Positive," we find its author contemplating the establishment of a
system of society, in which an organized spiritual power shall over-ride
and direct the temporal power, as completely as the Innocents and
Gregorys tried to govern Europe in the middle ages; and repudiating the
exercise of liberty of conscience against the "_hommes compétents_", of
whom, by the assumption, the new priesthood would be composed. Was Mr.
Congreve as forgetful of this, as he seems to have been of some other
parts of the "Philosophie Positive," when he wrote, that "in any
limited, careful use of the term, no candid man could say that the
Positive Philosophy contained a great deal as thoroughly antagonistic to
[the very essence of[28]] science as Catholicism"?
M. Comte, it will have been observed, desires to retain the whole of
Catholic organization; and the logical practical result of this part of
his doctrine would be the establishment of something corresponding with
that eminently Catholic, but admittedly anti-scientific,
institution--the Holy Office.
I hope I have said enough to show that I wrote the few lines I devoted
to M. Comte and his philosophy, neither unguardedly, nor ignorantly,
still less maliciously. I shall be sorry if what I have now added, in my
own justification, should lead any to suppose that I think M. Comte's
works worthless; or that I do not heartily respect, and sympathise with,
those who have been impelled by him to think deeply upon social
problems, and to strive nobly for social regeneration. It is the virtue
of that impulse, I believe, which will save the name and fame of Auguste
Comte from oblivion. As for his philosophy, I part with it by quoting
his own words, reported to me by a quondam Comtist, now an eminent
member of the Institute of France, M. Charles Robin:--
"La Philosophie est une tentative incessante de l'esprit humain
pour arriver au repos: mais elle se trouve incessamment aussi
dérangée par les progrès continus de la science. De là vient pour
le philosophe l'obligation de refaire chaque soir la synthèse de
ses conceptions; et un jour viendra où l'homme raisonnable ne fera
plus d'autre prière du soir."
FOOTNOTES:
[13] I am glad to observe that Mr. Congreve, in the criticism with which
he has favoured me in the number of the _Fortnightly Review_ for April
1869, does not venture to challenge the justice of the claim I make for
Hume. He merely suggests that I have been wanting in candour in not
mentioning Comte's high opinion of Hume. After mature reflection I am
unable to discern my fault. If I had suggested that Comte had borrowed
from Hume without acknowledgment; or if, instead of trying to express my
own sense of Hume's merits with the modesty which becomes a writer who
has no authority in matters of philosophy, I had affirmed that no one
had properly appreciated him, Mr. Congreve's remarks would apply: but as
I did neither of these things, they appear to me to be irrelevant, if
not unjustifiable. And even had it occurred to me to quote M. Comte's
expressions about Hume, I do not know that I should have cited them,
inasmuch as, on his own showing, M. Comte occasionally speaks very
decidedly touching writers of whose works he has not read a line. Thus,
in Tome VI. of the "Philosophie Positive," p. 619, M. Comte writes: "Le
plus grand des métaphysiciens modernes, l'illustre Kant, a noblement
mérité une éternelle admiration en tentant, le premier, d'échapper
directement a l'absolu philosophique par sa célèbre conception de la
double réalité, à la fois objective et subjective, qui indique un si
juste sentiment de la saine philosophie."
But in the "Préface Personnelle" in the same volume, p. 35, M. Comte
tells us:--"Je n'ai jamais lu, en aucune langue, ni Vico, _ni Kant_, ni
Herder, ni Hegel, &c.; je ne connais leurs divers ouvrages que d'après
quelques relations indirectes et certains extraits fort insuffisants."
Who knows but that the "&c." may include Hume? And in that case what is
the value of M. Comte's praise of him?
[14] Now and always I quote the second edition, by Littré.
[15] "Philosophie Positive," ii. p. 440.
[16] "Le brillant mais superficiel Cuvier."--_Philosophie Positive_, vi.
p. 383.
[17] "Philosophie Positive," iii. p. 369.
[18] Ibid. p. 387.
[19] Hear the late Dr. Whewell, who calls Comte "a shallow pretender,"
so far as all the modern sciences, except astronomy, are concerned; and
tells us that "his pretensions to discoveries are, as Sir John Herschel
has shown, absurdly fallacious."--"Comte and Positivism," _Macmillan's
Magazine_, March 1866.
[20] "Philosophie Positive," i. pp. 8, 9.
[21] "Philosophie Positive," iii. p. 188.
[22] The word "positive" is in every way objectionable. In one sense it
suggests that mental quality which was undoubtedly largely developed in
M. Comte, but can best be dispensed with in a philosopher; in another,
it is unfortunate in its application to a system which starts with
enormous negations; in its third, and specially philosophical sense, as
implying a system of thought which assumes nothing beyond the content of
observed facts, it implies that which never did exist, and never will.
[23] "Philosophie Positive," i. p. 56.
[24] "Philosophie Positive," i. p. 99.
[25] Ibid., i. p. 77.
[26] "Philosophie Positive," i. p. 78.
[27] Loc. cit., Préface Spéciale, pp. i. ii.
[28] Mr. Congreve leaves out these important words, which show that I
refer to the spirit, and not to the details of science.
IX.
ON A PIECE OF CHALK.
A LECTURE TO WORKING MEN.
If a well were to be sunk at our feet in the midst of the city of
Norwich, the diggers would very soon find themselves at work in that
white substance almost too soft to be called rock, with which we are all
familiar as "chalk."
Not only here, but over the whole county of Norfolk, the well-sinker
might carry his shaft down many hundred feet without coming to the end
of the chalk; and, on the sea-coast, where the waves have pared away the
face of the land which breasts them, the scarped faces of the high
cliffs are often wholly formed of the same material. Northward, the
chalk may be followed as far as Yorkshire; on the south coast it appears
abruptly in the picturesque western bays of Dorset, and breaks into the
Needles of the Isle of Wight; while on the shores of Kent it supplies
that long line of white cliffs to which England owes her name of Albion.
Were the thin soil which covers it all washed away, a curved band of
white chalk, here broader, and there narrower, might be followed
diagonally across England from Lulworth in Dorset, to Flamborough Head
in Yorkshire--a distance of over 280 miles as the crow flies.
From this band to the North Sea, on the east, and the Channel, on the
south, the chalk is largely hidden by other deposits; but, except in the
Weald of Kent and Sussex, it enters into the very foundation of all the
south-eastern counties.
Attaining, as it does in some places, a thickness of more than a
thousand feet, the English chalk must be admitted to be a mass of
considerable magnitude. Nevertheless, it covers but an insignificant
portion of the whole area occupied by the chalk formation of the globe,
which has precisely the same general characters as ours, and is found in
detached patches, some less, and others more extensive, than the
English.
Chalk occurs in north-west Ireland; it stretches over a large part of
France,--the chalk which underlies Paris being, in fact, a continuation
of that of the London basin; it runs through Denmark and Central Europe,
and extends southward to North Africa; while, eastward, it appears in
the Crimea and in Syria, and may be traced as far as the shores of the
Sea of Aral, in Central Asia.
If all the points at which true chalk occurs were circumscribed, they
would lie within an irregular oval about 3,000 miles in long
diameter--the area of which would be as great as that of Europe, and
would many times exceed that of the largest existing inland sea--the
Mediterranean.
Thus the chalk is no unimportant element in the masonry of the earth's
crust, and it impresses a peculiar stamp, varying with the conditions
to which it is exposed, on the scenery of the districts in which it
occurs. The undulating downs and rounded coombs, covered with
sweet-grassed turf, of our inland chalk country, have a peacefully
domestic and mutton-suggesting prettiness, but can hardly be called
either grand or beautiful. But, on our southern coasts, the wall-sided
cliffs, many hundred feet high, with vast needles and pinnacles standing
out in the sea, sharp and solitary enough to serve as perches for the
wary cormorant, confer a wonderful beauty and grandeur upon the chalk
headlands. And, in the East, chalk has its share in the formation of
some of the most venerable of mountain ranges, such as the Lebanon.
What is this wide-spread component of the surface of the earth? and
whence did it come?
You may think this no very hopeful inquiry. You may not unnaturally
suppose that the attempt to solve such problems as these can lead to no
result, save that of entangling the inquirer in vague speculations,
incapable of refutation and of verification.
If such were really the case, I should have selected some other subject
than a "piece of chalk" for my discourse. But, in truth, after much
deliberation, I have been unable to think of any topic which would so
well enable me to lead you to see how solid is the foundation upon which
some of the most startling conclusions of physical science rest.
A great chapter of the history of the world is written in the chalk. Few
passages in the history of man can be supported by such an overwhelming
mass of direct and indirect evidence as that which testifies to the
truth of the fragment of the history of the globe, which I hope to
enable you to read, with your own eyes, to-night.
Let me add, that few chapters of human history have a more profound
significance for ourselves. I weigh my words well when I assert, that
the man who should know the true history of the bit of chalk which every
carpenter carries about in his breeches-pocket, though ignorant of all
other history, is likely, if he will think his knowledge out to its
ultimate results, to have a truer, and therefore a better, conception of
this wonderful universe, and of man's relation to it, than the most
learned student who is deep-read in the records of humanity and ignorant
of those of Nature.
The language of the chalk is not hard to learn, not nearly so hard as
Latin, if you only want to get at the broad features of the story it has
to tell; and I propose that we now set to work to spell that story out
together.
We all know that if we "burn" chalk the result is quicklime. Chalk, in
fact, is a compound of carbonic acid gas and lime, and when you make it
very hot the carbonic acid flies away and the lime is left.
By this method of procedure we see the lime, but we do not see the
carbonic acid. If, on the other hand, you were to powder a little chalk,
and drop it into a good deal of strong vinegar, there would be a great
bubbling and fizzing, and, finally, a clear liquid, in which no sign of
chalk would appear. Here you see the carbonic acid in the bubbles; the
lime, dissolved in the vinegar, vanishes from sight. There are a great
many other ways of showing that chalk is essentially nothing but
carbonic acid and quicklime. Chemists enunciate the result of all the
experiments which prove this, by stating that chalk is almost wholly
composed of "carbonate of lime."
It is desirable for us to start from the knowledge of this fact, though
it may not seem to help us very far towards what we seek. For carbonate
of lime is a widely-spread substance, and is met with under very various
conditions. All sorts of limestones are composed of more or less pure
carbonate of lime. The crust which is often deposited by waters which
have drained through limestone rocks, in the form of what are called
stalagmites and stalactites, is carbonate of lime. Or, to take a more
familiar example, the fur on the inside of a tea-kettle is carbonate of
lime; and, for anything chemistry tells us to the contrary, the chalk
might be a kind of gigantic fur upon the bottom of the earth-kettle,
which is kept pretty hot below.
Let us try another method of making the chalk tell us its own history.
To the unassisted eye chalk looks simply like a very loose and open kind
of stone. But it is possible to grind a slice of chalk down so thin that
you can see through it--until it is thin enough, in fact, to be examined
with any magnifying power that may be thought desirable. A thin slice of
the fur of a kettle might be made in the same way. If it were examined
microscopically, it would show itself to be a more or less distinctly
laminated mineral substance, and nothing more.
But the slice of chalk presents a totally different appearance when
placed under the microscope. The general mass of it is made up of very
minute granules; but imbedded in this matrix, are innumerable bodies,
some smaller and some larger, but, on a rough average, not more than a
hundredth of an inch in diameter, having a well-defined shape and
structure. A cubic inch of some specimens of chalk may contain hundreds
of thousands of these bodies, compacted together with incalculable
millions of the granules.
The examination of a transparent slice gives a good notion of the manner
in which the components of the chalk are arranged, and of their relative
proportions. But, by rubbing up some chalk with a brush in water and
then pouring off the milky fluid, so as to obtain sediments of different
degrees of fineness, the granules and the minute rounded bodies may be
pretty well separated from one another, and submitted to microscopic
examination, either as opaque or as transparent objects. By combining
the views obtained in these various methods, each of the rounded bodies
may be proved to be a beautifully-constructed calcareous fabric, made up
of a number of chambers, communicating freely with one another. The
chambered bodies are of various forms. One of the commonest is something
like a badly-grown raspberry, being formed of a number of nearly
globular chambers of different sizes congregated together. It is called
_Globigerina_, and some specimens of chalk consist of little else than
_Globigerinæ_ and granules.
Let us fix our attention upon the _Globigerina_. It is the spoor of the
game we are tracking. If we can learn what it is and what are the
conditions of its existence, we shall see our way to the origin and past
history of the chalk.
A suggestion which may naturally enough present itself is, that these
curious bodies are the result of some process of aggregation which has
taken place in the carbonate of lime; that, just as in winter, the rime
on our windows simulates the most delicate and elegantly arborescent
foliage--proving that the mere mineral water may, under certain
conditions, assume the outward form of organic bodies--so this mineral
substance, carbonate of lime, hidden away in the bowels of the earth,
has taken the shape of these chambered bodies. I am not raising a merely
fanciful and unreal objection. Very learned men, in former days, have
even entertained the notion that all the formed things found in rocks
are of this nature; and if no such conception is at present held to be
admissible, it is because long and varied experience has now shown that
mineral matter never does assume the form and structure we find in
fossils. If any one were to try to persuade you that an oyster-shell
(which is also chiefly composed of carbonate of lime) had crystallized
out of sea-water, I suppose you would laugh at the absurdity. Your
laughter would be justified by the fact that all experience tends to
show that oyster-shells are formed by the agency of oysters, and in no
other way. And if there were no better reasons, we should be justified,
on like grounds, in believing that _Globigerina_ is not the product of
anything but vital activity.
Happily, however, better evidence in proof of the organic nature of the
_Globigerinæ_ than that of analogy is forthcoming. It so happens that
calcareous skeletons, exactly similar to the _Globigerinæ_ of the chalk,
are being formed, at the present moment, by minute living creatures,
which flourish in multitudes, literally more numerous than the sands of
the sea-shore, over a large extent of that part of the earth's surface
which is covered by the ocean.
The history of the discovery of these living _Globigerinæ_, and of the
part which they play in rock-building, is singular enough. It is a
discovery which, like others of no less scientific importance, has
arisen, incidentally, out of work devoted to very different and
exceedingly practical interests.
When men first took to the sea, they speedily learned to look out for
shoals and rocks; and the more the burthen of their ships increased, the
more imperatively necessary it became for sailors to ascertain with
precision the depth of the waters they traversed. Out of this necessity
grew the use of the lead and sounding-line; and, ultimately,
marine-surveying, which is the recording of the form of coasts and of
the depth of the sea, as ascertained by the sounding-lead, upon charts.
At the same time, it became desirable to ascertain and to indicate the
nature of the sea-bottom, since this circumstance greatly affects its
goodness as holding ground for anchors. Some ingenious tar, whose name
deserves a better fate than the oblivion into which it has fallen,
attained this object by "arming" the bottom of the lead with a lump of
grease, to which more or less of the sand or mud, or broken shells, as
the case might be, adhered, and was brought to the surface. But, however
well adapted such an apparatus might be for rough nautical purposes,
scientific accuracy could not be expected from the armed lead, and to
remedy its defects (especially when applied to sounding in great depths)
Lieut. Brooke, of the American Navy, some years ago invented a most
ingenious machine, by which a considerable portion of the superficial
layer of the sea-bottom can be scooped out and brought up, from any
depth to which the lead descends.
In 1853, Lieut. Brooke obtained mud from the bottom of the North
Atlantic, between Newfoundland and the Azores, at a depth of more than
10,000 feet, or two miles, by the help of this sounding apparatus. The
specimens were sent for examination to Ehrenberg of Berlin, and to
Bailey of West Point, and those able microscopists found that this
deep-sea mud was almost entirely composed of the skeletons of living
organisms--the greater proportion of these being just like the
_Globigerinæ_ already known to occur in the chalk.
Thus far, the work had been carried on simply in the interests of
science, but Lieut. Brooke's method of sounding acquired a high
commercial value, when the enterprise of laying down the telegraph-cable
between this country and the United States was undertaken. For it became
a matter of immense importance to know, not only the depth of the sea
over the whole line along which the cable was to be laid, but the exact
nature of the bottom, so as to guard against chances of cutting or
fraying the strands of that costly rope. The Admiralty consequently
ordered Captain Dayman, an old friend and shipmate of mine, to ascertain
the depth over the whole line of the cable, and to bring back specimens
of the bottom. In former days, such a command as this might have sounded
very much like one of the impossible things which the young prince in
the Fairy Tales is ordered to do before he can obtain the hand of the
Princess. However, in the months of June and July 1857, my friend
performed the task assigned to him with great expedition and precision,
without, so far as I know, having met with any reward of that kind. The
specimens of Atlantic mud which he procured were sent to me to be
examined and reported upon.[29]
The result of all these operations is, that we know the contours and the
nature of the surface-soil covered by the North Atlantic, for a distance
of 1,700 miles from east to west, as well as we know that of any part of
the dry land.
It is a prodigious plain--one of the widest and most even plains in the
world. If the sea were drained off, you might drive a wagon all the way
from Valentia, on the west coast of Ireland, to Trinity Bay, in
Newfoundland. And, except upon one sharp incline about 200 miles from
Valentia, I am not quite sure that it would even be necessary to put the
skid on, so gentle are the ascents and descents upon that long route.
From Valentia the road would lie down hill for about 200 miles to the
point at which the bottom is now covered by 1,700 fathoms of sea-water.
Then would come the central plain, more than a thousand miles wide, the
inequalities of the surface of which would be hardly perceptible, though
the depth of water upon it now varies from 10,000 to 15,000 feet; and
there are places in which Mont Blanc might be sunk without showing its
peak above water. Beyond this, the ascent on the American side
commences, and gradually leads, for about 300 miles, to the Newfoundland
shore.
Almost the whole of the bottom of this central plain (which extends for
many hundred miles in a north and south direction) is covered by a fine
mud, which, when brought to the surface, dries into a greyish-white
friable substance. You can write with this on a blackboard, if you are
so inclined; and, to the eye, it is quite like very soft, greyish chalk.
Examined chemically, it proves to be composed almost wholly of carbonate
of lime; and if you make a section of it, in the same way as that of the
piece of chalk was made, and view it with the microscope, it presents
innumerable _Globigerinæ_, embedded in a granular matrix.
Thus this deep-sea mud is substantially chalk. I say substantially,
because there are a good many minor differences: but as these have no
bearing on the question immediately before us,--which is the nature of
the _Globigerinæ_ of the chalk,--it is unnecessary to speak of them.
_Globigerinæ_ of every size, from the smallest to the largest, are
associated together in the Atlantic mud, and the chambers of many are
filled by a soft animal matter. This soft substance is, in fact, the
remains of the creature to which the _Globigerina_ shell, or rather
skeleton, owes its existence--and which is an animal of the simplest
imaginable description. It is, in fact, a mere particle of living jelly,
without defined parts of any kind--without a mouth, nerves, muscles, or
distinct organs, and only manifesting its vitality to ordinary
observation by thrusting out and retracting from all parts of its
surface, long filamentous processes, which serve for arms and legs. Yet
this amorphous particle, devoid of everything which, in the higher
animals, we call organs, is capable of feeding, growing, and
multiplying; of separating from the ocean the small proportion of
carbonate of lime which is dissolved in sea-water; and of building up
that substance into a skeleton for itself, according to a pattern which
can be imitated by no other known agency.
The notion that animals can live and flourish in the sea, at the vast
depths from which apparently living _Globigerinæ_ have been brought up,
does not agree very well with our usual conceptions respecting the
conditions of animal life; and it is not so absolutely impossible as it
might at first sight appear to be, that the _Globigerinæ_ of the
Atlantic sea-bottom do not live and die where they are found.