publication, in the year 1840, of Mr. Darwin's famous work on
coral reefs; in which a key was given to all the difficult problems
connected with the subject, and every difficulty was shown to be
capable of solution by deductive reasoning from a happy combination of
certain well-established geological and biological truths. Mr.
Darwin, in fact, showed, that so long as the level of the sea remains
unaltered in any area in which coral reefs are being formed, or if the
level of the sea relatively to that of the land is falling, the
only reefs which can be formed are fringing reefs. While if, on the
contrary, the level of the sea is rising relatively to that of the
land, at a rate not faster than that at which the upward growth of
the coral can keep pace with it, the reef will gradually pass from the
condition of a fringing, into that of an encircling or barrier reef.
And, finally, that if the relative level of the sea rise so much that
the encircled land is completely submerged, the reef must necessarily
pass into the condition of an atoll.
For, suppose the relative level of the sea to remain stationary, after
a fringing reef has reached that distance from the land at which
the depth of water amounts to 150 feet. Then the reef cannot extend
seaward by the migration of coral germs, because these coral germs
would find the bottom of the sea to be too deep for them to live in.
And the only manner in which the reef could extend outwards, would
be by the gradual accumulation, at the foot of its seaward face, of a
talus of coral fragments torn off by the violence of the waves, which
talus might, in course of time, become high enough to bring its upper
surface within the limits of coral growth, and in that manner provide
a sort of factitious sea-bottom upon which the coral embryos might
perch. If, on the other hand, the level of the sea were slowly and
gradually lowered, it is clear that the parts of its bottom originally
beyond the limit of coral growth, would gradually be brought within
the required distance of the surface, and thus the reef might be
indefinitely extended. But this process would give rise neither to an
encircling reef nor to an atoll, but to a broad belt of upheaved
coral rock, increasing the dimensions of the dry land, and continuous
seawards with the fresh fringing reef.
Suppose, however, that the sea-level rose instead of falling, at the
same slow and gradual rate at which we know it to be rising in some
parts of the world--not more, in fact, than a few inches, or, at
most, a foot or two, in a hundred years. Then, while the reef would
be unable to extend itself seaward, the sea-bottom outside it being
gradually more and more removed from the depth at which the life of
the coral polypes is possible, it would be able to grow upwards
as fast as the sea rose. But the growth would take place almost
exclusively around the circumference of the reef, this being the only
region in which the coral polypes would find the conditions favourable
for their existence. The bottom of the lagoon would be raised, in the
main, only by the coral _débris_ and coral mud, formed in the manner
already described; consequently, the margins of the reef would
rise faster than the bottom, or, in other words, the lagoon would
constantly become deeper. And, at the same time, it would gradually
increase in breadth; as the rising sea, covering more and more of the
land, would occupy a wider space between the edge of the reef and what
remained of the land. Thus the rising sea would eventually convert a
large island with a fringing reef, into a small island surrounded by
an encircling reef. And it will be obvious that when the rising of the
sea has gone so far as completely to cover the highest points of the
island, the reef will have passed into the condition of an atoll.
But how is it possible that the relative level of the land and sea
should be altered to this extent? Clearly, only in one of two ways:
either the sea must have risen over those areas which are now covered
by atolls and encircling reefs; or, the land upon which the sea rests
must have been depressed to a corresponding extent.
If the sea has risen, its rise must have taken place over the whole
world simultaneously, and it must have risen to the same height over
all parts of the coral zone. Grounds have been shown for the belief
that the general level of the sea may have been different at different
times; it has been suggested, for example, that the accumulation of
ice about the poles during one of the cold periods of the earth's
history, necessarily implies a diminution in the volume of the sea
proportioned to the amount of its water thus permanently locked up in
the Arctic and Antarctic ice-cellars; while, in the warm periods,
the greater or less disappearance of the polar ice-cap implies a
corresponding addition of water to the ocean. And no doubt this
reasoning must be admitted to be sound in principle; though it is very
hard to say what practical effect the additions and subtractions thus
made have had on the level of the ocean; inasmuch as such additions
and subtractions might be either intensified or nullified, by
contemporaneous changes in the level of the land. And no one has yet
shown that any such great melting of polar ice, and consequent raising
of the level of the water of the ocean, has taken place since the
existing atolls began to be formed.
In the absence of any evidence that the sea has ever risen to the
extent required to give rise to the encircling reefs and the atolls,
Mr. Darwin adopted the opposite hypothesis, viz. that the land has
undergone extensive and slow depression in those localities in which
these structures exist.
It seems, at first, a startling paradox, to suppose that the land
is less fixed than the sea; but that such is the case is the uniform
testimony of geology. Beds of sandstone or limestone, thousands of
feet thick, and all full of marine remains, occur in various parts of
the earth's surface, and prove, beyond a doubt, that when these beds
were formed, that portion of the sea-bottom which they then occupied
underwent a slow and gradual depression to a distance which cannot
have been less than the thickness of those beds, and may have been
very much greater. In supposing, therefore, that the great areas of
the Pacific and of the Indian Ocean, over which atolls and encircling
reefs are found scattered, have undergone a depression of some
hundreds, or, it may be, thousands of feet, Mr. Darwin made a
supposition which had nothing forced or improbable, but was entirely
in accordance with what we know to have taken place over similarly
extensive areas, in other periods of the world's history. But Mr.
Darwin subjected his hypothesis to an ingenious indirect test. If
his view be correct, it is clear that neither atolls, nor encircling
reefs, should be found in those portions of the ocean in which we have
reason to believe, on independent grounds, that the sea-bottom has
long been either stationary, or slowly rising. Now it is known that,
as a general rule, the level of the land is either stationary, or is
undergoing a slow upheaval, in the neighbourhood of active volcanoes;
and, therefore, neither atolls nor encircling reefs ought to be found
in regions in which volcanoes are numerous and active. And this turns
out to be the case. Appended to Mr. Darwin's great work on coral
reefs, there is a map on which atolls and encircling reefs are
indicated by one colour, fringing reefs by another, and active
volcanoes by a third. And it is at once obvious that the lines of
active volcanoes lie around the margins of the areas occupied by the
atolls and the encircling reefs. It is exactly as if the upheaving
volcanic agencies had lifted up the edges of these great areas, while
their centres had undergone a corresponding depression. An atoll area
may, in short, be pictured as a kind of basin, the margins of which
have been pushed up by the subterranean forces, to which the craters
of the volcanoes have, at intervals, given vent.
Thus we must imagine the area of the Pacific now covered by the
Polynesian Archipelago, as having been, at some former time,
occupied by large islands, or, may be, by a great continent, with the
ordinarily diversified surface of plain, and hill, and mountain chain.
The shores of this great land were doubtless fringed by coral reefs;
and, as it slowly underwent depression, the hilly regions, converted
into islands, became, at first, surrounded by fringing reefs, and
then, as depression went on, these became converted into encircling
reefs, and these, finally, into atolls, until a maze of reefs and
coral-girdled islets took the place of the original land masses.
Thus the atolls and the encircling reefs furnish us with clear, though
indirect, evidence of changes in the physical geography of large parts
of the earth's surface; and even, as my lamented friend, the late
Professor Jukes, has suggested, give us indications of the manner in
which some of the most puzzling facts connected with the distribution
of animals have been brought about. For example, Australia and New
Guinea are separated by Torres Straits, a broad belt of sea 100 or
120 miles wide. Nevertheless, there is in many respects a curious
resemblance between the land animals which inhabit New Guinea and
the land animals which inhabit Australia. But, at the same time, the
marine shell-fish which are found in the shallow waters of the shores
of New Guinea, are quite different from those which are met with upon
the coasts of Australia. Now, the eastern end of Torres Straits is
full of atolls, which, in fact, form the northern termination of the
Great Barrier Reef which skirts the eastern coast of Australia. It
follows, therefore, that the eastern end of Torres Straits is an area
of depression, and it is very possible, and on many grounds highly
probable, that, in former times, Australia and New Guinea were
directly connected together, and that Torres Straits did not exist.
If this were the case, the existence of cassowaries and of marsupial
quadrupeds, both in New Guinea and in Australia, becomes intelligible;
while the difference between the littoral molluscs of the north and
the south shores of Torres Straits is readily explained by the great
probability that, when the depression in question took place, and
what was, at first, an arm of the sea became converted into a strait
separating Australia from New Guinea, the northern shore of this new
sea became tenanted with marine animals from the north, while the
southern shore was peopled by immigrants from the already existing
marine Australian fauna.
Inasmuch as the growth of the reef depends upon that of successive
generations of coral polypes, and as each generation takes a certain
time to grow to its full size, and can only separate its calcareous
skeleton from the water in which it lives at a certain rate, it is
clear that the reefs are records not only of changes in physical
geography, but of the lapse of time. It is by no means easy, however,
to estimate the exact value of reef-chronology, and the attempts which
have been made to determine the rate at which a reef grows vertically,
have yielded anything but precise results. A cautious writer, Mr.
Dana, whose extensive study of corals and coral reefs makes him an
eminently competent judge, states his conclusion in the following
terms:--
"The rate of growth of the common branching madrepore is not
over one and a half inches a year. As the branches are open,
this would not be equivalent to more than half an inch in
height of solid coral for the whole surface covered by
the madrepore; and, as they are also porous, to not over
three-eighths of an inch of solid limestone. But a coral
plantation has large bare patches without corals, and the
coral sands are widely distributed by currents, part of them
to depths over one hundred feet where there are no living
corals; not more than one-sixth of the surface of a reef
region is, in fact, covered with growing species. This reduces
the three-eighths to _one-sixteenth_. Shells and other organic
relics may contribute one-fourth as much as corals. At the
outside, the average upward increase of the whole reef-ground
per year would not exceed _one-eighth_ of an inch.
"Now some reefs are at least two thousand feet thick, which at
one-eighth of an inch a year, corresponds to one hundred and
ninety-two thousand years."[1]
[Footnote 1: Dana, "Manual of Geology," p. 591.]
Halve, or quarter, this estimate if you will, in order to be certain
of erring upon the right side, and still there remains a prodigious
period during which the ancestors of the existing coral polypes have
been undisturbedly at work; and during which, therefore, the climatal
conditions over the coral area must have been much what they are now.
And all this lapse of time has occurred within the most recent period
of the history of the earth. The remains of reefs formed by coral
polypes of different kinds from those which exist now, enter largely
into the composition of the limestones of the Jurassic period; and
still more widely different coral polypes have contributed their quota
to the vast thickness of the carboniferous and Devonian strata. Then
as regards the latter group of rocks in America, the high authority
already quoted tells us:--
"The Upper Helderberg period is eminently the coral reef
period of the palaeozoic ages. Many of the rocks abound in
coral, and are as truly coral reefs as the modern reefs of the
Pacific. The corals are sometimes standing on the rocks in the
position they had when growing: others are lying in fragments,
as they were broken and heaped by the waves; and others were
reduced to a compact limestone by the finer trituration before
consolidation into rock. This compact variety is the most
common kind among the coral reef rocks of the present seas;
and it often contains but few distinct fossils, although
formed in water that abounded in life. At the fall of the
Ohio, near Louisville, there is a magnificent display of
the old reef. Hemispherical _Favosites_, five or six feet
in diameter, lie there nearly as perfect as when they were
covered by their flower-like polypes; and besides these,
there are various branching corals, and a profusion of
_Cyathophiyllia_, or cup-corals."[1]
[Footnote 1: Dana, "Manual of Geology," p. 272.]
Thus, in all the great periods of the earth's history of which we
know anything, a part of the then living matter has had the form of
polypes, competent to separate from the water of the sea the carbonate
of lime necessary for their own skeletons. Grain by grain, and
particle by particle, they have built up vast masses of rock, the
thickness of which is measured by hundreds of feet, and their area by
thousands of square miles. The slow oscillations of the crust of the
earth, producing great changes in the distribution of land and water,
have often obliged the living matter of the coral-builders to shift
the locality of its operations; and, by variation and adaptation to
these modifications of condition, its forms have as often changed. The
work it has done in the past is, for the most part, swept away, but
fragments remain; and, if there were no other evidence, suffice to
prove the general constancy of the operations of Nature in this world,
through periods of almost inconceivable duration.
VII.
ON THE METHODS AND RESULTS OF ETHNOLOGY.
Ethonology is the science which determines the distinctive characters
of the persistent modifications of mankind; which ascertains the
distribution of those modifications in present and past times, and
seeks to discover the causes, or conditions of existence, both of
the modifications and of their distribution. I say "persistent"
modifications, because, unless incidentally, ethnology has nothing to
do with chance and transitory peculiarities of human structure. And
I speak of "persistent modifications" or "stocks" rather than of
"varieties," or "races," or "species," because each of these last
well-known terms implies, on the part of its employer, a preconceived
opinion touching one of those problems, the solution of which is the
ultimate object of the science; and in regard to which, therefore,
ethnologists are especially bound to keep their minds open and their
judgments freely balanced.
Ethnology, as thus defined, is a branch of anthropology, the great
science which unravels the complexities of human structure; traces out
the relations of man to other animals; studies all that is especially
human in the mode in which man's complex functions are performed; and
searches after the conditions which have determined his presence in
the world. And anthropology is a section of zoology, which again is
the animal half of biology--the science of life and living things.
Such is the position of ethnology, such are the objects of the
ethnologist. The paths or methods, by following which he may hope to
reach his goal, are diverse. He may work at man from the point of
view of the pure zoologist, and investigate the anatomical and
physiological peculiarities of Negroes, Australians, or Mongolians,
just as he would inquire into those of pointers, terriers, and
turnspits,--"persistent modifications" of man's almost universal
companion. Or he may seek aid from researches into the most human
manifestation of humanity--language; and assuming that what is true of
speech is true of the speaker--a hypothesis as questionable in science
as it is in ordinary life--he may apply to mankind themselves the
conclusions drawn from a searching analysis of their words and
grammatical forms.
Or, the ethnologist may turn to the study of the practical life
of men; and relying upon the inherent conservatism and small
inventiveness of untutored mankind, he may hope to discover in manners
and customs, or in weapons, dwellings, and other handiwork, a clue to
the origin of the resemblances and differences of nations. Or, he may
resort to that kind of evidence which is yielded by history proper,
and consists of the beliefs of men concerning past events, embodied
in traditional, or in written, testimony. Or, when that thread breaks,
archaeology, which is the interpretation of the unrecorded remains of
man's works, belonging to the epoch since the world has reached its
present condition, may still guide him. And, when even the dim light
of archaeology fades, there yet remains paleontology, which, in these
latter years, has brought to daylight once more the exuvia of ancient
populations, whose world was not our world, who have been buried in
river beds immemorially dry, or carried by the rush of waters into
caves, inaccessible to inundation since the dawn of tradition.
Along each, or all, of these paths the ethnologist may press towards
his goal; but they are not equally straight, or sure, or easy to
tread. The way of palaeontology has but just been laid open to us.
Archaeological and historical investigations are of great value for
all those peoples whose ancient state has differed widely from their
present condition, and who have the good or evil fortune to possess a
history. But on taking a broad survey of the world, it is astonishing
how few nations present either condition. Respecting five-sixths of
the persistent modifications of mankind, history and archaeology are
absolutely silent. For half the rest, they might as well be silent for
anything that is to be made of their testimony. And, finally, when the
question arises as to what was the condition of mankind more than a
paltry two or three thousand years ago, history and archaeology are,
for the most part, mere dumb dogs. What light does either of these
branches of knowledge throw on the past of the man of the New World,
if we except the Central Americans and the Peruvians; on that of the
Africans, save those of the valley of the Nile and a fringe of the
Mediterranean; on that of all the Polynesian, Australian, and central
Asiatic peoples, the former of whom probably, and the last certainly,
were, at the dawn of history, substantially what they are now? While
thankfully accepting what history has to give him, therefore, the
ethnologist must not look for too much from her.
Is more to be expected from inquiries into the customs and handicrafts
of men? It is to be feared not. In reasoning from identity of custom
to identity of stock the difficulty always obtrudes itself, that
the minds of men being everywhere similar, differing in quality and
quantity but not in kind of faculty, like circumstances must tend to
produce like contrivances; at any rate, so long as the need to be
met and conquered is of a very simple kind. That two nations use
calabashes or shells for drinking-vessels, or that they employ
spears, or clubs, or swords and axes of stone and metal as weapons and
implements, cannot be regarded as evidence that these two nations
had a common origin, or even that intercommunication ever took place
between them; seeing that the convenience of using calabashes or
shells for such purposes, and the advantage of poking an enemy with a
sharp stick, or hitting him with a heavy one, must be early forced
by nature upon the mind of even the stupidest savage. And when he had
found out the use of a stick, he would need no prompting to discover
the value of a chipped or wetted stone, or an angular piece of native
metal, for the same object. On the other hand, it may be doubted
whether the chances are not greatly against independent peoples
arriving at the manufacture of a boomerang, or of a bow; which last,
if one comes to think of it, is a rather complicated apparatus; and
the tracing of the distribution of inventions as complex as these,
and of such strange customs as betel-chewing and tobacco-smoking, may
afford valuable ethnological hints.
Since the time of Leibnitz, and guided by such men as Humboldt, Abel
Remusat, and Klaproth, Philology has taken far higher ground. Thus
Prichard affirms that "the history of nations, termed Ethnology, must
be mainly founded on the relations of their languages."
An eminent living philologer, August Schleicher, in a recent essay,
puts forward the claims of his science still more forcibly:--
"If, however, language is the human [Greek: kat ezochhên], the
suggestion arises whether it should not form the basis of
any scientific systematic arrangement of mankind; whether the
foundation of the natural classification of the genus Homo has
not been discovered in it.
"How little constant are cranial peculiarities and other
so-called race characters! Language, on the other hand,
is always a perfectly constant diagnostic. A German may
occasionally compete in hair and prognathism with a negro,
but a negro language will never be his mother tongue. Of how
little importance for mankind the so-called race characters
are, is shown by the fact that speakers of languages belonging
to one and the same linguistic family may exhibit the
peculiarities of various races. Thus the settled Osmanli Turk
exhibits Caucasian characters, while other so-called Tartaric
Turks exemplify the Mongol type. On the other hand, the
Magyar and the Basque do not depart in any essential physical
peculiarity from the Indo-Germans, whilst the Magyar, Basque,
and Indo-Germanic tongues are widely different. Apart from
their inconstancy, again, the so-called race characters can
hardly yield a scientifically natural system. Languages, on
the other hand, readily fall into a natural arrangement, like
that of which other vital products are susceptible, especially
when viewed from their morphological side.... The externally
visible structure of the cerebral and facial skeletons, and
of the body generally, is less important than that no less
material but infinitely more delicate corporeal structure, the
function of which is speech. I conceive, therefore, that
the natural classification of languages is also the natural
classification of mankind. With language, moreover, all the
higher manifestations of man's vital activity are closely
interwoven, so that these receive due recognition in and by
that of speech."[1]