perhaps you will just

allude to my scanty remark in the fourth edition, because in my Essay

on Man I intend to discuss the whole subject of sexual selection,

explaining as I believe it does much with respect to man. I have

collected all my old notes, and partly written my discussion, and it

would be flat work for me to give the leading idea as exclusively from

you. But, as I am sure from your greater knowledge of Ornithology and

Entomology that you will write a much better discussion than I could,

your paper will be of great use to me. Nevertheless I must discuss the

subject fully in my Essay on Man. When we met at the Zoological Society,

and I asked you about the sexual differences in kingfishers, I had this

subject in view; as I had when I suggested to Bates the difficulty about

gaudy caterpillars, which you have so admirably (as I believe it will

prove) explained. (429/2. See a letter of February 26th, 1867, to Mr.

Wallace, "Life and Letters" III., page 94.) I have got one capital case

(genus forgotten) of a [Australian] bird in which the female has long

tail-plumes, and which consequently builds a different nest from all her

allies. (429/3. Menura superba: see "Descent of Man" (1901), page 687.

Rhynchoea, mentioned a line or two lower down, is discussed in the

"Descent," page 727. The female is more brightly coloured than the male,

and has a convoluted trachea, elsewhere a masculine character. There

seems some reason to suppose that "the male undertakes the duty of

incubation.") With respect to certain female birds being more brightly

coloured than the males, and the latter incubating, I have gone a little

into the subject, and cannot say that I am fully satisfied. I remember

mentioning to you the case of Rhynchoea, but its nesting seems unknown.

In some other cases the difference in brightness seemed to me hardly

sufficiently accounted for by the principle of protection. At the

Falkland Islands there is a carrion hawk in which the female (as I

ascertained by dissection) is the brightest coloured, and I doubt

whether protection will here apply; but I wrote several months ago to

the Falklands to make enquiries. The conclusion to which I have been

leaning is that in some of these abnormal cases the colour happened to

vary in the female alone, and was transmitted to females alone, and that

her variations have been selected through the admiration of the male.

It is a very interesting subject, but I shall not be able to go on with

it for the next five or six months, as I am fully employed in correcting

dull proof-sheets. When I return to the work I shall find it much better

done by you than I could have succeeded in doing.

It is curious how we hit on the same ideas. I have endeavoured to show

in my MS. discussion that nearly the same principles account for young

birds not being gaily coloured in many cases, but this is too complex a

point for a note.

On reading over your letter again, and on further reflection, I do not

think (as far as I remember my words) that I expressed myself nearly

strongly enough on the value and beauty of your generalisation (429/4.

See Letter 203, Volume I.), viz., that all birds in which the female

is conspicuously or brightly coloured build in holes or under domes. I

thought that this was the explanation in many, perhaps most cases, but

do not think I should ever have extended my view to your generalisation.

Forgive me troubling you with this P.S.

LETTER 430. TO A.R. WALLACE. Down, May 5th [1867].

The offer of your valuable notes is most generous, but it would vex me

to take so much from you, as it is certain that you could work up

the subject very much better than I could. Therefore I earnestly, and

without any reservation, hope that you will proceed with your paper, so

that I return your notes. You seem already to have well investigated the

subject. I confess on receiving your note that I felt rather flat at my

recent work being almost thrown away, but I did not intend to show this

feeling. As a proof how little advance I had made on the subject, I may

mention that though I had been collecting facts on the colouring, and

other sexual differences in mammals, your explanation with respect to

the females had not occurred to me. I am surprised at my own stupidity,

but I have long recognised how much clearer and deeper your insight into

matters is than mine. I do not know how far you have attended to the

laws of inheritance, so what follows may be obvious to you. I have begun

my discussion on sexual selection by showing that new characters often

appear in one sex and are transmitted to that sex alone, and that from

some unknown cause such characters apparently appear oftener in the

male than in the female. Secondly, characters may be developed and be

confined to the male, and long afterwards be transferred to the female.

Thirdly, characters may arise in either sex and be transmitted to both

sexes, either in an equal or unequal degree. In this latter case I have

supposed that the survival of the fittest has come into play with female

birds and kept the female dull-coloured. With respect to the absence of

spurs in the female gallinaceous birds, I presume that they would be

in the way during incubation; at least I have got the case of a German

breed of fowls in which the hens were spurred, and were found to disturb

and break their eggs much. With respect to the females of deer not

having horns, I presume it is to save the loss of organised matter. In

your note you speak of sexual selection and protection as sufficient to

account for the colouring of all animals, but it seems to me doubtful

how far this will come into play with some of the lower animals, such as

sea anemones, some corals, etc., etc. On the other hand Hackel (430/1.

See "Descent of Man" (1901) page 402.) has recently well shown that

the transparency and absence of colour in the lower oceanic animals,

belonging to the most different classes, may be well accounted for on

the principle of protection.

Some time or other I should like much to know where your paper on the

nests of birds has appeared, and I shall be extremely anxious to read

your paper in the "Westminster Review." (430/2. "Westminster Review,"

July, 1867.) Your paper on the sexual colouring of birds will, I have

no doubt, be very striking. Forgive me, if you can, for a touch of

illiberality about your paper.

LETTER 431. TO A.R. WALLACE. March 19th, 1868.

(431/1. "The Variation of Animals and Plants" having been published on

January 30th, 1868, Mr. Darwin notes in his diary that on February 4th

he "Began on Man and Sexual Selection." He had already (in 1864 and

1867) corresponded with Mr. Wallace on these questions--see for

instance the "Life and Letters," III., page 89; but, owing to various

interruptions, serious work on the subject did not begin until 1869. The

following quotations show the line of work undertaken early in 1868.

Mr. Wallace wrote (March 19th, 1868): "I am glad you have got good

materials on sexual selection. It is no doubt a difficult subject.

One difficulty to me is, that I do not see how the constant MINUTE

variations, which are sufficient for Natural Selection to work with,

could be SEXUALLY selected. We seem to require a series of bold and

abrupt variations. How can we imagine that an inch in the tail of the

peacock, or 1/4-inch in that of the Bird of Paradise, would be noticed

and preferred by the female.")

In regard to sexual selection. A girl sees a handsome man, and without

observing whether his nose or whiskers are the tenth of an inch longer

or shorter than in some other man, admires his appearance and says she

will marry him. So, I suppose, with the pea-hen; and the tail has been

increased in length merely by, on the whole, presenting a more gorgeous

appearance. J. Jenner Weir, however, has given me some facts showing

that birds apparently admire details of plumage.

LETTER 432. TO F. MULLER. March 28th [1868].

I am particularly obliged to you for your observations on the

stridulation of the two sexes of Lamellicorns. (432/1. We are unable

to find any mention of F. Muller's observations on this point; but

the reference is clearly to Darwin's observations on Necrophorus and

Pelobius, in which the stridulating rasp was bigger in the males in the

first individuals examined, but not so in succeeding specimens. "Descent

of Man," Edition II., Volume I., page 382.) I begin to fear that I am

completely in error owing to that common cause, viz. mistaking at first

individual variability for sexual difference.

I go on working at sexual selection, and, though never idle, I am able

to do so little work each day that I make very slow progress. I knew

from Azara about the young of the tapir being striped, and about young

deer being spotted (432/2. Fritz Muller's views are discussed in the

"Descent of Man," Edition II., Volume II., page 305.); I have often

reflected on this subject, and know not what to conclude about the loss

of the stripes and spots. From the geographical distribution of the

striped and unstriped species of Equus there seems to be something very

mysterious about the loss of stripes; and I cannot persuade myself

that the common ass has lost its stripes owing to being rendered more

conspicuous from having stripes and thus exposed to danger.

LETTER 433. TO J. JENNER WEIR.

(433/1. Mr. John Jenner Weir, to whom the following letters are

addressed, is frequently quoted in the "Descent of Man" as having

supplied Mr. Darwin with information on a variety of subjects.)

Down, February 27th [1868].

I must thank you for your paper on apterous lepidoptera (433/2.

Published by the West Kent Natural History, Microscopical and

Photographic Society, Greenwich, 1867. Mr. Weir's paper seems chiefly to

have interested Mr. Darwin as affording a good case of gradation in

the degree of degradation of the wings in various species.), which has

interested me exceedingly, and likewise for the very honourable mention

which you make of my name. It is almost a pity that your paper was

not published in some Journal in which it would have had a wider

distribution. It contained much that was new to me. I think the part

about the relation of the wings and spiracles and tracheae might have

been made a little clearer. Incidentally, you have done me a good

service by reminding me of the rudimentary spurs on the legs of the

partridge, for I am now writing on what I have called sexual selection.

I believe that I am not mistaken in thinking that you have attended much

to birds in confinement, as well as to insects. If you could call to

mind any facts bearing on this subject, with birds, insects, or any

animals--such as the selection by a female of any particular male--or

conversely of a particular female by a male, or on the rivalry between

males, or on the allurement of the females by the males, or any such

facts, I should be most grateful for the information, if you would have

the kindness to communicate it.

P.S.--I may give as instance of [this] class of facts, that Barrow

asserts that a male Emberiza (?) at the Cape has immensely long

tail-feathers during the breeding season (433/3. Barrow describes the

long tail feathers of Emberiza longicauda as enduring "but the season

of love." "An Account of Travels into the Interior of Southern Africa":

London, 1801, Volume I., page 244.); and that if these are cut off, he

has no chance of getting a wife. I have always felt an intense wish to

make analogous trials, but have never had an opportunity, and it is not

likely that you or any one would be willing to try so troublesome an

experiment. Colouring or staining the fine red breast of a bullfinch

with some innocuous matter into a dingy tint would be an analogous

case, and then putting him and ordinary males with a female. A

friend promised, but failed, to try a converse experiment with white

pigeons--viz., to stain their tails and wings with magenta or other

colours, and then observe what effect such a prodigious alteration would

have on their courtship. (433/4. See Letter 428.) It would be a fairer

trial to cut off the eyes of the tail-feathers of male peacocks; but who

would sacrifice the beauty of their bird for a whole season to please a

mere naturalist?

LETTER 434. TO J. JENNER WEIR. Down, February 29th [1868].

I have hardly ever received a note which has interested me more than

your last; and this is no exaggeration. I had a few cases of birds

perceiving slight changes in the dress of their owners, but your facts

are of tenfold value. I shall certainly make use of them, and need not

say how much obliged I should be for any others about which you feel

confident.

Do you know of any birds besides some of the gallinaceae which are

polygamous? Do you know of any birds besides pigeons, and, as it is

said, the raven, which pair for their whole lives?

Many years ago I visited your brother, who showed me his pigeons and

gave me some valuable information. Could you persuade him (but I fear

he would think it high treason) to stain a male pigeon some brilliant

colour, and observe whether it excited in the other pigeons, especially

the females, admiration or contempt?

For the chance of your liking to have a copy and being able to find some

parts which would interest you, I have directed Mr. Murray to send you

my recent book on "Variation under Domestication."

P.S.--I have somewhere safe references to cases of magpies, of which

one of a pair has been repeatedly (I think seven times) killed, and yet

another mate was always immediately found. (434/1. On this subject see

"Descent of Man," Edition I., Volume II., page 104, where Mr. Weir's

observations were made use of. This statement is quoted from Jenner

("Phil. Trans." 1824) in the "Descent of Man" (1901), page 620.) A

gamekeeper told me yesterday of analogous case. This perplexes me much.

Are there many unmarried birds? I can hardly believe it. Or will one of

a pair, of which the nest has been robbed, or which are barren, always

desert his or her mate for a strange mate with the attraction of a nest,

and in one instance with young birds in the nest? The gamekeeper said

during breeding season he had never observed a single or unpaired

partridge. How can the sexes be so equally matched?

P.S. 2nd.--I fear you will find me a great bore, but I will be as

reasonable as can be expected in plundering one so rich as you.

P.S. 3rd.--I have just received a letter from Dr. Wallace (434/2.

See "Descent of Man," Edition I., Volume I., pages 386-401, where

Dr. Wallace's observations are quoted.), of Colchester, about the

proportional numbers of the two sexes in Bombyx; and in this note,

apropos to an incidental remark of mine, he stoutly maintains that

female lepidoptera never notice the colours or appearance of the male,

but always receive the first male which comes; and this appears very

probable. He says he has often seen fine females receive old battered

and pale-tinted males. I shall have to admit this very great objection

to sexual selection in insects. His observations no doubt apply to

English lepidoptera, in most of which the sexes are alike. The brimstone

or orange-tip would be good to observe in this respect, but it is

hopelessly difficult. I think I have often seen several males following

one female; and what decides which male shall succeed? How is this about

several males; is it not so?

LETTER 435. TO J. JENNER WEIR. 6, Queen Anne Street, Cavendish Square,

W. [March 6th, 1868].

I have come here for a few weeks, for a little change and rest. Just as

I was leaving home I received your first note, and yesterday a second;

and both are most interesting and valuable to me. That is a very curious

observation about the goldfinch's beak (435/1. "Descent of Man,"

Edition I., Volume I., page 39. Mr. Weir is quoted as saying that the

birdcatchers can distinguish the males of the goldfinch, Carduelis

elegans, by their "slightly longer beaks."), but one would hardly like

to trust it without measurement or comparison of the beaks of several

male and female birds; for I do not understand that you yourself assert

that the beak of the male is sensibly longer than that of the female. If

you come across any acute birdcatchers (I do not mean to ask you to

go after them), I wish you would ask what is their impression on the

relative numbers of the sexes of any birds which they habitually catch,

and whether some years males are more numerous and some years females.

I see that I must trust to analogy (an unsafe support) for sexual

selection in regard to colour in butterflies. You speak of the brimstone

butterfly and genus Edusa (435/2. Colias Edusa.) (I forget what this is,

and have no books here, unless it is Colias) not opening their wings.

In one of my notes to Mr. Stainton I asked him (but he could or did not

answer) whether butterflies such as the Fritillaries, with wings bright

beneath and above, opened and shut their wings more than Vanessae, most

of which, I think, are obscure on the under surface. That is a most

curious observation about the red underwing moth and the robin (435/3.

"Descent of Man," Edition I., Volume I., page 395. Mr. Weir describes

the pursuit of a red-underwing, Triphoena pronuba, by a robin which was

attracted by the bright colour of the moth, and constantly missed the

insect by breaking pieces off the wing instead of seizing the body. Mr.

Wallace's facts are given on the same page.), and strongly supports a

suggestion (which I thought hardly credible) of A.R. Wallace, viz. that

the immense wings of some exotic lepidoptera served as a protection from

difficulty of birds seizing them. I will probably quote your case.

No doubt Dr. Hooker collected the Kerguelen moth, for I remember he told

me of the case when I suggested in the "Origin," the explanation of

the coleoptera of Madeira being apterous; but he did not know what had

become of the specimens.

I am quite delighted to hear that you are observing coloured birds

(435/4. "Descent of Man," Edition I., Volume II., page 110.), though the

probability, I suppose, will be that no sure result will be gained. I am

accustomed with my numerous experiments with plants to be well satisfied

if I get any good result in one case out of five.

You will not be able to read all my book--too much detail. Some of the

chapters in the second volume are curious, I think. If any man wants to

gain a good opinion of his fellow-men, he ought to do what I am doing,

pester them with letters.

LETTER 436. TO J. JENNER WEIR. 4, Chester Place, Regent's Park, N.W.,

March 13th [1868].

You make a very great mistake when you speak of "the risk of your notes

boring me." They are of the utmost value to me, and I am sure I shall

never be tired of receiving them; but I must not be unreasonable. I

shall give almost all the facts which you have mentioned in your two

last notes, as well as in the previous ones; and my only difficulty

will be not to give too much and weary my readers. Your last note is

especially valuable about birds displaying the beautiful parts of their

plumage. Audubon (436/1. In his "Ornithological Biography," 5 volumes,

Edinburgh, 1831-49.) gives a good many facts about the antics of birds

during courtship, but nothing nearly so much to the purpose as yours.

I shall never be able to resist giving the whole substance of your last

note. It is quite a new light to me, except with the peacock and Bird

of Paradise. I must now look to turkey's wings; but I do not think that

their wings are beautiful when opened during courtship. Its tail is

finely banded. How about the drake and Gallus bankiva? I forget how

their wings look when expanded. Your facts are all the more valuable

as I now clearly see that for butterflies I must trust to analogy

altogether in regard to sexual selection. But I think I shall make out a

strong case (as far as the rather deceitful guide of analogy will serve)

in the sexes of butterflies being alike or differing greatly--in moths

which do not display the lower surface of their wings not having them

gaudily coloured, etc., etc.--nocturnal moths, etc.--and in some male

insects fighting for the females, and attracting them by music.

My discussion on sexual selection will be a curious one--a mere

dovetailing of information derived from you, Bates, Wallace, etc., etc.,

etc.

We remain at above address all this month, and then return home. In the

summer, could I persuade you to pay us a visit of a day or two, and I

would try and get Bates and some others to come down? But my health is

so precarious, I can ask no one who will not allow me the privilege of

a poor old invalid; for talking, I find by long and dear-bought

experience, tries my head more than anything, and I am utterly incapable

of talking more than half an hour, except on rare occasions.

I fear this note is very badly written; but I was very ill all

yesterday, and my hand shakes to-day.

LETTER 437. TO J. JENNER WEIR. 4, Chester Place, Regent's Park, N.W.,

March 22nd [1868].

I hope that you will not think me ungrateful that I have not sooner

answered your note of the 16th; but in fact I have been overwhelmed both

with calls and letters; and, alas! one visit to the British Museum of an

hour or hour and a half does for me for the whole day.

I was particularly glad to hear your and your brother's statement about

the "gay" deceiver-pigeons. (437/1. Some cock pigeons "called by our

English fanciers gay birds are so successful in their gallantries that,

as Mr. H. Weir informs me, they must be shut up, on account of the

mischief which they cause.") I did not at all know that certain birds

could win the affections of the females more than other males, except,

indeed, in the case of the peacock. Conversely, Mr. Hewitt, I remember,

states that in making hybrids the cock pheasant would prefer certain hen

fowls and strongly dislike others. I will write to Mr. H. in a few days,

and ask him whether he has observed anything of this kind with pure

unions of fowls, ducks, etc. I had utterly forgotten the case of the

ruff (437/2. The ruff, Machetes pugnax, was believed by Montague to be

polygamous. "Descent of Man," Edition I., Volume I., page 270.), but now

I remember having heard that it was polygamous; but polygamy with birds,

at least, does not seem common enough to have played an important part.

So little is known of habits of foreign birds: Wallace does not even

know whether Birds of Paradise are polygamous. Have you been a large

collector of caterpillars? I believe so. I inferred from a letter from

Dr. Wallace, of Colchester, that he would account for Mr. Stainton

and others rearing more female than male by their having collected the

larger and finer caterpillars. But I misunderstood him, and he maintains

that collectors take all caterpillars, large and small, for that they

collect the caterpillars alone of the rarer moths or butterflies. What

think you? I hear from Professor Canestrini (437/3. See "Descent of Man"

(1901), page 385.) in Italy that females are born in considerable excess

with Bombyx mori, and in greater excess of late years than formerly!

Quatrefages writes to me that he believes they are equal in France.

So that the farther I go the deeper I sink into the mire. With cordial

thanks for your most valuable letters.

We remain here till April 1st, and then hurrah for home and quiet work.

LETTER 438. TO J. JENNER WEIR. 4, Chester Place, N.W., March 27th

[1868].

I hardly know which of your three last letters has interested me most.

What splendid work I shall have hereafter in selecting and arranging

all your facts. Your last letter is most curious--all about the

bird-catchers--and interested us all. I suppose the male chaffinch

in "pegging" approaches the captive singing-bird, from rivalry or

jealousy--if I am wrong please tell me; otherwise I will assume so. Can

you form any theory about all the many cases which you have given me,

and others which have been published, of when one [of a] pair is killed,

another soon appearing? Your fact about the bullfinches in your garden

is most curious on this head. (438/1. Mr. Weir stated that at Blackheath

he never saw or heard a wild bullfinch, yet when one of his caged males

died, a wild one in the course of a few days generally came and perched

near the widowed female, whose call-note is not loud. "Descent of Man"

(1901), page 623.) Are there everywhere many unpaired birds? What can

the explanation be?

Mr. Gould assures me that all the nightingales which first come over are

males, and he believes this is so with other migratory birds. But this

does not agree with what the bird-catchers say about the common linnet,

which I suppose migrates within the limits of England.

Many thanks for very curious case of Pavo nigripennis. (438/2. See

"Animals and Plants," Edition II., Volume I., page 306.) I am very glad

to get additional evidence. I have sent your fact to be inserted, if

not too late, in four foreign editions which are now printing. I am

delighted to hear that you approve of my book; I thought every mortal

man would find the details very tedious, and have often repented of

giving so many. You will find pangenesis stiff reading, and I fear will

shake your head in disapproval. Wallace sticks up for the great god Pan

like a man.

The fertility of hybrid canaries would be a fine subject for careful

investigation.

LETTER 439. TO J. JENNER WEIR. Down, April 4th [1868].

I read over your last ten (!) letters this morning, and made an index

of their contents for easy reference; and what a mine of wealth you

have bestowed on me. I am glad you will publish yourself on gay-coloured

caterpillars and birds (439/1. See "Descent of Man," Edition I., Volume

I., page 417, where Mr. Weir's experiments are given; they were made to

test Mr. Wallace's theory that caterpillars, which are protected against

birds by an unpleasant taste, have been rendered conspicuous, so that

they are easily recognised. They thus escape being pecked or tasted,

which to soft-skinned animals would be as fatal as being devoured. See

Mr. Jenner Weir's papers, "Transact. Entomolog. Soc." 1869, page 2;

1870, page 337. In regard to one of these papers Mr. Darwin wrote (May

13th, 1869): "Your verification of Wallace's suggestion seems to me

to amount to quite a discovery."); it seems to me much the best plan;

therefore, I will not forward your letter to Mr. Wallace. I was much

in the Zoological Gardens during my month in London, and picked up

what scraps of knowledge I could. Without my having mentioned your most

interesting observations on the display of the Fringillidae (439/2.

"Descent of Man" (1901), page 738.), Mr. Bartlett told me how the Gold

Pheasant erects his collar and turns from side to side, displaying it

to the hen. He has offered to give me notes on the display of all

Gallinaceae with which he is acquainted; but he is so busy a man that I

rather doubt whether he will ever do so.

I received about a week ago a remarkably kind letter from your brother,

and I am sorry to hear that he suffers much in health. He gave me some

fine facts about a Dun Hen Carrier which would never pair with a bird of

any other colour. He told me, also, of some one at Lewes who paints his

dog! and will inquire about it. By the way, Mr. Trimen tells me that as

a boy he used to paint butterflies, and that they long haunted the same

place, but he made no further observations on them. As far as colour is

concerned, I see I shall have to trust to mere inference from the males

displaying their plumage, and other analogous facts. I shall get

no direct evidence of the preference of the hens. Mr. Hewitt, of

Birmingham, tells me that the common hen prefers a salacious cock, but

is quite indifferent to colour.

Will you consider and kindly give me your opinion on the two following

points. Do very vigorous and well-nourished hens receive the male

earlier in the spring than weaker or poorer hens? I suppose that they

do. Secondly, do you suppose that the birds which pair first in the

season have any advantage in rearing numerous and healthy offspring over

those which pair later in the season? With respect to the mysterious

cases of which you have given me so many, in addition to those

previously collected, of when one bird of a pair is shot another

immediately supplying its place, I was drawing to the conclusion that

there must be in each district several unpaired birds; yet this seems

very improbable. You allude, also, to the unknown causes which keep down

the numbers of birds; and often and often have I marvelled over this

subject with respect to many animals.

LETTER 440. TO A.R. WALLACE.

(440/1. The following refers to Mr. Wallace's article "A Theory of

Birds' Nests," in Andrew Murray's "Journal of Travel," Volume I., page

73. He here treats in fuller detail the view already published in the

"Westminster Review," July 1867, page 38. The rule which Mr. Wallace

believes, with very few exceptions, to hold good is, "that when both

sexes are of strikingly gay and conspicuous colours, the nest is...such

as to conceal the sitting bird; while, whenever there is a striking

contrast of colours, the male being gay and conspicuous, the female dull

and obscure, the nest is open, and the sitting bird exposed to view."

At this time Mr. Wallace allowed considerably more influence to sexual

selection (in combination with the need of protection) than in his later

writings. The following extract from a letter from Mr. Wallace to Darwin

(July 23rd, 1877) fixes the period at which the change in his views

occurred: "I am almost afraid to tell you that in going over the subject

of the colours of animals, etc., etc., for a small volume of essays,

etc., I am preparing, I have come to conclusions directly opposed to

voluntary sexual selection, and believe that I can explain (in a general

way) all the phenomena of sexual ornaments and colours by laws of

development aided by simple 'Natural Selection.'" He finally rejected

Mr. Darwin's theory that colours "have been developed by the preference

of the females, the more ornamented males becoming the parents of each

successive generation." "Darwinism," 1889, page 285. See also Letters

442, 443, 449, 450, etc.)

Down, April 15th, [1868].

I have been deeply interested by your admirable article on birds' nests.

I am delighted to see that we really differ very little,--not more than

two men almost always will. You do not lay much or any stress on new

characters spontaneously appearing in one sex (generally the male), and

being transmitted exclusively, or more commonly only in excess, to that

sex. I, on the other hand, formerly paid far too little attention to

protection. I had only a glimpse of the truth; but even now I do not

go quite as far as you. I cannot avoid thinking rather more than you

do about the exceptions in nesting to the rule, especially the partial

exceptions, i.e., when there is some little difference between the sexes

in species which build concealed nests. I am not quite satisfied about

the incubating males; there is so little difference in conspicuousness

between the sexes. I wish with all my heart I could go the whole length

with you. You seem to think that male birds probably select the most

beautiful females; I must feel some doubt on this head, for I can find

no evidence of it. Though I am writing so carping a note, I admire the

article thoroughly.

And now I want to ask a question. When female butterflies are more

brilliant than their males you believe that they have in most cases, or

in all cases, been rendered brilliant so as to mimic some other species,

and thus escape danger. But can you account for the males not having

been rendered equally brilliant and equally protected? (440/2. See

Wallace in the "Westminster Review," July, 1867, page 37, on the

protection to the female insect afforded by its resemblance either to an

inanimate object or to another insect protected by its unpalatableness.

The cases are discussed in relation to the much greater importance (to

the species as a whole) of the preservation of the female insect with

her load of eggs than the male who may safely be sacrificed after

pairing. See Letter 189, note.) Although it may be most for the welfare

of the species that the female should be protected, yet it would be some

advantage, certainly no disadvantage, for the unfortunate male to enjoy

an equal immunity from danger. For my part, I should say that the female

alone had happened to vary in the right manner, and that the beneficial

variations had been transmitted to the same sex alone. Believing in

this, I can see no improbability (but from analogy of domestic animals

a strong probability) that variations leading to beauty must often have

occurred in the males alone, and been transmitted to that sex alone.

Thus I should account in many cases for the greater beauty of the male

over the female, without the need of the protective principle. I should

be grateful for an answer on the point.

LETTER 441. TO J. JENNER WEIR. Down, April 18th [1868].

You see that I have taken you at your word, and have not (owing to heaps

of stupid letters) earlier noticed your three last letters, which as

usual are rich in facts. Your letters make almost a little volume on my

table. I daresay you hardly knew yourself how much curious information

was lying in your mind till I began the severe pumping process. The case

of the starling married thrice in one day is capital, and beats the

case of the magpies of which one was shot seven times consecutively. A

gamekeeper here tells me that he has repeatedly shot one of a pair of

jays, and it has always been immediately replaced. I begin to think that

the pairing of birds must be as delicate and tedious an operation as

the pairing of young gentlemen and ladies. If I can convince myself that

there are habitually many unpaired birds, it will be a great aid to me

in sexual selection, about which I have lately had many troubles, and

am therefore rejoiced to hear in your last note that your faith keeps

staunch. That is a curious fact about the bullfinches all appearing to

listen to the German singer (441/1. See Letter 445, note.); and this

leads me to ask how much faith may I put in the statement that male

birds will sing in rivalry until they injure themselves. Yarrell

formerly told me that they would sometimes even sing themselves to

death. I am sorry to hear that the painted bullfinch turns out to be a

female; though she has done us a good turn in exhibiting her jealousy,

of which I had no idea.

Thank you for telling me about the wildness of the hybrid canaries:

nothing has hardly ever surprised me more than the many cases of

reversion from crossing. Do you not think it a very curious subject? I

have not heard from Mr. Bartlett about the Gallinaceae, and I daresay I

never shall. He told me about the Tragopan, and he is positive that the

blue wattle becomes gorged with blood, and not air.

Returning to the first of the last three letters. It is most curious the

number of persons of the name of Jenner who have had a strong taste for

Natural History. It is a pity you cannot trace your connection with the

great Jenner, for a duke might be proud of his blood.

I heard lately from Professor Rolleston of the inherited effects of an

injury in the same eye. Is the scar on your son's leg on the same side

and on exactly the same spot where you were wounded? And did the wound

suppurate, or heal by the first intention? I cannot persuade myself

of the truth of the common belief of the influence of the mother's

imagination on the child. A point just occurs to me (though it does

not at present concern me) about birds' nests. Have you read Wallace's

recent articles? (441/2. A full discussion of Mr. Wallace's views is

given in "Descent of Man," Edition I., Volume II., Chapter XV. Briefly,

Mr. Wallace's point is that the dull colour of the female bird is

protective by rendering her inconspicuous during incubation. Thus the

relatively bright colour of the male would not simply depend on sexual

selection, but also on the hen being "saved, through Natural Selection,

from acquiring the conspicuous colours of the male" (loc. cit., page

155).) I always distrust myself when I differ from him; but I cannot

admit that birds learn to make their nests from having seen them

whilst young. I must think it as true an instinct as that which leads a

caterpillar to suspend its cocoon in a particular manner. Have you had

any experience of birds hatched under a foster-mother making their nests

in the proper manner? I cannot thank you enough for all your kindness.

LETTER 442. TO A.R. WALLACE.

(442/1. Dr. Clifford Allbutt's view probably had reference to the fact

that the sperm-cell goes, or is carried, to the germ-cell, never vice

versa. In this letter Darwin gives the reason for the "law" referred

to. Mr. A.R. Wallace has been good enough to give us the following

note:--"It was at this time that my paper on 'Protective Resemblance'

first appeared in the 'Westminster Review,' in which I adduced the

greater, or rather, the more continuous, importance of the female

(in the lower animals) for the race, and my 'Theory of Birds' Nests'

('Journal of Travel and Natural History,' No. 2) in which I applied this

to the usually dull colours of female butterflies and birds. It is

to these articles as well as to my letters that Darwin chiefly

refers."--Note by Mr. Wallace, May 27th, 1902.)

Down, April 30th [1868].

Your letter, like so many previous ones, has interested me much. Dr.

Allbutt's view occurred to me some time ago, and I have written a short

discussion on it. It is, I think, a remarkable law, to which I have

found no exception. The foundation lies in the fact that in many cases

the eggs or seeds require nourishment and protection by the mother-form

for some time after impregnation. Hence the spermatozoa and antherozoids

travel in the lower aquatic animals and plants to the female, and pollen

is borne to the female organ. As organisms rise in the scale it seems

natural that the male should carry the spermatozoa to the female in his

own body. As the male is the searcher, he has required and gained more

eager passions than the female; and, very differently from you, I look

at this as one great difficulty in believing that the males select the

more attractive females; as far as I can discover, they are always ready

to seize on any female, and sometimes on many females. Nothing would

please me more than to find evidence of males selecting the more

attractive females. I have for months been trying to persuade myself of

this. There is the case of man in favour of this belief, and I know in

hybrid unions of males preferring particular females, but, alas, not

guided by colour. Perhaps I may get more evidence as I wade through my

twenty years' mass of notes.

I am not shaken about the female protected butterflies. I will grant

(only for argument) that the life of the male is of very little

value,--I will grant that the males do not vary, yet why has not the

protective beauty of the female been transferred by inheritance to the

male? The beauty would be a gain to the male, as far as we can see, as

a protection; and I cannot believe that it would be repulsive to the

female as she became beautiful. But we shall never convince each other.

I sometimes marvel how truth progresses, so difficult is it for one man

to convince another, unless his mind is vacant. Nevertheless, I myself

to a certain extent contradict my own remark, for I believe far more in

the importance of protection than I did before reading your articles.

I do not think you lay nearly stress enough in your articles on what

you admit in your letters: viz., "there seems to be some production of

vividness...of colour in the male independent of protection." This I

am making a chief point; and have come to your conclusion so far that

I believe that intense colouring in the female sex is often checked by

being dangerous.

That is an excellent remark of yours about no known case of male alone

assuming protective colours; but in the cases in which protection has

been gained by dull colours, I presume that sexual selection would

interfere with the male losing his beauty. If the male alone had

acquired beauty as a protection, it would be most readily overlooked, as

males are so often more beautiful than their females. Moreover, I grant

that the life of the male is somewhat less precious, and thus there

would be less rigorous selection with the male, so he would be less

likely to be made beautiful through Natural Selection for protection.

(442/2. This does not apply to sexual selection, for the greater the

excess of males, and the less precious their lives, so much the better

for sexual selection. [Note in original.]) But it seems to me a good

argument, and very good if it could be thoroughly established. I do not

know whether you will care to read this scrawl.

LETTER 443. TO A.R. WALLACE. Down, May 5th [1868?].

I am afraid I have caused you a great deal of trouble in writing to me

at such length. I am glad to say that I agree almost entirely with

your summary, except that I should put sexual selection as an equal,

or perhaps as even a more important agent in giving colour than Natural

Selection for protection. As I get on in my work I hope to get clearer

and more decided ideas. Working up from the bottom of the scale, I have

as yet only got to fishes. What I rather object to in your articles is

that I do not think any one would infer from them that you place sexual

selection even as high as No. 4 in your summary. It was very natural

that you should give only a line to sexual selection in the summary to

the "Westminster Review," but the result at first to my mind was that

you attributed hardly anything to its power. In your penultimate

note you say "in the great mass of cases in which there is great

differentiation of colour between the sexes, I believe it is due almost

wholly to the need of protection to the female." Now, looking to the

whole animal kingdom, I can at present by no means admit this view; but

pray do not suppose that because I differ to a certain extent, I do not

thoroughly admire your several papers and your admirable generalisation

on birds' nests. With respect to this latter point, however, although,

following you, I suspect that I shall ultimately look at the whole case

from a rather different point of view.

You ask what I think about the gay-coloured females of Pieris. (443/1.

See "Westminster Review," July, 1867, page 37; also Letter 440.) I

believe I quite follow you in believing that the colours are wholly due

to mimicry; and I further believe that the male is not brilliant from

not having received through inheritance colour from the female, and from

not himself having varied; in short, that he has not been influenced by

selection.

I can make no answer with respect to the elephants. With respect to

the female reindeer, I have hitherto looked at the horns simply as the

consequence of inheritance not having been limited by sex.

Your idea about colour being concentrated in the smaller males seems

good, and I presume that you will not object to my giving it as your

suggestion.

LETTER 444. TO J. JENNER WEIR. Down, May 7th [1868].

I have now to thank you for no less than four letters! You are so kind

that I will not apologise for the trouble I cause you; but it has lately

occurred to me that you ought to publish a paper or book on the habits

of the birds which you have so carefully observed. But should you do

this, I do not think that my giving some of the facts for a special

object would much injure the novelty of your work. There is such a

multitude of points in these last letters that I hardly know what to

touch upon. Thanks about the instinct of nidification, and for your

answers on many points. I am glad to hear reports about the ferocious

female bullfinch. I hope you will have another try in colouring males.

I have now finished lepidoptera, and have used your facts about

caterpillars, and as a caution the case of the yellow-underwings. I

have now begun on fishes, and by comparing different classes of facts my

views are getting a little more decided. In about a fortnight or three

weeks I shall come to birds, and then I dare say that I shall be extra

troublesome. I will now enclose a few queries for the mere chance of

your being able to answer some of them, and I think it will save you

trouble if I write them on a separate slip, and then you can sometimes

answer by a mere "no" or "yes."

Your last letter on male pigeons and linnets has interested me much, for

the precise facts which you have given me on display are of the utmost

value for my work. I have written to Mr. Bartlett on Gallinaceae, but I

dare say I shall not get an answer. I had heard before, but am glad to

have confirmation about the ruffs being the most numerous. I am greatly

obliged to your brother for sending out circulars. I have not heard from

him as yet. I want to ask him whether he has ever observed when several

male pigeons are courting one female that the latter decides with which

male she will pair. The story about the black mark on the lambs must be

a hoax. The inaccuracy of many persons is wonderful. I should like to

tell you a story, but it is too long, about beans growing on the wrong

side of the pod during certain years.

Queries:

Does any female bird regularly sing?

Do you know any case of both sexes, more especially of the female,

[being] more brightly coloured whilst young than when come to maturity

and fit to breed? An imaginary instance would be if the female

kingfisher (or male) became dull coloured when adult.

Do you know whether the male and female wild canary bird differ in

plumage (though I believe I could find this out for myself), and do any

of the domestic breeds differ sexually?

Do you know any gallinaceous bird in which the female has well developed

spurs?

It is very odd that my memory should fail me, but I cannot remember

whether, in accordance with your views, the wing of Gallus bankiva (or

Game-Cock, which is so like the wild) is ornamental when he opens and

scrapes it before the female. I fear it is not; but though I have often

looked at wing of the wild and tame bird, I cannot call to mind the

exact colours. What a number of points you have attended to; I did

not know that you were a horticulturist. I have often marvelled at the

different growth of the flowering and creeping branches of the ivy; but

had no idea that they kept their character when propagated by cuttings.

There is a S. American genus (name forgotten just now) which differs

in an analogous manner but even greater degree, but it is difficult to

cultivate in our hot-house. I have tried and failed.

LETTER 445. TO J. JENNER WEIR. Down, May 30th [1868].

I am glad to hear your opinion on the nest-making instinct, for I am

Tory enough not to like to give up all old beliefs. Wallace's view

(445/1. See Letter 440, etc.) is also opposed to a great mass of

analogical facts. The cases which you mention of suddenly reacquired

wildness seem curious. I have also to thank you for a previous valuable

letter. With respect to spurs on female Gallinaceae, I applied to Mr.

Blyth, who has wonderful systematic knowledge, and he tells me that the

female Pavo muticus and Fire-back pheasants are spurred. From various

interruptions I get on very slowly with my Bird MS., but have already

often and often referred to your volume of letters, and have used

various facts, and shall use many more. And now I am ashamed to say

that I have more questions to ask; but I forget--you told me not to

apologise.

1. In your letter of April 14th you mention the case of about twenty

birds which seemed to listen with much interest to an excellent piping

bullfinch. (445/2. Quoted in the "Descent of Man" (1901), page 564. "A

bullfinch which had been taught to pipe a German waltz...when this bird

was first introduced into a room where other birds were kept and he

began to sing, all the others, consisting of about twenty linnets and

canaries, ranged themselves on the nearest side of their cages, and

listened with the greatest interest to the new performer.") What kind of

birds were these twenty?

2. Is it true, as often stated, that a bird reared by foster-parents,

and who has never heard the song of its own species, imitates to a

certain extent the song of the species which it may be in the habit of

hearing?

Now for a more troublesome point. I find it very necessary to make

out relation of immature plumage to adult plumage, both when the sexes

differ and are alike in the adult state. Therefore, I want much to learn

about the first plumage (answering, for instance, to the speckled state

of the robin before it acquires the red breast) of the several varieties

of the canary. Can you help me? What is the character or colour of the

first plumage of bright yellow or mealy canaries which breed true to

these tints? So with the mottled-brown canaries, for I believe that

there are breeds which always come brown and mottled. Lastly, in the

"prize-canaries," which have black wing- and tail-feathers during their

first (?) plumage, what colours are the wings and tails after the first

(?) moult or when adult? I should be particularly glad to learn this.

Heaven have mercy on you, for it is clear that I have none. I am going

to investigate this same point with all the breeds of fowls, as Mr.

Tegetmeier will procure for me young birds, about two months old, of all

the breeds.

In the course of this next month I hope you will come down here on the

Saturday and stay over the Sunday. Some months ago Mr. Bates said

he would pay me a visit during June, and I have thought it would be

pleasanter for you to come here when I can get him, so that you would

have a companion if I get knocked up, as is sadly too often my bad habit

and great misfortune.

Did you ever hear of the existence of any sub-breed of the canary in

which the male differs in plumage from the female?

LETTER 446. TO F. MULLER. Down, June 3rd [1868].

Your letter of April 22nd has much interested me. I am delighted that

you approve of my book, for I value your opinion more than that of

almost any one. I have yet hopes that you will think well of pangenesis.

I feel sure that our minds are somewhat alike, and I find it a great

relief to have some definite, though hypothetical view, when I reflect

on the wonderful transformations of animals, the re-growth of parts, and

especially the direct action of pollen on the mother form, etc. It often

appears to me almost certain that the characters of the parents are

"photographed" on the child, only by means of material atoms derived

from each cell in both parents, and developed in the child. I am sorry

about the mistake in regard to Leptotes. (446/1. See "Animals and

Plants," Edition I., Volume II., page 134, where it is stated that

Oncidium is fertile with Leptotes, a mistake corrected in the 2nd

edition.) I daresay it was my fault, yet I took pains to avoid such

blunders. Many thanks for all the curious facts about the unequal number

of the sexes in crustacea, but the more I investigate this subject

the deeper I sink in doubt and difficulty. Thanks, also, for the

confirmation of the rivalry of Cicadae. (446/2. See "Descent of Man,"

Edition I., Volume I., page 351, for F. Muller's observations; and for

a reference to Landois' paper.) I have often reflected with surprise on

the diversity of the means for producing music with insects, and still

more with birds. We thus get a high idea of the importance of song in

the animal kingdom. Please to tell me where I can find any account of

the auditory organs in the orthoptera? Your facts are quite new to me.

Scudder has described an annectant insect in Devonian strata, furnished

with a stridulating apparatus. (446/3. The insect is no doubt Xenoneura

antiquorum, from the Devonian rocks of New Brunswick. Scudder compared

a peculiar feature in the wing of this species to the stridulating

apparatus of the Locustariae, but afterwards stated that he had been led

astray in his original description, and that there was no evidence in

support of the comparison with a stridulating organ. See the "Devonian

Insects of New Brunswick," reprinted in S.H. Scudder's "Fossil Insects

of N. America," Volume I., page 179, New York, 1890.) I believe he is to

be trusted, and if so the apparatus is of astonishing antiquity. After

reading Landois' paper I have been working at the stridulating organ in

the lamellicorn beetles, in expectation of finding it sexual, but I have

only found it as yet in two cases, and in these it was equally developed

in both sexes. I wish you would look at any of your common lamellicorns

and take hold of both males and females and observe whether they make

the squeaking or grating noise equally. If they do not, you could

perhaps send me a male and female in a light little box. How curious

it is that there should be a special organ for an object apparently so

unimportant as squeaking. Here is another point: have you any Toucans?

if so, ask any trustworthy hunter whether the beaks of the males, or of

both sexes, are more brightly coloured during the breeding season than

at other times of the year? I have also to thank you for a previous

letter of April 3rd, with some interesting facts on the variation of

maize, the sterility of Bignonia and on conspicuous seeds. Heaven knows

whether I shall ever live to make use of half the valuable facts which

you have communicated to me...

LETTER 447. TO J. JENNER WEIR. Down, June 18th [1868].

Many thanks. I am glad that you mentioned the linnet, for I had much

difficulty in persuading myself that the crimson breast could be due to

change in the old feathers, as the books say. I am glad to hear of the

retribution of the wicked old she-bullfinch. You remember telling me how

many Weirs and Jenners have been naturalists; now this morning I have

been putting together all my references about one bird of a pair being

killed, and a new mate being soon found; you, Jenner Weir, have given

me some most striking cases with starlings; Dr. Jenner gives the most

curious case of all in "Philosophical Transactions" (447/1. "Phil.

Trans." 1824.), and a Mr. Weir gives the next most striking in

Macgillivray. (447/2. Macgillivray's "History of British Birds," Volume

I., page 570. See "Descent of Man" (1901), page 621.) Now, is this not

odd? Pray remember how very glad we shall be to see you here whenever

you can come.

Did some ancient progenitor of the Weirs and Jenners puzzle his brains

about the mating of birds, and has the question become indelibly fixed

in all your minds?

LETTER 448. TO A.R. WALLACE. August 19th [1868].

I had become, before my nine weeks' horrid interruption of all work,

extremely interested in sexual selection, and was making fair progress.

In truth it has vexed me much to find that the farther I get on the more

I differ from you about the females being dull-coloured for protection.

I can now hardly express myself as strongly, even, as in the "Origin."

This has much decreased the pleasure of my work. In the course of

September, if I can get at all stronger, I hope to get Mr. J. Jenner

Weir (who has been wonderfully kind in giving me information) to pay

me a visit, and I will then write for the chance of your being able to

come, and I hope bring with you Mrs. Wallace. If I could get several of

you together it would be less dull for you, for of late I have found

it impossible to talk with any human being for more than half an hour,

except on extraordinary good days.

(448/1. On September 16th Darwin wrote to Wallace on the same

subject:--)

You will be pleased to hear that I am undergoing severe distress about

protection and sexual selection; this morning I oscillated with joy

towards you; this evening I have swung back to the old position, out of

which I fear I shall never get.

LETTER 449. TO A.R. WALLACE.

(449/1. From "Life and Letters," Volume III., page 123.)

Down, September 23rd [1868].

I am very much obliged for all your trouble in writing me your long

letter, which I will keep by me and ponder over. To answer it would

require at least 200 folio pages! If you could see how often I have

rewritten some pages you would know how anxious I am to arrive as near

as I can to the truth. I lay great stress on what I know takes place

under domestication; I think we start with different fundamental

notions on inheritance. I find it is most difficult, but not, I think,

impossible to see how, for instance, a few red feathers appearing on the

head of a male bird, and which are at first transmitted to both sexes,

would come to be transmitted to males alone. It is not enough that

females should be produced from the males with red feathers, which

should be destitute of red feathers; but these females must have a

latent tendency to produce such feathers, otherwise they would cause

deterioration in the red head-feathers of their male offspring. Such

latent tendency would be shown by their producing the red feathers when

old, or diseased in their ovaria. But I have no difficulty in making the

whole head red if the few red feathers in the male from the first tended

to be sexually transmitted. I am quite willing to admit that the female

may have been modified, either at the same time or subsequently,

for protection by the accumulation of variations limited in their

transmission to the female sex. I owe to your writings the consideration

of this latter point. But I cannot yet persuade myself that females

alone have often been modified for protection. Should you grudge the

trouble briefly to tell me, whether you believe that the plainer head

and less bright colours of female chaffinch, the less red on the head

and less clean colours of female goldfinch, the much less red on the

breast of the female bullfinch, the paler crest of golden-crested wren,

etc., have been acquired by them for protection? I cannot think so, any

more than I can that the considerable differences between female and

male house-sparrow, or much greater brightness of male Parus caeruleus

(both of which build under cover) than of female Parus, are related to

protection. I even misdoubt much whether the less blackness of female

blackbird is for protection.

Again, can you give me reasons for believing that the moderate

differences between the female pheasant, the female Gallus bankiva,

the female of black grouse, the pea-hen, the female partridge, have all

special references to protection under slightly different conditions? I,

of course, admit that they are all protected by dull colours, derived,

as I think, from some dull-ground progenitor; and I account partly for

their difference by partial transference of colour from the male, and by

other means too long to specify; but I earnestly wish to see reason

to believe that each is specially adapted for concealment to its

environment.

I grieve to differ from you, and it actually terrifies me and makes me

constantly distrust myself. I fear we shall never quite understand each

other. I value the cases of bright-coloured, incubating male fisher, and

brilliant female butterflies, solely as showing that one sex may be made

brilliant without any necessary transference of beauty to the other sex;

for in these cases I cannot suppose that beauty in the other sex was

checked by selection.

I fear this letter will trouble you to read it. A very short answer

about your belief in regard to the female finches and Gallinaceae would

suffice.

LETTER 450. A.R. WALLACE TO CHARLES DARWIN. 9, St. Mark's Crescent,

N.W., September 27th, 1868.

Your view seems to be that variations occurring in one sex are

transmitted either to that sex exclusively or to both sexes equally, or

more rarely partially transferred. But we have every gradation of

sexual colours, from total dissimilarity to perfect identity. If this is

explained solely by the laws of inheritance, then the colours of one or

other sex will be always (in relation to the environment) a matter of

chance. I cannot think this. I think selection more powerful than laws

of inheritance, of which it makes use, as shown by cases of two, three

or four forms of female butterflies, all of which have, I have little

doubt, been specialised for protection.

To answer your first question is most difficult, if not impossible,

because we have no sufficient evidence in individual cases of slight

sexual difference, to determine whether the male alone has acquired his

superior brightness by sexual selection, or the female been made duller

by need of protection, or whether the two causes have acted. Many of the

sexual differences of existing species may be inherited differences from

parent forms, which existed under different conditions and had greater

or less need of protection.

I think I admitted before, the general tendency (probably) of males to

acquire brighter tints. Yet this cannot be universal, for many female

birds and quadrupeds have equally bright tints.

To your second question I can reply more decidedly. I do think the

females of the Gallinaceae you mention have been modified or been

prevented from acquiring the brighter plumage of the male, by need of

protection. I know that the Gallus bankiva frequents drier and more open

situations than the pea-hen of Java, which is found among grassy and

leafy vegetation, corresponding with the colours of the two. So the

Argus pheasant, male and female, are, I feel sure, protected by their

tints corresponding to the dead leaves of the lofty forest in which

they dwell, and the female of the gorgeous fire-back pheasant Lophura

viellottii is of a very similar rich brown colour.

I do not, however, at all think the question can be settled by

individual cases, but by only large masses of facts. The colours of the

mass of female birds seem to me strictly analogous to the colours of

both sexes of snipes, woodcocks, plovers, etc., which are undoubtedly

protective.

Now, supposing, on your view, that the colours of a male bird become

more and more brilliant by sexual selection, and a good deal of that

colour is transmitted to the female till it becomes positively injurious

to her during incubation, and the race is in danger of extinction; do

you not think that all the females who had acquired less of the male's

bright colours, or who themselves varied in a protective direction,

would be preserved, and that thus a good protective colouring would soon

be acquired?

If you admit that this could occur, and can show no good reason why it

should not often occur, then we no longer differ, for this is the main

point of my view.

Have you ever thought of the red wax-tips of the Bombycilla beautifully

imitating the red fructification of lichens used in the nest, and

therefore the FEMALES have it too? Yet this is a very sexual-looking

character.

If sexes have been differentiated entirely by sexual selection the

females can have no relation to environment. But in groups when both

sexes require protection during feeding or repose, as snipes, woodcock,

ptarmigan, desert birds and animals, green forest birds, etc., arctic

birds of prey, and animals, then both sexes are modified for protection.

Why should that power entirely cease to act when sexual differentiation

exists and when the female requires protection, and why should the

colour of so many FEMALE BIRDS seem to be protective, if it has not been

made protective by selection.

It is contrary to the principles of "Origin of Species," that colour

should have been produced in both sexes by sexual selection and

never have been modified to bring the female into harmony with the

environment. "Sexual selection is less rigorous than Natural Selection,"

and will therefore be subordinate to it.

I think the case of female Pieris pyrrha proves that females alone can

be greatly modified for protection. (450/1. My latest views on this

subject, with many new facts and arguments, will be found in the later

editions of my "Darwinism," Chapter X. (A.R.W.))

LETTER 451. A.R. WALLACE TO CHARLES DARWIN.

(451/1. On October 4th, 1868, Mr. Wallace wrote again on the same

subject without adding anything of importance to his arguments of

September 27th. We give his final remarks:--)

October 4th, 1868.

I am sorry to find that our difference of opinion on this point is a

source of anxiety to you. Pray do not let it be so. The truth will come

out at last, and our difference may be the means of setting others to

work who may set us both right. After all, this question is only an

episode (though an important one) in the great question of the "Origin

of Species," and whether you or I are right will not at all affect the

main doctrine--that is one comfort.

I hope you will publish your treatise on "Sexual Selection" as a

separate book as soon as possible; and then, while you are going on with

your other work, there will no doubt be found some one to battle with me

over your facts on this hard problem.

LETTER 452. TO A.R. WALLACE. Down, October 6th [1868].

Your letter is very valuable to me, and in every way very kind. I will

not inflict a long answer, but only answer your queries. There are

breeds (viz. Hamburg) in which both sexes differ much from each other

and from both sexes of Gallus bankiva; and both sexes are kept constant

by selection. The comb of the Spanish male has been ordered to be

upright, and that of Spanish female to lop over, and this has been

effected. There are sub-breeds of game fowl, with females very distinct

and males almost identical; but this, apparently, is the result of

spontaneous variation, without special selection. I am very glad to hear

of case of female Birds of Paradise.

I have never in the least doubted possibility of modifying female birds

alone for protection, and I have long believed it for butterflies. I

have wanted only evidence for the female alone of birds having had their

colour modified for protection. But then I believe that the variations

by which a female bird or butterfly could get or has got protective

colouring have probably from the first been variations limited in their

transmission to the female sex. And so with the variations of the

male: when the male is more beautiful than the female, I believe the

variations were sexually limited in their transmission to the males.

LETTER 453. TO B.D. WALSH. Down, October 31st, 1868.

(453/1. A short account of the Periodical Cicada (C. septendecim) is

given by Dr. Sharp in the Cambridge Natural History, Insects II., page

570. We are indebted to Dr. Sharp for calling our attention to Mr. C.L.

Marlatt's full account of the insect in "Bulletin No. 14 [NS.] of the

U.S. Department of Agriculture," 1898. The Cicada lives for long periods

underground as larva and pupa, so that swarms of the adults of one

race (septendecim) appear at intervals of 17 years, while those of the

southern form or race (tredecim) appear at intervals of 13 years.

This fact was first made out by Phares in 1845, but was overlooked or

forgotten, and was only re-discovered by Walsh and Riley in 1868, who

published a joint paper in the "American Entomologist," Volume I., page

63. Walsh appears to have adhered to the view that the 13- and 17-year

forms are distinct species, though, as we gather from Marlatt's paper

(page 14), he published a letter to Mr. Darwin in which he speaks of the

13-year form as an incipient species; see "Index to Missouri Entomolog.

Reports Bull. 6," U.S.E.C., page 58 (as given by Marlatt). With regard

to the cause of the difference in period of the two forms, Marlatt

(pages 15, 16) refers doubtfully to difference of temperature as the

determining factor. Experiments have been instituted by moving 17-year

eggs to the south, and vice versa with 13-year eggs. The results were,

however, not known at the time of publication of Marlatt's paper.)

I am very much obliged for the extracts about the "drumming," which will

be of real use to me.

I do not at all know what to think of your extraordinary case of the

Cicadas. Professor Asa Gray and Dr. Hooker were staying here, and I told

them of the facts. They thought that the 13-year and the 17-year forms

ought not to be ranked as distinct species, unless other differences

besides the period of development could be discovered. They thought the

mere rarity of variability in such a point was not sufficient, and I

think I concur with them. The fact of both the forms presenting the same

case of dimorphism is very curious. I have long wished that some one

would dissect the forms of the male stag-beetle with smaller mandibles,

and see if they were well developed, i.e., whether there was an

abundance of spermatozoa; and the same observations ought, I think,

to be made on the rarer form of your Cicada. Could you not get some

observer, such as Dr. Hartman (453/2. Mr. Walsh sent Mr. Darwin

an extract from Dr. Hartman's "Journal of the doings of a Cicada

septendecim," in which the females are described as flocking round the

drumming males. "Descent of Man" (1901), page 433.), to note whether the

females flocked in equal numbers to the "drumming" of the rarer form as

to the common form? You have a very curious and perplexing subject of

investigation, and I wish you success in your work.

LETTER 454. TO A.R. WALLACE. Down, June 15th [1869?].

You must not suppose from my delay that I have not been much interested

by your long letter. I write now merely to thank you, and just to say

that probably you are right on all the points you touch on, except, as

I think, about sexual selection, which I will not give up. My belief in

it, however, is contingent on my general belief in sexual selection. It

is an awful stretcher to believe that a peacock's tail was thus formed;

but, believing it, I believe in the same principle somewhat modified

applied to man.

LETTER 455. TO G.H.K. THWAITES. Down, February 13th [N.D.]

I wrote a little time ago asking you an odd question about elephants,

and now I am going to ask you an odder. I hope that you will not think

me an intolerable bore. It is most improbable that you could get me

an answer, but I ask on mere chance. Macacus silenus (455/1. Macacus

silenus L., an Indian ape.) has a great mane of hair round neck, and

passing into large whiskers and beard. Now what I want most especially

to know is whether these monkeys, when they fight in confinement (and

I have seen it stated that they are sometimes kept in confinement), are

protected from bites by this mane and beard. Any one who watched them

fighting would, I think, be able to judge on this head. My object is to

find out with various animals how far the mane is of any use, or a mere

ornament. Is the male Macacus silenus furnished with longer hair than

the female about the neck and face? As I said, it is a hundred or a

thousand to one against your finding out any one who has kept these

monkeys in confinement.

LETTER 456. TO F. MULLER. Down, August 28th [1870].

I have to thank you very sincerely for two letters: one of April 25th,

containing a very curious account of the structure and morphology of

Bonatea. I feel that it is quite a sin that your letters should not all

be published! but, in truth, I have no spare strength to undertake any

extra work, which, though slight, would follow from seeing your letters

in English through the press--not but that you write almost as clearly

as any Englishman. This same letter also contained some seeds for Mr.

Farrer, which he was very glad to receive.

Your second letter, of July 5th, was chiefly devoted to mimicry in

lepidoptera: many of your remarks seem to me so good, that I have

forwarded your letter to Mr. Bates; but he is out of London having his

summer holiday, and I have not yet heard from him. Your remark about

imitators and imitated being of such different sizes, and the lower

surface of the wings not being altered in colour, strike me as the most

curious points. I should not be at all surprised if your suggestion

about sexual selection were to prove true; but it seems rather too

speculative to be introduced in my book, more especially as my book is

already far too speculative. The very same difficulty about brightly

coloured caterpillars had occurred to me, and you will see in my book

what, I believe, is the true explanation from Wallace. The same view

probably applies in part to gaudy butterflies. My MS. is sent to the

printers, and, I suppose, will be published in about three months:

of course I will send you a copy. By the way, I settled with Murray

recently with respect to your book (456/1. The translation of "Fur

Darwin," published in 1869.), and had to pay him only 21 pounds

2 shillings 3 pence, which I consider a very small price for the

dissemination of your views; he has 547 copies as yet unsold. This most

terrible war will stop all science in France and Germany for a long

time. I have heard from nobody in Germany, and know not whether your

brother, Hackel, Gegenbaur, Victor Carus, or my other friends are

serving in the army. Dohrn has joined a cavalry regiment. I have not yet

met a soul in England who does not rejoice in the splendid triumph of

Germany over France (456/2. See Letter 239, Volume I.): it is a most

just retribution against that vainglorious, war-liking nation. As the

posts are all in confusion, I will not send this letter through

France. The Editor has sent me duplicate copies of the "Revue des Cours

Scientifiques," which contain several articles about my views; so I send

you copies for the chance of your liking to see them.

LETTER 457. A.R. WALLACE TO CHARLES DARWIN. Holly House, Barking, E.,

January 27th, 1871.

Many thanks for your first volume (457/1. "The Descent of Man".), which

I have just finished reading through with the greatest pleasure and

interest; and I have also to thank you for the great tenderness with

which you have treated me and my heresies.

On the subject of "sexual selection" and "protection," you do not yet

convince me that I am wrong; but I expect your heaviest artillery will

be brought up in your second volume, and I may have to capitulate. You

seem, however, to have somewhat misunderstood my exact meaning, and I

do not think the difference between us is quite so great as you seem to

think it. There are a number of passages in which you argue against the

view that the female has in any large number of cases been "specially

modified" for protection, or that colour has generally been obtained by

either sex for purposes of protection. But my view is, as I thought

I had made it clear, that the female has (in most cases) been simply

prevented from acquiring the gay tints of the male (even when there was

a tendency for her to inherit it), because it was hurtful; and that,

when protection is not needed, gay colours are so generally acquired

by both sexes as to show that inheritance by both sexes of colour

variations is the most usual, when not prevented from acting by Natural

Selection. The colour itself may be acquired either by sexual selection

or by other unknown causes.

There are, however, difficulties in the very wide application you give

to sexual selection which at present stagger me, though no one was or

is more ready than myself to admit the perfect truth of the principle or

the immense importance and great variety of its applications.

Your chapters on "Man" are of intense interest--but as touching my

special heresy, not as yet altogether convincing, though, of course, I

fully agree with every word and every argument which goes to prove

the "evolution" or "development" of man out of a lower form. My ONLY

difficulties are, as to whether you have accounted for EVERY STEP of the

development by ascertained laws.

I feel sure that the book will keep up and increase your high

reputation, and be immensely successful, as it deserves to be...

LETTER 458. TO G.B. MURDOCH. Down, March 13th, 1871.

(458/1. We are indebted to Mr. Murdoch for a draft of his letter dated

March 10th, 1871. It is too long to be quoted at length; the following

citations give some idea of its contents: "In your 'Descent of Man,' in

treating of the external differences between males and females of the

same variety, have you attached sufficient importance to the different

amount and kind of energy expended by them in reproduction?" Mr. Murdoch

sums up: "Is it wrong, then, to suppose that extra growth, complicated

structure, and activity in one sex exist as escape-valves for surplus

vigour, rather than to please or fight with, though they may serve these

purposes and be modified by them?")

I am much obliged for your valuable letter. I am strongly inclined to

think that I have made a great and complete oversight with respect to

the subject which you discuss. I am the more surprised at this, as I

remember reflecting on some points which ought to have led me to your

conclusion. By an odd chance I received the day before yesterday a

letter from Mr. Lowne (author of an excellent book on the anatomy of

the Blow-fly) (458/2. "The Anatomy and Physiology of the Blow-fly (Musca

vomitaria L.)," by B.T. Lowne. London, 1870.) with a discussion very

nearly to the same effect as yours. His conclusions were drawn from

studying male insects with great horns, mandibles, etc. He informs me

that his paper on this subject will soon be published in the "Transact.

Entomolog. Society." (458/3. "Observations on Immature Sexuality and

Alternate Generation in Insects." By B.T. Lowne. "Trans. Entomolog.

Soc." 1871 [Read March 6th, 1871]. "I believe that certain cutaneous

appendages, as the gigantic mandibles and thoracic horns of many males,

are complemental to the sexual organs; that, in point of fact, they are

produced by the excess of nutriment in the male, which in the female

would go to form the generative organs and ova" (loc. cit., page 197).)

I am inclined to look at your and Mr. Lowne's view as specially valuable

from probably throwing light on the greater variability of male than

female animals, which manifestly has much bearing on sexual selection.

I will keep your remarks in mind whenever a new edition of my book is

demanded.

LETTER 459. TO GEORGE FRASER.

(459/1. The following letter refers to two letters to Mr. Darwin, in

which Mr. Fraser pointed out that illustrations of the theory of Sexual

Selection might be found amongst British butterflies and moths. Mr.

Fraser, in explanation of the letters, writes: "As an altogether unknown

and far from experienced naturalist, I feared to send my letters

for publication without, in the first place, obtaining Mr. Darwin's

approval." The information was published in "Nature," Volume III., April

20th, 1871, page 489. The article was referred to in the second edition

of the "Descent of Man" (1874), pages 312, 316, 319. Mr. Fraser

adds: "This is only another illustration of Mr. Darwin's great

conscientiousness in acknowledging suggestions received by him from the

most humble sources." (Letter from Mr. Fraser to F. Darwin, March 21,

1888.)

Down, April 14th [1871].

I am very much obliged for your letter and the interesting facts which

it contains, and which are new to me. But I am at present so much

engaged with other subjects that I cannot fully consider them; and, even

if I had time, I do not suppose that I should have anything to say worth

printing in a scientific journal. It would obviously be absurd in me to

allow a mere note of thanks from me to be printed. Whenever I have

to bring out a corrected edition of my book I will well consider

your remarks (which I hope that you will send to "Nature"), but

the difficulty will be that my friends tell me that I have already

introduced too many facts, and that I ought to prune rather than to

introduce more.

LETTER 460. TO E.S. MORSE. Down, December 3rd, 1871.

I am much obliged to you for having sent me your two interesting papers,

and for the kind writing on the cover. I am very glad to have my error

corrected about the protective colouring of shells. (460/1. "On Adaptive

Coloration of the Mollusca," "Boston Society of Natural History Proc."

Volume XIV., April 5th, 1871. Mr. Morse quotes from the "Descent of

Man," I., page 316, a passage to the effect that the colours of the

mollusca do not in general appear to be protective. Mr. Morse goes on to

give instances of protective coloration.) It is no excuse for my broad

statement, but I had in my mind the species which are brightly or

beautifully coloured, and I can as yet hardly think that the colouring

in such cases is protective.

LETTER 461. TO AUG. WEISMANN. Down, February 29th, 1872.

I am rejoiced to hear that your eyesight is somewhat better; but I fear

that work with the microscope is still out of your power. I have often

thought with sincere sympathy how much you must have suffered from your

grand line of embryological research having been stopped. It was very

good of you to use your eyes in writing to me. I have just received your

essay (461/1. "Ueber der Einfluss der Isolirung auf die Artbildung":

Leipzig, 1872.); but as I am now staying in London for the sake of rest,

and as German is at all times very difficult to me, I shall not be able

to read your essay for some little time. I am, however, very curious to

learn what you have to say on isolation and on periods of variation.

I thought much about isolation when I wrote in Chapter IV. on the

circumstances favourable to Natural Selection. No doubt there remains

an immense deal of work to do on "Artbildung." I have only opened a path

for others to enter, and in the course of time to make a broad and clear

high-road. I am especially glad that you are turning your attention to

sexual selection. I have in this country hardly found any naturalists

who agree with me on this subject, even to a moderate extent. They think

it absurd that a female bird should be able to appreciate the splendid

plumage of the male; but it would take much to persuade me that the

peacock does not spread his gorgeous tail in the presence of the female

in order to fascinate or excite her. The case, no doubt, is much more

difficult with insects. I fear that you will find it difficult to

experiment on diurnal lepidoptera in confinement, for I have never heard

of any of these breeding in this state. (461/2. We are indebted to Mr.

Bateson for the following note: "This belief does not seem to be well

founded, for since Darwin's time several species of Rhopalocera (e.g.

Pieris, Pararge, Caenonympha) have been successfully bred in confinement

without any special difficulty; and by the use of large cages members

even of strong-flying genera, such as Vanessa, have been induced to

breed.") I was extremely pleased at hearing from Fritz Muller that he

liked my chapter on lepidoptera in the "Descent of Man" more than any

other part, excepting the chapter on morals.

LETTER 462. TO H. MULLER. Down [May, 1872].

I have now read with the greatest interest your essay, which contains

a vast amount of matter quite new to me. (462/1. "Anwendung der

Darwin'schen Lehre auf Bienen," "Verhandl. d. naturhist. Vereins fur

preuss. Rheinld. u. Westf." 1872. References to Muller's paper occur in

the second edition of the "Descent of Man.") I really have no criticisms

or suggestions to offer. The perfection of the gradation in the

character of bees, especially in such important parts as the

mouth-organs, was altogether unknown to me. You bring out all such facts

very clearly by your comparison with the corresponding organs in the

allied hymenoptera. How very curious is the case of bees and wasps

having acquired, independently of inheritance from a common source, the

habit of building hexagonal cells and of producing sterile workers!

But I have been most interested by your discussion on secondary sexual

differences; I do not suppose so full an account of such differences in

any other group of animals has ever been published. It delights me

to find that we have independently arrived at almost exactly the

same conclusion with respect to the more important points deserving

investigation in relation to sexual selection. For instance, the

relative number of the two sexes, the earlier emergence of the males,

the laws of inheritance, etc. What an admirable illustration you give of

the transference of characters acquired by one sex--namely, that of the

male of Bombus possessing the pollen-collecting apparatus. Many of

your facts about the differences between male and female bees are

surprisingly parallel with those which occur with birds. The reading

your essay has given me great confidence in the efficacy of sexual

selection, and I wanted some encouragement, as extremely few naturalists

in England seem inclined to believe in it. I am, however, glad to find

that Prof. Weismann has some faith in this principle.

The males of Bombus follow one remarkable habit, which I think it would

interest you to investigate this coming summer, and no one could do

it better than you. (462/2. Mr. Darwin's observations on this curious

subject were sent to Hermann Muller, and after his death were translated

and published in Krause's "Gesammelte kleinere Schriften von Charles

Darwin," 1887, page 84. The male bees had certain regular lines of

flight at Down, as from the end of the kitchen garden to the corner of

the "sand-walk," and certain regular "buzzing places" where they stopped

on the wing for a moment or two. Mr. Darwin's children remember vividly

the pleasure of helping in the investigation of this habit.) I have

therefore enclosed a briefly and roughly drawn-up account of this habit.

Should you succeed in making any observations on this subject, and if

you would like to use in any way my MS. you are perfectly welcome. I

could, should you hereafter wish to make any use of the facts, give them

in rather fuller detail; but I think that I have given enough.

I hope that you may long have health, leisure, and inclination to do

much more work as excellent as your recent essay.

2.VIII.III. EXPRESSION, 1868-1874.

LETTER 463. TO F. MULLER. Down, January 30th [1868].

I am very much obliged for your answers, though few in number (October

5th), about expression. I was especially glad to hear about shrugging

the shoulders. You say that an old negro woman, when expressing

astonishment, wonderfully resembled a Cebus when astonished; but are you

sure that the Cebus opened its mouth? I ask because the Chimpanzee does

not open its mouth when astonished, or when listening. (463/1. Darwin

in the "Expression of the Emotions," adheres to this statement as being

true of monkeys in general.) Please have the kindness to remember that

I am very anxious to know whether any monkey, when screaming violently,

partially or wholly closes its eyes.

LETTER 464. TO W. BOWMAN.

(464/1. The late Sir W. Bowman, the well-known surgeon, supplied a good

deal of information of value to Darwin in regard to the expression of

the emotions. The gorging of the eyes with blood during screaming is

an important factor in the physiology of weeping, and indirectly in the

obliquity of the eyebrows--a characteristic expression of suffering. See

"Expression of the Emotions," pages 160 and 192.)

Down, March 30th [1868].

I called at your house about three weeks since, and heard that you were

away for the whole month, which I much regretted, as I wished to

have had the pleasure of seeing you, of asking you a question, and

of thanking you for your kindness to my son George. You did not quite

understand the last note which I wrote to you--viz., about Bell's

precise statement that the conjunctiva of an infant or young child

becomes gorged with blood when the eyes are forcibly opened during

a screaming fit. (464/2. Sir C. Bell's statement in his "Anatomy

of Expression" (1844, page 106) is quoted in the "Expression of the

Emotions," page 158.) I have carefully kept your previous note, in which

you spoke doubtfully about Bell's statement. I intended in my former

note only to express a wish that if, during your professional work, you

were led to open the eyelids of a screaming child, you would specially

observe this point about the eye showing signs of becoming gorged with

blood, which interests me extremely. Could you ask any one to observe

this for me in an eye-dispensary or hospital? But I now have to beg you

kindly to consider one other question at any time when you have half an

hour's leisure.

When a man coughs violently from choking or retches violently, even when

he yawns, and when he laughs violently, tears come into the eyes. Now,

in all these cases I observe that the orbicularis muscle is more or less

spasmodically contracted, as also in the crying of a child. So, again,

when the muscles of the abdomen contract violently in a propelling

manner, and the breath is, I think, always held, as during the

evacuation of a very costive man, and as (I hear) with a woman during

severe labour-pains, the orbicularis contracts, and tears come into

the eyes. Sir J.E. Tennant states that tears roll down the cheeks

of elephants when screaming and trumpeting at first being captured;

accordingly I went to the Zoological Gardens, and the keeper made two

elephants trumpet, and when they did this violently the orbicularis was

invariably plainly contracted. Hence I am led to conclude that there

must be some relation between the contraction of this muscle and the

secretion of tears. Can you tell me what this relation is? Does the

orbicularis press against, and so directly stimulate, the lachrymal

gland? As a slight blow on the eye causes, by reflex action, a

copious effusion of tears, can the slight spasmodic contraction of the

orbicularis act like a blow? This seems hardly possible. Does the same

nerve which runs to the orbicularis send off fibrils to the lachrymal

glands; and if so, when the order goes for the muscle to contract,

is nervous force sent sympathetically at the same time to the glands?

(464/3. See "Expression of the Emotions," page 169.)

I should be extremely much obliged if you [would] have the kindness to

give me your opinion on this point.

LETTER 465. TO F.C. DONDERS.

(465/1. Mr. Darwin was indebted to Sir W. Bowman for an introduction to

Professor Donders, whose work on Sir Charles Bell's views is quoted in

the "Expression of the Emotions," pages 160-62.)

Down, June 3rd [1870?].

I do not know how to thank you enough for the very great trouble which

you have taken in writing at such length, and for your kind expressions

towards me. I am particularly obliged for the abstract with respect to

Sir C. Bell's views (465/2. See "Expression of the Emotions," pages 158

et seq.: Sir Charles Bell's view is that adopted by Darwin--viz. that

the contraction of the muscles round the eyes counteracts the gorging of

the parts during screaming, etc. The essay of Donders is, no doubt,

"On the Action of the Eyelids in Determination of Blood from Expiratory

Effort" in Beale's "Archives of Medicine," Volume V., 1870, page 20,

which is a translation of the original in Dutch.), as I shall now

proceed with some confidence; but I am intensely curious to read your

essay in full when translated and published, as I hope, in the "Dublin

Journal," as you speak of the weak point in the case--viz., that

injuries are not known to follow from the gorging of the eye with blood.

I may mention that my son and his friend at a military academy tell me

that when they perform certain feats with their heads downwards their

faces become purple and veins distended, and that they then feel an

uncomfortable sensation in their eyes; but that as it is necessary for

them to see, they cannot protect their eyes by closing the eyelids. The

companions of one young man, who naturally has very prominent eyes, used

to laugh at him when performing such feats, and declare that some day

both eyes would start out of his head.

Your essay on the physiological and anatomical relations between the

contraction of the orbicular muscles and the secretion of tears is

wonderfully clear, and has interested me greatly. I had not thought

about irritating substances getting into the nose during vomiting; but

my clear impression is that mere retching causes tears. I will, however,

try to get this point ascertained. When I reflect that in vomiting

(subject to the above doubt), in violent coughing from choking, in

yawning, violent laughter, in the violent downward action of the

abdominal muscle...and in your very curious case of the spasms (465/3.

In some cases a slight touch to the eye causes spasms of the orbicularis

muscle, which may continue for so long as an hour, being accompanied by

a flow of tears. See "Expression of the Emotions," page 166.)--that in

all these cases the orbicular muscles are strongly and unconsciously

contracted, and that at the same time tears often certainly flow, I must

think that there is a connection of some kind between these phenomena;

but you have clearly shown me that the nature of the relation is at

present quite obscure.

LETTER 466. TO A.D. BARTLETT. 6, Queen Anne Street, W., December 19th

[1870?].

I was with Mr. Wood this morning, and he expressed himself strongly

about your and your daughter's kindness in aiding him. He much wants

assistance on another point, and if you would aid him, you would greatly

oblige me. You know well the appearance of a dog when approaching

another dog with hostile intentions, before they come close together.

The dog walks very stiffly, with tail rigid and upright, hair on back

erected, ears pointed and eyes directed forwards. When the dog attacks

the other, down go the ears, and the canines are uncovered. Now, could

you anyhow arrange so that one of your dogs could see a strange dog from

a little distance, so that Mr. Wood could sketch the former attitude,

viz., of the stiff gesture with erected hair and erected ears. (466/1.

In Chapter II. of the "Expression of the Emotions" there are sketches

of dogs in illustration of the "Principle of Antithesis," drawn by Mr.

Riviere and by Mr. A. May (figures 5-8). Mr. T.W. Wood supplied similar

drawings of a cat (figures 9, 10), also a sketch of the head of a

snarling dog (figure 14).) And then he could afterwards sketch the same

dog, when fondled by his master and wagging his tail with drooping ears.

These two sketches I want much, and it would be a great favour to Mr.

Wood, and myself, if you could aid him.

P.S.--When a horse is turned out into a field he trots with high,

elastic steps, and carries his tail aloft. Even when a cow frisks about

she throws up her tail. I have seen a drawing of an elephant, apparently

trotting with high steps, and with the tail erect. When the elephants in

the garden are turned out and are excited so as to move quickly, do they

carry their tails aloft? How is this with the rhinoceros? Do not trouble

yourself to answer this, but I shall be in London in a couple of months,

and then perhaps you will be able to answer this trifling question. Or,

if you write about wolves and jackals turning round, you can tell me

about the tails of elephants, or of any other animals. (466/2. In the

"Expression of the Emotions," page 44, reference is made under the head

of "Associated habitual movements in the lower animals," to dogs and

other animals turning round and round and scratching the ground with

their fore-paws when they wish to go to sleep on a carpet, or other

similar surface.)

LETTER 467. TO A.D. BARTLETT. Down, January 5th, [1871?]

Many thanks about Limulus. I am going to ask another favour, but I do

not want to trouble you to answer it by letter. When the Callithrix

sciureus screams violently, does it wrinkle up the skin round the eyes

like a baby always does? (467/1. "Humboldt also asserts that the eyes

of the Callithrix sciureus 'instantly fill with tears when it is seized

with fear'; but when this pretty little monkey in the Zoological Gardens

was teased, so as to cry out loudly, this did not occur. I do not,

however, wish to throw the least doubt on the accuracy of Humboldt's

statement." ("The Expression of the Emotions in Man and Animals,"

1872, page 137.) When thus screaming do the eyes become suffused with

moisture? Will you ask Sutton to observe carefully? (467/2. One of the

keepers who made many observations on monkeys for Mr. Darwin.) Could you

make it scream without hurting it much? I should be truly obliged some

time for this information, when in spring I come to the Gardens.

LETTER 468. TO W. OGLE. Down, March 7th [1871].

I wrote to Tyndall, but had no clear answer, and have now written to

him again about odours. (468/1. Dr. Ogle's work on the Sense of Smell

("Medico-Chirurgical Trans." LIII., page 268) is referred to in the

"Expression of the Emotions," page 256.) I write now to ask you to be so

kind (if there is no objection) to tell me the circumstances under which

you saw a man arrested for murder. (468/2. Given in the "Expression of

the Emotions," page 294.) I say in my notes made from your conversation:

utmost horror--extreme pallor--mouth relaxed and open--general

prostration--perspiration--muscle of face contracted--hair observed on

account of having been dyed, and apparently not erected. Secondly, may

I quote you that you have often (?) seen persons (young or old? men

or women?) who, evincing no great fear, were about to undergo severe

operation under chloroform, showing resignation by (alternately?)

folding one open hand over the other on the lower part of chest (whilst

recumbent?)--I know this expression, and think I ought to notice it.

Could you look out for an additional instance?

I fear you will think me very troublesome, especially when I remind you

(not that I am in a hurry) about the Eustachian tube.

LETTER 469. TO J. JENNER WEIR. Down, June 14th [1870].

As usual, I am going to beg for information. Can you tell me whether

any Fringillidae or Sylviadae erect their feathers when frightened or

enraged? (469/1. See "Expression of the Emotions," page 99.) I want to

show that this expression is common to all or most of the families of

birds. I know of this only in the fowl, swan, tropic-bird, owl, ruff and

reeve, and cuckoo. I fancy that I remember having seen nestling birds

erect their feathers greatly when looking into nests, as is said to

be the case with young cuckoos. I should much like to know whether

nestlings do really thus erect their feathers. I am now at work on

expression in animals of all kinds, and birds; and if you have any hints

I should be very glad for them, and you have a rich wealth of facts of

all kinds. Any cases like the following: the sheldrake pats or dances on

the tidal sands to make the sea-worms come out; and when Mr. St. John's

tame sheldrakes came to ask for their dinners they used to pat the

ground, and this I should call an expression of hunger and impatience.

How about the Quagga case? (469/2. See Letter 235, Volume I.)

I am working away as hard as I can on my book; but good heavens, how

slow my progress is.

LETTER 470. TO F.C. DONDERS. Down, March 18th, 1871.

Very many thanks for your kind letter. I have been interested by what

you tell me about your views published in 1848, and I wish I could

read your essay. It is clear to me that you were as near as possible in

preceding me on the subject of Natural Selection.

You will find very little that is new to you in my last book; whatever

merit it may possess consists in the grouping of the facts and in

deductions from them. I am now at work on my essay on Expression.

My last book fatigued me much, and I have had much correspondence,

otherwise I should have written to you long ago, as I often intended to

tell you in how high a degree your essay published in Beale's Archives

interested me. (470/1. Beale's "Archives of Medicine," Volume V., 1870.)

I have heard others express their admiration at the complete manner in

which you have treated the subject. Your confirmation of Sir C. Bell's

rather loose statement has been of paramount importance for my work.

(470/2. On the contraction of the muscles surrounding the eye. See

"Expression of the Emotions," page 158. See Letters 464, 465.) You told

me that I might make further enquiries from you.

When a person is lost in meditation his eyes often appear as if fixed

on a distant object (470/3. The appearance is due to divergence of the

lines of vision produced by muscular relaxation. See "Expression of the

Emotions," Edition II., page 239.), and the lower eyelids may be seen to

contract and become wrinkled. I suppose the idea is quite fanciful, but

as you say that the eyeball advances in adaptation for vision for close

objects, would the eyeball have to be pushed backwards in adaptation for

distant objects? (470/4. Darwin seems to have misunderstood a remark of

Donders.) If so, can the wrinkling of the lower eyelids, which has often

perplexed me, act in pushing back the eyeball?

But, as I have said, I daresay this is quite fanciful. Gratiolet says

that the pupil contracts in rage, and dilates enormously in terror.

(470/5. See "Expression of the Emotions," Edition II., page 321.) I have

not found this great anatomist quite trustworthy on such points, and am

making enquiries on this subject. But I am inclined to believe him, as

the old Scotch anatomist Munro says, that the iris of parrots contracts

and dilates under passions, independently of the amount of light. Can

you give any explanation of this statement? When the heart beats hard

and quick, and the head becomes somewhat congested with blood in any

illness, does the pupil contract? Does the pupil dilate in incipient

faintness, or in utter prostration, as when after a severe race a man

is pallid, bathed in perspiration, with all his muscles quivering? Or in

extreme prostration from any illness?

LETTER 471. TO W. TURNER. Down, March 28th [1871].

I am much obliged for your kind note, and especially for your offer of

sending me some time corrections, for which I shall be truly grateful. I

know that there are many blunders to which I am very liable. There is

a terrible one confusing the supra-condyloid foramen with another one.

(471/1. In the first edition of the "Descent of Man," I., page 28,

in quoting Mr. Busk "On the Caves of Gibraltar," Mr. Darwin confuses

together the inter-condyloid foramen in the humerus with the

supra-condyloid foramen. His attention was called to the mistake by

Sir William Turner, to whom he had been previously indebted for other

information on the anatomy of man. The error is one, as Sir William

Turner points out in a letter, "which might easily arise where the

writer is not minutely acquainted with human anatomy." In speaking of

his correspondence with Darwin, Sir William remarks on a characteristic

of Darwin's method of asking for information, namely, his care in

avoiding leading questions.) This, however, I have corrected in all the

copies struck off after the first lot of 2500. I daresay there will be

a new edition in the course of nine months or a year, and this I will

correct as well as I can. As yet the publishers have kept up type,

and grumble dreadfully if I make heavy corrections. I am very far from

surprised that "you have not committed yourself to full acceptation" of

the evolution of man. Difficulties and objections there undoubtedly are,

enough and to spare, to stagger any cautious man who has much knowledge

like yourself.

I am now at work at my hobby-horse essay on Expression, and I have been

reading some old notes of yours. In one you say it is easy to see that

the spines of the hedgehog are moved by the voluntary panniculus. Now,

can you tell me whether each spine has likewise an oblique unstriped

or striped muscle, as figured by Lister? (472/2. "Expression of the

Emotions," page 101.) Do you know whether the tail-coverts of peacock or

tail of turkey are erected by unstriped or striped muscles, and whether

these are homologous with the panniculus or with the single oblique

unstriped muscles going to each separate hair in man and many animals? I

wrote some time ago to Kolliker to ask this question (and in relation to

quills of porcupine), and I received a long and interesting letter, but

he could not answer these questions. If I do not receive any answer (for

I know how busy you must be), I will understand you cannot aid me.

I heard yesterday that Paget was very ill; I hope this is not true. What

a loss he would be; he is so charming a man.

P.S.--As I am writing I will trouble you with one other question. Have

you seen anything or read of any facts which could induce you to think

that the mind being intently and long directed to any portion of

the skin (or, indeed, any organ) would influence the action of the

capillaries, causing them either to contract or dilate? Any information

on this head would be of great value to me, as bearing on blushing.

If I remember right, Paget seems to be a great believer in the influence

of the mind in the nutrition of parts, and even in causing disease. It

is awfully audacious on my part, but I remember thinking (with respect

to the latter assertion on disease) when I read the passage that it

seemed rather fanciful, though I should like to believe in it. Sir H.

Holland alludes to this subject of the influence of the mind on local

circulation frequently, but gives no clear evidence. (472/3. Ibid.,

pages 339 et seq.)

LETTER 472. TO W. TURNER. Down, March 29th [1871].

Forgive me for troubling you with one line. Since writing my P.S. I have

read the part on the influence of the nervous system on the nutrition of

parts in your last edition of Paget's "Lectures." (472/1. "Lectures on

Surgical Pathology," Edition III., revised by Professor Turner, 1870.)

I had not read before this part in this edition, and I see how foolish I

was. But still, I should be extremely grateful for any hint or

evidence of the influence of mental attention on the capillary or

local circulation of the skin, or of any part to which the mind may be

intently and long directed. For instance, if thinking intently about a

local eruption on the skin (not on the face, for shame might possibly

intervene) caused it temporarily to redden, or thinking of a tumour

caused it to throb, independently of increased heart action.

LETTER 473. TO HUBERT AIRY.

(473/1. Dr. Airy had written to Mr. Darwin on April 3rd:--

"With regard to the loss of voluntary movement of the ears in man and

monkey, may I ask if you do not think it might have been caused, as it

is certainly compensated, by the facility and quickness in turning the

head, possessed by them in virtue of their more erect stature, and the

freedom of the atlanto-axial articulation? (in birds the same end is

gained by the length and flexibility of the neck.) The importance, in

case of danger, of bringing the eyes to help the ears would call for a

quick turn of the head whenever a new sound was heard, and so would tend

to make superfluous any special means of moving the ears, except in the

case of quadrupeds and the like, that have great trouble (comparatively

speaking) in making a horizontal turn of the head--can only do it by a

slow bend of the whole neck." (473/2. We are indebted to Dr. Airy for

furnishing us with a copy of his letter to Mr. Darwin, the original of

which had been mislaid.)

Down, April 5th [1871].

I am greatly obliged for your letter. Your idea about the easy turning

of the head instead of the ears themselves strikes me as very good, and

quite new to me, and I will keep it in mind; but I fear that there are

some cases opposed to the notion.

If I remember right the hedgehog has very human ears, but birds support

your view, though lizards are opposed to it.

Several persons have pointed out my error about the platysma. (473/3.

The error in question occurs on page 19 of the "Descent of Man," Edition

I., where it is stated that the Platysma myoides cannot be voluntarily

brought into action. In the "Expression of the Emotions" Darwin remarks

that this muscle is sometimes said not to be under voluntary control,

and he shows that this is not universally true.) Nor can I remember how

I was misled. I find I can act on this muscle myself, now that I know

the corners of the mouth have to be drawn back. I know of the case of a

man who can act on this muscle on one side, but not on the other; yet

he asserts positively that both contract when he is startled. And this

leads me to ask you to be so kind as to observe, if any opportunity

should occur, whether the platysma contracts during extreme terror,

as before an operation; and secondly, whether it contracts during a

shivering fit. Several persons are observing for me, but I receive most

discordant results.

I beg you to present my most respectful and kind compliments to your

honoured father [Sir G.B. Airy].

LETTER 474. TO FRANCIS GALTON.

(474/1. Mr. Galton had written on November 7th, 1872, offering to send

to various parts of Africa Darwin's printed list of questions intended

to guide observers on expression. Mr. Galton goes on: "You do not,

I think, mention in "Expression" what I thought was universal among

blubbering children (when not trying to see if harm or help was coming

out of the corner of one eye) of pressing the knuckles against the

eyeballs, thereby reinforcing the orbicularis.")

Down, November 8th [1872].

Many thanks for your note and offer to send out the queries; but my

career is so nearly closed that I do not think it worth while. What

little more I can do shall be chiefly new work. I ought to have thought

of crying children rubbing their eyes with their knuckles, but I did not

think of it, and cannot explain it. As far as my memory serves, they do

not do so whilst roaring, in which case compression would be of use. I

think it is at the close of the crying fit, as if they wished to stop

their eyes crying, or possibly to relieve the irritation from the salt

tears. I wish I knew more about the knuckles and crying.

What a tremendous stir-up your excellent article on prayer has made in

England and America! (474/2. The article entitled "Statistical Inquiries

into the Efficacy of Prayer" appeared in the "Fortnightly Review," 1872.

In Mr. Francis Galton's book on "Enquiries into Human Faculty and its

Development," London, 1883, a section (pages 277-94) is devoted to a

discussion on the "Objective Efficacy of Prayer.")

LETTER 475. TO F.C. DONDERS.

(475/1. We have no means of knowing whether the observations suggested

in the following letter were made--if not, the suggestion is worthy of

record.)

Down, December 21st, 1872.

You will have received some little time ago my book on Expression, in

writing which I was so deeply indebted to your kindness. I want now to

beg a favour of you, if you have the means to grant it. A clergyman, the

head of an institution for the blind in England (475/2. The Rev. R.H.

Blair, Principal of the Worcester College: "Expression of the Emotions,"

Edition II., page 237.), has been observing the expression of those born

blind, and he informs me that they never or very rarely frown. He kept

a record of several cases, but at last observed a frown on two of the

children who he thought never frowned; and then in a foolish manner tore

up his notes, and did not write to me until my book was published. He

may be a bad observer and altogether mistaken, but I think it would

be worth while to ascertain whether those born blind, when young, and

whilst screaming violently, contract the muscles round the eyes like

ordinary infants. And secondly, whether in after years they rarely or

never frown. If it should prove true that infants born blind do not

contract their orbicular muscles whilst screaming (though I can hardly

believe it) it would be interesting to know whether they shed tears as

copiously as other children. The nature of the affection which causes

blindness may possibly influence the contraction of the muscles, but on

all such points you will judge infinitely better than I can. Perhaps you

could get some trustworthy superintendent of an asylum for the blind to

attend to this subject. I am sure that you will forgive me asking this

favour.

LETTER 476. TO D. HACK TUKE. Down, December 22nd, 1872.

I have now finished your book, and have read it with great interest.

(476/1. "Influence of the Mind upon the Body. Designed to elucidate the

Power of the Imagination." 1872.)

Many of your cases are very striking. As I felt sure would be the case,

I have learnt much from it; and I should have modified several passages

in my book on Expression, if I had had the advantage of reading your

work before my publication. I always felt, and said so a year ago to

Professor Donders, that I had not sufficient knowledge of Physiology to

treat my subject in a proper way.

With many thanks for the interest which I have felt in reading your

work...

LETTER 477. TO A.R. WALLACE. Down, January 10th [1873].

I have read your Review with much interest, and I thank you sincerely

for the very kind spirit in which it is written. I cannot say that I am

convinced by your criticisms. (477/1. "Quarterly Journal of Science,"

January, 1873, page 116: "I can hardly believe that when a cat, lying

on a shawl or other soft material, pats or pounds it with its feet, or

sometimes sucks a piece of it, it is the persistence of the habit of

pressing the mammary glands and sucking during kittenhood." Mr. Wallace

goes on to say that infantine habits are generally completely lost in

adult life, and that it seems unlikely that they should persist in a few

isolated instances.) If you have ever actually observed a kitten sucking

and pounding, with extended toes, its mother, and then seen the same

kitten when a little older doing the same thing on a soft shawl, and

ultimately an old cat (as I have seen), and do not admit that it is

identically the same action, I am astonished. With respect to the

decapitated frog, I have always heard of Pfluger as a most trustworthy

observer. (477/2. Mr. Wallace speaks of "a readiness to accept the most

marvellous conclusions or interpretations of physiologists on what

seem very insufficient grounds," and he goes on to assert that the frog

experiment is either incorrectly recorded or else that it "demonstrates

volition, and not reflex action.") If, indeed, any one knows a frog's

habits so well as to say that it never rubs off a bit of leaf or other

object which may stick to its thigh, in the same manner as it did the

acid, your objection would be valid. Some of Flourens' experiments, in

which he removed the cerebral hemispheres from a pigeon, indicate that

acts apparently performed consciously can be done without consciousness.

I presume through the force of habit, in which case it would appear that

intellectual power is not brought into play. Several persons have made

suggestions and objections as yours about the hands being held up

in astonishment; if there was any straining of the muscles, as with

protruded arms under fright, I would agree; as it is I must keep to

my old opinion, and I dare say you will say that I am an obstinate old

blockhead. (477/3. The raising of the hands in surprise is explained

("Expression of Emotions," Edition I., page 287) on the doctrine of

antithesis as being the opposite of listlessness. Mr. Wallace's view

(given in the 2nd edition of "Expression of the Emotions," page 300) is

that the gesture is appropriate to sudden defence or to the giving of

aid to another person.)

The book has sold wonderfully; 9,000 copies have now been printed.

LETTER 478. TO CHAUNCEY WRIGHT. Down, September 21st, 1874.

I have read your long letter with the greatest interest, and it was

extremely kind of you to take such great trouble. Now that you call my

attention to the fact, I well know the appearance of persons moving

the head from side to side when critically viewing any object; and I am

almost sure that I have seen the same gesture in an affected person when

speaking in exaggerated terms of some beautiful object not present.

I should think your explanation of this gesture was the true one. But

there seems to me a rather wide difference between inclining or moving

the head laterally, and moving it in the same plane, as we do in

negation, and, as you truly add, in disapprobation. It may, however, be

that these two movements of the head have been confounded by travellers

when speaking of the Turks. Perhaps Prof. Lowell would remember whether

the movement was identically the same. Your remarks on the effects of

viewing a sunset, etc., with the head inverted are very curious. (478/1.

The letter dated September 3rd, 1874, is published in Mr. Thayer's

"Letters" of Chauncey Wright, privately printed, Cambridge, Mass., 1878.

Wright quotes Mr. Sophocles, a native of Greece, at the time Professor

of Modern and Ancient Greek at Harvard University, to the effect that

the Turks do not express affirmation by a shake of the head, but by a

bow or grave nod, negation being expressed by a backward nod. From

the striking effect produced by looking at a landscape with the head

inverted, or by looking at its reflection, Chauncey Wright was led to

the lateral movement of the head, which is characteristic of critical

inspection--eg. of a picture. He thinks that in this way a gesture of

deliberative assent arose which may have been confused with our ordinary

sign of negation. He thus attempts to account for the contradictions

between Lieber's statement that a Turk or Greek expresses "yes" by a

shake of the head, and the opposite opinion of Prof. Sophocles, and

lastly, Mr. Lowell's assertion that in Italy our negative shake of the

head is used in affirmation (see "Expression of the Emotions," Edition

II., page 289).) We have a looking-glass in the drawing-room opposite

the flower-garden, and I have often been struck how extremely pretty

and strange the flower garden and surrounding bushes appear when thus

viewed. Your letter will be very useful to me for a new edition of my

Expression book; but this will not be for a long time, if ever, as the

publisher was misled by the very large sale at first, and printed far

too many copies.

I daresay you intend to publish your views in some essay, and I think

you ought to do so, for you might make an interesting and instructive

discussion.

I have been half killing myself of late with microscopical work on

plants. I begin to think that they are more wonderful than animals.

P.S., January 29th, 1875.--You will see that by a stupid mistake in

the address this letter has just been returned to me. It is by no

means worth forwarding, but I cannot bear that you should think me

so ungracious and ungrateful as not to have thanked you for your long

letter.

As I forget whether "Cambridge" is sufficient address, I will send this

through Asa Gray.

(PLATE: CHARLES LYELL. Engraved by G.I. (J). Stodart from a photograph.)

CHAPTER 2.IX. GEOLOGY, 1840-1882.

I. Vulcanicity and Earth-movements.--II. Ice-action.--III. The Parallel

Roads of Glen Roy.--IV. Coral Reefs, Fossil and Recent.--V. Cleavage

and Foliation.--VI. Age of the World.--VII. Geological Action of

Earthworms.--VIII. Miscellaneous.

2.IX.I. VULCANICITY AND EARTH-MOVEMENTS, 1840-1881.

LETTER 479. TO DAVID MILNE. 12, Upper Gower Street, Thursday [March]

20th [1840].

I much regret that I am unable to give you any information of the kind

you desire. You must have misunderstood Mr. Lyell concerning the object

of my paper. (479/1. "On the Connexion of certain Volcanic Phenomena,

and on the Formation of Mountain-chains and the Effects of Continental

Elevations." "Trans. Geol. Soc." Volume V., 1840, pages 601-32 [March

7th, 1838].) It is an account of the shock of February, 1835, in Chile,

which is particularly interesting, as it ties most closely together

volcanic eruptions and continental elevations. In that paper I notice a

very remarkable coincidence in volcanic eruptions in S. America at very

distant places. I have also drawn up some short tables showing, as

it appears to me, that there are periods of unusually great volcanic

activity affecting large portions of S. America. I have no record of any

coincidences between shocks there and in Europe. Humboldt, by his table

in the "Pers. Narrative" (Volume IV., page 36, English Translation),

seems to consider the elevation of Sabrina off the Azores as connected

with S. American subterranean activity: this connection appears to be

exceedingly vague. I have during the past year seen it stated that a

severe shock in the northern parts of S. America coincided with one

in Kamstchatka. Believing, then, that such coincidences are purely

accidental, I neglected to take a note of the reference; but I

believe the statement was somewhere in "L'Institut" for 1839. (479/2.

"L'Institut, Journal General des Societes et Travaux Scientifiques de la

France et de l'Etranger," Tome VIII. page 412, Paris, 1840. In a note

on some earthquakes in the province Maurienne it is stated that they

occurred during a change in the weather, and at times when a south wind

followed a north wind, etc.) I was myself anxious to see the list of the

1200 shocks alluded to by you, but I have not been able to find out that

the list has been published. With respect to any coincidences you may

discover between shocks in S. America and Europe, let me venture to

suggest to you that it is probably a quite accurate statement that

scarcely one hour in the year elapses in S. America without an

accompanying shock in some part of that large continent. There are many

regions in which earthquakes take place every three and four days; and

after the severer shocks the ground trembles almost half-hourly for

months. If, therefore, you had a list of the earthquakes of two or

three of these districts, it is almost certain that some of them would

coincide with those in Scotland, without any other connection than mere

chance.

My paper will be published immediately in the "Geological Transactions,"

and I will do myself the pleasure of sending you a copy in the course of

(as I hope) a week or ten days. A large part of it is theoretical, and

will be of little interest to you; but the account of the Concepcion

shock of 1835 will, I think, be worth your perusal. I have understood

from Mr. Lyell that you believe in some connection between the state of

the weather and earthquakes. Under the very peculiar climate of Northern

Chile, the belief of the inhabitants in such connection can hardly, in

my opinion, be founded in error. It must possibly be worth your while to

turn to pages 430-433 in my "Journal of Researches during the Voyage of

the 'Beagle'," where I have stated this circumstance. (479/3. "Journal

of Researches into the Natural History and Geology of the Countries

visited during the Voyage of H.M.S. 'Beagle' round the World." London,

1870, page 351.) On the hypothesis of the crust of the earth resting on

fluid matter, would the influence of the moon (as indexed by the tides)

affect the periods of the shocks, when the force which causes them is

just balanced by the resistance of the solid crust? The fact you mention

of the coincidence between the earthquakes of Calabria and Scotland

appears most curious. Your paper will possess a high degree of interest

to all geologists. I fancied that such uniformity of action, as seems

here indicated, was probably confined to large continents, such as the

Americas. How interesting a record of volcanic phenomena in Iceland

would be, now that you are collecting accounts of every slight trembling

in Scotland. I am astonished at their frequency in that quiet country,

as any one would have called it. I wish it had been in my power to

have contributed in any way to your researches on this most interesting

subject.

LETTER 480. TO L. HORNER. Down, August 29th [1844].

I am greatly obliged for your kind note, and much pleased with its

contents. If one-third of what you say be really true, and not the

verdict of a partial judge (as from pleasant experience I much suspect),

then should I be thoroughly well contented with my small volume which,

small as it is, cost me much time. (480/1. "Geological Observations

on the Volcanic Islands visited during the Voyage of H.M.S. 'Beagle'":

London, 1844. A French translation has been made by Professor Renard

of Ghent, and published by Reinwald of Paris in 1902.) The pleasure

of observation amply repays itself: not so that of composition; and it

requires the hope of some small degree of utility in the end to make up

for the drudgery of altering bad English into sometimes a little better

and sometimes worse. With respect to craters of elevation (480/2.

"Geological Observations," pages 93-6.), I had no sooner printed off

the few pages on that subject than I wished the whole erased. I utterly

disbelieve in Von Buch and de Beaumont's views; but on the other

hand, in the case of the Mauritius and St. Jago, I cannot, perhaps

unphilosophically, persuade myself that they are merely the basal

fragments of ordinary volcanoes; and therefore I thought I would suggest

the notion of a slow circumferential elevation, the central part

being left unelevated, owing to the force from below being spent

and [relieved?] in eruptions. On this view, I do not consider these

so-called craters of elevation as formed by the ejection of ashes,

lava, etc., etc., but by a peculiar kind of elevation acting round and

modified by a volcanic orifice. I wish I had left it all out; I trust

that there are in other parts of the volume more facts and less theory.

The more I reflect on volcanoes, the more I appreciate the importance

of E. de Beaumont's measurements (480/3. Elie de Beaumont's views are

discussed by Sir Charles Lyell both in the "Principles of Geology"

(Edition X., 1867, Volume I. pages 633 et seq.) and in the "Elements

of Geology" (Edition III., 1878, pages 495, 496). See also Darwin's

"Geological Observations," Edition II., 1876, page 107.) (even if

one does not believe them implicitly) of the natural inclination of

lava-streams, and even more the importance of his view of the dikes,

or unfilled fissures, in every volcanic mountain, being the proofs

and measures of the stretching and consequent elevation which all

such mountains must have undergone. I believe he thus unintentionally

explains most of his cases of lava-streams being inclined at a greater

angle than that at which they could have flowed.

But excuse this lengthy note, and once more let me thank you for the

pleasure and encouragement you have given me--which, together with

Lyell's never-failing kindness, will help me on with South America, and,

as my books will not sell, I sometimes want such aid. I have been lately

reading with care A. d'Orbigny's work on South America (480/4. "Voyage

dans l'Amerique Meridionale--execute pendant les annees 1826-33": six

volumes, Paris, 1835-43.), and I cannot say how forcibly impressed I am

with the infinite superiority of the Lyellian school of Geology over

the continental. I always feel as if my books came half out of Lyell's

brain, and that I never acknowledge this sufficiently; nor do I know how

I can without saying so in so many words--for I have always thought that

the great merit of the "Principles" was that it altered the whole tone

of one's mind, and therefore that, when seeing a thing never seen by

Lyell, one yet saw it partially through his eyes--it would have been in

some respects better if I had done this less: but again excuse my long,

and perhaps you will think presumptuous, discussion. Enclosed is a note

from Emma to Mrs. Horner, to beg you, if you can, to give us the great

pleasure of seeing you here. We are necessarily dull here, and can offer

no amusements; but the weather is delightful, and if you could see how

brightly the sun now shines you would be tempted to come. Pray remember

me most kindly to all your family, and beg of them to accept our

proposal, and give us the pleasure of seeing them.

LETTER 481. TO C. LYELL. Down, [September, 1844].

I was glad to get your note, and wanted to hear about your work. I

have been looking to see it advertised; it has been a long task. I had,

before your return from Scotland, determined to come up and see you; but

as I had nothing else to do in town, my courage has gradually eased

off, more especially as I have not been very well lately. We get so many

invitations here that we are grown quite dissipated, but my stomach has

stood it so ill that we are going to have a month's holidays, and go

nowhere.

The subject which I was most anxious to talk over with you I have

settled, and having written sixty pages of my "S. American Geology," I

am in pretty good heart, and am determined to have very little theory

and only short descriptions. The two first chapters will, I think, be

pretty good, on the great gravel terraces and plains of Patagonia and

Chili and Peru.

I am astonished and grieved over D'Orbigny's nonsense of sudden

elevations. (481/1. D'Orbigny's views are referred to by Lyell in

chapter vii. of the "Principles," Volume I. page 131. "This mud [i.e.

the Pampean mud] contains in it recent species of shells, some of them

proper to brackish water, and is believed by Mr. Darwin to be an

estuary or delta deposit. M.A. D'Orbigny, however, has advanced an

hypothesis...that the agitation and displacement of the waters of the

ocean, caused by the elevation of the Andes, gave rise to a deluge, of

which this Pampean mud, which reaches sometimes the height of 12,000

feet, is the result and monument.") I must give you one of his cases:

He finds an old beach 600 feet above sea. He finds STILL ATTACHED to the

rocks at 300 feet six species of truly littoral shells. He finds at 20

to 30 feet above sea an immense accumulation of chiefly littoral shells.

He argues the whole 600 feet uplifted at one blow, because the attached

shells at 300 feet have not been displaced. Therefore when the sea

formed a beach at 600 feet the present littoral shells were attached

to rocks at 300 feet depth, and these same shells were accumulating by

thousands at 600 feet.

Hear this, oh Forbes. Is it not monstrous for a professed conchologist?

This is a fair specimen of his reasoning.

One of his arguments against the Pampas being a slow deposit, is that

mammifers are very seldom washed by rivers into the sea!

Because at 12,000 feet he finds the same kind of clay with that of

the Pampas he never doubts that it is contemporaneous with the Pampas

[debacle?] which accompanied the right royal salute of every volcano

in the Cordillera. What a pity these Frenchmen do not catch hold of

a comet, and return to the good old geological dramas of Burnett and

Whiston. I shall keep out of controversy, and just give my own facts. It

is enough to disgust one with Geology; though I have been much pleased

with the frank, decided, though courteous manner with which D'Orbigny

disputes my conclusions, given, unfortunately, without facts, and

sometimes rashly, in my journal.

Enough of S. America. I wish you would ask Mr. Horner (for I forgot to

do so, and am unwilling to trouble him again) whether he thinks there

is too much detail (quite independent of the merits of the book) in my

volcanic volume; as to know this would be of some real use to me. You

could tell me when we meet after York, when I will come to town. I had

intended being at York, but my courage has failed. I should much like

to hear your lecture, but still more to read it, as I think reading is

always better than hearing.

I am very glad you talk of a visit to us in the autumn if you can spare

the time. I shall be truly glad to see Mrs. Lyell and yourself here; but

I have scruples in asking any one--you know how dull we are here. Young

Hooker (481/2. Sir J.D. Hooker.) talks of coming; I wish he might meet

you,--he appears to me a most engaging young man.

I have been delighted with Prescott, of which I have read Volume I. at

your recommendation; I have just been a good deal interested with W.

Taylor's (of Norwich) "Life and Correspondence."

On your return from York I shall expect a great supply of Geological

gossip.

LETTER 482. TO C. LYELL. [October 3rd, 1846.]

I have been much interested with Ramsay, but have no particular

suggestions to offer (482/1. "On the Denudation of South Wales and the

Adjacent Counties of England." A.C. Ramsay, "Mem. Geol. Survey Great

Britain," Volume I., London, 1846.); I agree with all your remarks made

the other day. My final impression is that the only argument against

him is to tell him to read and re-read the "Principles," and if not

then convinced to send him to Pluto. Not but what he has well read the

"Principles!" and largely profited thereby. I know not how carefully you

have read this paper, but I think you did not mention to me that he does

(page 327) (482/2. Ramsay refers the great outlines of the country to

the action of the sea in Tertiary times. In speaking of the denudation

of the coast, he says: "Taking UNLIMITED time into account, we can

conceive that any extent of land might be so destroyed...If to this be

added an EXCEEDINGLY SLOW DEPRESSION of the land and sea bottom, the

wasting process would be materially assisted by this depression" (loc.

cit., page 327).) believe that the main part of his great denudation

was effected during a vast (almost gratuitously assumed) slow Tertiary

subsidence and subsequent Tertiary oscillating slow elevation. So

our high cliff argument is inapplicable. He seems to think his great

subsidence only FAVOURABLE for great denudation. I believe from

the general nature of the off-shore sea's bottoms that it is almost

necessary; do look at two pages--page 25 of my S. American volume--on

this subject. (482/3. "Geological Observations on S. America," 1846,

page 25. "When viewing the sea-worn cliffs of Patagonia, in some parts

between 800 and 900 feet in height, and formed of horizontal Tertiary

strata, which must once have extended far seaward...a difficulty often

occurred to me, namely, how the strata could possibly have been removed

by the action of the sea at a considerable depth beneath its surface."

The cliffs of St. Helena are referred to in illustration of the same

problem; speaking of these, Darwin adds: "Now, if we had any reason

to suppose that St. Helena had, during a long period, gone on slowly

subsiding, every difficulty would be removed...I am much inclined to

suspect that we shall hereafter find in all such cases that the land

with the adjoining bed of the sea has in truth subsided..." (loc. cit.,

pages 25-6).)

The foundation of his views, viz., of one great sudden upheaval, strikes

me as threefold. First, to account for the great dislocations. This

strikes me as the odder, as he admits that a little northwards there

were many and some violent dislocations at many periods during the

accumulation of the Palaeozoic series. If you argue against him, allude

to the cool assumption that petty forces are conflicting: look at

volcanoes; look at recurrent similar earthquakes at same spots; look at

repeatedly injected intrusive masses. In my paper on Volcanic Phenomena

in the "Geol. Transactions." (482/4. "On the Connection of certain

Volcanic Phenomena, and on the Formation of Mountain-chains and the

Effects of Continental Elevations." "Geol. Soc. Proc." Volume II., pages

654-60, 1838; "Trans. Geol. Soc." Volume V., pages 601-32, 1842. [Read

March 7th, 1838.]) I have argued (and Lonsdale thought well of the

argument, in favour, as he remarked, of your original doctrine) that if

Hopkins' views are correct, viz., that mountain chains are subordinate

consequences to changes of level in mass, then, as we have evidence of

such horizontal movements in mass having been slow, the foundation of

mountain chains (differing from volcanoes only in matter being injected

instead of ejected) must have been slow.

Secondly, Ramsay has been influenced, I think, by his Alpine insects;

but he is wrong in thinking that there is any necessary connection

of tropics and large insects--videlicet--Galapagos Arch., under the

equator. Small insects swarm in all parts of tropics, though accompanied

generally with large ones.

Thirdly, he appears influenced by the absence of newer deposits on the

old area, blinded by the supposed necessity of sediment accumulating

somewhere near (as no doubt is true) and being PRESERVED--an example,

as I think, of the common error which I wrote to you about. The

preservation of sedimentary deposits being, as I do not doubt, the

exception when they are accumulated during periods of elevation or of

stationary level, and therefore the preservation of newer deposits would

not be probable, according to your view that Ramsay's great Palaeozoic

masses were denuded, whilst slowly rising. Do pray look at end of

Chapter II., at what little I have said on this subject in my S.

American volume. (482/5. The second chapter of the "Geological

Observations" concludes with a Summary on the Recent Elevations of the

West Coast of South America, (page 53).)

I do not think you can safely argue that the whole surface was probably

denuded at same time to the level of the lateral patches of Magnesian

conglomerate.

The latter part of the paper strikes me as good, but obvious.

I shall send him my S. American volume for it is curious on how many

similar points we enter, and I modestly hope it may be a half-oz. weight

towards his conversion to better views. If he would but reject his great

sudden elevations, how sound and good he would be. I doubt whether this

letter will be worth the reading.

LETTER 483. TO C. LYELL. Down [September 4th, 1849].

It was very good of you to write me so long a letter, which has

interested me much. I should have answered it sooner, but I have not

been very well for the few last days. Your letter has also flattered

me much in many points. I am very glad you have been thinking over the

relation of subsidence and the accumulation of deposits; it has to me

removed many great difficulties; please to observe that I have carefully

abstained from saying that sediment is not deposited during periods of

elevation, but only that it is not accumulated to sufficient thickness

to withstand subsequent beach action; on both coasts of S. America the

amount of sediment deposited, worn away, and redeposited, oftentimes

must have been enormous, but still there have been no wide formations

produced: just read my discussion (page 135 of my S. American book

(483/1. See Letter 556, note. The discussion referred to ("Geological

Observations on South America," 1846) deals with the causes of

the absence of recent conchiferous deposits on the coasts of South

America.)) again with this in your mind. I never thought of your

difficulty (i.e. in relation to this discussion) of where was the land

whence the three miles of S. Wales strata were derived! (483/2. In

his classical paper "On the Denudation of South Wales and the Adjacent

Counties of England" ("Mem. Geol. Survey," Volume I., page 297, 1846),

Ramsay estimates the thickness of certain Palaeozoic formations in South

Wales, and calculates the cubic contents of the strata in the area they

now occupy together with the amount removed by denudation; and he goes

on to say that it is evident that the quantity of matter employed to

form these strata was many times greater than the entire amount of solid

land they now represent above the waves. "To form, therefore, so great

a thickness, a mass of matter of nearly equal cubic contents must have

been worn by the waves and the outpourings of rivers from neighbouring

lands, of which perhaps no original trace now remains" (page 334.)) Do

you not think that it may be explained by a form of elevation which I

have always suspected to have been very common (and, indeed, had once

intended getting all facts together), viz. thus?--

(Figure 1. A line drawing of ocean bottom subsiding beside mountains and

continent rising.)

The frequency of a DEEP ocean close to a rising continent bordered with

mountains, seems to indicate these opposite movements of rising and

sinking CLOSE TOGETHER; this would easily explain the S. Wales and

Eocene cases. I will only add that I should think there would be a

little more sediment produced during subsidence than during elevation,

from the resulting outline of coast, after long period of rise. There

are many points in my volume which I should like to have discussed with

you, but I will not plague you: I should like to hear whether you think

there is anything in my conjecture on Craters of Elevation (483/3. In

the "Geological Observations on Volcanic Islands," 1844, pages 93-6,

Darwin speaks of St. Helena, St. Jago and Mauritius as being bounded by

a ring of basaltic mountains which he regards as "Craters of Elevation."

While unable to accept the theory of Elie de Beaumont and attribute

their formation to a dome-shaped elevation and consequent arching of the

strata, he recognises a "very great difficulty in admitting that these

basaltic mountains are merely the basal fragments of great volcanoes,

of which the summits have been either blown off, or, more probably,

swallowed by subsidence." An explanation of the origin and structure of

these volcanic islands is suggested which would keep them in the class

of "Craters of Elevation," but which assumes a slow elevation, during

which the central hollow or platform having been formed "not by the

arching of the surface, but simply by that part having been upraised to

a less height."); I cannot possibly believe that Saint Jago or Mauritius

are the basal fragments of ordinary volcanoes; I would sooner even admit

E. de Beaumont's views than that--much as I would sooner in my own mind

in all cases follow you. Just look at page 232 in my "S. America" for a

trifling point, which, however, I remember to this day relieved my

mind of a considerable difficulty. (483/4. This probably refers to

a paragraph (page 232) "On the Eruptive Sources of the Porphyritic

Claystone and Greenstone Lavas." The opinion is put forward that "the

difficulty of tracing the streams of porphyries to their ancient and

doubtless numerous eruptive sources, may be partly explained by the very

general disturbance which the Cordillera in most parts has suffered";

but, Darwin adds, "a more specific cause may be that 'the original

points of eruption tend to become the points of injection'...On this

view of there being a tendency in the old points of eruption to become

the points of subsequent injection and disturbance, and consequently of

denudation, it ceases to be surprising that the streams of lava in the

porphyritic claystone conglomerate formation, and in other analogous

cases, should most rarely be traceable to their actual sources." The

latter part of this letter is published in "Life and Letters," I.,

pages 377, 378.) I remember being struck with your discussion on the

Mississippi beds in relation to Pampas, but I should wish to read them

over again; I have, however, re-lent your work to Mrs. Rich, who, like

all whom I have met, has been much interested by it. I will stop about

my own Geology. But I see I must mention that Scrope did suggest (and I

have alluded to him, page 118 (483/5. "Geological Observations," Edition

II., 1876. Chapter VI. opens with a discussion "On the Separation of the

Constituent Minerals of Lava, according to their Specific Gravities."

Mr. Darwin calls attention to the fact that Mr. P. Scrope had speculated

on the subject of the separation of the trachytic and basaltic series

of lavas (page 113).), but without distinct reference and I fear not

sufficiently, though I utterly forgot what he wrote) the separation of

basalt and trachyte; but he does not appear to have thought about the

crystals, which I believe to be the keystone of the phenomenon. I cannot

but think this separation of the molten elements has played a great part

in the metamorphic rocks: how else could the basaltic dykes have come in

the great granitic districts such as those of Brazil? What a wonderful

book for labour is d'Archiac!...(483/6. Possibly this refers to

d'Archiac's "Histoire des Progres de la Geologie," 1848.)

LETTER 484. TO LADY LYELL. Down, Wednesday night [1849?].

I am going to beg a very very great favour of you: it is to translate

one page (and the title) of either Danish or Swedish or some such

language. I know not to whom else to apply, and I am quite dreadfully

interested about the barnacles therein described. Does Lyell know Loven,

or his address and title? for I must write to him. If Lyell knows him I

would use his name as introduction; Loven I know by name as a first-rate

naturalist.

Accidentally I forgot to give you the "Footsteps," which I now return,

having ordered a copy for myself.

I sincerely hope the "Craters of Denudation" prosper; I pin my faith to

this view. (484/1. "On Craters of Denudation, with Observations on the

Structure and Growth of Volcanic Cones." "Proc. Geol. Soc." Volume VI.,

1850, pages 207-34. In a letter to Bunbury (January 17th, 1850)

Lyell wrote:..."Darwin adopts my views as to Mauritius, St. Jago, and

so-called elevation craters, which he has examined, and was puzzled

with."--"Life of Sir Charles Lyell," Volume II., page 158.)

Please tell Sir C. Lyell that outside the crater-like mountains at St.

Jago, even throughout a distance of two or three miles, there has been

much denudation of the older volcanic rocks contemporaneous with those

of the ring of mountains. (484/2. The island of St. Jago, one of the

Cape de Verde group, is fully described in the "Volcanic Islands,"

Chapter 1.)

I hope that you will not find the page troublesome, and that you will

forgive me asking you.

LETTER 485. TO C. LYELL. [November 6th, 1849].

I have been deeply interested in your letter, and so far, at least,

worthy of the time it must have cost you to write it. I have not much to

say. I look at the whole question as settled. Santorin is splendid!

it is conclusive! it is perfect! (485/1. "The Gulf of Santorin, in the

Grecian Archipelago, has been for two thousand years a scene of active

volcanic operations. The largest of the three outer islands of the

groups (to which the general name of Santorin is given) is called Thera

(or sometimes Santorin), and forms more than two-thirds of the circuit

of the Gulf" ("Principles of Geology," Volume II., Edition X., London,

1868, page 65). Lyell attributed "the moderate slope of the beds in

Thera...to their having originally descended the inclined flanks of a

large volcanic cone..."; he refuted the theory of "Elevation Craters" by

Leopold von Buch, which explained the slope of the rocks in a volcanic

mountain by assuming that the inclined beds had been originally

horizontal and subsequently tilted by an explosion.) You have read

Dufrenoy in a hurry, I think, and added to the difficulty--it is

the whole hill or "colline" which is composed of tuff with

cross-stratification; the central boss or "monticule" is simply

trachyte. Now, I have described one tuff crater at Galapagos (page 108)

(485/2. The pages refer to Darwin's "Geological Observations on the

Volcanic Islands, etc." 1844.) which has broken through a great solid

sheet of basalt: why should not an irregular mass of trachyte have

been left in the middle after the explosion and emission of mud which

produced the overlying tuff? Or, again, I see no difficulty in a mass of

trachyte being exposed by subsequent dislocations and bared or cleaned

by rain. At Ascension (page 40), subsequent to the last great aeriform

explosion, which has covered the country with fragments, there have been

dislocations and a large circular subsidence...Do not quote Banks' case

(485/3. This refers to Banks' Cove: see "Volcanic Islands," page 107.)

(for there has been some denudation there), but the "elliptic one"

(page 105), which is 1,500 yards (three-quarters of a nautical mile)

in internal diameter...and is the very one the inclination of whose

mud stream on tuff strata I measured (before I had ever heard the name

Dufrenoy) and found varying from 25 to 30 deg. Albemarle Island, instead

of being a crater of elevation, as Von Buch foolishly guessed, is formed

of four great subaerial basaltic volcanoes (page 103), of one of which

you might like to know the external diameter of the summit or crater

was above three nautical miles. There are no "craters of denudation"

at Galapagos. (485/4. See Lyell "On Craters of Denudation, with

Observations on the Structure and Growth of Volcanic Cones," "Quart.

Journ. Geol. Soc." Volume VI., 1850, page 207.)

I hope you will allude to Mauritius. I think this is the instance on the

largest scale of any known, though imperfectly known.

If I were you I would give up consistency (or, at most, only allude in

note to your old edition) and bring out the Craters of Denudation as

a new view, which it essentially is. You cannot, I think, give it

prominence as a novelty and yet keep to consistency and passages in old

editions. I should grudge this new view being smothered in your address,

and should like to see a separate paper. The one great channel to

Santorin and Palma, etc., etc., is just like the one main channel

being kept open in atolls and encircling barrier reefs, and on the same

principle of water being driven in through several shallow breaches.

I of course utterly reprobate my wild notion of circular elevation;

it is a satisfaction to me to think that I perceived there was a screw

loose in the old view, and, so far, I think I was of some service to

you.

Depend on it, you have for ever smashed, crushed, and abolished craters

of elevation. There must be craters of engulfment, and of explosion

(mere modifications of craters of eruption), but craters of denudation

are the ones which have given rise to all the discussions.

Pray give my best thanks to Lady Lyell for her translation, which was as

clear as daylight to me, including "leglessness."

LETTER 486. TO C. LYELL.

Down [November 20th, 1849].

I remembered the passage in E. de B. [Elie de Beaumont] and have now

re-read it. I have always and do still entirely disbelieve it; in such a

wonderful case he ought to have hammered every inch of rock up to actual

junction; he describes no details of junction, and if I were in your

place I would absolutely dispute the fact of junction (or articulation

as he oddly calls it) on such evidence. I go farther than you; I do not

believe in the world there is or has been a junction between a dike and

stream of lava of exact shape of either (1) or (2) Figure 2].

(Figures 2, 3 and 4.)

If dike gave immediate origin to volcanic vent we should have craters of

[an] elliptic shape [Figure 3]. I believe that when the molten rock in a

dike comes near to the surface, some one two or three points will

always certainly chance to afford an easier passage upward to the actual

surface than along the whole line, and therefore that the dike will be

connected (if the whole were bared and dissected) with the vent by a

column or cone (see my elegant drawing) of lava [Figure 4]. I do not

doubt that the dikes are thus indirectly connected with eruptive vents.

E. de B. seems to have observed many of his T; now without he supposes

the whole line of fissure or dike to have poured out lava (which

implies, as above remarked, craters of an elliptic or almost linear

shape) on both sides, how extraordinarily improbable it is, that there

should have been in a single line of section so many intersections of

points eruption; he must, I think, make his orifices of eruption almost

linear or, if not so, astonishingly numerous. One must refer to what one

has seen oneself: do pray, when you go home, look at the section of a

minute cone of eruption at the Galapagos, page 109 (486/1. "Geological

Observations on Volcanic Islands." London, 1890, page 238.), which is

the most perfect natural dissection of a crater which I have ever heard

of, and the drawing of which you may, I assure you, trust; here the

arching over of the streams as they were poured out over the lip of

the crater was evident, and are now thus seen united to the central

irregular column. Again, at St. Jago I saw some horizontal sections of

the bases of small craters, and the sources or feeders were circular. I

really cannot entertain a doubt that E. de B. is grossly wrong, and that

you are right in your view; but without most distinct evidence I will

never admit that a dike joins on rectangularly to a stream of lava. Your

argument about the perpendicularity of the dike strikes me as good.

The map of Etna, which I have been just looking at, looks like a sudden

falling in, does it not? I am not much surprised at the linear vent

in Santorin (this linear tendency ought to be difficult to a

circular-crater-of-elevation-believer), I think Abich (486/2.

"Geologische Beobachtungen uber die vulkanischen Erscheinungen und

Bildungen in Unter- und Mittel-Italien." Braunschweig, 1841.) describes

having seen the same actual thing forming within the crater of Vesuvius.

In such cases what outline do you give to the upper surface of the lava

in the dike connecting them? Surely it would be very irregular and would

send up irregular cones or columns as in my above splendid drawing.

At the Royal on Friday, after more doubt and misgiving than I almost

ever felt, I voted to recommend Forbes for Royal Medal, and that view

was carried, Sedgwick taking the lead.

I am glad to hear that all your party are pretty well. I know from

experience what you must have gone through. From old age with suffering

death must be to all a happy release. (486/3. This seems to refer to

the death of Sir Charles Lyell's father, which occurred on November 8th,

1849.)

I saw Dan Sharpe the other day, and he told me he had been working at

the mica schist (i.e. not gneiss) in Scotland, and that he was quite

convinced my view was right. You are wrong and a heretic on this point,

I know well.

LETTER 487. TO C.H.L. WOODD. Down, March 4th [1850].

(487/1. The paper was sent in MS., and seems not to have been published.

Mr. Woodd was connected by marriage with Mr. Darwin's cousin, the late

Rev. W. Darwin Fox. It was perhaps in consequence of this that Mr.

Darwin proposed Mr. Woodd for the Geological Society.)

I have read over your paper with attention; but first let me thank you

for your very kind expressions towards myself. I really feel hardly

competent to discuss the questions raised by your paper; I feel the

want of mathematical mechanics. All such problems strike me as awfully

complicated; we do not even know what effect great pressure has on

retarding liquefaction by heat, nor, I apprehend, on expansion. The

chief objection which strikes me is a doubt whether a mass of strata,

when heated, and therefore in some slight degree at least softened,

would bow outwards like a bar of metal. Consider of how many subordinate

layers each great mass would be composed, and the mineralogical changes

in any length of any one stratum: I should have thought that the strata

would in every case have crumpled up, and we know how commonly in

metamorphic strata, which have undergone heat, the subordinate layers

are wavy and sinuous, which has always been attributed to their

expansion whilst heated.

Before rocks are dried and quarried, manifold facts show how extremely

flexible they are even when not at all heated. Without the bowing out

and subsequent filling in of the roof of the cavity, if I understand

you, there would be no subsidence. Of course the crumpling up of the

strata would thicken them, and I see with you that this might compress

the underlying fluidified rock, which in its turn might escape by

a volcano or raise a weaker part of the earth's crust; but I am too

ignorant to have any opinion whether force would be easily propagated

through a viscid mass like molten rock; or whether such viscid mass

would not act in some degree like sand and refuse to transmit pressure,

as in the old experiment of trying to burst a piece of paper tied

over the end of a tube with a stick, an inch or two of sand being

only interposed. I have always myself felt the greatest difficulty in

believing in waves of heat coming first to this and then to that quarter

of the world: I suspect that heat plays quite a subordinate part in the

upward and downward movements of the earth's crust; though of course

it must swell the strata where first affected. I can understand Sir

J. Herschel's manner of bringing heat to unheated strata--namely, by

covering them up by a mile or so of new strata, and then the heat would

travel into the lower ones. But who can tell what effect this mile or

two of new sedimentary strata would have from mere gravity on the level

of the supporting surface? Of course such considerations do not render

less true that the expansion of the strata by heat would have some

effect on the level of the surface; but they show us how awfully

complicated the phenomenon is. All young geologists have a great turn

for speculation; I have burned my fingers pretty sharply in that way,

and am now perhaps become over-cautious; and feel inclined to cavil at

speculation when the direct and immediate effect of a cause in question

cannot be shown. How neatly you draw your diagrams; I wish you would

turn your attention to real sections of the earth's crust, and then

speculate to your heart's content on them; I can have no doubt that

speculative men, with a curb on, make far the best observers. I

sincerely wish I could have made any remarks of more interest to you,

and more directly bearing on your paper; but the subject strikes me as

too difficult and complicated. With every good wish that you may go

on with your geological studies, speculations, and especially

observations...

LETTER 488. TO C. LYELL. Down, March 24th [1853].

I have often puzzled over Dana's case, in itself and in relation to the

trains of S. American volcanoes of different heights in action at the

same time (page 605, Volume V. "Geological Transactions." (488/1. "On

the Connection of certain Volcanic Phenomena in South America, and on

the Formation of Mountain Chains and Volcanoes, as the Effect of the

same Power by which Continents are Elevated" ("Trans. Geol. Soc."

Volume V., page 601, 1840). On page 605 Darwin records instances of the

simultaneous activity after an earthquake of several volcanoes in

the Cordillera.)) I can throw no light on the subject. I presume you

remember that Hopkins (488/2. See "Report on the Geological Theories

of Elevation and Earthquakes," by W. Hopkins, "Brit. Assoc. Rep." 1847,

page 34.) in some one (I forget which) of his papers discusses such

cases, and urgently wishes the height of the fluid lava was known in

adjoining volcanoes when in contemporaneous action; he argues vehemently

against (as far as I remember) volcanoes in action of different heights

being connected with one common source of liquefied rock. If lava was as

fluid as water, the case would indeed be hopeless; and I fancy we should

be led to look at the deep-seated rock as solid though intensely hot,

and becoming fluid as soon as a crack lessened the tension of the

super-incumbent strata. But don't you think that viscid lava might be

very slow in communicating its pressure equally in all directions? I

remember thinking strongly that Dana's case within the one crater of

Kilauea proved too much; it really seems monstrous to suppose that the

lava within the same crater is not connected at no very great depth.

When one reflects on (and still better sees) the enormous masses of lava

apparently shot miles high up, like cannon-balls, the force seems out of

all proportion to the mere gravity of the liquefied lava; I should think

that a channel a little straightly or more open would determine the line

of explosion, like the mouth of a cannon compared to the touch-hole.

If a high-pressure boiler was cracked across, no one would think for a

moment that the quantity of water and steam expelled at different points

depended on the less or greater height of the water within the boiler

above these points, but on the size of the crack at these points; and

steam and water might be driven out both at top and bottom. May not a

volcano be likened to a protruding and cracked portion on a vast natural

high-pressure boiler, formed by the surrounding area of country? In

fact, I think my simile would be truer if the difference consisted only

in the cracked case of the boiler being much thicker in some parts than

in others, and therefore having to expel a greater thickness or depth of

water in the thicker cracks or parts--a difference of course absolutely

as nothing.

I have seen an old boiler in action, with steam and drops of water

spurting out of some of the rivet-holes. No one would think whether the

rivet-holes passed through a greater or less thickness of iron, or were

connected with the water higher or lower within the boiler, so small

would the gravity be compared with the force of the steam. If the boiler

had been not heated, then of course there would be a great difference

whether the rivet-holes entered the water high or low, so that there

was greater or less pressure of gravity. How to close my volcanic

rivet-holes I don't know.

I do not know whether you will understand what I am driving at, and it

will not signify much whether you do or not. I remember in old days (I

may mention the subject as we are on it) often wishing I could get

you to look at continental elevations as THE phenomenon, and volcanic

outbursts and tilting up of mountain chains as connected, but quite

secondary, phenomena. I became deeply impressed with the truth of this

view in S. America, and I do not think you hold it, or if so make it

clear: the same explanation, whatever it may be, which will account for

the whole coast of Chili rising, will and must apply to the volcanic

action of the Cordillera, though modified no doubt by the liquefied

rock coming to the surface and reaching water, and so [being] rendered

explosive. To me it appears that this ought to be borne in mind in your

present subject of discussion. I have written at too great length; and

have amused myself if I have done you no good--so farewell.

LETTER 489. TO C. LYELL. Down, July 5th [1856].

I am very much obliged for your long letter, which has interested me

much; but before coming to the volcanic cosmogony I must say that I

cannot gather your verdict as judge and jury (and not as advocate)

on the continental extensions of late authors (489/1. See "Life and

Letters," II., page 74; Letter to Lyell, June 25th, 1856: also

letters in the sections of the present work devoted to Evolution and

Geographical Distribution.), which I must grapple with, and which as yet

strikes me as quite unphilosophical, inasmuch as such extensions must be

applied to every oceanic island, if to any one, as to Madeira; and this

I cannot admit, seeing that the skeletons, at least, of our continents

are ancient, and seeing the geological nature of the oceanic islands

themselves. Do aid me with your judgment: if I could honestly admit

these great [extensions], they would do me good service.

With respect to active volcanic areas being rising areas, which looks

so pretty on the coral maps, I have formerly felt "uncomfortable" on

exactly the same grounds with you, viz. maritime position of volcanoes;

and still more from the immense thicknesses of Silurian, etc., volcanic

strata, which thicknesses at first impress the mind with the idea of

subsidence. If this could be proved, the theory would be smashed; but

in deep oceans, though the bottom were rising, great thicknesses of

submarine lava might accumulate. But I found, after writing Coral Book,

cases in my notes of submarine vesicular lava-streams in the upper

masses of the Cordillera, formed, as I believe, during subsidence,

which staggered me greatly. With respect to the maritime position of

volcanoes, I have long been coming to the conclusion that there must

be some law causing areas of elevation (consequently of land) and of

subsidence to be parallel (as if balancing each other) and closely

approximate; I think this from the form of continents with a deep ocean

on one side, from coral map, and especially from conversations with you

on immense subsidences of the Carboniferous and [other] periods, and yet

with continued great supply of sediment. If this be so, such areas,

with opposite movements, would probably be separated by sets of parallel

cracks, and would be the seat of volcanoes and tilts, and consequently

volcanoes and mountains would be apt to be maritime; but why volcanoes

should cling to the rising edge of the cracks I cannot conjecture. That

areas with extinct volcanic archipelagoes may subside to any extent I do

not doubt.

Your view of the bottom of Atlantic long sinking with continued volcanic

outbursts and local elevations at Madeira, Canaries, etc., grates (but

of course I do not know how complex the phenomena are which are thus

explained) against my judgment; my general ideas strongly lead me to

believe in elevatory movements being widely extended. One ought, I

think, never to forget that when a volcano is in action we have distinct

proof of an action from within outwards. Nor should we forget, as I

believe follows from Hopkins (489/2. "Researches in Physical Geology,"

W. Hopkins, "Trans. Phil. Soc. Cambridge," Volume VI., 1838. See also

"Report on the Geological Theories of Elevation and Earthquakes," W.

Hopkins, "Brit. Assoc. Rep." page 33, 1847 (Oxford meeting).), and as I

have insisted in my Earthquake paper, that volcanoes and mountain chains

are mere accidents resulting from the elevation of an area, and as

mountain chains are generally long, so should I view areas of elevation

as generally large. (489/3. "On the Connexion of certain Volcanic

Phenomena in S. America, and on the Formation of Mountain Chains and

Volcanoes, as the Effect of the same Power by which Continents are

Elevated," "Trans. Geol. Soc." Volume V., page 601, 1840. "Bearing in

mind Mr. Hopkins' demonstration, if there be considerable elevation

there must be fissures, and, if fissures, almost certainly unequal

upheaval, or subsequent sinking down, the argument may be finally

thus put: mountain chains are the effects of continental elevations;

continental elevations and the eruptive force of volcanoes are due to

one great motive, now in progressive action..." (loc. cit., page 629).)

Your old original view that great oceans must be sinking areas, from

there being causes making land and yet there being little land, has

always struck me till lately as very good. But in some degree this

starts from the assumption that within periods of which we know anything

there was either a continent in such areas, or at least a sea-bottom of

not extreme depth.

LETTER 490. TO C. LYELL. King's Head Hotel, Sandown, Isle of Wight, July

18th [1858].

I write merely to thank you for the abstract of the Etna paper. (490/1.

"On the Structure of Lavas which have Consolidated on Steep Slopes,

with Remarks on the Mode of Origin of Mount Etna and on the Theory of

'Craters of Elevation,'" by C. Lyell, "Phil. Trans. R. Soc." Volume

CXLVIII., page 703, 1859.) It seems to me a very grand contribution to

our volcanic knowledge. Certainly I never expected to see E. de B.'s

[Elie de Beaumont] theory of slopes so completely upset. He must have

picked out favourable cases for measurement. And such an array of facts

he gives! You have scotched, and will see die, I now think, the Crater

of Elevation theory. But what vitality there is in a plausible theory!

(490/2. The rest of this letter is published in "Life and Letters," II.,

page 129.)

LETTER 491. TO C. LYELL. Down, November 25th [1860].

I have endeavoured to think over your discussion, but not with much

success. You will have to lay down, I think, very clearly, what

foundation you argue from--four parts (which seems to me exceedingly

moderate on your part) of Europe being now at rest, with one part

undergoing movement. How it is, that from this you can argue that the

one part which is now moving will have rested since the commencement of

the Glacial period in the proportion of four to one, I do not pretend

to see with any clearness; but does not your argument rest on the

assumption that within a given period, say two or three million years,

the whole of Europe necessarily has to undergo movement? This may

be probable or not so, but it seems to me that you must explain the

foundation of your argument from space to time, which at first, to me

was very far from obvious. I can, of course, see that if you can make

out your argument satisfactorily to yourself and others it would be most

valuable. I can imagine some one saying that it is not fair to argue

that the great plains of Europe and the mountainous districts of

Scotland and Wales have been at all subjected to the same laws of

movement. Looking to the whole world, it has been my opinion, from the

very size of the continents and oceans, and especially from the enormous

ranges of so many mountain-chains (resulting from cracks which follow

from vast areas of elevation, as Hopkins argues (491/1. See "Report

on the Geological Theories of Elevation and Earthquakes." by William

Hopkins. "Brit. Assoc. Rep." 1847, pages 33-92; also the Anniversary

Address to the Geological Society by W. Hopkins in 1852 ("Quart. Journ.

Geol. Soc." Volume VIII.); in this Address, pages lxviii et seq.)

reference is made to the theory of elevation which rests on the

supposition "of the simultaneous action of an upheaving force at every

point of the area over which the phenomena of elevation preserve a

certain character of continuity...The elevated mass...becomes stretched,

and is ultimately torn and fissured in those directions in which

the tendency thus to tear is greatest...It is thus that the complex

phenomena of elevation become referable to a general and simple

mechanical cause...")) and from other reasons, it has been my opinion

that, as a general rule, very large portions of the world have been

simultaneously affected by elevation or subsidence. I can see that this

does not apply so strongly to broken Europe, any more than to the Malay

Archipelago. Yet, had I been asked, I should have said that probably

nearly the whole of Europe was subjected during the Glacial period

to periods of elevation and of subsidence. It does not seem to me so

certain that the kinds of partial movement which we now see going on

show us the kind of movement which Europe has been subjected to since

the commencement of the Glacial period. These notions are at least

possible, and would they not vitiate your argument? Do you not rest on

the belief that, as Scandinavia and some few other parts are now rising,

and a few others sinking, and the remainder at rest, so it has been

since the commencement of the Glacial period? With my notions I

should require this to be made pretty probable before I could put much

confidence in your calculations. You have probably thought this all

over, but I give you the reflections which come across me, supposing

for the moment that you took the proportions of space at rest and in

movement as plainly applicable to time. I have no doubt that you have

sufficient evidence that, at the commencement of the Glacial period, the

land in Scotland, Wales, etc., stood as high or higher than at present,

but I forget the proofs.

Having burnt my own fingers so consumedly with the Wealden, I am fearful

for you, but I well know how infinitely more cautious, prudent, and

far-seeing you are than I am; but for heaven's sake take care of your

fingers; to burn them severely, as I have done, is very unpleasant.

Your 2 1/2 feet for a century of elevation seems a very handsome

allowance. can D. Forbes really show the great elevation of Chili? I am

astounded at it, and I took some pains on the point.

I do not pretend to say that you may not be right to judge of the past

movements of Europe by those now and recently going on, yet it somehow

grates against my judgment,--perhaps only against my prejudices.

As a change from elevation to subsidence implies some great subterranean

or cosmical change, one may surely calculate on long intervals of

rest between. Though, if the cause of the change be ever proved to be

astronomical, even this might be doubtful.

P.S.--I do not know whether I have made clear what I think probable, or

at least possible: viz., that the greater part of Europe has at times

been elevated in some degree equably; at other times it has all subsided

equably; and at other times might all have been stationary; and at other

times it has been subjected to various unequal movements, up and down,

as at present.

LETTER 492. TO C. LYELL. Down, December 4th [1860].

It certainly seems to me safer to rely solely on the slowness of

ascertained up-and-down movement. But you could argue length of probable

time before the movement became reversed, as in your letter. And might

you not add that over the whole world it would probably be admitted that

a larger area is NOW at rest than in movement? and this I think would be

a tolerably good reason for supposing long intervals of rest. You might

even adduce Europe, only guarding yourself by saying that possibly (I

will not say probably, though my prejudices would lead me to say so)

Europe may at times have gone up and down all together. I forget whether

in a former letter you made a strong point of upward movement being

always interrupted by long periods of rest. After writing to you, out

of curiosity I glanced at the early chapters in my "Geology of South

America," and the areas of elevation on the E. and W. coasts are so

vast, and proofs of many successive periods of rest so striking,

that the evidence becomes to my mind striking. With regard to the

astronomical causes of change: in ancient days in the "Beagle" when I

reflected on the repeated great oscillations of level on the very same

area, and when I looked at the symmetry of mountain chains over such

vast spaces, I used to conclude that the day would come when the slow

change of form in the semi-fluid matter beneath the crust would be found

to be the cause of volcanic action, and of all changes of level. And the

late discussion in the "Athenaeum" (492/1. "On the Change of Climate

in Different Regions of the Earth." Letters from Sir Henry James, Col.

R.E., "Athenaeum," August 25th, 1860, page 256; September 15th, page

355; September 29th, page 415; October 13th, page 483. Also letter from

J. Beete Jukes, Local Director of the Geological Survey of Ireland, loc.

cit., September 8th, page 322; October 6th, page 451.), by Sir H. James

(though his letter seemed to me mighty poor, and what Jukes wrote good),

reminded me of this notion. In case astronomical agencies should ever

be proved or rendered probable, I imagine, as in nutation or precession,

that an upward movement or protrusion of fluidified matter below might

be immediately followed by movement of an opposite nature. This is all

that I meant.

I have not read Jamieson, or yet got the number. (492/2. Possibly

William Jameson, "Journey from Quito to Cayambe," "Geog. Soc. Journ."

Volume XXXI., page 184, 1861.) I was very much struck with Forbes'

explanation of n[itrate] of soda beds and the saliferous crust, which

I saw and examined at Iquique. (492/3. "On the Geology of Bolivia and

Southern Peru," by D. Forbes, "Quart. Journ. Geol. Soc." Volume XVII.,

page 7, 1861. Mr. Forbes attributes the formation of the saline deposits

to lagoons of salt water, the communication of which with the sea has

been cut off by the rising of the land (loc. cit., page 13).) I often

speculated on the greater rise inland of the Cordilleras, and could

never satisfy myself...

I have not read Stur, and am awfully behindhand in many things...(492/4.

The end of this letter is published as a footnote in "Life and Letters,"

II., page 352.)

(FIGURE 5. Map of part of South America and the Galapagos Archipelago.)

LETTER 493. TO C. LYELL. Down, July 18th [1867].

(493/1. The first part of this letter is published in "Life and

Letters," III., page 71.)

(493/2. Tahiti (Society Islands) is coloured blue in the map showing

the distribution of the different kinds of reefs in "The Structure and

Distribution of Coral Reefs," Edition III., 1889, page 185. The blue

colour indicates the existence of barrier reefs and atolls which, on

Darwin's theory, point to subsidence.)

Tahiti is, I believe, rightly coloured, for the reefs are so far from

the land, and the ocean so deep, that there must have been subsidence,

though not very recently. I looked carefully, and there is no evidence

of recent elevation. I quite agree with you versus Herschel on Volcanic

Islands. (493/3. Sir John Herschel suggested that the accumulation on

the sea-floor of sediment, derived from the waste of the island,

presses down the bed of the ocean, the continent being on the other hand

relieved of pressure; "this brings about a state of strain in the crust

which will crack in its weakest spot, the heavy side going down, and the

light side rising." In discussing this view Lyell writes ("Principles,"

Volume II. Edition X., page 229), "This hypothesis appears to me of

very partial application, for active volcanoes, even such as are on the

borders of continents, are rarely situated where great deltas have been

forming, whether in Pliocene or post-Tertiary times. The number, also,

of active volcanoes in oceanic islands is very great, not only in

the Pacific, but equally in the Atlantic, where no load of coral

matter...can cause a partial weighting and pressing down of a supposed

flexible crust.") Would not the Atlantic and Antarctic volcanoes be the

best examples for you, as there then can be no coral mud to depress

the bottom? In my "Volcanic Islands," page 126, I just suggest that

volcanoes may occur so frequently in the oceanic areas as the surface

would be most likely to crack when first being elevated. I find one

remark, page 128 (493/4. "Volcanic Islands," page 128: "The islands,

moreover, of some of the small volcanic groups, which thus border

continents, are placed in lines related to those along which the

adjoining shores of the continents trend" [see Figure 5].), which seems

to me worth consideration--viz. the parallelism of the lines of eruption

in volcanic archipelagoes with the coast lines of the nearest continent,

for this seems to indicate a mechanical rather than a chemical

connection in both cases, i.e. the lines of disturbance and cracking. In

my "South American Geology," page 185 (493/5. "Geological Observations

on South America," London, 1846, page 185.), I allude to the remarkable

absence at present of active volcanoes on the east side of the

Cordillera in relation to the absence of the sea on this side. Yet I

must own I have long felt a little sceptical on the proximity of water

being the exciting cause. The one volcano in the interior of Asia is

said, I think, to be near great lakes; but if lakes are so important,

why are there not many other volcanoes within other continents? I have

always felt rather inclined to look at the position of volcanoes on the

borders of continents, as resulting from coast lines being the lines of

separation between areas of elevation and subsidence. But it is useless

in me troubling you with my old speculations.

LETTER 494. TO A.R. WALLACE. March 22nd [1869].

(494/1. The following extract from a letter to Mr. Wallace refers to his

"Malay Archipelago," 1869.)

I have only one criticism of a general nature, and I am not sure that

other geologists would agree with me. You repeatedly speak as if the

pouring out of lava, etc., from volcanoes actually caused the subsidence

of an adjoining area. I quite agree that areas undergoing opposite

movements are somehow connected; but volcanic outbursts must, I think,

be looked at as mere accidents in the swelling up of a great dome or

surface of plutonic rocks, and there seems no more reason to conclude

that such swelling or elevation in mass is the cause of the subsidence,

than that the subsidence is the cause of the elevation, which latter

view is indeed held by some geologists. I have regretted to find so

little about the habits of the many animals which you have seen.

LETTER 495. TO C. LYELL. Down, May 20th, 1869.

I have been much pleased to hear that you have been looking at my

S. American book (495/1. "Geological Observations on South America,"

London, 1846.), which I thought was as completely dead and gone as any

pre-Cambrian fossil. You are right in supposing that my memory about

American geology has grown very hazy. I remember, however, a paper on

the Cordillera by D. Forbes (495/2. "Geology of Bolivia and South Peru,"

by Forbes, "Quart. Journ. Geol. Soc." Volume XVII., pages 7-62, 1861.

Forbes admits that there is "the fullest evidence of elevation of the

Chile coast since the arrival of the Spaniards. North of Arica, if we

accept the evidence of M. d'Orbigny and others, the proof of elevation

is much more decided; and consequently it may be possible that here,

as is the case about Lima, according to Darwin, the elevation may have

taken place irregularly in places..." (loc. cit., page 11).), with

splendid sections, which I saw in MS., but whether "referred" to me or

lent to me I cannot remember. This would be well worth your looking to,

as I think he both supports and criticises my views. In Ormerod's

Index to the Journal (495/3. "Classified Index to the Transactions,

Proceedings and Quarterly Journal of the Geological Society."), which I

do not possess, you would, no doubt, find a reference; but I think the

sections would be worth borrowing from Forbes. Domeyko (495/4. Reference

is made by Forbes in his paper on Bolivia and Peru to the work of

Ignacio Domeyko on the geology of Chili. Several papers by this author

were published in the "Annales des Mines" between 1840 and 1869, also in

the "Comptes Rendus" of 1861, 1864, etc.) has published in the "Comptes

Rendus" papers on Chili, but not, as far as I can remember, on the

structure of the mountains. Forbes, however, would know. What you say

about the plications being steepest in the central and generally highest

part of the range is conclusive to my mind that there has been the chief

axis of disturbance. The lateral thrusting has always appeared to me

fearfully perplexing. I remember formerly thinking that all lateral

flexures probably occurred deep beneath the surface, and have been

brought into view by an enormous superincumbent mass having been

denuded. If a large and deep box were filled with layers of damp paper

or clay, and a blunt wedge was slowly driven up from beneath, would not

the layers above it and on both sides become greatly convoluted, whilst

those towards the top would be only slightly arched? When I spoke of

the Andes being comparatively recent, I suppose that I referred to the

absence of the older formations. In looking to my volume, which I have

not done for many years, I came upon a passage (page 232) which would be

worth your looking at, if you have ever felt perplexed, as I often was,

about the sources of volcanic rocks in mountain chains. You have stirred

up old memories, and at the risk of being a bore I should like to call

your attention to another point which formerly perplexed me much--viz.

the presence of basaltic dikes in most great granitic areas. I cannot

but think the explanation given at page 123 of my "Volcanic Islands" is

the true one. (495/5. On page 123 of the "Geological Observations on the

Volcanic Islands visited during the Voyage of H.M.S. 'Beagle,'" 1844,

Darwin quotes several instances of greenstone and basaltic dikes

intersecting granitic and allied metamorphic rocks. He suggests that

these dikes "have been formed by fissures penetrating into partially

cooled rocks of the granitic and metamorphic series, and by their more

fluid parts, consisting chiefly of hornblende oozing out, and being

sucked into such fissures.")

LETTER 496. TO VICTOR CARUS. Down, March 21st, 1876.

The very kind expressions in your letter have gratified me deeply.

I quite forget what I said about my geological works, but the papers

referred to in your letter are the right ones. I enclose a list with

those which are certainly not worth translating marked with a red line;

but whether those which are not thus marked with a red line are worth

translation you will have to decide. I think much more highly of my

book on "Volcanic Islands" since Mr. Judd, by far the best judge on the

subject in England, has, as I hear, learnt much from it.

I think the short paper on the "formation of mould" is worth

translating, though, if I have time and strength, I hope to write

another and longer paper on the subject.

I can assure you that the idea of any one translating my books better

than you never even momentarily crossed my mind. I am glad that you can

give a fairly good account of your health, or at least that it is not

worse.

LETTER 497. TO T. MELLARD READE. London, December 9th, 1880.

I am sorry to say that I do not return home till the middle of next

week, and as I order no pamphlets to be forwarded to me by post, I

cannot return the "Geolog. Mag." until my return home, nor could my

servants pick it out of the multitude which come by the post. (497/1.

Article on "Oceanic Islands," by T. Mellard Reade, "Geol. Mag." Volume

VIII., page 75, 1881.)

As I remarked in a letter to a friend, with whom I was discussing

Wallace's last book (497/2. Wallace's "Island Life," 1880.), the subject

to which you refer seems to me a most perplexing one. The fact which

I pointed out many years ago, that all oceanic islands are volcanic

(except St. Paul's, and now this is viewed by some as the nucleus of an

ancient volcano), seems to me a strong argument that no continent ever

occupied the great oceans. (497/3. "During my investigations on coral

reefs I had occasion to consult the works of many voyagers, and I

was invariably struck with the fact that, with rare exceptions, the

innumerable islands scattered through the Pacific, Indian, and Atlantic

Oceans were composed either of volcanic or of modern coral rocks"

("Geological Observations on Volcanic Islands, etc." Edition II., 1876,

page 140).) Then there comes the statement from the "Challenger" that

all sediment is deposited within one or two hundred miles from the

shores, though I should have thought this rather doubtful with respect

to great rivers like the Amazons.

The chalk formerly seemed to me the best case of an ocean having

extended where a continent now stands; but it seems that some good

judges deny that the chalk is an oceanic deposit. On the whole, I lean

to the side that the continents have since Cambrian times occupied

approximately their present positions. But, as I have said, the question

seems a difficult one, and the more it is discussed the better.

LETTER 498. TO A. AGASSIZ. Down, January 1st, 1881.

I must write a line or two to thank you much for having written to me so

long a letter on coral reefs at a time when you must have been so busy.

Is it not difficult to avoid believing that the wonderful elevation

in the West Indies must have been accompanied by much subsidence,

notwithstanding the state of Florida? (498/1. The Florida reefs cannot

be explained by subsidence. Alexander Agassiz, who has described these

reefs in detail ("Three Cruises of the U.S. Coast and Geodetic Survey

Steamer 'Blake,'" 2 volumes, London, 1888), shows that the southern

extremity of the peninsula "is of comparatively recent growth,

consisting of concentric barrier-reefs, which have been gradually

converted into land by the accumulation of intervening mud-flats" (see

also Appendix II., page 287, to Darwin's "Coral Reefs," by T.G. Bonney,

Edition III., 1889.)) When reflecting in old days on the configuration

of our continents, the position of mountain chains, and especially on

the long-continued supply of sediment over the same areas, I used to

think (as probably have many other persons) that areas of elevation and

subsidence must as a general rule be separated by a single great line

of fissure, or rather of several closely adjoining lines of fissure. I

mention this because, when looking within more recent times at charts

with the depths of the sea marked by different tints, there seems to be

some connection between the profound depths of the ocean and the trends

of the nearest, though distant, continents; and I have often wished

that some one like yourself, to whom the subject was familiar, would

speculate on it.

P.S.--I do hope that you will re-urge your views about the reappearance

of old characters (498/2. See "Life and Letters," III., pages 245,

246.), for, as far as I can judge, the most important views are often

neglected unless they are urged and re-urged.

I am greatly indebted to you for sending me very many most valuable

works published at your institution.

2.IX.II. ICE-ACTION, 1841-1882.

LETTER 499. TO C. LYELL. [1841.]

Your extract has set me puzzling very much, and as I find I am better

at present for not going out, you must let me unload my mind on paper.

I thought everything so beautifully clear about glaciers, but now your

case and Agassiz's statement about the cavities in the rock formed by

cascades in the glaciers, shows me I don't understand their structure at

all. I wish out of pure curiosity I could make it out. (499/1. "Etudes

sur les Glaciers," by Louis Agassiz, 1840, contains a description of

cascades (page 343), and "des cavites interieures" (page 348).)

If the glacier travelled on (and it certainly does travel on), and the

water kept cutting back over the edge of the ice, there would be a great

slit in front of the cascade; if the water did not cut back, the whole

hollow and cascade, as you say, must travel on; and do you suppose the

next season it falls down some crevice higher up? In any case, how in

the name of Heaven can it make a hollow in solid rock, which surely must

be a work of many years? I must point out another fact which Agassiz

does not, as it appears to me, leave very clear. He says all the blocks

on the surface of the glaciers are angular, and those in the moraines

rounded, yet he says the medial moraines whence the surface rocks come

and are a part [of], are only two lateral moraines united. Can he

refer to terminal moraines alone when he says fragments in moraines are

rounded? What a capital book Agassiz's is. In [reading] all the early

part I gave up entirely the Jura blocks, and was heartily ashamed of my

appendix (499/2. "M. Agassiz has lately written on the subject of the

glaciers and boulders of the Alps. He clearly proves, as it appears to

me, that the presence of the boulders on the Jura cannot be explained

by any debacle, or by the power of ancient glaciers driving before them

moraines...M. Agassiz also denies that they were transported by floating

ice." ("Voyages of the 'Adventure' and 'Beagle,'" Volume III., 1839:

"Journal and Remarks: Addenda," page 617.)) (and am so still of the

manner in which I presumptuously speak of Agassiz), but it seems by his

own confession that ordinary glaciers could not have transported the

blocks there, and if an hypothesis is to be introduced the sea is much

simpler; floating ice seems to me to account for everything as well

as, and sometimes better than the solid glaciers. The hollows, however,

formed by the ice-cascades appear to me the strongest hostile fact,

though certainly, as you said, one sees hollow round cavities on present

rock-beaches.

I am glad to observe that Agassiz does not pretend that direction

of scratches is hostile to floating ice. By the way, how do you and

Buckland account for the "tails" of diluvium in Scotland? (499/3. Mr.

Darwin speaks of the tails of diluvium in Scotland extending from

the protected side of a hill, of which the opposite side, facing the

direction from which the ice came, is marked by grooves and striae

(loc. cit., pages 622, 623).) I thought in my appendix this made out the

strongest argument for rocks having been scratched by floating ice.

Some facts about boulders in Chiloe will, I think, in a very small

degree elucidate some parts of Jura case. What a grand new feature all

this ice work is in Geology! How old Hutton would have stared! (499/4.

Sir Charles Lyell speaks of the Huttonian theory as being characterised

by "the exclusion of all causes not supposed to belong to the present

order of Nature" (Lyell's "Principles," Edition XII., volume I., page

76, 1875). Sir Archibald Geikie has recently edited the third volume of

Hutton's "Theory of the Earth," printed by the Geological Society, 1899.

See also "The Founders of Geology," by Sir Archibald Geikie; London,

1897.)

I ought to be ashamed of myself for scribbling on so. Talking of shame,

I have sent a copy of my "Journal" (499/5. "Journal and Remarks,"

1832-36. See note 2, page 148.) with very humble note to Agassiz, as an

apology for the tone I used, though I say, I daresay he has never seen

my appendix, or would care at all about it.

I did not suppose my note about Glen Roy could have been of any use to

you--I merely scribbled what came uppermost. I made one great oversight,

as you would perceive. I forgot the Glacier theory: if a glacier most

gradually disappeared from mouth of Spean Valley [this] would account

for buttresses of shingle below lowest shelf. The difficulty I put about

the ice-barrier of the middle Glen Roy shelf keeping so long at exactly

same level does certainly appear to me insuperable. (499/5. For a

description of the shelves or parallel roads in Glen Roy see Darwin's

"Observations on the Parallel Roads of Glen Roy, etc." "Phil. Trans. R.

Soc." 1839, page 39; also Letter 517 et seq.)

What a wonderful fact this breakdown of old Niagara is. How it disturbs

the calculations about lengths of time before the river would have

reached the lakes.

I hope Mrs. Lyell will read this to you, then I shall trust for

forgiveness for having scribbled so much. I should have sent back

Agassiz sooner, but my servant has been very unwell. Emma is going on

pretty well.

My paper on South American boulders and "till," which latter deposit

is perfectly characterised in Tierra del Fuego, is progressing rapidly.

(499/6. "On the Distribution of the Erratic Boulders and on the

Contemporaneous Unstratified Deposits of South America," "Trans. Geol.

Soc." Volume VI., page 415, 1842.)

I much like the term post-Pliocene, and will use it in my present paper

several times.

P.S.--I should have thought that the most obvious objection to the

marine-beach theory for Glen Roy would be the limited extension of the

shelves. Though certainly this is not a valid one, after an intermediate

one, only half a mile in length, and nowhere else appearing, even in the

valley of Glen Roy itself, has been shown to exist.

LETTER 500. TO C. LYELL. 1842.

I had some talk with Murchison, who has been on a flying visit into

Wales, and he can see no traces of glaciers, but only of the trickling

of water and of the roots of the heath. It is enough to make

an extraneous man think Geology from beginning to end a work of

imagination, and not founded on observation. Lonsdale, I observe, pays

Buckland and myself the compliment of thinking Murchison not seeing as

worth nothing; but I confess I am astonished, so glaringly clear after

two or three days did the evidence appear to me. Have you seen last "New

Edin. Phil. Journ.", it is ice and glaciers almost from beginning to

end. (500/1. "The Edinburgh New Philosophical Journal," Volume XXXIII.

(April-October), 1842, contains papers by Sir G.S. Mackenzie, Prof.

H.G. Brown, Jean de Charpentier, Roderick Murchison, Louis Agassiz, all

dealing with glaciers or ice; also letters to the Editor relating to

Prof. Forbes' account of his recent observations on Glaciers, and a

paper by Charles Darwin entitled "Notes on the Effects produced by the

Ancient Glaciers of Carnarvonshire, and on the Boulders transported by

Floating Ice.") Agassiz says he saw (and has laid down) the two lowest

terraces of Glen Roy in the valley of the Spean, opposite mouth of Glen

Roy itself, where no one else has seen them. (500/2. "The Glacial Theory

and its Recent Progress," by Louis Agassiz, loc. cit., page 216. Agassiz

describes the parallel terraces on the flanks of Glen Roy and Glen Spean

(page 236), and expresses himself convinced "that the Glacial theory

alone satisfies all the exigencies of the phenomenon" of the parallel

roads.) I carefully examined that spot, owing to the sheep tracks

[being] nearly but not quite parallel to the terrace. So much, again,

for difference of observation. I do not pretend to say who is right.

LETTER 501. TO J.D. HOOKER. Down, October 12th, 1849.

I was heartily glad to get your last letter; but on my life your thanks

for my very few and very dull letters quite scalded me. I have been very

indolent and selfish in not having oftener written to you and kept

my ears open for news which would have interested you; but I have not

forgotten you. Two days after receiving your letter, there was a short

leading notice about you in the "Gardeners' Chronicle" (501/1. The

"Gardeners' Chronicle," 1849, page 628.); in which it is said you

have discovered a noble crimson rose and thirty rhododendrons. I must

heartily congratulate you on these discoveries, which will interest

the public; and I have no doubt that you will have made plenty of most

interesting botanical observations. This last letter shall be put with

all your others, which are now safe together. I am very glad that

you have got minute details about the terraces in the valleys: your

description sounds curiously like the terraces in the Cordillera of

Chili; these latter, however, are single in each valley; but you will

hereafter see a description of these terraces in my "Geology of S.

America." (501/2. "Geological Observations," pages 10 et passim.) At the

end of your letter you speak about giving up Geology, but you must not

think of it; I am sure your observations will be very interesting. Your

account of the great dam in the Yangma valley is most curious, and quite

full; I find that I did not at all understand its wonderful structure in

your former letter. Your notion of glaciers pushing detritus into

deep fiords (and ice floating fragments on their channels), is in many

respects new to me; but I cannot help believing your dam is a lateral

moraine: I can hardly persuade myself that the remains of floating ice

action, at a period so immensely remote as when the Himalaya stood at

a low level in the sea, would now be distinguishable. (501/3. Hooker's

"Himalayan Journals," Volume II., page 121, 1854. In describing certain

deposits in the Lachoong valley, Hooker writes: "Glaciers might have

forced immense beds of gravel into positions that would dam up lakes

between the ice and the flanks of the valley" (page 121). In a footnote

he adds: "We are still very ignorant of many details of ice action, and

especially of the origin of many enormous deposits which are not true

moraines." Such deposits are referred to as occurring in the Yangma

valley.) Your not having found scored boulders and solid rocks is an

objection both to glaciers and floating ice; for it is certain that

both produce such. I believe no rocks escape scoring, polishing and

mammillation in the Alps, though some lose it easily when exposed. Are

you familiar with appearance of ice-action? If I understand rightly, you

object to the great dam having been produced by a glacier, owing to the

dryness of the lateral valley and general infrequency of glaciers in

Himalaya; but pray observe that we may fairly (from what we see in

Europe) assume that the climate was formerly colder in India, and when

the land stood at a lower height more snow might have fallen. Oddly

enough, I am now inclined to believe that I saw a gigantic moraine

crossing a valley, and formerly causing a lake above it in one of the

great valleys (Valle del Yeso) of the Cordillera: it is a mountain of

detritus, which has puzzled me. If you have any further opportunities,

do look for scores on steep faces of rock; and here and there remove

turf or matted parts to have a look. Again I beg, do not give up

Geology:--I wish you had Agassiz's work and plates on Glaciers. (501/4.

"Etudes sur les Glaciers." L. Agassiz, Neuchatel, 1840.) I am extremely

sorry that the Rajah, ill luck to him, has prevented your crossing

to Thibet; but you seem to have seen most interesting country: one is

astonished to hear of Fuegian climate in India. I heard from the Sabines

that you were thinking of giving up Borneo; I hope that this report may

prove true.

LETTER 502. TO C. LYELL. Down, May 8th [1855].

The notion you refer to was published in the "Geological Journal"

(502/1. "on the Transportal of Erratic Boulders from a lower to a higher

Level." By C. Darwin.), Volume IV. (1848), page 315, with reference to

all the cases which I could collect of boulders apparently higher than

the parent rock.

The argument of probable proportion of rock dropped by sea ice compared

to land glaciers is new to me. I have often thought of the idea of the

viscosity and enormous momentum of great icebergs, and still think that

the notion I pointed out in appendix to Ramsay's paper is probable, and

can hardly help being applicable in some cases. (502/2. The paper by

Ramsay has no appendix; probably, therefore Mr. Darwin's notes were

published separately as a paper in the "Phil. Mag.") I wonder whether

the "Phil. Journal [Magazine?.]" would publish it, if I could get it

from Ramsay or the Geological Society. (502/3. "On the Power of Icebergs

to make rectilinear, uniformly-directed grooves across a Submarine

Undulatory Surface." By C. Darwin, "Phil. Mag." Volume X., page 96,

1855.) If you chance to meet Ramsay will you ask him whether he has it?

I think it would perhaps be worth while just to call the N. American

geologists' attention to the idea; but it is not worth any trouble. I am

tremendously busy with all sorts of experiments. By the way, Hopkins at

the Geological Society seemed to admit some truth in the idea of scoring

by (viscid) icebergs. If the Geological Society takes so much [time] to

judge of truth of notions, as you were telling me in regard to Ramsay's

Permian glaciers (502/4. "On the Occurrence of angular, sub-angular,

polished, and striated Fragments and Boulders in the Permian Breccia

of Shropshire, Worcestershire, etc.; and on the Probable Existence of

Glaciers and Icebergs in the Permian Epoch." By A.C. Ramsay, "Quart.

Journ. Geol. Soc." Volume XI., page 185, 1855.), it will be as injurious

to progress as the French Institut.

LETTER 503. TO J.D. HOOKER. Cliff Cottage, Bournemouth, [September] 21st

[1862].

I am especially obliged to you for sending me Haast's communications.

(503/1. "Quart. Journ. Geol. Soc." Volume XXI., pages 130, 133, 1865;

Volume XXIII., page 342, 1867.) They are very interesting and grand

about glacial and drift or marine glacial. I see he alludes to the

whole southern hemisphere. I wonder whether he has read the "Origin."

Considering your facts on the Alpine plants of New Zealand and remarks,

I am particularly glad to hear of the geological evidence of glacial

action. I presume he is sure to collect and send over the mountain rat

of which he speaks. I long to know what it is. A frog and rat together

would, to my mind, prove former connection of New Zealand to some

continent; for I can hardly suppose that the Polynesians introduced the

rat as game, though so esteemed in the Friendly Islands. Ramsay sent

me his paper (503/2. "On the Glacial Origin of certain Lakes in

Switzerland, etc." "Quart. Journ. Geol. Soc." Volume XVIII., page 185,

1862.) and asked my opinion on it. I agree with you and think highly of

it. I cannot doubt that it is to a large extent true; my only doubt

is, that in a much disturbed country, I should have thought that some

depressions, and consequently lakes, would almost certainly have been

left. I suggested a careful consideration of mountainous tropical

countries such as Brazil, peninsula of India, etc.; if lakes are there,

[they are] very rare. I should fully subscribe to Ramsay's views.

What presumption, as it seems to me, in the Council of Geological

Society that it hesitated to publish the paper.

We return home on the 30th. I have made up [my] mind, if I can keep up

my courage, to start on the Saturday for Cambridge, and stay the last

few days of the [British] Association there. I do so hope that you may

be there then.

LETTER 504. TO J.D. HOOKER. November 3rd [1864].

When I wrote to you I had not read Ramsay. (504/1. "On the Erosion

of Valleys and Lakes: a Reply to Sir Roderick Murchison's Anniversary

Address to the Geographical Society." "Phil. Mag." Volume XXVIII., page

293, 1864) How capitally it is written! It seems that there is nothing

for style like a man's dander being put up. I think I agree largely with

you about denudation--but the rocky-lake-basin theory is the part

which interests me at present. It seems impossible to know how much to

attribute to ice, running water, and sea. I did not suppose that Ramsay

would deny that mountains had been thrown up irregularly, and that the

depressions would become valleys. The grandest valleys I ever saw were

at Tahiti, and here I do not believe ice has done anything; anyhow there

were no erratics. I said in my S. American Geology (504/2. "Finally, the

conclusion at which I have arrived with respect to the relative powers

of rain, and sea-water on the land is, that the latter is by far the

most efficient agent, and that its chief tendency is to widen the

valleys, whilst torrents and rivers tend to deepen them and to remove

the wreck of the sea's destroying action" ("Geol. Observations," pages

66, 67).) that rivers deepen and the sea widens valleys, and I am

inclined largely to stick to this, adding ice to water. I am sorry to

hear that Tyndall has grown dogmatic. H. Wedgwood was saying the

other day that T.'s writings and speaking gave him the idea of intense

conceit. I hope it is not so, for he is a grand man of science.

...I have had a prospectus and letter from Andrew Murray (504/3. See

Volume II., Letters 379, 384, etc.) asking me for suggestions. I think

this almost shows he is not fit for the subject, as he gives me no idea

what his book will be, excepting that the printed paper shows that all

animals and all plants of all groups are to be treated of. Do you know

anything of his knowledge?

In about a fortnight I shall have finished, except concluding chapter,

my book on "Variation under Domestication"; (504/4. Published in 1868.)

but then I have got to go over the whole again, and this will take me

very many months. I am able to work about two hours daily.

LETTER 505. TO J.D. HOOKER. Down [July, 1865].

I was glad to read your article on Glaciers, etc., in Yorkshire. You

seem to have been struck with what most deeply impressed me at Glen Roy

(wrong as I was on the whole subject)--viz. the marvellous manner in

which every detail of surface of land had been preserved for an enormous

period. This makes me a little sceptical whether Ramsay, Jukes, etc.,

are not a little overdoing sub-aerial denudation.

In the same "Reader" (505/1. Sir J.D. Hooker wrote to Darwin, July

13th, 1865, from High Force Inn, Middleton, Teesdale: "I am studying the

moraines all day long with as much enthusiasm as I am capable of after

lying in bed till nine, eating heavy breakfasts, and looking forward to

dinner as the summum bonum of existence." The result of his work, under

the title "Moraines of the Tees Valley," appeared in the "Reader"

(July 15th, 1865, page 71), of which Huxley was one of the managers

or committee-men, and Norman Lockyer was scientific editor ("Life and

Letters of T.H. Huxley," I., page 211). Hooker describes the moraines

and other evidence of glacial action in the upper part of the Tees

valley, and speaks of the effect of glaciers in determining the present

physical features of the country.) there was a striking article

on English and Foreign Men of Science (505/2. "British and Foreign

Science," "The Reader," loc. cit., page 61. The writer of the article

asserts the inferiority of English scientific workers.), and I think

unjust to England except in pure Physiology; in biology Owen and R.

Brown ought to save us, and in Geology we are most rich.

It is curious how we are reading the same books. We intend to read Lecky

and certainly to re-read Buckle--which latter I admired greatly before.

I am heartily glad you like Lubbock's book so much. It made me grieve

his taking to politics, and though I grieve that he has lost his

election, yet I suppose, now that he is once bitten, he will never give

up politics, and science is done for. Many men can make fair M.P.'s; and

how few can work in science like him!

I have been reading a pamphlet by Verlot on "Variation of Flowers,"

which seems to me very good; but I doubt whether it would be worth your

reading. it was published originally in the "Journal d'Hort.," and

so perhaps you have seen it. It is a very good plan this republishing

separately for sake of foreigners buying, and I wish I had tried to get

permission of Linn. Soc. for my Climbing paper, but it is now too late.

Do not forget that you have my paper on hybridism, by Max Wichura.

(505/3. Wichura, M.E., "L'Hybridisation dans le regne vegetal etudiee

sur les Saules," "Arch. Sci. Phys. Nat." XXIII., page 129, 1865.)

I hope you are returned to your work, refreshed like a giant by your

huge breakfasts. How unlucky you are about contagious complaints with

your children!

I keep very weak, and had much sickness yesterday, but am stronger this

morning.

Can you remember how we ever first met? (505/4. See "Life and Letters,"

II., page 19.) It was in Park Street; but what brought us together? I

have been re-reading a few old letters of yours, and my heart is very

warm towards you.

LETTER 506. TO C. LYELL. Down, March 8th [1866].

(506/1. In a letter from Sir Joseph Hooker to Mr. Darwin on February

21st, 1866, the following passage occurs: "I wish I could explain to you

my crude notions as to the Glacial period and your position towards it.

I suppose I hold this doctrine: that there was a Glacial period, but

that it was not one of universal cold, because I think that the

existing distribution of glaciers is sufficiently demonstrative of the

proposition that by comparatively slight redispositions of sea and

land, and perhaps axis of globe, you may account for all the leading

palaeontological phenomena." This letter was sent by Mr. Darwin to Sir

Charles Lyell, and the latter, writing on March 1st, 1866, expresses

his belief that "the whole globe must at times have been superficially

cooler. Still," he adds, "during extreme excentricity the sun would make

great efforts to compensate in perihelion for the chill of a long winter

in aphelion in one hemisphere, and a cool summer in the other. I

think you will turn out to be right in regard to meridional lines of

mountain-chains by which the migrations across the equator took place

while there was contemporaneous tropical heat of certain lowlands, where

plants requiring heat and moisture were saved from extinction by the

heat of the earth's surface, which was stored up in perihelion, being

prevented from radiating off freely into space by a blanket of aqueous

vapour caused by the melting of ice and snow. But though I am inclined

to profit by Croll's maximum excentricity for the glacial period, I

consider it quite subordinate to geographical causes or the relative

position of land and sea and the abnormal excess of land in polar

regions." In another letter (March 5th, 1866) Lyell writes: "In the

beginning of Hooker's letter to you he speaks hypothetically of a change

in the earth's axis as having possibly co-operated with redistribution

of land and sea in causing the cold of the Glacial period. Now, when we

consider how extremely modern, zoologically and botanically, the Glacial

period is proved to be, I am shocked at any one introducing, with what I

may call so much levity, so organic a change as a deviation in the axis

of the planet...' (see Lyell's "Principles," 1875, Chapter XIII.; also a

letter to Sir Joseph Hooker printed in the "Life of Sir Charles Lyell,"

Volume II., page 410.))

Many thanks for your interesting letter. From the serene elevation of

my old age I look down with amazement at your youth, vigour, and

indomitable energy. With respect to Hooker and the axis of the earth, I

suspect he is too much overworked to consider now any subject properly.

His mind is so acute and critical that I always expect to hear a torrent

of objections to anything proposed; but he is so candid that he often

comes round in a year or two. I have never thought on the causes of the

Glacial period, for I feel that the subject is beyond me; but though I

hope you will own that I have generally been a good and docile pupil

to you, yet I must confess that I cannot believe in change of land and

water, being more than a subsidiary agent. (506/2. In Chapter XI. of the

"Origin," Edition V., 1869, page 451, Darwin discusses Croll's theory,

and is clearly inclined to trust in Croll's conclusion that "whenever

the northern hemisphere passes through a cold period the temperature of

the southern hemisphere is actually raised..." In Edition VI., page 336,

he expresses his faith even more strongly. Mr. Darwin apparently sent

his MS. on the climate question, which was no doubt prepared for a

new edition of the "Origin," to Sir Charles. The arrival of the MS. is

acknowledged in a letter from Lyell on March 10th, 1866 ("Life of Sir

Charles Lyell," II., page 408), in which the writer says that he is

"more than ever convinced that geographical changes...are the principal

and not the subsidiary causes.") I have come to this conclusion from

reflecting on the geographical distribution of the inhabitants of the

sea on the opposite sides of our continents and of the inhabitants of

the continents themselves.

LETTER 507. TO C. LYELL. Down, September 8th [1866].

Many thanks for the pamphlet, which was returned this morning. I was

very glad to read it, though chiefly as a psychological curiosity. I

quite follow you in thinking Agassiz glacier-mad. (507/1. Agassiz's

pamphlet, ("Geology of the Amazons") is referred to by Lyell in a letter

written to Bunbury in September, 1866 ("Life of Sir Charles Lyell," II.,

page 409): "Agassiz has written an interesting paper on the 'Geology of

the Amazons,' but, I regret to say, he has gone wild about glaciers, and

has actually announced his opinion that the whole of the great valley,

down to its mouth in latitude 0 deg., was filled by ice..." Agassiz

published a paper, "Observations Geologiques faites dans la Vallee de

l'Amazone," in the "Comptes Rendus," Volume LXIV., page 1269, 1867. See

also a letter addressed to M. Marcou, published in the "Bull. Soc. Geol.

France," Volume XXIV., page 109, 1866.) His evidence reduces itself to

supposed moraines, which would be difficult to trace in a forest-clad

country; and with respect to boulders, these are not said to be angular,

and their source cannot be known in a country so imperfectly explored.

When I was at Rio, I was continually astonished at the depth (sometimes

100 feet) to which the granitic rocks were decomposed in situ, and this

soft matter would easily give rise to great alluvial accumulations; I

well remember finding it difficult to draw a line between the alluvial

matter and the softened rock in situ. What a splendid imagination

Agassiz has, and how energetic he is! What capital work he would have

done, if he had sucked in your "Principles" with his mother's milk. It

is wonderful that he should have written such wild nonsense about the

valley of the Amazon; yet not so wonderful when one remembers that he

once maintained before the British Association that the chalk was all

deposited at once.

With respect to the insects of Chili, I knew only from Bates that the

species of Carabus showed no special affinity to northern species;

from the great difference of climate and vegetation I should not have

expected that many insects would have shown such affinity. It is more

remarkable that the birds on the broad and lofty Cordillera of Tropical

S. America show no affinity with European species. The little power of

diffusion with birds has often struck me as a most singular fact--even

more singular than the great power of diffusion with plants. Remember

that we hope to see you in the autumn.

P.S.--There is a capital paper in the September number of "Annals

and Magazine," translated from Pictet and Humbert, on Fossil Fish of

Lebanon, but you will, I daresay, have received the original. (507/2.

"Recent Researches on the Fossil Fishes of Mount Lebanon," "Ann. Mag.

Nat. Hist." Volume XVIII., page 237, 1866.) It is capital in relation to

modification of species; I would not wish for more confirmatory facts,

though there is no direct allusion to the modification of species.

Hooker, by the way, gave an admirable lecture at Nottingham; I read it

in MS., or rather, heard it. I am glad it will be published, for it was

capital. (507/3. Sir Joseph Hooker delivered a lecture at the Nottingham

meeting of the British Association (1866) on "Insular Floras," published

in the "Gardeners' Chronicle," 1867. See Letters 366-377, etc.)

Sunday morning.

P.S.--I have just received a letter from Asa Gray with the following

passage, so that, according to this, I am the chief cause of Agassiz's

absurd views:--

"Agassiz is back (I have not seen him), and he went at once down to the

National Academy of Sciences, from which I sedulously keep away, and, I

hear, proved to them that the Glacial period covered the whole continent

of America with unbroken ice, and closed with a significant gesture and

the remark: 'So here is the end of the Darwin theory.' How do you like

that?

"I said last winter that Agassiz was bent on covering the whole

continent with ice, and that the motive of the discovery he was sure

to make was to make sure that there should be no coming down of any

terrestrial life from Tertiary or post-Tertiary period to ours. You

cannot deny that he has done his work effectually in a truly imperial

way."

LETTER 508. TO C. LYELL. Down, July 14th, 1868.

Mr. Agassiz's book has been read aloud to me, and I am wonderfully

perplexed what to think about his precise statements of the existence of

glaciers in the Ceara Mountains, and about the drift formation near Rio.

(508/1. "Sur la Geologie de l'Amazone," by MM. Agassiz and Continho,

"Bull. Soc. Geol. France," Volume XXV., page 685, 1868. See also "A

Journey in Brazil," by Professor and Mrs. Louis Agassiz, Boston, 1868.)

There is a sad want of details. Thus he never mentions whether any of

the blocks are angular, nor whether the embedded rounded boulders, which

cannot all be disintegrated, are scored. Yet how can so experienced an

observer as A. be deceived about lateral and terminal moraines? If there

really were glaciers in the Ceara Mountains, it seems to me one of the

most important facts in the history of the inorganic and organic world

ever observed. Whether true or not, it will be widely believed, and

until finally decided will greatly interfere with future progress

on many points. I have made these remarks in the hope that you will

coincide. If so, do you think it would be possible to persuade some

known man, such as Ramsay, or, what would be far better, some two men,

to go out for a summer trip, which would be in many respects delightful,

for the sole object of observing these phenomena in the Ceara Mountains,

and if possible also near Rio? I would gladly put my name down for 50

pounds in aid of the expense of travelling. Do turn this over in your

mind. I am so very sorry not to have seen you this summer, but for the

last three weeks I have been good for nothing, and have had to stop

almost all work. I hope we may meet in the autumn.

LETTER 509. TO JAMES CROLL. Down, November 24th, 1868.

I have read with the greatest interest the last paper which you have

kindly sent me. (509/1. Croll discussed the power of icebergs as

grinding and striating agents in the latter part of a paper ("On

Geological Time, and the probable Dates of the Glacial and the Upper

Miocene Period") published in the "Philosophical Magazine," Volume

XXXV., page 363, 1868, Volume XXXVI., pages 141, 362, 1868. His

conclusion was that the advocates of the Iceberg theory had formed "too

extravagant notions regarding the potency of floating ice as a striating

agent.") If we are to admit that all the scored rocks throughout the

more level parts of the United States result from true glacier action,

it is a most wonderful conclusion, and you certainly make out a very

strong case; so I suppose I must give up one more cherished belief. But

my object in writing is to trespass on your kindness and ask a question,

which I daresay I could answer for myself by reading more carefully,

as I hope hereafter to do, all your papers; but I shall feel much more

confidence in a brief reply from you. Am I right in supposing that you

believe that the glacial periods have always occurred alternately in the

northern and southern hemispheres, so that the erratic deposits which I

have described in the southern parts of America, and the glacial work in

New Zealand, could not have been simultaneous with our Glacial period?

From the glacial deposits occurring all round the northern hemisphere,

and from such deposits appearing in S. America to be as recent as in the

north, and lastly, from there being some evidence of the former lower

descent of glaciers all along the Cordilleras, I inferred that the whole

world was at this period cooler. It did not appear to me justifiable

without distinct evidence to suppose that the N. and S. glacial deposits

belonged to distinct epochs, though it would have been an immense

relief to my mind if I could have assumed that this had been the

case. Secondly, do you believe that during the Glacial period in one

hemisphere the opposite hemisphere actually becomes warmer, or does

it merely retain the same temperature as before? I do not ask these

questions out of mere curiosity; but I have to prepare a new edition

of my "Origin of Species," and am anxious to say a few words on this

subject on your authority. I hope that you will excuse my troubling you.

LETTER 510. TO J. CROLL. Down, January 31st, 1869.

To-morrow I will return registered your book, which I have kept so long.

I am most sincerely obliged for its loan, and especially for the MS.,

without which I should have been afraid of making mistakes. If you

require it, the MS. shall be returned. Your results have been of more

use to me than, I think, any other set of papers which I can remember.

Sir C. Lyell, who is staying here, is very unwilling to admit the

greater warmth of the S. hemisphere during the Glacial period in the N.;

but, as I have told him, this conclusion which you have arrived at from

physical considerations, explains so well whole classes of facts in

distribution, that I must joyfully accept it; indeed, I go so far as to

think that your conclusion is strengthened by the facts in distribution.

Your discussion on the flowing of the great ice-cap southward is

most interesting. I suppose that you have read Mr. Moseley's recent

discussion on the force of gravity being quite insufficient to account

for the downward movement of glaciers (510/1. Canon Henry Moseley, "On

the Mechanical Impossibility of the Descent of Glaciers by their Weight

only." "Proc. R. Soc." Volume XVII., page 202, 1869; "Phil. Mag." Volume

XXXVII., page 229, 1869.): if he is right, do you not think that the

unknown force may make more intelligible the extension of the great

northern ice-cap? Notwithstanding your excellent remarks on the work

which can be effected within the million years (510/2. In his paper

"On Geological Time, and the probable Date of the Glacial and the Upper

Miocene Period" ("Phil. Mag." Volume XXXV., page 363, 1868), Croll

endeavours to convey to the mind some idea of what a million years

really is: "Take a narrow strip of paper, an inch broad or more, and 83

feet 4 inches in length, and stretch it along the wall of a large hall,

or round the walls of an apartment somewhat over 20 feet square.

Recall to memory the days of your boyhood, so as to get some adequate

conception of what a period of a hundred years is. Then mark off from

one of the ends of the strip one-tenth of an inch. The one-tenth of an

inch will then represent a hundred years, and the entire length of the

strip a million of years" (loc. cit., page 375).), I am greatly troubled

at the short duration of the world according to Sir W. Thomson (510/3.

In a paper communicated to the Royal Society of Edinburgh, Lord Kelvin

(then Sir William Thomson) stated his belief that the age of our planet

must be more than twenty millions of years, but not more than four

hundred millions of years ("Trans. R. Soc. Edinb." Volume XXIII., page

157, 1861, "On the Secular Cooling of the Earth."). This subject has

been recently dealt with by Sir Archibald Geikie in his address as

President of the Geological Section of the British Association, 1899

("Brit. Assoc. Report," Dover Meeting, 1899, page 718).), for I

require for my theoretical views a very long period BEFORE the Cambrian

formation. If it would not trouble you, I should like to hear what you

think of Lyell's remark on the magnetic force which comes from the sun

to the earth: might not this penetrate the crust of the earth and then

be converted into heat? This would give a somewhat longer time during

which the crust might have been solid; and this is the argument on which

Sir W. Thomson seems chiefly to rest. You seem to argue chiefly on

the expenditure of energy of all kinds by the sun, and in this respect

Lyell's remark would have no bearing.

My new edition of the "Origin" (510/4. Fifth edition, May, 1869.) will

be published, I suppose, in about two months, and for the chance of your

liking to have a copy I will send one.

P.S.--I wish that you would turn your astronomical knowledge to the

consideration whether the form of the globe does not become periodically

slightly changed, so as to account for the many repeated ups and downs

of the surface in all parts of the world. I have always thought that

some cosmical cause would some day be discovered.

LETTER 511. TO C. LYELL. Down, July 12th [1872].

I have been glad to see the enclosed and return it. It seems to me

very cool in Agassiz to doubt the recent upheaval of Patagonia, without

having visited any part; and he entirely misrepresents me in saying that

I infer upheaval from the form of the land, as I trusted entirely to

shells embedded and on the surface. It is simply monstrous to suppose

that the terraces stretching on a dead level for leagues along the

coast, and miles in breadth, and covered with beds of stratified gravel,

10 to 30 feet in thickness, are due to subaerial denudation.

As for the pond of salt-water twice or thrice the density of sea-water,

and nearly dry, containing sea-shells in the same relative proportions

as on the adjoining coast, it almost passes my belief. Could there have

been a lively midshipman on board, who in the morning stocked the pool

from the adjoining coast?

As for glaciation, I will not venture to express any opinion, for when

in S. America I knew nothing about glaciers, and perhaps attributed much

to icebergs which ought to be attributed to glaciers. On the other hand,

Agassiz seems to me mad about glaciers, and apparently never thinks of

drift ice.

I did see one clear case of former great extension of a glacier in T.

del Fuego.

LETTER 512. TO J. GEIKIE.

(512/1. The following letter was in reply to a request from Prof. James

Geikie for permission to publish Mr. Darwin's views, communicated in a

previous letter (November 1876), on the vertical position of stones in

gravelly drift near Southampton. Prof. Geikie wrote (July 15th, 1880):

"You may remember that you attributed the peculiar position of those

stones to differential movements in the drift itself arising from the

slow melting of beds of frozen snow interstratified into the gravels...I

have found this explanation of great service even in Scotland, and

from what I have seen of the drift-gravels in various parts of southern

England and northern France, I am inclined to think that it has a wide

application.")

Down, July 19th, 1880.

Your letter has pleased me very much, and I truly feel it an honour that

anything which I wrote on the drift, etc., should have been of the least

use or interest to you. Pray make any use of my letter (512/2. Professor

James Geikie quotes the letter in "Prehistoric Europe," London, 1881

(page 141). Practically the whole of it is given in the "Life and

Letters," III., page 213.): I forget whether it was written carefully or

clearly, so pray touch up any passages that you may think fit to quote.

All that I have seen since near Southampton and elsewhere has

strengthened my notion. Here I live on a chalk platform gently sloping

down from the edge of the escarptment to the south (512/3. Id est,

sloping down from the escarpment which is to the south.) (which is

about 800 feet in height) to beneath the Tertiary beds to the north. The

(512/4. From here to the end of the paragraph is quoted by Prof. Geikie,

loc. cit., page 142.) beds of the large and broad valleys (and only of

these) are covered with an immense mass of closely packed broken and

angular flints; in which mass the skull of the musk-ox [musk-sheep]

and woolly elephant have been found. This great accumulation of unworn

flints must therefore have been made when the climate was cold, and I

believe it can be accounted for by the larger valleys having been filled

up to a great depth during a large part of the year with drifted frozen

snow, over which rubbish from the upper parts of the platforms was

washed by the summer rains, sometimes along one line and sometimes along

another, or in channels cut through the snow all along the main course

of the broad valleys.

I suppose that I formerly mentioned to you the frequent upright position

of elongated flints in the red clayey residue over the chalk, which

residue gradually subsides into the troughs and pipes corroded in the

solid chalk. This letter is very untidy, but I am tired.

P.S. Several palaeolithic celts have recently been found in the great

angular gravel-bed near Southampton in several places.

LETTER 513. TO D. MACKINTOSH. Down, November 13th, 1880.

Your discovery is a very interesting one, and I congratulate you on

it. (513/1. "On the Precise Mode of Accumulation and Derivation of the

Moel-Tryfan Shelly Deposits; on the Discovery of Similar High-level

Deposits along the Eastern Slopes of the Welsh Mountains; and on the

Existence of Drift-Zones, showing probable Variations in the Rate

of Submergence." By D. Mackintosh, "Quart. Journ. Geol. Soc." Volume

XXXVII., pages 351-69, 1881. [Read April 27th, 1881.]) I failed to find

shells on Moel Tryfan, but was interested by finding ("Philosoph. Mag."

3rd series, Volume XXI., page 184) shattered rocks (513/2. In reviewing

the work by previous writers on the Moel-Tryfan deposits, Mackintosh

refers to Darwin's "very suggestive description of the Moel-Tryfan

deposits...Under the drift he saw that the surface of the slate, TO

A DEPTH OF SEVERAL FEET, HAD BEEN SHATTERED AND CONTORTED IN A VERY

PECULIAR MANNER." The contortion of the slate, which Mackintosh

regarded as "the most interesting of the Moel-Tryfan phenomena," had not

previously been regarded as "sufficiently striking to arrest attention"

by any geologist except Darwin. The Pleistocene gravel and sand

containing marine shells on Moel-Tryfan, about five miles south-east of

Caernarvon, have been the subject of considerable controversy. By some

geologists the drift deposits have been regarded as evidence of a great

submergence in post-Pliocene times, while others have explained their

occurrence at a height of 1300 feet by assuming that the gravel and sand

had been thrust uphill by an advancing ice-sheet. (See H.B. Woodward,

"Geology of England and Wales," Edition II., 1887, pages 491, 492.)

Darwin attributed the shattering and contorting of the slates below the

drift to "icebergs grating over the surface.") and far-distant rounded

boulders, which I attributed to the violent impact of icebergs or

coast-ice. I can offer no opinion on whether the more recent changes of

level in England were or were not accompanied by earthquakes. It does

not seem to me a correct expression (which you use probably from

haste in your note) to speak of elevations or depressions as caused

by earthquakes: I suppose that every one admits that an earthquake

is merely the vibration from the fractured crust when it yields to an

upward or downward force. I must confess that of late years I have often

begun to suspect (especially when I think of the step-like plains of

Patagonia, the heights of which were measured by me) that many of the

changes of level in the land are due to changes of level in the sea.

(513/3. This view is an agreement with the theory recently put forward

by Suess in his "Antlitz der Erde" (Prag and Leipzig, 1885). Suess

believes that "the local invasions and transgressions of the continental

areas by the sea" are due to "secular movements of the hydrosphere

itself." (See J. Geikie, F.R.S., Presidential Address before Section E

at the Edinburgh Meeting of the British Association, "Annual Report,"

page 794.) I suppose that there can be no doubt that when there was much

ice piled up in the Arctic regions the sea would be attracted to them,

and the land on the temperate regions would thus appear to have risen.

There would also be some lowering of the sea by evaporation and the

fixing of the water as ice near the Pole.

I shall read your paper with much interest when published.

LETTER 514. TO J. GEIKIE. Down, December 13th, 1880.

You must allow me the pleasure of thanking you for the great interest

with which I have read your "Prehistoric Europe." (514/1. "Prehistoric

Europe: a Geological Sketch," London, 1881.) Nothing has struck me more

than the accumulated evidence of interglacial periods, and assuredly

the establishment of such periods is of paramount importance for

understanding all the later changes of the earth's surface. Reading

your book has brought vividly before my mind the state of knowledge, or

rather ignorance, half a century ago, when all superficial matter was

classed as diluvium, and not considered worthy of the attention of a

geologist. If you can spare the time (though I ask out of mere idle

curiosity) I should like to hear what you think of Mr. Mackintosh's

paper, illustrated by a little map with lines showing the courses or

sources of the erratic boulders over the midland counties of England.

(514/2. "Results of a Systematic Survey, in 1878, of the Directions and

Limits of Dispersion, Mode of Occurrence, and Relation to Drift-Deposits

of the Erratic Blocks or Boulders of the West of England and East of

Wales, including a Revision of Many Years' Previous Observations," D.

Mackintosh, "Quart. Journ. Geol. Soc." Volume XXXV., page 425, 1879.) It

is a little suspicious their ending rather abruptly near Wolverhampton,

yet I must think that they were transported by floating ice. Fifty years

ago I knew Shropshire well, and cannot remember anything like till, but

abundance of gravel and sand beds, with recent marine shells. A great

boulder (514/3. Mackintosh alludes (loc. cit., page 442) to felstone

boulders around Ashley Heath, the highest ground between the Pennine and

Welsh Hills north of the Wrekin; also to a boulder on the summit of the

eminence (774 feet above sea-level), "probably the same as that noticed

many years ago by Mr. Darwin." In a later paper, "On the Correlation

of the Drift-Deposits of the North-West of England with those of the

Midland and Eastern Counties" ("Quart. Journ. Geol. Soc." Volume XXXVI.,

page 178, 1880) Mackintosh mentions a letter received from Darwin, "who

was the first to elucidate the boulder-transporting agency of floating

ice," containing an account of the great Ashley Heath boulder, which

he was the first to discover and expose,...so as to find that the block

rested on fragments of New Red Sandstone, one of which was split into

two and deeply scored...The facts mentioned in the letter from Mr.

Darwin would seem to show that the boulder must have fallen through

water from floating ice with a force sufficient to split the underlying

lump of sandstone, but not sufficient to crush it.") which I had

undermined on the summit of Ashley Heath, 720 (?) feet above the sea,

rested on clean blocks of the underlying red sandstone. I was also

greatly interested by your long discussion on the Loss (514/4. For an

account of the Loss of German geologists--"a fine-grained, more or less

homogeneous, consistent, non-plastic loam, consisting of an intimate

admixture of clay and carbonate of lime," see J. Geikie, loc. cit., page

144 et seq.); but I do not feel satisfied that all has been made

out about it. I saw much brick-earth near Southampton in some manner

connected with the angular gravel, but had not strength enough to

make out relations. It might be worth your while to bear in mind the

possibility of fine sediment washed over and interstratified with thick

beds of frozen snow, and therefore ultimately dropped irrespective of

the present contour of the country.

I remember as a boy that it was said that the floods of the Severn were

more muddy when the floods were caused by melting snow than from the

heaviest rains; but why this should be I cannot see.

Another subject has interested me much--viz. the sliding and travelling

of angular debris. Ever since seeing the "streams of stones" at the

Falkland Islands (514/5. "Geological Observations on South America"

(1846), page 19 et seq.), I have felt uneasy in my mind on this subject.

I wish Mr. Kerr's notion could be fully elucidated about frozen snow.

Some one ought to observe the movements of the fields of snow which

supply the glaciers in Switzerland.

Yours is a grand book, and I thank you heartily for the instruction and

pleasure which it has given me.

For heaven's sake forgive the untidiness of this whole note.

LETTER 515. TO JOHN LUBBOCK [Lord Avebury]. Down, November 6th, 1881.

If I had written your Address (515/1. Address delivered by Lord Avebury

as President of the British Association at York in 1881. Dr. Hicks

is mentioned as having classed the pre-Cambrian strata in "four great

groups of immense thickness and implying a great lapse of time" and

giving no evidence of life. Hicks' third formation was named by him the

Arvonian ("Quart. Journ. Geol. Soc." Volume XXXVII., 1881, Proc., page

55.) (but this requires a fearful stretch of imagination on my part) I

should not alter what I had said about Hicks. You have the support of

the President [of the] Geological Society (515/2. Robert Etheridge.),

and I think that Hicks is more likely to be right than X. The latter

seems to me to belong to the class of objectors general. If Hicks should

be hereafter proved to be wrong about this third formation, it would

signify very little to you.

I forget whether you go as far as to support Ramsay about lakes as large

as the Italian ones: if so, I would myself modify the passage a little,

for these great lakes have always made me tremble for Ramsay, yet

some of the American geologists support him about the still larger N.

American lakes. I have always believed in the main in Ramsay's views

from the date of publication, and argued the point with Lyell, and am

convinced that it is a very interesting step in Geology, and that you

were quite right to allude to it. (515/3. "Glacial Origin of Lakes in

Switzerland, Black Forest, etc." ("Quart. Journ. Geol. Soc." Volume

XVIII., pages 185-204, 1862). Sir John Lubbock (Lord Avebury) gives

a brief statement of Ramsay's views concerning the origin of lakes

(Presidential Address, Brit. Assoc. 1881, page 22): "Prof. Ramsay

divides lakes into three classes: (1) Those which are due to irregular

accumulations of drift, and which are generally quite shallow; (2) those

which are formed by moraines; and (3) those which occupy true basins

scooped by glaciers out of the solid rocks. To the latter class belong,

in his opinion, most of the great Swiss and Italian lakes...Professor

Ramsay's theory seems, therefore, to account for a large number of

interesting facts." Sir Archibald Geikie has given a good summary of

Ramsay's theory in his "Memoir of Sir Andrew Crombie Ramsay," page 361,

London, 1895.)

LETTER 516. TO D. MACKINTOSH. Down, February 28th, 1882.

I have read professor Geikie's essay, and it certainly appears to

me that he underrated the importance of floating ice. (516/1. "The

Intercrossing of Erratics in Glacial Deposits," by James Geikie,

"Scottish Naturalist," 1881.) Memory extending back for half a century

is worth a little, but I can remember nothing in Shropshire like till

or ground moraine, yet I can distinctly remember the appearance of many

sand and gravel beds--in some of which I found marine shells. I think it

would be well worth your while to insist (but perhaps you have done so)

on the absence of till, if absent in the Western Counties, where you

find many erratic boulders.

I was pleased to read the last sentence in Geikie's essay about the

value of your work. (516/2. The concluding paragraph reads as follows:

"I cannot conclude this paper without expressing my admiration for the

long-continued and successful labours of the well-known geologist whose

views I have been controverting. Although I entered my protest against

his iceberg hypothesis, and have freely criticised his theoretical

opinions, I most willingly admit that the results of his unwearied

devotion to the study of those interesting phenomena with which he is

so familiar have laid all his fellow-workers under a debt of gratitude."

Mr. Darwin used to speak with admiration of Mackintosh's work, carried

on as it was under considerable difficulties.)

With respect to the main purport of your note, I hardly know what to

say. Though no evidence worth anything has as yet, in my opinion, been

advanced in favour of a living being, being developed from inorganic

matter, yet I cannot avoid believing the possibility of this will be

proved some day in accordance with the law of continuity. I remember the

time, above fifty years ago, when it was said that no substance found

in a living plant or animal could be produced without the aid of vital

forces. As far as external form is concerned, Eozoon shows how difficult

it is to distinguish between organised and inorganised bodies. If it is

ever found that life can originate on this world, the vital phenomena

will come under some general law of nature. Whether the existence of a

conscious God can be proved from the existence of the so-called laws

of nature (i.e., fixed sequence of events) is a perplexing subject, on

which I have often thought, but cannot see my way clearly. If you have

not read W. Graham's "Creed of Science," (516/3. "The Creed of Science:

Religious, Moral, and Social," London, 1881.), it would, I think,

interest you, and he supports the view which you are inclined to uphold.

2.IX.III. THE PARALLEL ROADS OF GLEN ROY, 1841-1880.

(517/1. In the bare hilly country of Lochaber, in the Scotch Highlands,

the slopes of the mountains overlooking the vale of Glen Roy are marked

by narrow terraces or parallel roads, which sweep round the shoulders of

the hills with "undeviating horizontality." These roads are described

by Sir Archibald Geikie as having long been "a subject of wonderment and

legendary story among the Highlanders, and for so many years a source

of sore perplexity among men of science." (517/2. "The Scenery of

Scotland," 1887, page 266.) In Glen Roy itself there are three distinct

shelves or terraces, and the mountain sides of the valley of the Spean

and other glens bear traces of these horizontal "roads."

The first important papers dealing with the origin of this striking

physical feature were those of MacCulloch (517/3. "Trans. Geol. Soc."

Volume IV., page 314, 1817.) and Sir Thomas Lauder Dick (517/4. "Trans.

R. Soc. Edinb." Volume IX., page 1, 1823.), in which the writers

concluded that the roads were the shore-lines of lakes which once filled

the Lochaber valleys. Towards the end of June 1838 Mr. Darwin devoted

"eight good days" (517/5. "Life and Letters," I., page 290.) to the

examination of the Lochaber district, and in the following year he

communicated a paper to the Royal Society of London, in which he

attributed their origin to the action of the sea, and regarded them

as old sea beaches which had been raised to their present level by a

gradual elevation of the Lochaber district.

In 1840 Louis Agassiz and Buckland (517/6. "Edinb. New Phil. Journal,"

Volume XXXIII., page 236, 1842.) proposed the glacier-ice theory; they

described the valleys as having been filled with lakes dammed back by

glaciers which formed bars across the valleys of Glen Roy, Glen

Spean, and the other glens in which the hill-sides bear traces of old

lake-margins. Agassiz wrote in 1842: "When I visited the parallel roads

of Glen Roy with Dr. Buckland we were convinced that the glacial theory

alone satisfied all the exigencies of the phenomenon." (517/7. Ibid.,

page 236.)

Mr. David Milne (afterwards Milne-Home) (517/8. "Trans. R. Soc. Edinb."

Volume XVI., page 395, 1847.) in 1847 upheld the view that the ledges

represent the shore-lines of lakes which were imprisoned in the valleys

by dams of detrital material left in the glens during a submergence

of 3,000 feet, at the close of the Glacial period. Chambers, in his

"Ancient Sea Margins" (1848), expressed himself in agreement with Mr.

Darwin's marine theory. The Agassiz-Buckland theory was supported by

Mr. Jamieson (517/9. "Quart. Journ. Geol. Soc." Volume XIX., page 235,

1863.), who brought forward additional evidence in favour of the glacial

barriers. Sir Charles Lyell at first (517/10. "Elements of Geology,"

Edition II., 1841.) accepted the explanation given by Mr. Darwin, but

afterwards (517/11. "Antiquity of Man," 1863, pages 252 et seq.) came to

the conclusion that the terrace-lines represent the beaches of glacial

lakes. In a paper published in 1878 (517/12. "Phil. Trans. R. Soc."

1879, page 663.), Prof. Prestwich stated his acceptance of the lake

theory of MacCulloch and Sir T. Lauder Dick and of the glacial theory

of Agassiz, but differed from these authors in respect of the age of the

lakes and the manner of formation of the roads.

The view that has now gained general acceptance is that the parallel

roads of Glen Roy represent the shores of a lake "that came into being

with the growth of the glaciers and vanished as these melted away."

(517/13. Sir Archibald Geikie, loc. cit., page 269.)

Mr. Darwin became a convert to the glacier theory after the publication

of Mr. Jamieson's paper. He speaks of his own paper as "a great

failure"; he argued in favour of sea action as the cause of the terraces

"because no other explanation was possible under our then state of

knowledge." Convinced of his mistake, Darwin looked upon his error as

"a good lesson never to trust in science to the principle of exclusion."

(517/14. "Life and Letters," I., page 69.)

LETTER 517. TO C. LYELL. [March 9th, 1841.]

I have just received your note. It is the greatest pleasure to me to

write or talk Geology with you...

I think I have thought over the whole case without prejudice, and

remain firmly convinced they [the parallel roads] are marine beaches. My

principal reason for doing so is what I have urged in my paper (517/15.

"Observations on the Parallel Roads of Glen Roy, and of other parts of

Lochaber in Scotland, with an attempt to prove that they are of Marine

Origin." "Phil. Trans. R. Soc." 1839, page 39.), the buttress-like

accumulations of stratified shingle on sides of valley, especially those

just below the lowest shelf in Spean Valley.

2nd. I can hardly conceive the extension of the glaciers in front of the

valley of Kilfinnin, where I found a new road--where the sides of Great

Glen are not very lofty.

3rd. The flat watersheds which I describe in places where there are

no roads, as well as those connected with "roads." These remain

unexplained.

I might continue to add many other such reasons, all of which, however,

I daresay would appear trifling to any one who had not visited the

district. With respect to equable elevation, it cannot be a valid

objection to any one who thinks of Scandinavia or the Pampas. With

respect to the glacier theory, the greatest objection appears to me the

following, though possibly not a sound one. The water has beyond doubt

remained very long at the levels of each shelf--this is unequivocally

shown by the depth of the notch or beach formed in many places in

the hard mica-slate, and the large accumulations or buttresses of

well-rounded pebbles at certain spots on the level of old beaches. (The

time must have been immense, if formed by lakes without tides.) During

the existence of the lakes their drainage must have been at the head of

the valleys, and has given the flat appearance of the watersheds. All

this is very clear for four of the shelves (viz., upper and lower in

Glen Roy, the 800-foot one in Glen Spean, and the one in Kilfinnin), and

explains the coincidence of "roads" with the watersheds more simply than

my view, and as simply as the common lake theory. But how was the Glen

Roy lake drained when the water stood at level of the middle "road"? It

must (for there is no other exit whatever) have been drained over the

glacier. Now this shelf is full as narrow in a vertical line and

as deeply worn horizontally into the mountain side and with a large

accumulation of shingle (I can give cases) as the other shelves. We

must, therefore, on the glacier theory, suppose that the surface of

the ice remained at exactly the same level, not being worn down by the

running water, or the glacier moved by its own movement during the very

long period absolutely necessary for a quiet lake to form such a beach

as this shelf presents in its whole course. I do not know whether I have

explained myself clearly. I should like to know what you think of this

difficulty. I shall much like to talk over the Jura case with you. I am

tired, so goodbye.

LETTER 518. TO L. HORNER. Down [1846].

(518/1. It was agreed at the British Association meeting held at

Southampton in 1846 "That application be made to Her Majesty's

Government to direct that during the progress of the Ordnance

Trigonometrical Surveys in the North of Scotland, the so-called Parallel

Roads of Glen Roy and the adjoining country be accurately surveyed, with

the view of determining whether they are truly parallel and horizontal,

the intervening distances, and their elevations above the present

sea-level" ("British Association Report," 1846, page xix). The survey

was undertaken by the Government Ordnance Survey Office under Col. Sir

Henry James, who published the results in 1874 ("Notes on the Parallel

Roads of Glen Roy"); the map on which the details are given is sheet 63

(one-inch scale).)

In following your suggestion in drawing out something about Glen Roy for

the Geological Committee, I have been completely puzzled how to do it.

I have written down what I should say if I had to meet the head of the

Survey and wished to persuade him to undertake the task; but as I have

written it, it is too long, ill expressed, seems as if it came from

nobody and was going to nobody, and therefore I send it to you in

despair, and beg you to turn the subject in your mind. I feel a

conviction if it goes through the Geological part of Ordnance Survey it

will be swamped, and as it is a case for mere accurate measurements it

might, I think without offence, go to the head of the real Surveyors.

If Agassiz or Buckland are on the Committee they will sneer at the whole

thing and declare the beaches are those of a glacier-lake, than which I

am sure I could convince you that there never was a more futile theory.

I look forward to Southampton (518/2. The British Association meeting

(1846).) with much interest, and hope to hear to-morrow that the

lodgings are secured to us. You cannot think how thoroughly I enjoyed

our geological talks, and the pleasure of seeing Mrs. Horner and

yourself here. (518/3. This letter is published in the privately printed

"Memoir of Leonard Horner," II., page 103.)

[Here follows Darwin's Memorandum.]

The Parallel Roads of Glen Roy, in Scotland, have been the object of

repeated examination, but they have never hitherto been levelled with

sufficient accuracy. Sir T. Lauder Dick (518/4. "On the Parallel Roads

of Lochaber" (with map and plates), by Sir Thomas Lauder Dick, "Trans.

R. Soc. Edinb." Volume IX., page 1, 1823.) procured the assistance of an

engineer for this purpose, but owing to the want of a true ground-plan

it was impossible to ascertain their exact curvature, which, as far as

could be estimated, appeared equal to that of the surface of the sea.

Considering how very rarely the sea has left narrow and well-defined

marks of its action at any considerable height on the land, and more

especially considering the remarkable observations by M. Bravais (518/5.

"On the Lines of Ancient Level of the Sea in Finmark," by M. A. Bravais,

translated from "Voyages de la Commission Scientifique du Nord, etc.";

"Quart. Journ. Geol. Soc." Volume I., page 534, 1845.) on the ancient

sea-beaches of Scandinavia, showing the they are not strictly parallel

to each other, and that the movement has been greater nearer the

mountains than on the coast, it appears highly desirable that the roads

of Glen Roy should be examined with the utmost care during the execution

of the Ordnance Survey of Scotland. The best instruments and the most

accurate measurements being necessary for this end almost precludes the

hope of its being ever undertaken by private individuals; but by the

means at the disposal of the Ordnance, measurements would be easily made

even more accurate than those of M. Bravais. It would be desirable to

take two lines of the greatest possible length in the district, and at

nearly right angles to each other, and to level from the beach at one

extremity to that at the other, so that it might be ascertained whether

the curvature does exactly correspond with that of the globe, or, if

not, what is the direction of the line of greatest elevation. Much

attention would be requisite in fixing on either the upper or lower edge

of the ancient beaches as the standard of measurement, and in rendering

this line conspicuous. The heights of the three roads, one above

the other and above the level of the sea, ought to be accurately

ascertained. Mr. Darwin observed one short beach-line north of Glen Roy,

and he has indicated, on the authority of Sir David Brewster, others

in the valley of the Spey. If these could be accurately connected, by

careful measurements of their absolute heights or by levelling, with

those of Glen Roy, it would make a most valuable addition to our

knowledge on this subject. Although the observations here specified

would probably be laborious, yet, considering how rarely such evidence

is afforded in any quarter of the world, it cannot be doubted that one

of the most important problems in Geology--namely, the exact manner in

which the crust of the earth rises in mass--would be much elucidated,

and a great service done to geological science.

LETTER 519. R. CHAMBERS TO D. MILNE-HOME. St. Andrews, September 7th,

1847.

I have had a letter to-day from Mr. Charles Darwin, beseeching me to

obtain for him a copy of your paper on Glen Roy. (519/1. No doubt Mr.

Milne's paper "On the Parallel Roads of Lochaber," "Trans. R. Soc.

Edinb." Volume XVI., page 395, 1849. [Read March 1st and April 5th,

1847.]) I am sure you will have pleasure in sending him one; his

address is "Down, Farnborough, Kent." I have again read over your paper

carefully, and feel assured that the careful collection and statement of

facts which are found in it must redound to your credit with all candid

persons. The suspicions, however, which I obtained some time ago as to

land-straits and heights of country being connected with sea-margins and

their ordinary memorials still possesses me, and I am looking forward to

some means of further testing the Glen Roy mystery. If my suspicion turn

out true, I shall at once be regretful on your account, and shall feel

it as a great check and admonition to myself not to be too confident

about anything in science till it has been proved over and over again.

The ground hereabouts is now getting clear of the crops; perhaps when I

am in town a few days hence we may be able to make some appointment for

an examination of the beaches of the district, my list of which has been

greatly enlarged during the last two months.

LETTER 520. TO R. CHAMBERS. September 11th, 1847.

I hope you will read the first part of my paper before you go [to Glen

Roy], and attend to the manner in which the lines end in Glen Collarig.

I wish Mr. Milne had read it more carefully. He misunderstands me in

several respects, but [I] suppose it is my own fault, for my paper is

most tediously written. Mr. Milne fights me very pleasantly, and I plead

guilty to his rebuke about "demonstration." (520/1. See Letter 521,

note.) I do not know what you think; but Mr. Milne will think me as

obstinate as a pig when I say that I think any barriers of detritus at

the mouth of Glen Roy, Collarig and Glaster more utterly impossible

than words can express. I abide by all that I have written on that head.

Conceive such a mass of detritus having been removed, without great

projections being left on each side, in the very close proximity to

every little delta preserved on the lines of the shelves, even on the

shelf 4, which now crosses with uniform breadth the spot where the

barrier stood, with the shelves dying gradually out, etc. To my mind it

is monstrous. Oddly enough, Mr. Milne's description of the mouth of Loch

Treig (I do not believe that valley has been well examined in its upper

end) leaves hardly a doubt that a glacier descended from it, and, if the

roads were formed by a lake of any kind, I believe it must have been

an ice-lake. I have given in detail to Lyell my several reasons for

not thinking ice-lakes probable (520/2. Mr. Darwin gives some arguments

against the glacier theory in the letter (517) to Sir Charles Lyell;

but the letter alluded to is no doubt the one written to Lyell on

"Wednesday, 8th" (Letter 522), in which the reasons are fully stated.);

but to my mind they are incomparably more probable than detritus of

rock-barriers. Have you ever attended to glacier action? After having

seen N. Wales, I can no more doubt the former existence of gigantic

glaciers than I can the sun in the heaven. I could distinguish in N.

Wales to a certain extent icebergs from glacier action (Lyell has shown

that icebergs at the present day score rocks), and I suspect that in

Lochaber the two actions are united, and that the scored rock on the

watersheds, when tideways, were rubbed and bumped by half-stranded

icebergs. You will, no doubt, attend to Glen Glaster. Mr. Milne, I

think, does not mention whether shelf 4 enters it, which I should like

to know, and especially he does not state whether rocks worn on their

upper faces are found on the whole 212 [feet] vertical course of this

Glen down to near L. Loggan, or whether only in the upper part; nor does

he state whether these rocks are scored, or polished, or moutonnees, or

whether there are any "perched" boulders there or elsewhere. I suspect

it would be difficult to distinguish between a river-bed and tidal

channel. Mr. Milne's description of the Pass of Mukkul, expanding to a

width of several hundred yards 21 feet deep in the shoalest part, and

with a worn islet in the middle, sounds to me much more like a tidal

channel than a river-bed. There must have been, on the latter view,

plenty of fresh water in those days. With respect to the coincidence

of the shelves with the now watersheds, Mr. Milne only gives half of my

explanation. Please read page 65 of my paper. (520/3. "Observations

on the Parallel Roads of Glen Roy, and of other Parts of Lochaber in

Scotland, with an Attempt to Prove that they are of Marine Origin."

"Phil. Trans. R. Soc." 1839, page 39. [Read February 7th, 1839.]) I

allude only to the head of Glen Roy and Kilfinnin as silted up. I did

not know Mukkul Pass; and Glen Roy was so much covered up that I did not

search it well, as I was not able to walk very well. It has been an old

conjectural belief of mine that a rising surface becomes stationary,

not suddenly, but by the movement becoming very slow. Now, this would

greatly aid the tidal currents cutting down the passes between the

mountains just before, and to the level of, the stationary periods.

The currents in the fiords in T. del Fuego in a narrow crooked part are

often most violent; in other parts they seem to silt up.

Shall you do any levelling? I believe all the levelling has been

[done] in Glen Roy, nearly parallel to the Great Glen of Scotland. For

inequalities of elevation, the valley of the Spean, at right angles to

the apparent axes of elevation, would be the one to examine. If you go

to the head of Glen Roy, attend to the apparent shelf above the highest

one in Glen Roy, lying on the south side of Loch Spey, and therefore

beyond the watershed of Glen Roy. It would be a crucial case. I was

too unwell on that day to examine it carefully, and I had no levelling

instruments. Do these fragments coincide in level with Glen Gluoy shelf?

MacCulloch talks of one in Glen Turret above the shelf. I could not see

it. These would be important discoveries. But I will write no more, and

pray your forgiveness for this long, ill-written outpouring. I am very

glad you keep to your subject of the terraces. I have lately observed

that you have one great authority (C. Prevost), [not] that authority

signifies a [farthing?] on your side respecting your heretical and

damnable doctrine of the ocean falling. You see I am orthodox to the

burning pitch.

LETTER 521. TO D. MILNE-HOME. Down, [September] 20th, [1847].

I am much obliged by your note. I returned from London on Saturday, and

I found then your memoir (521/1. "On the Parallel Roads of Lochaber,

with Remarks on the Change of Relative Levels of Sea and Land in

Scotland, and on the Detrital Deposits in that Country," "Trans. R.

Soc. Edinb." Volume XVI., page 395, 1849. [Read March 1st and April 5th,

1847.]), which I had not then received, owing to the porter having been

out when I last sent to the Geological Society. I have read your paper

with the greatest interest, and have been much struck with the novelty

and importance of many of your facts. I beg to thank you for the

courteous manner in which you combat me, and I plead quite guilty to

your rebuke about demonstration. (521/2. Mr. Milne quotes a passage from

Mr. Darwin's paper ("Phil. Trans. R. Soc." 1839, page 56), in which the

latter speaks of the marine origin of the parallel roads of Lochaber as

appearing to him as having been demonstrated. Mr. Milne adds: "I regret

that Mr. Darwin should have expressed himself in these very decided and

confident terms, especially as his survey was incomplete; for I venture

to think that it can be satisfactorily established that the parallel

roads of Lochaber were formed by fresh-water lakes" (Milne, loc. cit.,

page 400).) You have misunderstood my paper on a few points, but I do

not doubt that is owing to its being badly and tediously written. You

will, I fear, think me very obstinate when I say that I am not in the

least convinced about the barriers (521/3. Mr. Milne believed that the

lower parts of the valleys were filled with detritus, which constituted

barriers and thus dammed up the waters into lakes.): they remain to me

as improbable as ever. But the oddest result of your paper on me (and I

assure you, as far as I know myself, it is not perversity) is that I

am very much staggered in favour of the ice-lake theory of Agassiz and

Buckland (521/4. Agassiz and Buckland believed that the lakes which

formed the "roads" were confined by glaciers or moraines. See "The

Glacial Theory and its Recent Progress," by Louis Agassiz, "Edinb. New

Phil. Journ." Volume XXXIII., page 217, 1842 (with map).): until I read

your important discovery of the outlet in Glen Glaster I never thought

this theory at all tenable. (521/5. Mr. Milne discovered that the middle

shelf of Glen Roy, which Mr. Darwin stated was "not on a level with

any watershed" (Darwin, loc. cit., page 43), exactly coincided with a

watershed at the head of Glen Glaster (Milne, loc. cit., page 398).) Now

it appears to me that a very good case can be made in its favour. I am

not, however, as yet a believer in the ice-lake theory, but I tremble

for the result. I have had a good deal of talk with Mr. Lyell on

the subject, and from his advice I am going to send a letter to the

"Scotsman," in which I give briefly my present impression (though there

is not space to argue with you on such points as I think I could argue),

and indicate what points strike me as requiring further investigation

with respect, chiefly, to the ice-lake theory, so that you will not care

about it...

P.S.--Some facts mentioned in my "Geology of S. America," page 24

(521/6. The creeks which penetrate the western shores of Tierra del

Fuego are described as "almost invariably much shallower close to

the open sea at their mouths than inland...This shoalness of the

sea-channels near their entrances probably results from the quantity of

sediment formed by the wear and tear of the outer rocks exposed to

the full force of the open sea. I have no doubt that many lakes--for

instance, in Scotland--which are very deep within, and are separated

from the sea apparently only by a tract of detritus, were originally

sea-channels, with banks of this nature near their mouths, which have

since been upheaved" ("Geol. Obs. S. America," page 24, footnote.), with

regard to the shoaling of the deep fiords of T. del Fuego near their

mouths, and which I have remarked would tend, with a little elevation,

to convert such fiords into lakes with a great mound-like barrier of

detritus at their mouths, might, possibly, have been of use to you with

regard to the lakes of Glen Roy.

LETTER 522. TO C. LYELL. Down, Wednesday, 8th.

Many thanks for your paper. (522/1. "On the Ancient Glaciers of

Forfarshire." "Proc. Geol. Soc." Volume III., page 337, 1840.) I do

admire your zeal on a subject on which you are not immediately at work.

I will give my opinion as briefly as I can, and I have endeavoured my

best to be honest. Poor Mrs. Lyell will have, I foresee, a long letter

to read aloud, but I will try to write better than usual. Imprimis, it

is provoking that Mr. Milne (522/2. "On the Parallel Roads of Lochaber,

etc." "Trans. R. Soc. Edinb." Volume XVI., page 395, 1849. [Read March

1st and April 5th, 1847.]) has read my paper (522/3. "Observations on

the Parallel Roads of Glen Roy, etc." "Phil. Trans. R. Soc." 1839, page

39. [Read February 7th, 1839.].) with little attention, for he makes

me say several things which I do not believe--as, that the water sunk

suddenly! (page 10), that the Valley of Glen Roy, page 13, and Spean was

filled up with detritus to level of the lower shelf, against which there

is, I conceive, good evidence, etc., but I suppose it is the consequence

of my paper being most tediously written. He gives me a just snub for

talking of demonstration, and he fights me in a very pleasant manner.

Now for business. I utterly disbelieve in the barriers (522/4. See note,

Letter 521.) for his lakes, and think he has left that point exactly

where it was in the time of MacCulloch (522/5. "On the Parallel Roads of

Glen Roy." "Geol. Trans." Volume IV., page 314, 1817 (with several maps

and sections).) and Dick. (522/6. "On the Parallel Roads of Lochaber."

"Trans. R. Soc. Edinb." Volume IX., page 1, 1823.) Indeed, in showing

that there is a passage at Glen Glaster at the level of the intermediate

shelf, he makes the difficulty to my mind greater. (522/7. See Letter

521, note.) When I think of the gradual manner in which the two upper

terraces die out at Glen Collarig and at the mouth of Glen Roy, the

smooth rounded form of the hills there, and the lower shelf retaining

its usual width where the immense barrier stood, I can deliberately

repeat "that more convincing proofs of the non-existence of the

imaginary Loch Roy could scarcely have been invented with full play

given to the imagination," etc.: but I do not adhere to this remark

with such strength when applied to the glacier-lake theory. Oddly, I was

never at all staggered by this theory until now, having read Mr. Milne's

argument against it. I now can hardly doubt that a great glacier did

emerge from Loch Treig, and this by the ice itself (not moraine) might

have blocked up the three outlets from Glen Roy. I do not, however, yet

believe in the glacier theory, for reasons which I will presently give.

There are three chief hostile considerations in Mr. Milne's paper.

First, the Glen [shelf?], not coinciding in height with the upper one

[outlet?], from observations giving 12 feet, 15 feet, 29 feet, 23 feet:

if the latter are correct the terrace must be quite independent, and the

case is hostile; but Mr. Milne shows that there is one in Glen Roy 14

feet below the upper one, and a second one again (which I observed)

beneath this, and then we come to the proper second shelf. Hence there

is no great improbability in an independent shelf having been found in

Glen Gluoy.

This leads me to Mr. Milne's second class of facts (obvious to every

one), namely the non-extension of the three shelves beyond Glen Roy; but

I abide by what I have written on that point, and repeat that if in Glen

Roy, where circumstances have been so favourable for the preservation

or formation of the terraces, a terrace could be formed quite plain for

three-quarters of a mile with hardly a trace elsewhere, we cannot argue,

from the non-existence of shelves, that water did not stand at the same

levels in other valleys. Feeling absolutely convinced that there was no

barrier of detritus at the mouth of Glen Roy, and pretty well convinced

that there was none of ice, the manner in which the terraces die out

when entering Glen Spean, which must have been a tideway, shows on

what small circumstances the formation of these shelves depended. With

respect to the non-existence of shelves in other parts of Scotland, Mr.

Milne shows that many others do exist, and their heights above the sea

have not yet been carefully measured, nor have even those of Glen

Roy, which I suspect are all 100 feet too high. Moreover, according to

Bravais (522/8. "On the Lines of Ancient Level of the Sea in Finmark."

By A. Bravais, Member of the Scientific Commission of the North. "Quart.

Journ. Geol. Soc." Volume I., page 534, 1845 (a translation).), we

must not feel sure that either the absolute height or the intermediate

heights between the terraces would be at all the same at distant points.

In levelling the terraces in Lochaber, all, I believe, have been taken

in Glen Roy, nearly N. and S. There should be levels taken at right

angles to this line and to the Great Glen of Scotland or chief line of

elevation.

Thirdly, the nature of the outlets from the supposed lakes. This appears

to me the best and newest part of the paper. If Sir James Clark would

like to attend to any particular points, direct his attention to this:

especially to follow Glen Glaster from Glen Roy to L. Laggan. Mr. Milne

describes this as an old and great river-course with a fall of 212 feet.

He states that the rocks are smooth on upper face and rough on lower,

but he does not mention whether this character prevails throughout the

whole 212 vertical feet--a most important consideration; nor does he

state whether these rocks are polished or scratched, as might have

happened even to a considerable depth beneath the water (Mem. great

icebergs in narrow fiords of T. del Fuego (522/9. In the "Voyage of the

'Beagle'" a description is given of the falling of great masses of ice

from the icy cliffs of the glaciers with a crash that "reverberates

like the broadside of a man-of-war, through the lonely channels" which

intersect the coast-line of Tierra del Fuego. Loc. cit., page 246.))

by the action of icebergs, for that icebergs transported boulders on to

terraces, I have no doubt. Mr. Milne's description of the outlets of

his lake sound to me more like tidal channels, nor does he give any

arguments how such are to be distinguished from old river-courses.

I cannot believe in the body of fresh water which must, on the lake

theory, have flowed out of them. At the Pass of Mukkul he states that

the outlet is 70 feet wide and the rocky bottom 21 feet below the level

of the shelf, and that the gorge expands to the eastwards into a broad

channel of several hundred yards in width, divided in the middle by what

has formerly been a rocky islet, against which the waters of this large

river had chafed in issuing from the pass. We know the size of the river

at the present day which would flow out through this pass, and it seems

to me (and in the other given cases) to be as inadequate; the whole

seems to me far easier explained by a tideway than by a formerly more

humid climate.

With respect to the very remarkable coincidence between the shelves and

the outlets (rendered more remarkable by Mr. Milne's discovery of the

outlet to the intermediate shelf at Glen Glaster (522/10. See Letter

521, note.)), Mr. Milne gives only half of my explanation; he alludes

to (and disputes) the smoothing and silting-up action, which I still

believe in. I state: If we consider what must take place during

the gradual rise of a group of islands, we shall have the currents

endeavouring to cut down and deepen some shallow parts in the channels

as they are successively brought near the surface, but tending from the

opposition of tides to choke up others with littoral deposits. During

a long interval of rest, from the length of time allowed to the above

processes, the tendency would often prove effective, both in forming, by

accumulation of matter, isthmuses, and in keeping open channels. Hence

such isthmuses and channels just kept open would oftener be formed at

the level which the waters held at the interval of rest, than at any

other (page 65). I look at the Pass of Mukkul (21 feet deep, Milne) as a

channel just kept open, and the head of Glen Roy (where there is a

great bay silted up) and of Kilfinnin (at both which places there are

level-topped mounds of detritus above the level of the terraces) as

instances of channels filled up at the stationary levels. I have long

thought it a probable conjecture that when a rising surface becomes

stationary it becomes so, not at once, but by the movements first

becoming very slow; this would greatly favour the cutting down many gaps

in the mountains to the level of the stationary periods.

GLACIER THEORY.

If a glacialist admitted that the sea, before the formation of the

terraces, covered the country (which would account for land-straits

above level of terraces), and that the land gradually emerged, and if

he supposed his lakes were banked by ice alone, he would make out, in my

opinion, the best case against the marine origin of the terraces. From

the scattered boulders and till, you and I must look at it as certain

that the sea did cover the whole country, and I abide quite by my

arguments from the buttresses, etc., that water of some kind receded

slowly from the valleys of Lochaber (I presume Mr. Milne admits this).

Now, I do not believe in the ice-lake theory, from the following weak

but accumulating reasons: because, 1st, the receding water must have

been that of a lake in Glen Spean, and of the sea in the other valleys

of Scotland, where I saw similar buttresses at many levels; 2nd, because

the outlets of the supposed lakes as already stated seem, from Mr.

Milne's statements, too much worn and too large; 3rd, when the lake

stood at the three-quarters of a mile shelf the water from it must have

flowed over ice itself for a very long time, and kept at the same exact

level: certainly this shelf required a long time for its formation; 4th,

I cannot believe a glacier would have blocked up the short, very wide

valley of Kilfinnin, the Great Glen of Scotland also being very low

there; 5th, the country at some places where Mr. Milne has described

terraces is not mountainous, and the number of ice-lakes appears to me

very improbable; 6th, I do not believe any lake could scoop the rocks

so much as they are at the entrance to Loch Treig or cut them off at the

head of Upper Glen Roy; 7th, the very gradual dying away of the terraces

at the mouth of Glen Roy does not look like a barrier of any kind; 8th,

I should have expected great terminal moraines across the mouth of Glen

Roy, Glen Collarig, and Glaster, at least at the bottom of the valleys.

Such, I feel pretty sure, do not exist.

I fear I must have wearied you with the length of this letter, which

I have not had time to arrange properly. I could argue at great length

against Mr. Milne's theory of barriers of detritus, though I could help

him in one way--viz., by the soundings which occur at the entrances of

the deepest fiords in T. del Fuego. I do not think he gives the smallest

satisfaction with respect to the successive and comparatively sudden

breakage of his many lakes.

Well, I enjoyed my trip to Glen Roy very much, but it was time thrown

away. I heartily wish you would go there; it should be some one who

knows glacier and iceberg action, and sea action well. I wish the Queen

would command you. I had intended being in London to-morrow, but one of

my principal plagues will, I believe, stop me; if I do I will assuredly

call on you. I have not yet read Mr. Milne on Elevation (522/11. "On

a Remarkable Oscillation of the Sea, observed at Various Places on the

Coasts of Great Britain in the First Week of July, 1843." "Trans. R.

Soc. Edinb." Volume XV., page 609, 1844.), so will keep his paper for a

day or two.

P.S.--As you cannot want this letter, I wish you would return it to me,

as it will serve as a memorandum for me. Possibly I shall write to Mr.

Chambers, though I do not know whether he will care about what I think

on the subject. This letter is too long and ill-written for Sir J.

Clark.

LETTER 523. TO LADY LYELL. [October 4th, 1847.]

I enclose a letter from Chambers, which has pleased me very much (which

please return), but I cannot feel quite so sure as he does. If the

Lochaber and Tweed roads really turn out exactly on a level, the sea

theory is proved. What a magnificent proof of equality of elevation,

which does not surprise me much; but I fear I see cause of doubt, for

as far as I remember there are numerous terraces, near Galashiels, with

small intervals of height, so that the coincidence of height might be

cooked. Chambers does not seem aware of one very striking coincidence,

viz., that I made by careful measurement my Kilfinnin terrace 1202 feet

above sea, and now Glen Gluoy is 1203 feet, according to the recent more

careful measurements. Even Agassiz (523/1. "On the Glacial Theory," by

Louis Agassiz, "Edinb. New Phil. Journ." Volume XXXIII., page 217, 1842.

The parallel terraces are dealt with by Agassiz, pages 236 et seq.)

would be puzzled to block up Glen Gluoy and Kilfinnin by the same

glacier, and then, moreover, the lake would have two outlets. With

respect to the middle terrace of Glen Roy--seen by Chambers in the Spean

(figured by Agassiz, and seen by myself but not noticed, as I thought

it might have been a sheep track)--it might yet have been formed on the

ice-lake theory by two independent glaciers going across the Spean, but

it is very improbable that two such immense ones should not have been

united into one. Chambers, unfortunately, does not seem to have visited

the head of the Spey, and I have written to propose joining funds and

sending some young surveyor there. If my letter is published in the

"Scotsman," how Buckland (523/2. Professor Buckland may be described as

joint author, with Agassiz, of the Glacier theory.), as I have foreseen,

will crow over me: he will tell me he always knew that I was wrong, but

now I shall have rather ridiculously to say, "but I am all right again."

I have been a good deal interested in Miller (523/3. Hugh Miller's

"First Impressions of England and its People," London, 1847.), but I

find it not quick reading, and Emma has hardly begun it yet. I rather

wish the scenic descriptions were shorter, and that there was a little

less geologic eloquence.

Lyell's picture now hangs over my chimneypiece, and uncommonly glad I am

to have it, and thank you for it.

LETTER 524. TO C. LYELL. Down, September 6th [1861].

I think the enclosed is worth your reading. I am smashed to atoms about

Glen Roy. My paper was one long gigantic blunder from beginning to end.

Eheu! Eheu! (524/1. See "Life and Letters," I., pages 68, 69, also pages

290, 291.)

LETTER 525. TO C. LYELL. Down, September 22nd [1861].

I have read Mr. Jamieson's last letter, like the former ones, with very

great interest. (525/1. Mr. Jamieson visited Glen Roy in August 1861 and

in July 1862. His paper "On the Parallel Roads of Glen Roy, and their

Place in the History of the Glacial Period," was published in the

"Quarterly Journal of the Geological Society" in 1863, Volume XIX.,

page 235. His latest contribution to this subject was published in the

"Quarterly Journal," Volume XLVIII., page 5, 1892.) What a problem you

have in hand! It beats manufacturing new species all to bits. It would

be a great personal consolation to me if Mr. J. can admit the sloping

Spean terrace to be marine, and would remove one of my greatest

difficulties--viz. the vast contrast of Welsh and Lochaber valleys. But

then, as far as I dare trust my observations, the sloping terraces ran

far up the Roy valley, so as to reach not far below the lower shelf. If

the sloping fringes are marine and the shelves lacustrine, all I can

say is that nature has laid a shameful trap to catch an unwary wretch. I

suppose that I have underrated the power of lakes in producing pebbles;

this, I think, ought to be well looked to. I was much struck in Wales

on carefully comparing the glacial scratches under a lake (formed by a

moraine and which must have existed since the Glacial epoch) and above

water, and I could perceive NO difference. I believe I saw many such

beds of good pebbles on level of lower shelf, which at the time I could

not believe could have been found on shores of lake. The land-straits

and little cliffs above them, to which I referred, were quite above the

highest shelf; they may be of much more ancient date than the shelves.

Some terrace-like fringes at head of the Spey strike me as very

suspicious. Mr. J. refers to absence of pebbles at considerable heights:

he must remember that every storm, every deer, every hare which runs

tends to roll pebbles down hill, and not one ever goes up again. I

may mention that I particularly alluded to this on S. Ventanao (525/2.

"Geolog. Obs. on South America," page 79. "On the flanks of the

mountains, at a height of 300 or 400 feet above the plain, there were

a few small patches of conglomerate and breccia, firmly cemented by

ferruginous matter to the abrupt and battered face of the quartz--traces

being thus exhibited of ancient sea-action.") in N. Patagonia, a great

isolated rugged quartz-mountain 3,000 feet high, and I could find not

one pebble except on one very small spot, where a ferruginous spring had

firmly cemented a few to the face of mountain. If the Lochaber lakes had

been formed by an ice-period posterior to the (marine?) sloping terraces

in the Spean, would not Mr. J. have noticed gigantic moraines across the

valley opposite the opening of Lake Treig? I go so far as not to like

making the elevation of the land in Wales and Scotland considerably

different with respect to the ice-period, and still more do I dislike

it with respect to E. and W. Scotland. But I may be prejudiced by having

been so long accustomed to the plains of Patagonia. But the equality of

level (barring denudation) of even the Secondary formations in Britain,

after so many ups and downs, always impresses my mind, that, except when

the crust-cracks and mountains are formed, movements of elevation and

subsidence are generally very equable.

But it is folly my scribbling thus. You have a grand problem, and heaven

help you and Mr. Jamieson through it. It is out of my line nowadays, and

above and beyond me.

LETTER 526. TO J.D. HOOKER. Down, September 28th [1861].

It is, I believe, true that Glen Roy shelves (I remember your Indian

letter) were formed by glacial lakes. I persuaded Mr. Jamieson, an

excellent observer, to go and observe them; and this is his result.

There are some great difficulties to be explained, but I presume this

will ultimately be proved the truth...

LETTER 527. TO C. LYELL. Down, October 1st [1861].

Thank you for the most interesting correspondence. What a wonderful case

that of Bedford. (527/1. No doubt this refers to the discovery of flint

implements in the Valley of the Ouse, near Bedford, in 1861 (see Lyell's

"Antiquity of Man," pages 163 et seq., 1863.) I thought the problem

sufficiently perplexing before, but now it beats anything I ever heard

of. Far from being able to give any hypothesis for any part, I cannot

get the facts into my mind. What a capital observer and reasoner Mr.

Jamieson is. The only way that I can reconcile my memory of Lochaber

with the state of the Welsh valleys is by imagining a great barrier,

formed by a terminal moraine, at the mouth of the Spean, which the

river had to cut slowly through, as it drained the lowest lake after

the Glacial period. This would, I can suppose, account for the sloping

terraces along the Spean. I further presume that sharp transverse

moraines would not be formed under the waters of the lake, where the

glacier came out of L. Treig and abutted against the opposite side of

the valley. A nice mess I made of Glen Roy! I have no spare copy of

my Welsh paper (527/2. "Notes on the Effects produced by the Ancient

Glaciers of Caernarvonshire, and on the Boulders transported by Floating

Ice," "Edinb. New Phil. Journ." Volume XXXIII., page 352, 1842.); it

would do you no good to lend it. I suppose I thought that there must

have been floating ice on Moel Tryfan. I think it cannot be disputed

that the last event in N. Wales was land-glaciers. I could not decide

where the action of land-glaciers ceased and marine glacial action

commenced at the mouths of the valleys.

What a wonderful case the Bedford case. Does not the N. American view of

warmer or more equable period, after great Glacial period, become much

more probable in Europe?

But I am very poorly to-day, and very stupid, and hate everybody and

everything. One lives only to make blunders. I am going to write a

little book for Murray on Orchids (527/3. "On the Various Contrivances

by which Orchids are Fertilised by Insects," London, 1862.), and to-day

I hate them worse than everything. So farewell, in a sweet frame of

mind.

LETTER 528. TO C. LYELL. Down, October 14th [1861].

I return Jamieson's capital letter. I have no comments, except to say

that he has removed all my difficulties, and that now and for evermore I

give up and abominate Glen Roy and all its belongings. It certainly is

a splendid case, and wonderful monument of the old Ice-period. You ought

to give a woodcut. How many have blundered over those horrid shelves!

That was a capital paper by Jamieson in the last "Geol. Journal."

(528/1. "On the Drift and Rolled Gravel of the North of Scotland,"

"Quart. Journ. Geol. Soc." Volume XVI., page 347, 1860.) I was never

before fully convinced of the land glacialisation of Scotland before,

though Chambers tried hard to convince me.

I must say I differ rather about Ramsay's paper; perhaps he pushes it

too far. (528/2. "On the Glacial Origin of Certain Lakes, etc." "Quart.

Journ. Geol. Soc." Volume XVIII., page 185. See Letter 503.) It struck

me the more from remembering some years ago marvelling what could be

the meaning of such a multitude of lakes in Friesland and other northern

districts. Ramsay wrote to me, and I suggested that he ought to compare

mountainous tropical regions with northern regions. I could not remember

many lakes in any mountainous tropical country. When Tyndall talks of

every valley in Switzerland being formed by glaciers, he seems to forget

there are valleys in the tropics; and it is monstrous, in my opinion,

the accounting for the Glacial period in the Alps by greater height

of mountains, and their lessened height, if I understand, by glacial

erosion. "Ne sutor ultra crepidam," I think, applies in this case to

him. I am hard at work on "Variation under Domestication." (528/3.

Published 1868.)

P.S.--I am rather overwhelmed with letters at present, and it has just

occurred to me that perhaps you will forward my note to Mr. Jamieson; as

it will show that I entirely yield. I do believe every word in my Glen

Roy paper is false.

LETTER 529. TO C. LYELL. Down, October 20th [1861].

Notwithstanding the orchids, I have been very glad to see Jamieson's

letter; no doubt, as he says, certainty will soon be reached.

With respect to the minor points of Glen Roy, I cannot feel easy with

a mere barrier of ice; there is so much sloping, stratified detritus in

the valleys. I remember that you somewhere have stated that a running

stream soon cuts deeply into a glacier. I have been hunting up all old

references and pamphlets, etc., on shelves in Scotland, and will

send them off to Mr. J., as they possibly may be of use to him if he

continues the subject. The Eildon Hills ought to be specially examined.

Amongst MS. I came across a very old letter from me to you, in which I

say: "If a glacialist admitted that the sea, before the formation of the

shelves, covered the country (which would account for the land-straits

above the level of the shelves), and if he admitted that the land

gradually emerged, and if he supposed that his lakes were banked up by

ice alone, he would make out, in my opinion, the best case against the

marine origin of the shelves." (529/1. See Letter 522.) This seems very

much what you and Mr. J. have come to.

The whole glacial theory is really a magnificent subject.

LETTER 530. TO C. LYELL. Down, April 1st [1862].

I am not quite sure that I understand your difficulty, so I must give

what seems to me the explanation of the glacial lake theory at some

little length. You know that there is a rocky outlet at the level of

all the shelves. Please look at my map. (530/1. The map accompanying

Mr. Darwin's paper in the "Phil. Trans. R. Soc." 1839.) I suppose whole

valley of Glen Spean filled with ice; then water would escape from

an outlet at Loch Spey, and the highest shelf would be first formed.

Secondly, ice began to retreat, and water will flow for short time over

its surface; but as soon as it retreated from behind the hill marked

Craig Dhu, where the outlet on level of second shelf was discovered by

Milne (530/2. See note, Letter 521.), the water would flow from it and

the second shelf would be formed. This supposes that a vast barrier

of ice still remains under Ben Nevis, along all the lower part of the

Spean. Lastly, I suppose the ice disappeared everywhere along L. Loggan,

L. Treig, and Glen Spean, except close under Ben Nevis, where it still

formed a barrier, the water flowing out at level of lowest shelf by the

Pass of Mukkul at head of L. Loggan. This seems to me to account for

everything. It presupposes that the shelves were formed towards the

close of the Glacial period. I come up to London to read on Thursday a

short paper at the Linnean Society. Shall I call on Friday morning at

9.30 and sit half an hour with you? Pray have no scruple to send a line

to Queen Anne Street to say "No" if it will take anything out of you. If

I do not hear, I will come.

LETTER 531. TO J. PRESTWICH. Down, January 3rd, 1880.

You are perfectly right. (531/1. Prof. Prestwich's paper on Glen Roy was

published in the "Phil. Trans. R. Soc." for 1879, page 663.) As soon as

I read Mr. Jamieson's article on the parallel roads, I gave up the ghost

with more sighs and groans than on almost any other occasion in my life.

2.IX.IV. CORAL REEFS, FOSSIL AND RECENT, 1841-1881.

LETTER 532. TO C. LYELL. Shrewsbury, Tuesday, 6th [July, 1841].

Your letter was forwarded me here. I was the more glad to receive it, as

I never dreamed of your being able to find time to write, now that you

must be so very busy; and I had nothing to tell you about myself, else I

should have written. I am pleased to hear how extensive and successful

a trip you appear to have made. You must have worked hard, and got your

Silurian subject well in your head, to have profited by so short an

excursion. How I should have enjoyed to have followed you about the

coral-limestone. I once was close to Wenlock (532/1. The Wenlock

limestone (Silurian) contains an abundance of corals. "The rock seems

indeed to have been formed in part by massive sheets and bunches of

coral" (Geikie, "Text-book of Geology," 1882, page 678.), something such

as you describe, and made a rough drawing, I remember, of the masses of

coral. But the degree in which the whole mass was regularly stratified,

and the quantity of mud, made me think that the reefs could never have

been like those in the Pacific, but that they most resembled those on

the east coast of Africa, which seem (from charts and descriptions)

to confine extensive flats and mangrove swamps with mud, or like some

imperfect ones about the West India Islands, within the reefs of which

there are large swamps. All the reefs I have myself seen could be

associated only with nearly pure calcareous rocks. I have received a

description of a reef lying some way off the coast near Belize (terra

firma), where a thick bed of mud seems to have invaded and covered a

coral reef, leaving but very few islets yet free from it. But I can

give you no precise information without my notes (even if then) on these

heads...

Bermuda differs much from any other island I am acquainted with. At

first sight of a chart it resembles an atoll; but it differs from this

structure essentially in the gently shelving bottom of the sea all round

to some distance; in the absence of the defined circular reefs, and, as

a consequence, of the defined central pool or lagoon; and lastly, in

the height of the land. Bermuda seems to be an irregular, circular, flat

bank, encrusted with knolls and reefs of coral, with land formed on one

side. This land seems once to have been more extensive, as on some parts

of the bank farthest removed from the island there are little pinnacles

of rock of the same nature as that of the high larger islands. I cannot

pretend to form any precise notion how the foundation of so anomalous an

island has been produced, but its whole history must be very different

from that of the atolls of the Indian and Pacific oceans--though, as

I have said, at first glance of the charts there is a considerable

resemblance.

LETTER 533. TO C. LYELL. [1842.]

Considering the probability of subsidence in the middle of the great

oceans being very slow; considering in how many spaces, both large ones

and small ones (within areas favourable to the growth of corals), reefs

are absent, which shows that their presence is determined by peculiar

conditions; considering the possible chance of subsidence being more

rapid than the upward growth of the reefs; considering that reefs not

very rarely perish (as I cannot doubt) on part, or round the whole, of

some encircled islands and atolls: considering these things, I admit as

very improbable that the polypifers should continue living on and

above the same reef during a subsidence of very many thousand feet; and

therefore that they should form masses of enormous thickness, say at

most above 5,000 feet. (533/1. "...As we know that some inorganic causes

are highly injurious to the growth of coral, it cannot be expected that

during the round of change to which earth, air, and water are exposed,

the reef-building polypifers should keep alive for perpetuity in any

one place; and still less can this be expected during the progressive

subsidences...to which by our theory these reefs and islands have been

subjected, and are liable" ("The Structure and Distribution of Coral

Reefs," page 107: London, 1842).) This admission, I believe, is in no

way fatal to the theory, though it is so to certain few passages in my

book.

In the areas where the large groups of atolls stand, and where likewise

a few scattered atolls stand between such groups, I always imagined that

there must have been great tracts of land, and that on such large tracts

there must have been mountains of immense altitudes. But not, it appears

to me, that one is only justified in supposing that groups of islands

stood there. There are (as I believe) many considerable islands and

groups of islands (Galapagos Islands, Great Britain, Falkland Islands,

Marianas, and, I believe, Viti groups), and likewise the majority of

single scattered islands, all of which a subsidence between 4,000

and 5,000 feet would entirely submerge or would leave only one or two

summits above water, and hence they would produce either groups of

nothing but atolls, or of atolls with one or two encircled islands. I

am far from wishing to say that the islands of the great oceans have not

subsided, or may not continue to subside, any number of feet, but if the

average duration (from all causes of destruction) of reefs on the same

spot is limited, then after this limit has elapsed the reefs would

perish, and if the subsidence continued they would be carried down; and

if the group consisted only of atolls, only open ocean would be left; if

it consisted partly or wholly of encircled islands, these would be left

naked and reefless, but should the area again become favourable for

growth of reefs, new barrier-reefs might be formed round them. As an

illustration of this notion of a certain average duration of reefs on

the same spot, compared with the average rate of subsidence, we may take

the case of Tahiti, an island of 7,000 feet high. Now here the present

barrier-reefs would never be continued upwards into an atoll, although,

should the subsidence continue at a period long after the death of the

present reefs, new ones might be formed high up round its sides and

ultimately over it. The case resolves itself into: what is the ordinary

height of groups of islands, of the size of existing groups of atolls

(excepting as many of the highest islands as there now ordinarily occur

encircling barrier-reefs in the existing groups of atolls)? and likewise

what is the height of the single scattered islands standing between such

groups of islands? Subsidence sufficient to bury all these islands (with

the exception of as many of the highest as there are encircled islands

in the present groups of atolls) my theory absolutely requires, but no

more. To say what amount of subsidence would be required for this end,

one ought to know the height of all existing islands, both single ones

and those in groups, on the face of the globe--and, indeed, of half a

dozen worlds like ours. The reefs may be of much greater [thickness]

than that just sufficient on an average to bury groups of islands; and

the probability of the thickness being greater seems to resolve itself

into the average rate of subsidence allowing upward growth, and average

duration of reefs on the same spot. Who will say what this rate and

what this duration is? but till both are known, we cannot, I think, tell

whether we ought to look for upraised coral formations (putting on one

side denudation) above the unknown limit, say between 3,000 and 5,000

feet, necessary to submerge groups of common islands. How wretchedly

involved do these speculations become.

LETTER 534. TO E. VON MOJSISOVICS. Down, January 29th, 1879.

I thank you cordially for the continuation of your fine work on the

Tyrolese Dolomites (534/1. "Dolomitriffe Sudtirols und Venetiens":

Wien, 1878.), with its striking engravings and the maps, which are quite

wonderful from the amount of labour which they exhibit, and its extreme

difficulty. I well remember more than forty years ago examining a

section of Silurian limestone containing many corals, and thinking to

myself that it would be for ever impossible to discover whether the

ancient corals had formed atolls or barrier reefs; so you may well

believe that your work will interest me greatly as soon as I can find

time to read it. I am much obliged for your photograph, and from its

appearance rejoice to see that much more good work may be expected from

you.

I enclose my own photograph, in case you should like to possess a copy.

LETTER 535. TO A. AGASSIZ.

(535/1. Part of this letter is published in "Life and Letters," III.,

pages 183, 184.)

Down, May 5th, 1881.

It was very good of you to write to me from Tortugas, as I always feel

much interested in hearing what you are about, and in reading your

many discoveries. It is a surprising fact that the peninsula of Florida

should have remained at the same level for the immense period requisite

for the accumulation of so vast a pile of debris. (535/2. Alexander

Agassiz published a paper on "The Tortugas and Florida Reefs" in the

"Mem. Amer. Acad. Arts and Sci." XI., page 107, 1885. See also his

"Three Cruises of the 'Blake,'" Volume I., 1888.)

You will have seen Mr. Murray's views on the formation of atolls and

barrier reefs. (535/3. "On the Structure and Origin of Coral Reefs and

Islands," "Proc. R. Soc. Edin." Volume X., page 505, 1880. Prof. Bonney

has given a summary of Sir John Murray's views in Appendix II. of the

third edition of Darwin's "Coral Reefs," 1889.) Before publishing my

book, I thought long over the same view, but only as far as ordinary

marine organisms are concerned, for at that time little was known of the

multitude of minute oceanic organisms. I rejected this view, as from

the few dredgings made in the 'Beagle' in the S. Temperate regions, I

concluded that shells, the smaller corals, etc., etc., decayed and were

dissolved when not protected by the deposition of sediment; and sediment

could not accumulate in the open ocean. Certainly shells, etc., were

in several cases completely rotten, and crumbled into mud between my

fingers; but you will know well whether this is in any degree common. I

have expressly said that a bank at the proper depth would give rise

to an atoll, which could not be distinguished from one formed during

subsidence. I can, however, hardly believe, in the former presence of as

many banks (there having been no subsidence) as there are atolls in

the great oceans, within a reasonable depth, on which minute oceanic

organisms could have accumulated to the thickness of many hundred feet.

I think that it has been shown that the oscillations from great waves

extend down to a considerable depth, and if so the oscillating water

would tend to lift up (according to an old doctrine propounded by

Playfair) minute particles lying at the bottom, and allow them to be

slowly drifted away from the submarine bank by the slightest current.

Lastly, I cannot understand Mr. Murray, who admits that small calcareous

organisms are dissolved by the carbonic acid in the water at great

depths, and that coral reefs, etc., etc., are likewise dissolved near

the surface, but that this does not occur at intermediate depths, where

he believes that the minute oceanic calcareous organisms accumulate

until the bank reaches within the reef-building depth. But I suppose

that I must have misunderstood him.

Pray forgive me for troubling you at such a length, but it has occurred

to me that you might be disposed to give, after your wide experience,

your judgment. If I am wrong, the sooner I am knocked on the head and

annihilated so much the better. It still seems to me a marvellous thing

that there should not have been much and long-continued subsidence in

the beds of the great oceans. I wish that some doubly rich millionaire

would take it into his head to have borings made in some of the Pacific

and Indian atolls, and bring home cores for slicing from a depth of 500

or 600 feet. (535/4. In 1891 a Committee of the British Association was

formed for the investigation of an atoll by means of boring. The Royal

Society took up the scheme, and an expedition was sent to Funafuti, with

Prof. Sollas as leader. Another expedition left Sydney in 1897 under the

direction of Prof. Edgeworth David, and a deeper boring was made. The

Reports will be published in the "Philosophical Transactions," and will

contain Prof. David's notes upon the boring and the island generally,

Dr. Hinde's description of the microscopic structure of the cores and

other examinations of them, carried on at the Royal College of Science,

South Kensington. The boring reached a depth of 1114 feet; the cores

were found to consist entirely of reef-forming corals in situ and in

fragments, with foraminifera and calcareous algae; at the bottom there

were no traces of any other kind of rock. It seems, therefore, to us,

that unless it can be proved that reef-building corals began their work

at depths of at least 180 fathoms--far below that hitherto assigned--the

result gives the strongest support to Darwin's theory of subsidence; the

test which Darwin wished to be applied has been fairly tried, and the

verdict is entirely in his favour.)

2.IX.V. CLEAVAGE AND FOLIATION, 1846-1856.

LETTER 536. TO D. SHARPE.

(536/1. The following eight letters were written at a time when the

subjects of cleavage and foliation were already occupying the minds of

several geologists, including Sharpe, Sorby, Rogers, Haughton, Phillips,

and Tyndall. The paper by Sharpe referred to was published in 1847

("Quart. Journ. Geol. Soc." Volume III.), and his ideas were amplified

in two later papers (ibid., Volume V., 1849, and "Phil. Trans." 1852).

Darwin's own views, based on his observations during the "Beagle"

expedition, had appeared in Chapter XIII. of "South America" (1846) and

in the "Manual of Scientific Enquiry" (1849), but are perhaps nowhere

so clearly expressed as in this correspondence. His most important

contribution to the question was in establishing the fact that foliation

is often a part of the same process as cleavage, and is in nowise

necessarily connected with planes of stratification. Herein he was

opposed to Lyell and the other geologists of the day, but time has

made good his position. The postscript to Letter 542 is especially

interesting. We are indebted to Mr. Harker, of St. John's College, for

this note.)

Down, August 23rd [1846?].

I must just send one line to thank you for your note, and to say

how heartily glad I am that you stick to the cleavage and foliation

question. Nothing will ever convince me that it is not a noble subject

of investigation, which will lead some day to great views. I think it

quite extraordinary how little the subject seems to interest British

geologists. You will, I think live to see the importance of your paper

recognised. (536/2. Probably the paper "On Slaty Cleavage." "Quart.

Journ. Geol. Soc." Volume III., page 74, 1847.) I had always thought

that Studer was one of the few geologists who had taken a correct and

enlarged view on the subject.

LETTER 537. TO D. SHARPE. Down [November 1846].

I have been much interested with your letter, and am delighted that

you have thought my few remarks worth attention. My observations on

foliation are more deserving confidence than those on cleavage; for

during my first year in clay-slate countries, I was quite unaware of

there being any marked difference between cleavage and stratification; I

well remember my astonishment at coming to the conclusion that they

were totally different actions, and my delight at subsequently reading

Sedgwick's views (537/1. "Remarks on the Structure of Large Mineral

Masses, and especially on the Chemical Changes produced in the

Aggregation of Stratified Rocks during different periods after their

Deposition." "Trans. Geol. Soc." Volume III., page 461, 1835. In the

section of this paper dealing with cleavage (page 469) Prof. Sedgwick

lays stress on the fact that "the cleavage is in no instance parallel

to the true beds."); hence at that time I was only just getting out of

a mist with respect to cleavage-laminae dipping inwards on mountain

flanks. I have certainly often observed it--so often that I thought

myself justified in propounding it as usual. I might perhaps have been

in some degree prejudiced by Von Buch's remarks, for which in those

days I had a somewhat greater deference than I now have. The Mount at

M. Video (page 146 of my book (537/2. "Geol. Obs. S. America." page 146.

The mount is described as consisting of hornblendic slate; "the laminae

of the slate on the north and south side near the summit dip inwards."))

is certainly an instance of the cleavage-laminae of a hornblendic schist

dipping inwards on both sides, for I examined this hill carefully

with compass in hand and notebook. I entirely admit, however, that a

conclusion drawn from striking a rough balance in one's mind is worth

nothing compared with the evidence drawn from one continuous line of

section. I read Studer's paper carefully, and drew the conclusion stated

from it; but I may very likely be in an error. I only state that I have

frequently seen cleavage-laminae dipping inwards on mountain sides;

that I cannot give up, but I daresay a general extension of the rule (as

might justly be inferred from the manner of my statement) would be quite

erroneous. Von Buch's statement is in his "Travels in Norway" (537/3.

"Travels through Norway and Lapland during the years 1806-8": London,

1813.); I have unfortunately lost the reference, and it is a high crime,

I confess, even to refer to an opinion without a precise reference. If

you never read these travels they might be worth skimming, chiefly as an

amusement; and if you like and will send me a line by the general

post of Monday or Tuesday, I will either send it up with Hopkins on

Wednesday, or bring it myself to the Geological Society. I am very glad

you are going to read Hopkins (537/4. "Researches in Physical Geology,"

by W. Hopkins. "Phil. Trans. R. Soc." 1839, page 381; ibid, 1842, page

43, etc.); his views appear to me eminently worth well comprehending;

false views and language appear to me to be almost universally held by

geologists on the formation of fissures, dikes and mountain chains. If

you would have the patience, I should be glad if you would read in my

"Volcanic Islands" from page 65, or even pages 54 to 72--viz., on

the lamination of volcanic rocks; I may add that I sent the series

of specimens there described to Professor Forbes of Edinburgh, and he

thought they bore out my views.

There is a short extract from Prof. Rogers (537/5. "On Cleavage of

Slate-strata." "Edinburgh New Phil. Journ." Volume XLI., page 422,

1846.) in the last "Edinburgh New Phil. Journal," well worth your

attention, on the cleavage of the Appalachian chain, and which seems far

more uniform in the direction of dip than in any case which I have met

with; the Rogers doctrine of the ridge being thrown up by great waves

I believe is monstrous; but the manner in which the ridges have been

thrown over (as if by a lateral force acting on one side on a higher

level than on the other) is very curious, and he now states that the

cleavage is parallel to the axis-planes of these thrown-over ridges.

Your case of the limestone beds to my mind is the greatest difficulty

on any mechanical doctrine; though I did not expect ever to find

actual displacement, as seems to be proved by your shell evidence. I am

extremely glad you have taken up this most interesting subject in such

a philosophical spirit; I have no doubt you will do much in it; Sedgwick

let a fine opportunity slip away. I hope you will get out another

section like that in your letter; these are the real things wanted.

LETTER 538. TO D. SHARPE. Down, [January 1847].

I am very much obliged for the MS., which I return. I do not quite

understand from your note whether you have struck out all on this point

in your paper: I much hope not; if you have, allow me to urge on you to

append a note, briefly stating the facts, and that you omitted them in

your paper from the observations not being finished.

I am strongly tempted to suspect that the cleavage planes will be proved

by you to have slided a little over each other, and to have been planes

of incipient tearing, to use Forbes' expression in ice; it will in that

case be beautifully analogical with my laminated lavas, and these in

composition are intimately connected with the metamorphic schists.

The beds without cleavage between those with cleavage do not weigh quite

so heavily on me as on you. You remember, of course, Sedgwick's facts

of limestone, and mine of sandstone, breaking in the line of cleavage,

transversely to the planes of deposition. If you look at cleavage as

I do, as the result of chemical action or crystalline forces,

super-induced in certain places by their mechanical state of tension,

then it is not surprising that some rocks should yield more or less

readily to the crystalline forces.

I think I shall write to Prof. Forbes (538/1. Prof. D. Forbes.) of

Edinburgh, with whom I corresponded on my laminated volcanic rocks, to

call his early attention to your paper.

LETTER 539. TO D. SHARPE. Down, October 16th [1851].

I am very much obliged to you for telling me the results of your

foliaceous tour, and I am glad you are drawing up an account for the

Royal Society. (539/1. "On the Arrangement of the Foliation and Cleavage

of the Rocks of the North of Scotland." "Phil. Trans. R. Soc." 1852,

page 445, with Plates XXIII. and XXIV.) I hope you will have a good

illustration or map of the waving line of junction of the slate and

schist with uniformly directed cleavage and foliation. It strikes me as

crucial. I remember longing for an opportunity to observe this point.

All that I say is that when slate and the metamorphic schists occur in

the same neighbourhood, the cleavage and foliation are uniform: of

this I have seen many cases, but I have never observed slate overlying

mica-slate. I have, however, observed many cases of glossy clay-slate

included within mica-schist and gneiss. All your other observations on

the order, etc., seem very interesting. From conversations with Lyell,

etc., I recommend you to describe in a little detail the nature of the

metamorphic schists; especially whether there are quasi-substrata of

different varieties of mica-slate or gneiss, etc.; and whether you

traced such quasi beds into the cleavage slate. I have not the least

doubt of such facts occurring, from what I have seen (and described at

M. Video) of portions of fine chloritic schists being entangled in the

midst of a gneiss district. Have you had any opportunity of tracing a

bed of marble? This, I think, from reasons given at page 166 of my

"S. America," would be very interesting. (539/2. "I have never had an

opportunity of tracing, for any distance, along the line both of strike

and dip, the so-called beds in the metamorphic schists, but I strongly

suspect that they would not be found to extend, with the same character,

very far in the line either of their dip or strike. Hence I am led to

believe that most of the so-called beds are of the nature of complex

folia, and have not been separately deposited. Of course, this view

cannot be extended to THICK masses included in the metamorphic series,

which are of totally different composition from the adjoining schists,

and which are far-extended, as is sometimes the case with quartz

and marble; these must generally be of the nature of true strata"

("Geological Observations," page 166).) A suspicion has sometimes

occurred to me (I remember more especially when tracing the clay-slate

at the Cape of Good Hope turning into true gneiss) that possibly all the

metamorphic schists necessarily once existed as clay-slate, and that

the foliation did not arise or take its direction in the metamorphic

schists, but resulted simply from the pre-existing cleavage. The

so-called beds in the metamorphic schists, so unlike common cleavage

laminae, seems the best, or at least one argument against such a

suspicion. Yet I think it is a point deserving your notice. Have you

thought at all over Rogers' Law, as he reiterates it, of cleavage being

parallel to his axes-planes of elevation?

If you know beforehand, will you tell me when your paper is read, for

the chance of my being able to attend? I very seldom leave home, as I

find perfect quietude suits my health best.

(PLATE: CHARLES DARWIN, Cir. 1854. Maull & Fox, photo. Walker &

Cockerell, ph. sc.)

LETTER 540. TO C. LYELL. Down, January 10th, 1855.

I received your letter yesterday, but was unable to answer it, as I had

to go out at once on business of importance. I am very glad that you

are reconsidering the subject of foliation; I have just read over what

I have written on the subject, and admire it very much, and abide by it

all. (540/1. "Geological Observations on South America," Chapter VI.,

1846.) You will not readily believe how closely I attended to the

subject, and in how many and wide areas I verified my remarks. I see I

have put pretty strongly the mechanical view of origin; but I might even

then, but was afraid, have put my belief stronger. Unfortunately I have

not D. Sharpe's paper here to look over, but I think his chief points

[are] (1) the foliation forming great symmetrical curves, and (2)

the proof from effects of form of shell (540/2. This refers to the

distortion of shells in cleaved rocks.) of the mechanical action in

cleaved rocks. The great curvature would be, I think, a grand discovery

of Sharpe's, but I confess there is some want of minuteness in the

statement of Sharpe which makes me wish to see his facts confirmed. That

the foliation and cleavage are parts of curves I am quite prepared,

from what I have seen, to believe; but the simplicity and grandeur of

Sharpe's curves rather stagger me. I feel deeply convinced that when

(and I and Sharpe have seen several most striking and obvious examples)

great neighbouring or alternating regions of true metamorphic schists

and clay-slate have their foliations and cleavage parallel, there is

no way of escaping the conclusion, that the layers of pure quartz,

feldspar, mica, chlorite, etc., etc., are due not to original

deposition, but to segregation; and this is I consider the point which I

have established. This is very odd, but I suspect that great metamorphic

areas are generally derived from the metamorphosis of clay-slate, and

not from alternating layers of ordinary sedimentary matter. I think you

have exactly put the chief difficulty in its strongest light--viz. what

would be the result of pure or nearly pure layers of very different

mineralogical composition being metamorphosed? I believe even such might

be converted into an ordinary varying mass of metamorphic schists. I am

certain of the correctness of my account of patches of chlorite schists

enclosed in other schist, and of enormous quartzose veins of segregation

being absolutely continuous and contemporaneous with the folia of

quartz, and such, I think, might be the result of the folia crossing

a true stratum of quartz. I think my description of the wonderful and

beautiful laminated volcanic rocks at Ascension would be worth your

looking at. (540/3. "Geological Observations on S. America," pages 166,

167; also "Geological Observations on the Volcanic Islands," Chapter

III. (Ascension), 1844.)

LETTER 541. TO C. LYELL. Down, January 14th [1855].

We were yesterday and the day before house-hunting, so I could not

answer your letter. I hope we have succeeded in a house, after infinite

trouble, but am not sure, in York Place, Baker Street.

I do not doubt that I either read or heard from Sharpe about the

Grampians; otherwise from my own old suspicion I should not have

inserted the passage in the manual.

The laminated rocks at Ascension are described at page 54. (541/1.

"Volcanic Islands," page 54. "Singular laminated beds alternating with

and passing into obsidian.")

As far as my experience has gone, I should speak only of clay-slate

being associated with mica-slate, for when near the metamorphic schists

I have found stratification so gone that I should not dare to speak of

them as overlying them. With respect to the difficulty of beds of quartz

and marble, this has for years startled me, and I have longed (since I

have felt its force) to have some opportunity of testing this point,

for without you are sure that the beds of quartz dip, as well as strike,

parallel to the foliation, the case is only just like true strata of

sandstone included in clay-slate and striking parallel to the cleavage

of the clay-slate, but of course with different dip (excepting in those

rare cases when cleavage and stratification are parallel). Having this

difficulty before my eyes, I was much struck with MacCulloch's statement

(page 166 of my "S. America") about marble in the metamorphic series not

forming true strata.

(FIGURE 6.)

Your expectation of the metamorphic schists sending veins into

neighbouring rocks is quite new to me; but I much doubt whether you have

any right to assume fluidity from almost any amount of molecular

change. I have seen in fine volcanic sandstone clear evidence of all

the calcareous matter travelling at least 4 1/2 feet in distance to

concretions on either hand (page 113 of "S. America") (541/2. "Some

of these concretions (flattened spherical concretions composed of hard

calcareous sandstone, containing a few shells, occurring in a bed of

sandstone) were 4 feet in diameter, and in a horizontal line 9 feet

apart, showing that the calcareous matter must have been drawn to the

centres of attraction from a distance of four feet and a half on both

sides" ("Geological Observations on S. America," page 113).) I have not

examined carefully, from not soon enough seeing all the difficulties;

but I believe, from what I have seen, that the folia in the metamorphic

schists (I do not here refer to the so-called beds) are not of great

length, but thin out, and are succeeded by others; and the notion I have

of the molecular movements is shown in the indistinct sketch herewith

sent [Figure 6]. The quartz of the strata might here move into the

position of the folia without much more movement of molecules than in

the formation of concretions. I further suspect in such cases as this,

when there is a great original abundance of quartz, that great branching

contemporaneous veins of segregation (as sometimes called) of quartz

would be formed. I can only thus understand the relation which exists

between the distorted foliation (not appearing due to injection) and the

presence of such great veins.

I believe some gneiss, as the gneiss-granite of Humboldt, has been as

fluid as granite, but I do not believe that this is usually the case,

from the frequent alternations of glossy clay and chlorite slates, which

we cannot suppose to have been melted.

I am far from wishing to doubt that true sedimentary strata have been

converted into metamorphic schists: all I can say is, that in the three

or four great regions, where I could ascertain the relations of the

metamorphic schists to the neighbouring cleaved rocks, it was impossible

(as it appeared to me) to admit that the foliation was due to aqueous

deposition. Now that you intend agitating the subject, it will soon be

cleared up.

LETTER 542. TO C. LYELL. 27, York Place, Baker Street [1855].

I have received your letter from Down, and I have been studying my S.

American book.

I ought to have stated [it] more clearly, but undoubtedly in W. Tierra

del Fuego, where clay-slate passes by alternation into a grand district

of mica-schist, and in the Chonos Islands and La Plata, where glossy

slates occur within the metamorphic schists, the foliation is parallel

to the cleavage--i.e. parallel in strike and dip; but here comes, I am

sorry and ashamed to say, a great hiatus in my reasoning. I have assumed

that the cleavage in these neighbouring or intercalated beds was (as in

more distant parts) distinct from stratification. If you choose to

say that here the cleavage was or might be parallel to true bedding,

I cannot gainsay it, but can only appeal to apparent similarity to

the great areas of uniformity of strike and high angle--all certainly

unlike, as far as my experience goes, to true stratification. I have

long known how easily I overlook flaws in my own reasoning, and this is

a flagrant case. I have been amused to find, for I had quite forgotten,

how distinctly I give a suspicion (top of page 155) to the idea, before

Sharpe, of cleavage (not foliation) being due to the laminae forming

parts of great curves. (542/1. "I suspect that the varying and opposite

dips (of the cleavage-planes) may possibly be accounted for by the

cleavage-laminae...being parts of large abrupt curves, with their

summits cut off and worn down" ("Geological Observations on S. America,"

page 155). I well remember the fine section at the end of a region where

the cleavage (certainly cleavage) had been most uniform in strike and

most variable in dip.

I made with really great care (and in MS. in detail) observations on

a case which I believe is new, and bears on your view of metamorphosis

(page 149, at bottom). (Ibid., page 149.)

(FIGURE 7.)

In a clay-slate porphyry region, where certain thin sedimentary layers

of tuff had by self-attraction shortened themselves into little curling

pieces, and then again into crystals of feldspar of large size, and

which consequently were all strictly parallel, the series was perfect

and beautiful. Apparently also the rounded grains of quartz had in other

parts aggregated themselves into crystalline nodules of quartz. [Figure

7.]

I have not been able to get Sorby yet, but shall not probably have

anything to write on it. I am delighted you have taken up the subject,

even if I am utterly floored.

P.S.--I have a presentiment it will turn out that when clay-slate has

been metamorphosed the foliation in the resultant schist has been due

generally (if not, as I think, always) to the cleavage, and this to a

certain degree will "save my bacon" (please look at my saving clause,

page 167) (542/2. "As in some cases it appears that where a fissile rock

has been exposed to partial metamorphic action (for instance, from

the irruption of granite) the foliation has supervened on the already

existing cleavage-planes; so, perhaps in some instances, the foliation

of a rock may have been determined by the original planes of deposition

or of oblique current laminae. I have, however, myself never seen such

a case, and I must maintain that in most extensive metamorphic areas the

foliation is the extreme result of that process, of which cleavage is

the first effect" (Ibid., page 167).), but [with] other rocks than that,

stratification has been the ruling agent, the strike, but not the dip,

being in such cases parallel to any adjoining clay-slate. If this be

so, pre-existing planes of division, we must suppose on my view of the

cause, determining the lines of crystallisation and segregation, and

not planes of division produced for the first time during the act of

crystallisation, as in volcanic rocks. If this should ever be proved, I

shall not look back with utter shame at my work.

LETTER 543. TO J.D. HOOKER. Down, September 8th [1856].

I got your letter of the 1st this morning, and a real good man you have

been to write. Of all the things I ever heard, Mrs. Hooker's pedestrian

feats beat them. My brother is quite right in his comparison of "as

strong as a woman," as a type of strength. Your letter, after what

you have seen in the Himalayas, etc., gives me a wonderful idea of the

beauty of the Alps. How I wish I was one-half or one-quarter as strong

as Mrs. Hooker: but that is a vain hope. You must have had some very

interesting work with glaciers, etc. When will the glacier structure

and motion ever be settled! When reading Tyndall's paper it seemed to me

that movement in the particles must come into play in his own doctrine

of pressure; for he expressly states that if there be pressure on all

sides, there is no lamination. I suppose I cannot have understood him,

for I should have inferred from this that there must have been movement

parallel to planes of pressure. (543/1. Prof. Tyndall had published

papers "On Glaciers," and "On some Physical Properties of Ice" ("Proc.

R. Inst." 1854-58) before the date of this letter. In 1856 he wrote

a paper entitled "Observations on 'The Theory of the Origin of Slaty

Cleavage,' by H.C. Sorby." "Phil. Mag." XII., 1856, page 129.)

Sorby read a paper to the Brit. Assoc., and he comes to the conclusion

that gneiss, etc., may be metamorphosed cleavage or strata; and I

think he admits much chemical segregation along the planes of division.

(543/2. "On the Microscopical Structure of Mica-schist:" "Brit. Ass.

Rep." 1856, page 78. See also Letters 540-542.) I quite subscribe to

this view, and should have been sorry to have been so utterly wrong, as

I should have been if foliation was identical with stratification.

I have been nowhere and seen no one, and really have no news of any kind

to tell you. I have been working away as usual, floating plants in salt

water inter alia, and confound them, they all sink pretty soon, but at

very different rates. Working hard at pigeons, etc., etc. By the way,

I have been astonished at the differences in the skeletons of domestic

rabbits. I showed some of the points to Waterhouse, and asked him

whether he could pretend that they were not as great as between species,

and he answered, "They are a great deal more." How very odd that no

zoologist should ever have thought it worth while to look to the real

structure of varieties...

2.IX.VI. AGE OF THE WORLD, 1868-1877.

LETTER 544. TO J. CROLL. Down, September 19th, 1868.

I hope that you will allow me to thank you for sending me your papers

in the "Phil. Magazine." (544/1. Croll published several papers in

the "Philosophical Magazine" between 1864 and the date of this letter

(1868).) I have never, I think, in my life been so deeply interested

by any geological discussion. I now first begin to see what a million

means, and I feel quite ashamed of myself at the silly way in which I

have spoken of millions of years. I was formerly a great believer in the

power of the sea in denudation, and this was perhaps natural, as most of

my geological work was done near sea-coasts and on islands. But it is a

consolation to me to reflect that as soon as I read Mr. Whitaker's paper

(544/2. "On Subaerial Denudation," and "On Cliffs and Escarpments of

the Chalk and Lower Tertiary Beds," "Geol. Mag." Volume IV., page 447,

1867.) on the escarpments of England, and Ramsay (544/3. "Quart. Journ.

Geol. Soc." Volume XVIII., page 185, 1862. "On the Glacial Origin of

certain Lakes in Switzerland, the Black Forest, Great Britain, Sweden,

North America, and elsewhere.') and Jukes' papers (544/4. "Quart. Journ.

Geol. Soc." Volume XVIII., page 378, 1862. "On the Mode of Formation of

some River-Valleys in the South of Ireland."), I gave up in my own mind

the case; but I never fully realised the truth until reading your papers

just received. How often I have speculated in vain on the origin of the

valleys in the chalk platform round this place, but now all is clear. I

thank you cordially for having cleared so much mist from before my eyes.

LETTER 545. TO T. MELLARD READE. Down, February 9th, 1877.

I am much obliged for your kind note, and the present of your essay.

I have read it with great interest, and the results are certainly most

surprising. (545/1. Presidential Address delivered by T. Mellard Reade

before the Liverpool Geological Society ("Proc. Liverpool Geol. Soc."

Volume III., pt. iii., page 211, 1877). See also "Examination of a

Calculation of the Age of the Earth, based upon the hypothesis of the

Permanence of Oceans and Continents." "Geol. Mag." Volume X., page 309,

1883.) It appears to me almost monstrous that Professor Tait should

say that the duration of the world has not exceeded ten million years.

(545/2. "Lecture on Some Recent Advances in Physical Science," by P.G.

Tait, London, 1876.) The argument which seems the most weighty in favour

of the belief that no great number of millions of years have elapsed

since the world was inhabited by living creatures is the rate at which

the temperature of the crust increases, and I wish that I could see this

argument answered.

LETTER 546. TO J. CROLL. Down, August 9th, 1877.

I am much obliged for your essay, which I have read with the greatest

interest. With respect to the geological part, I have long wished to see

the evidence collected on the time required for denudation, and you have

done it admirably. (546/1. In a paper "On the Tidal Retardation Argument

for the Age of the Earth" ("Brit. Assoc. Report," 1876, page 88), Croll

reverts to the influence of subaerial denudation in altering the form of

the earth as an objection to the argument from tidal retardation. He had

previously dealt with this subject in "Climate and Time," Chapter

XX., London, 1875.) I wish some one would in a like spirit compare

the thickness of sedimentary rocks with the quickest estimated rate of

deposition by a large river, and other such evidence. Your main argument

with respect to the sun seems to me very striking.

My son George desires me to thank you for his copy, and to say how much

he has been interested by it.

2.IX.VII. GEOLOGICAL ACTION OF EARTHWORMS, 1880-1882.

"My whole soul is absorbed with worms just at present." (From a letter

to Sir W. Thistleton-Dyer, November 26th, 1880.)

LETTER 547. TO T.H. FARRER (Lord Farrer).

(547/1. The five following letters, written shortly before and after the

publication of "The Formation of Vegetable Mould through the Action of

Worms," 1881, deal with questions connected with Mr. Darwin's work on

the habits and geological action of earthworms.)

Down, October 20th, 1880.

What a man you are to do thoroughly whatever you undertake to do! The

supply of specimens has been magnificent, and I have worked at them for

a day and a half. I find a very few well-rounded grains of brick in

the castings from over the gravel walk, and plenty over the hole in the

field, and over the Roman floor. (547/2. See "The Formation of Vegetable

Mould," 1881, pages 178 et seq. The Roman remains formed part of a villa

discovered at Abinger, Surrey. Excavations were carried out, under Lord

Farrer's direction, in a field adjoining the ground in which the Roman

villa was first found, and extended observations were made by Lord

Farrer, which led Mr. Darwin to conclude that a large part of the fine

vegetable mould covering the floor of the villa had been brought up

from below by worms.) You have done me the greatest possible service

by making me more cautious than I should otherwise have been--viz., by

sending me the rubbish from the road itself; in this rubbish I find

very many particles, rounded (I suppose) by having been crushed, angles

knocked off, and somewhat rolled about. But not a few of the particles

may have passed through the bodies of worms during the years since the

road was laid down. I still think that the fragments are ground in the

gizzards of worms, which always contain bits of stone; but I must try

and get more evidence. I have to-day started a pot with worms in very

fine soil, with sharp fragments of hard tiles laid on the surface, and

hope to see in the course of time whether any of those become rounded. I

do not think that more specimens from Abinger would aid me...

LETTER 548. TO G.J. ROMANES. Down, March 7th.

I was quite mistaken about the "Gardeners' Chronicle;" in my index there

are only the few enclosed and quite insignificant references having any

relation to the minds of animals. When I returned to my work, I found

that I had nearly completed my statement of facts about worms plugging

up their burrows with leaves (548/1. Chapter II., of "The Formation

of Vegetable Mould through the Action of Worms," 1881, contains a

discussion on the intelligence shown by worms in the manner of plugging

up their burrows with leaves (pages 78 et seq.).), etc., etc., so I

waited until I had naturally to draw up a few concluding remarks. I hope

that it will not bore you to read the few accompanying pages, and in the

middle you will find a few sentences with a sort of definition of, or

rather discussion on, intelligence. I am altogether dissatisfied with

it. I tried to observe what passed in my own mind when I did the work

of a worm. If I come across a professed metaphysician, I will ask him

to give me a more technical definition, with a few big words about the

abstract, the concrete, the absolute, and the infinite; but seriously, I

should be grateful for any suggestions, for it will hardly do to assume

that every fool knows what "intelligent" means. (548/2. "Mr. Romanes,

who has specially studied the minds of animals, believes that we can

safely infer intelligence only when we see an individual profiting

by its own experience...Now, if worms try to drag objects into their

burrows, first in one way and then in another, until they at last

succeed, they profit, at least in each particular instance, by

experience" ("The Formation of Vegetable Mould," 1881, page 95).) You

will understand that the MS. is only the first rough copy, and will need

much correction. Please return it, for I have no other copy--only a few

memoranda. When I think how it has bothered me to know what I mean by

"intelligent," I am sorry for you in your great work on the minds of

animals.

I daresay that I shall have to alter wholly the MS.

LETTER 549. TO FRANCIS GALTON. Down, March 8th [1881].

Very many thanks for your note. I have been observing the [worm] tracks

on my walks for several months, and they occur (or can be seen) only

after heavy rain. As I know that worms which are going to die (generally

from the parasitic larva of a fly) always come out of their burrows,

I have looked out during these months, and have usually found in the

morning only from one to three or four along the whole length of my

walks. On the other hand, I remember having in former years seen scores

or hundreds of dead worms after heavy rain. (549/1. "After heavy

rain succeeding dry weather, an astonishing number of dead worms may

sometimes be seen lying on the ground. Mr. Galton informs me that on

one occasion (March, 1881), the dead worms averaged one for every

two-and-a-half paces in length on a walk in Hyde Park, four paces in

width" (loc. cit., page 14).) I cannot possibly believe that worms are

drowned in the course of even three or four days' immersion; and I am

inclined to conclude that the death of sickly (probably with parasites)

worms is thus hastened. I will add a few words to what I have said about

these tracks. Occasionally worms suffer from epidemics (of what nature I

know not) and die by the million on the surface of the ground. Your ruby

paper answers capitally, but I suspect that it is only for dimming the

light, and I know not how to illuminate worms by the same intensity of

light, and yet of a colour which permits the actinic rays to pass. I

have tried drawing triangles of damp paper through a small cylindrical

hole, as you suggested, and I can discover no source of error. (549/2.

Triangles of paper were used in experiments to test the intelligence of

worms (loc. cit., page 83).) Nevertheless, I am becoming more doubtful

about the intelligence of worms. The worst job is that they will do

their work in a slovenly manner when kept in pots (549/3. Loc. cit.,

page 75.), and I am beyond measure perplexed to judge how far such

observations are trustworthy.

LETTER 550. TO E. RAY LANKESTER.

(550/1. Mr. Lankester had written October 11th, 1881, to thank Mr.

Darwin for the present of the Earthworm book. He asks whether Darwin

knows of "any experiments on the influence of sea-water on earthworms.

I have assumed that it is fatal to them. But there is a littoral species

(Pontodrilus of Perrier) found at Marseilles." Lankester adds, "It is

a great pleasure and source of pride to me to see my drawing of the

earthworm's alimentary canal figuring in your pages."

Down, October 13th [1881].

I have been much pleased and interested by your note. I never actually

tried sea-water, but I was very fond of angling when a boy, and as I

could not bear to see the worms wriggling on the hook, I dipped them

always first in salt water, and this killed them very quickly. I

remember, though not very distinctly, seeing several earthworms dead on

the beach close to where a little brook entered, and I assumed that they

had been brought down by the brook, killed by the sea-water, and cast

on shore. With your skill and great knowledge, I have no doubt that you

will make out much new about the anatomy of worms, whenever you take up

the subject again.

LETTER 551. TO J.H. GILBERT. Down, January, 12th, 1882.

I have been much interested by your letter, for which I thank you

heartily. There was not the least cause for you to apologise for not

having written sooner, for I attributed it to the right cause, i.e. your

hands being full of work.

Your statement about the quantity of nitrogen in the collected castings

is most curious, and much exceeds what I should have expected. In lately

reading one of your and Mr. Lawes' great papers in the "Philosophical

Transactions" (551/1. The first Report on "Agricultural, Botanical,

and Chemical Results of Experiments on the Mixed Herbage of Permanent

Grassland, conducted for many years in succession on the same land," was

published in the "Philosophical Transactions of the Royal Society" in

1880, the second paper appeared in the "Phil. Trans." for 1882, and the

third in the "Phil. Trans." of 1900, Volume 192, page 139.) (the value

and importance of which cannot, in my opinion, be exaggerated) I

was struck with the similarity of your soil with that near here; and

anything observed here would apply to your land. Unfortunately I have

never made deep sections in this neighbourhood, so as to see how deep

the worms burrow, except in one spot, and here there had been left on

the surface of the chalk a little very fine ferruginous sand, probably

of Tertiary age; into this the worms had burrowed to a depth of 55 and

61 inches. I have never seen here red castings on the surface, but it

seems possible (from what I have observed with reddish sand) that much

of the red colour of the underlying clay would be discharged in passing

through the intestinal canal.

Worms usually work near the surface, but I have noticed that at certain

seasons pale-coloured earth is brought up from beneath the outlying

blackish mould on my lawn; but from what depth I cannot say. That some

must be brought up from a depth of four or five or six feet is certain,

as the worms retire to this depth during very dry and very cold weather.

As worms devour greedily raw flesh and dead worms, they could devour

dead larvae, eggs, etc., etc., in the soil, and thus they might locally

add to the amount of nitrogen in the soil, though not of course if the

whole country is considered. I saw in your paper something about

the difference in the amount of nitrogen at different depths in the

superficial mould, and here worms may have played a part. I wish that

the problem had been before me when observing, as possibly I might have

thrown some little light on it, which would have pleased me greatly.

2.IX.VIII. MISCELLANEOUS, 1846-1878.

(552/1. The following four letters refer to questions connected with the

origin of coal.)

LETTER 552. TO J.D. HOOKER. Down, May [1846].

I am delighted that you are in the field, geologising or

palaeontologising. I beg you to read the two Rogers' account of the

Coal-fields of N. America; in my opinion they are eminently instructive

and suggestive. (552/1. "On the Physical Structure of the Appalachian

Chain," by W.B. and H.D. Rogers. Boston, 1843. See also "Geology of

Pennsylvania," by H.D. Rogers. 4 volumes. London and Philadelphia,

1843.) I can lend you their resume of their own labours, and, indeed, I

do not know that their work is yet published in full. L. Horner gives

a capital balance of difficulties on the Coal-theory in his last

Anniversary Address, which, if you have not read, will, I think,

interest you. (552/2. "Quart. Journ. Geol. Soc." Volume II., 1846, page

170.) In a paper just read an author (552/3. "On the Remarkable Fossil

Trees lately discovered near St. Helen's." By E.W. Binney. "Phil.

Mag." Volume XXIV., page 165, 1844. On page 173 the author writes: "The

Stigmaria or Sigillaria, whichever name is to be retained... was a

tree that undoubtedly grew in water.") throws out the idea that the

Sigillaria was an aquatic plant (552/4. See "Life and Letters," I.,

pages 356 et seq.)--I suppose a Cycad-Conifer with the habits of the

mangrove. From simple geological reasoning I have for some time been led

to suspect that the great (and great and difficult it is) problem of

the Coal would be solved on the theory of the upright plants having been

aquatic. But even on such, I presume improbable notion, there are, as it

strikes me, immense difficulties, and none greater than the width of the

coal-fields. On what kind of coast or land could the plants have lived?

It is a grand problem, and I trust you will grapple with it. I shall

like much to have some discussion with you. When will you come here

again? I am very sorry to infer from your letter that your sister has

been ill.

LETTER 553. TO J.D. HOOKER. [June 2nd, 1847.]

I received your letter the other day, full of curious facts, almost all

new to me, on the coal-question. (553/1. Sir Joseph Hooker deals with

the formation of coal in his classical paper "On the Vegetation of the

Carboniferous Period, as compared with that of the Present Day." "Mem.

Geol. Surv. Great Britain," Volume II., pt. ii., 1848.) I will bring

your note to Oxford (553/2. The British Association met at Oxford in

1847.), and then we will talk it over. I feel pretty sure that some of

your purely geological difficulties are easily solvable, and I can, I

think, throw a very little light on the shell difficulty. Pray put

no stress in your mind about the alternate, neatly divided, strata of

sandstone and shale, etc. I feel the same sort of interest in the coal

question as a man does watching two good players at play, he knowing

little or nothing of the game. I confess your last letter (and this

you will think very strange) has almost raised Binney's notion (an old,

growing hobby-horse of mine) to the dignity of an hypothesis (553/3.

Binney suggested that the Coal-plants grew in salt water. (See Letters

102, 552.) Recent investigations have shown that several of the plants

of the Coal period possessed certain anatomical peculiarities, which

indicate xerophytic characteristics, and lend support to the view that

some at least of the plants grew in seashore swamps.), though very far

yet below the promotion of being properly called a theory.

I will bring the remainder of my species-sketch to Oxford to go over

your remarks. I have lately been getting a good many rich facts. I saw

the poor old Dean of Manchester (553/4. Dean Herbert.) on Friday, and

he received me very kindly. He looked dreadfully ill, and about an hour

afterwards died! I am most sincerely sorry for it.

LETTER 554. TO J.D. HOOKER. [May 12th, 1847.]

I cannot resist thanking you for your most kind note. Pray do not

think that I was annoyed by your letter. I perceived that you had been

thinking with animation, and accordingly expressed yourself strongly,

and so I understood it. Forefend me from a man who weighs every

expression with Scotch prudence. I heartily wish you all success in your

noble problem, and I shall be very curious to have some talk with you

and hear your ultimatum. (554/1. The above paragraph was published in

"Life and Letters," I., page 359.) I do really think, after Binney's

pamphlet (554/2. "On the Origin of Coal," "Mem. Lit. Phil. Soc."

Manchester Volume VIII., page 148, 1848.), it will be worth your while

to array your facts and ideas against an aquatic origin of the coal,

though I do not know whether you object to freshwater. I am sure I have

read somewhere of the cones of Lepidodendron being found round the

stump of a tree, or am I confusing something else? How interesting all

rooted--better, it seems from what you say, than upright--specimens

become.

I wish Ehrenberg would undertake a microscopical hunt for infusoria in

the underclay and shales; it might reveal something. Would a comparison

of the ashes of terrestrial peat and coal give any clue? (554/3. In an

article by M. F. Rigaud on "La Formation de la Houille," published in

the "Revue Scientifique," Volume II., page 385, 1894, the author lays

stress on the absence of certain elements in the ash of coals, which

ought to be present, on the assumption that the carbon has been derived

from plant tissues. If coal consists of altered vegetable debris, we

ought to find a certain amount of alkalies and phosphoric acid in

its ash. Had such substances ever been present, it is difficult to

understand how they could all have been removed by the solvent action of

water. (Rigaud's views are given at greater length in an article on the

"Structure and Formation of Coal," "Science Progress," Volume II., pages

355 and 431, 1895.)) Peat ashes are good manure, and coal ashes, except

mechanically, I believe are of little use. Does this indicate that the

soluble salts have been washed out? i.e., if they are NOT present. I go

up to Geological Council to-day--so farewell.

(554/4. In a letter to Sir Joseph Hooker, October 6th, 1847, Mr. Darwin,

in referring to the origin of Coal, wrote: "...I sometimes think it

could not have been formed at all. Old Sir Anthony Carlisle once said to

me gravely that he supposed Megatherium and such cattle were just sent

down from heaven to see whether the earth would support them, and I

suppose the coal was rained down to puzzle mortals. You must work the

coal well in India.")

LETTER 555. TO J.D. HOOKER. Down, May 22nd, 1860.

Lyell tells me that Binney has published in Proceedings of Manchester

Society a paper trying to show that Coal plants must have grown in very

marine marshes. (555/1. "On the Origin of Coal," by E.W. Binney, "Mem.

Lit. Phil. Soc. Manchester," Volume VIII., 1848, page 148. Binney

examines the evidence on which dry land has been inferred to exist

during the formation of the Coal Measures, and comes to the conclusion

that the land was covered by water, confirming Brongniart's opinion that

Sigillaria was an aquatic plant. He believes the Sigillaria "grew in

water, on the deposits where it is now discovered, and that it is the

plant which in a great measure contributed to the formation of our

valuable beds of coal." (Loc. cit., page 193.)) Do you remember how

savage you were long years ago at my broaching such a conjecture?

LETTER 556. TO L. HORNER. Down [1846?].

I am truly pleased at your approval of my book (556/1. "Geological

Observations on South America," London, 1846.): it was very kind of

you taking the trouble to tell me so. I long hesitated whether I

would publish it or not, and now that I have done so at a good cost of

trouble, it is indeed highly satisfactory to think that my labour has

not been quite thrown away.

I entirely acquiesce in your criticism on my calling the Pampean

formation "recent" (556/2. "We must, therefore, conclude that the

Pampean formation belongs, in the ordinary geological sense of the word,

to the Recent Period." ("Geol. Obs." page 101).); Pleistocene would have

been far better. I object, however, altogether on principle (whether I

have always followed my principle is another question) to designate any

epoch after man. It breaks through all principles of classification

to take one mammifer as an epoch. And this is presupposing we know

something of the introduction of man: how few years ago all beds earlier

than the Pleistocene were characterised as being before the monkey

epoch. It appears to me that it may often be convenient to speak of an

Historical or Human deposit in the same way as we speak of an Elephant

bed, but that to apply it to an epoch is unsound.

I have expressed myself very ill, and I am not very sure that my notions

are very clear on this subject, except that I know that I have often

been made wroth (even by Lyell) at the confidence with which people

speak of the introduction of man, as if they had seen him walk on the

stage, and as if, in a geological chronological sense, it was more

important than the entry of any other mammifer.

You ask me to do a most puzzling thing, to point out what is newest in

my volume, and I found myself incapable of doing almost the same for

Lyell. My mind goes from point to point without deciding: what has

interested oneself or given most trouble is, perhaps quite falsely,

thought newest. The elevation of the land is perhaps more carefully

treated than any other subject, but it cannot, of course, be called new.

I have made out a sort of index, which will not take you a couple of

minutes to skim over, and then you will perhaps judge what seems newest.

The summary at the end of the book would also serve same purpose.

I do not know where E. de B. [Elie de Beaumont] has lately put forth

on the recent elevation of the Cordillera. He "rapported" favourably

on d'Orbigny, who in late times fires off a most Royal salute; every

volcano bursting forth in the Andes at the same time with their

elevation, the debacle thus caused depositing all the Pampean mud and

all the Patagonian shingle! Is not this making Geology nice and simple

for beginners?

We have been very sorry to hear of Bunbury's severe illness; I believe

the measles are often dangerous to grown-up people. I am very glad that

your last account was so much better.

I am astonished that you should have had the courage to go right through

my book. It is quite obvious that most geologists find it far easier to

write than to read a book.

Chapter I. and II.--Elevation of the land: equability on E. coast as

shown by terraces, page 19; length on W. coast, page 53; height at

Valparaiso, page 32; number of periods of rest at Coquimbo, page 49;

elevation within Human period near Lima greater than elsewhere observed;

the discussion (page 41) on non-horizontality of terraces perhaps one of

newest features--on formation of terraces rather newish.