can justly claim a very much greater antiquity than even the oldest
physical traces of mankind. But we may go further and demonstrate, by
evidence of the same authority as that which testifies to the existence
of the father of men, that the chalk is vastly older than Adam himself.
The Book of Genesis informs us that Adam, immediately upon his creation,
and before the appearance of Eve, was placed in the Garden of Eden. The
problem of the geographical position of Eden has greatly vexed the
spirits of the learned in such matters, but there is one point respecting
which, so far as I know, no commentator has ever raised a doubt. This is,
that of the four rivers which are said to run out of it, Euphrates and
Hiddekel are identical with the rivers now known by the names of
Euphrates and Tigris. But the whole country in which these mighty rivers
take their origin, and through which they run, is composed of rocks which
are either of the same age as the chalk, or of later date. So that the
chalk must not only have been formed, but, after its formation, the time
required for the deposit of these later rocks, and for their upheaval
into dry land, must have elapsed, before the smallest brook which feeds
the swift stream of "the great river, the river of Babylon," began to
flow.
Thus, evidence which cannot be rebutted, and which need not be
strengthened, though if time permitted I might indefinitely increase its
quantity, compels you to believe that the earth, from the time of the
chalk to the present day, has been the theatre of a series of changes as
vast in their amount, as they were slow in their progress. The area on
which we stand has been first sea and then land, for at least four
alternations; and has remained in each of these conditions for a period
of great length.
Nor have these wonderful metamorphoses of sea into land, and of land into
sea, been confined to one corner of England. During the chalk period, or
"cretaceous epoch," not one of the present great physical features of the
globe was in existence. Our great mountain ranges, Pyrenees, Alps,
Himalayas, Andes, have all been upheaved since the chalk was deposited,
and the cretaceous sea flowed over the sites of Sinai and Ararat. All
this is certain, because rocks of cretaceous, or still later, date have
shared in the elevatory movements which gave rise to these mountain
chains; and may be found perched up, in some cases, many thousand feet
high upon their flanks. And evidence of equal cogency demonstrates that,
though, in Norfolk, the forest-bed rests directly upon the chalk, yet it
does so, not because the period at which the forest grew immediately
followed that at which the chalk was formed, but because an immense lapse
of time, represented elsewhere by thousands of feet of rock, is not
indicated at Cromer.
I must ask you to believe that there is no less conclusive proof that a
still more prolonged succession of similar changes occurred, before the
chalk was deposited. Nor have we any reason to think that the first term
in the series of these changes is known. The oldest sea-beds preserved to
us are sands, and mud, and pebbles, the wear and tear of rocks which were
formed in still older oceans.
But, great as is the magnitude of these physical changes of the world,
they have been accompanied by a no less striking series of modifications
in its living inhabitants. All the great classes of animals, beasts of
the field, fowls of the air, creeping things, and things which dwell in
the waters, flourished upon the globe long ages before the chalk was
deposited. Very few, however, if any, of these ancient forms of animal
life were identical with those which now live. Certainly not one of the
higher animals was of the same species as any of those now in existence.
The beasts of the field, in the days before the chalk, were not our
beasts of the field, nor the fowls of the air such as those which the eye
of men has seen flying, unless his antiquity dates infinitely further
back than we at present surmise. If we could be carried back into those
times, we should be as one suddenly set down in Australia before it was
colonized. We should see mammals, birds, reptiles, fishes, insects,
snails, and the like, clearly recognizable as such, and yet not one of
them would be just the same as those with which we are familiar, and many
would be extremely different.
From that time to the present, the population of the world has undergone
slow and gradual, but incessant, changes. There has been no grand
catastrophe--no destroyer has swept away the forms of life of one period,
and replaced them by a totally new creation: but one species has vanished
and another has taken its place; creatures of one type of structure have
diminished, those of another have increased, as time has passed on. And
thus, while the differences between the living creatures of the time
before the chalk and those of the present day appear startling, if placed
side by side, we are led from one to the other by the most gradual
progress, if we follow the course of Nature through the whole series of
those relics of her operations which she has left behind. It is by the
population of the chalk sea that the ancient and the modern inhabitants
of the world are most completely connected. The groups which are dying
out flourish, side by side, with the groups which are now the dominant
forms of life. Thus the chalk contains remains of those strange flying
and swimming reptiles, the pterodactyl, the ichthyosaurus, and the
plesiosaurus, which are found in no later deposits, but abounded in
preceding ages. The chambered shells called ammonites and belemnites,
which are so characteristic of the period preceding the cretaceous, in
like manner die with it.
But, amongst these fading remainders of a previous state of things, are
some very modern forms of life, looking like Yankee pedlars among a tribe
of Red Indians. Crocodiles of modern type appear; bony fishes, many of
them very similar to existing species, almost supplant the forms of fish
which predominate in more ancient seas; and many kinds of living shell-
fish first become known to us in the chalk. The vegetation acquires a
modern aspect. A few living animals are not even distinguishable as
species, from those which existed at that remote epoch. The _Globigerina_
of the present day, for example, is not different specifically from that
of the chalk; and the same maybe said of many other _Foraminifera_. I
think it probable that critical and unprejudiced examination will show
that more than one species of much higher animals have had a similar
longevity; but the only example which I can at present give confidently
is the snake's-head lampshell (_Terebratulina caput serpentis_), which
lives in our English seas and abounded (as _Terebratulina striata_ of
authors) in the chalk.
The longest line of human ancestry must hide its diminished head before
the pedigree of this insignificant shell-fish. We Englishmen are proud to
have an ancestor who was present at the Battle of Hastings. The ancestors
of _Terebratulina caput serpentis_ may have been present at a battle of
_Ichthyosauria_ in that part of the sea which, when the chalk was
forming, flowed over the site of Hastings. While all around has changed,
this _Terebratulina_ has peacefully propagated its species from
generation to generation, and stands to this day, as a living testimony
to the continuity of the present with the past history of the globe.
Up to this moment I have stated, so far as I know, nothing but well-
authenticated facts, and the immediate conclusions which they force upon
the mind. But the mind is so constituted that it does not willingly rest
in facts and immediate causes, but seeks always after a knowledge of the
remoter links in the chain of causation.
Taking the many changes of any given spot of the earth's surface, from
sea to land and from land to sea, as an established fact, we cannot
refrain from asking ourselves how these changes have occurred. And when
we have explained them--as they must be explained--by the alternate slow
movements of elevation and depression which have affected the crust of
the earth, we go still further back, and ask, Why these movements?
I am not certain that any one can give you a satisfactory answer to that
question. Assuredly I cannot. All that can be said, for certain, is, that
such movements are part of the ordinary course of nature, inasmuch as
they are going on at the present time. Direct proof may be given, that
some parts of the land of the northern hemisphere are at this moment
insensibly rising and others insensibly sinking; and there is indirect,
but perfectly satisfactory, proof, that an enormous area now covered by
the Pacific has been deepened thousands of feet, since the present
inhabitants of that sea came into existence. Thus there is not a shadow
of a reason for believing that the physical changes of the globe, in past
times, have been effected by other than natural causes. Is there any more
reason for believing that the concomitant modifications in the forms of
the living inhabitants of the globe have been brought about in other
ways?
Before attempting to answer this question, let us try to form a distinct
mental picture of what has happened in some special case. The crocodiles
are animals which, as a group, have a very vast antiquity. They abounded
ages before the chalk was deposited; they throng the rivers in warm
climates, at the present day. There is a difference in the form of the
joints of the back-bone, and in some minor particulars, between the
crocodiles of the present epoch and those which lived before the chalk;
but, in the cretaceous epoch, as I have already mentioned, the crocodiles
had assumed the modern type of structure. Notwithstanding this, the
crocodiles of the chalk are not identically the same as those which lived
in the times called "older tertiary," which succeeded the cretaceous
epoch; and the crocodiles of the older tertiaries are not identical with
those of the newer tertiaries, nor are these identical with existing
forms. I leave open the question whether particular species may have
lived on from epoch to epoch. But each epoch has had its peculiar
crocodiles; though all, since the chalk, have belonged to the modern
type, and differ simply in their proportions, and in such structural
particulars as are discernible only to trained eyes.
How is the existence of this long succession of different species of
crocodiles to be accounted for? Only two suppositions seem to be open to
us--Either each species of crocodile has been specially created, or it
has arisen out of some pre-existing form by the operation of natural
causes. Choose your hypothesis; I have chosen mine. I can find no
warranty for believing in the distinct creation of a score of successive
species of crocodiles in the course of countless ages of time. Science
gives no countenance to such a wild fancy; nor can even the perverse
ingenuity of a commentator pretend to discover this sense, in the simple
words in which the writer of Genesis records the proceedings of the fifth
and six days of the Creation.
On the other hand, I see no good reason for doubting the necessary
alternative, that all these varied species have been evolved from pre-
existing crocodilian forms, by the operation of causes as completely a
part of the common order of nature as those which have effected the
changes of the inorganic world. Few will venture to affirm that the
reasoning which applies to crocodiles loses its force among other
animals, or among plants. If one series of species has come into
existence by the operation of natural causes, it seems folly to deny that
all may have arisen in the same way.
A small beginning has led us to a great ending. If I were to put the bit
of chalk with which we started into the hot but obscure flame of burning
hydrogen, it would presently shine like the sun. It seems to me that this
physical metamorphosis is no false image of what has been the result of
our subjecting it to a jet of fervent, though nowise brilliant, thought
to-night. It has become luminous, and its clear rays, penetrating the
abyss of the remote past, have brought within our ken some stages of the
evolution of the earth. And in the shifting "without haste, but without
rest" of the land and sea, as in the endless variation of the forms
assumed by living beings, we have observed nothing but the natural
product of the forces originally possessed by the substance of the
universe.
II
THE PROBLEMS OF THE DEEP SEA
[1873]
On the 21st of December, 1872, H.M.S. _Challenger_, an eighteen gun
corvette, of 2,000 tons burden, sailed from Portsmouth harbour for a
three, or perhaps four, years' cruise. No man-of-war ever left that
famous port before with so singular an equipment. Two of the eighteen
sixty-eight pounders of the _Challenger's_ armament remained to enable
her to speak with effect to sea-rovers, haply devoid of any respect for
science, in the remote seas for which she is bound; but the main-deck
was, for the most part, stripped of its war-like gear, and fitted up with
physical, chemical, and biological laboratories; Photography had its dark
cabin; while apparatus for dredging, trawling, and sounding; for
photometers and for thermometers, filled the space formerly occupied by
guns and gun-tackle, pistols and cutlasses.
The crew of the _Challenger_ match her fittings. Captain Nares, his
officers and men, are ready to look after the interests of hydrography,
work the ship, and, if need be, fight her as seamen should; while there
is a staff of scientific civilians, under the general direction of Dr.
Wyville Thomson, F.R.S. (Professor of Natural History in Edinburgh
University by rights, but at present detached for duty _in partibus_),
whose business it is to turn all the wonderfully packed stores of
appliances to account, and to accumulate, before the ship returns to
England, such additions to natural knowledge as shall justify the labour
and cost involved in the fitting out and maintenance of the expedition.
Under the able and zealous superintendence of the Hydrographer, Admiral
Richards, every precaution which experience and forethought could devise
has been taken to provide the expedition with the material conditions of
success; and it would seem as if nothing short of wreck or pestilence,
both most improbable contingencies, could prevent the _Challenger_ from
doing splendid work, and opening up a new era in the history of
scientific voyages.
The dispatch of this expedition is the culmination of a series of such
enterprises, gradually increasing in magnitude and importance, which the
Admiralty, greatly to its credit, has carried out for some years past;
and the history of which is given by Dr. Wyville Thomson in the
beautifully illustrated volume entitled "The Depths of the Sea,"
published since his departure.
"In the spring of the year 1868, my friend Dr. W.B. Carpenter, at that
time one of the Vice-Presidents of the Royal Society, was with me in
Ireland, where we were working out together the structure and development
of the Crinoids. I had long previously had a profound conviction that the
land of promise for the naturalist, the only remaining region where there
were endless novelties of extraordinary interest ready to the hand which
had the means of gathering them, was the bottom of the deep sea. I had
even had a glimpse of some of these treasures, for I had seen, the year
before, with Prof. Sars, the forms which I have already mentioned dredged
by his son at a depth of 300 to 400 fathoms off the Loffoten Islands. I
propounded my views to my fellow-labourer, and we discussed the subject
many times over our microscopes. I strongly urged Dr. Carpenter to use
his influence at head-quarters to induce the Admiralty, probably through
the Council of the Royal Society, to give us the use of a vessel properly
fitted with dredging gear and all necessary scientific apparatus, that
many heavy questions as to the state of things in the depths of the
ocean, which were still in a state of uncertainty, might be definitely
settled. After full consideration, Dr. Carpenter promised his hearty co-
operation, and we agreed that I should write to him on his return to
London, indicating generally the results which I anticipated, and
sketching out what I conceived to be a promising line of inquiry. The
Council of the Royal Society warmly supported the proposal; and I give
here in chronological order the short and eminently satisfactory
correspondence which led to the Admiralty placing at the disposal of Dr.
Carpenter and myself the gunboat _Lightninq_, under the command of Staff-
Commander May, R.N., in the summer of 1868, for a trial cruise to the
North of Scotland, and afterwards to the much wider surveys in H.M.S.
_Porcupine_, Captain Calver, R.N., which were made with the additional
association of Mr. Gwyn Jeffreys, in the summers of the years 1869 and
1870."[1]
[Footnote 1: The Depths of the Sea, pp. 49-50.]
Plain men may be puzzled to understand why Dr. Wyville Thomson, not being
a cynic, should relegate the "Land of Promise" to the bottom of the deep
sea, they may still more wonder what manner of "milk and honey" the
_Challenger_ expects to find; and their perplexity may well rise to its
maximum, when they seek to divine the manner in which that milk and honey
are to be got out of so inaccessible a Canaan. I will, therefore,
endeavour to give some answer to these questions in an order the reverse
of that in which I have stated them.
Apart from hooks, and lines, and ordinary nets, fishermen have, from time
immemorial, made use of two kinds of implements for getting at sea-
creatures which live beyond tide-marks--these are the "dredge" and the
"trawl." The dredge is used by oyster-fishermen. Imagine a large bag, the
mouth of which has the shape of an elongated parallelogram, and is
fastened to an iron frame of the same shape, the two long sides of this
rim being fashioned into scrapers. Chains attach the ends of the frame to
a stout rope, so that when the bag is dragged along by the rope the edge
of one of the scrapers rests on the ground, and scrapes whatever it
touches into the bag. The oyster-dredger takes one of these machines in
his boat, and when he has reached the oyster-bed the dredge is tossed
overboard; as soon as it has sunk to the bottom the rope is paid out
sufficiently to prevent it from pulling the dredge directly upwards, and
is then made fast while the boat goes ahead. The dredge is thus dragged
along and scrapes oysters and other sea-animals and plants, stones, and
mud into the bag. When the dredger judges it to be full he hauls it up,
picks out the oysters, throws the rest overboard, and begins again.
Dredging in shallow water, say ten to twenty fathoms, is an easy
operation enough; but the deeper the dredger goes, the heavier must be
his vessel, and the stouter his tackle, while the operation of hauling up
becomes more and more laborious. Dredging in 150 fathoms is very hard
work, if it has to be carried on by manual labour; but by the use of the
donkey-engine to supply power,[2] and of the contrivances known as
"accumulators," to diminish the risk of snapping the dredge rope by the
rolling and pitching of the vessel, the dredge has been worked deeper and
deeper, until at last, on the 22nd of July, 1869, H.M.S. _Porcupine_
being in the Bay of Biscay, Captain Calver, her commander, performed the
unprecedented feat of dredging in 2,435 fathoms, or 14,610 feet, a depth
nearly equal to the height of Mont Blanc. The dredge "was rapidly hauled
on deck at one o'clock in the morning of the 23rd, after an absence of
7-1/4 hours, and a journey of upwards of eight statute miles," with a
hundred weight and a half of solid contents.
[Footnote 2: The emotional side of the scientific nature has its
singularities. Many persons will call to mind a certain philosopher's
tenderness over his watch--"the little creature"--which was so singularly
lost and found again. But Dr. Wyville Thomson surpasses the owner of the
watch in his loving-kindness towards a donkey-engine. "This little engine
was the comfort of our lives. Once or twice it was overstrained, and then
we pitied the willing little thing, panting like an overtaxed horse."]
The trawl is a sort of net for catching those fish which habitually live
at the bottom of the sea, such as soles, plaice, turbot, and gurnett. The
mouth of the net may be thirty or forty feet wide, and one edge of its
mouth is fastened to a beam of wood of the same length. The two ends of
the beam are supported by curved pieces of iron, which raise the beam and
the edge of the net which is fastened to it, for a short distance, while
the other edge of the mouth of the net trails upon the ground. The closed
end of the net has the form of a great pouch; and, as the beam is dragged
along, the fish, roused from the bottom by the sweeping of the net,
readily pass into its mouth and accumulate in the pouch at its end. After
drifting with the tide for six or seven hours the trawl is hauled up, the
marketable fish are picked out, the others thrown away, and the trawl
sent overboard for another operation.
More than a thousand sail of well-found trawlers are constantly engaged
in sweeping the seas around our coast in this way, and it is to them that
we owe a very large proportion of our supply of fish. The difficulty of
trawling, like that of dredging, rapidly increases with the depth at
which the operation is performed; and, until the other day, it is
probable that trawling at so great a depth as 100 fathoms was something
unheard of. But the first news from the _Challenger_ opens up new
possibilities for the trawl.
Dr. Wyville Thomson writes ("Nature," March 20, 1873):--
"For the first two or three hauls in very deep water off the coast of
Portugal, the dredge came up filled with the usual 'Atlantic ooze,'
tenacious and uniform throughout, and the work of hours, in sifting, gave
the very smallest possible result. We were extremely anxious to get some
idea of the general character of the Fauna, and particularly of the
distribution of the higher groups; and after various suggestions for
modification of the dredge, it was proposed to try the ordinary trawl. We
had a compact trawl, with a 15-feet beam, on board, and we sent it down
off Cape St. Vincent at a depth of 600 fathoms. The experiment looked
hazardous, but, to our great satisfaction, the trawl came up all right
and contained, with many of the larger invertebrate, several fishes....
After the first attempt we tried the trawl several times at depths of
1090, 1525, and, finally, 2125 fathoms, and always with success."
To the coral-fishers of the Mediterranean, who seek the precious red
coral, which grows firmly fixed to rocks at a depth of sixty to eighty
fathoms, both the dredge and the trawl would be useless. They, therefore,
have recourse to a sort of frame, to which are fastened long bundles of
loosely netted hempen cord, and which is lowered by a rope to the depth
at which the hempen cords can sweep over the surface of the rocks and
break off the coral, which is brought up entangled in the cords. A
similar contrivance has arisen out of the necessities of deep-sea
exploration.