On his return home, Darwin speedily placed himself in communication with
the leaders of scientific progress, and, in consequence of the valuable
results of his voyage, he soon found himself in a most advantageous
position. On November 20, 1836, he was elected a Fellow of the
Geological Society, and before the end of the year he had sent the
manuscript of one of his early papers to Lyell, who writes to him
(December 26, 1836): "I have read your paper with the greatest
pleasure.... What a splendid field you have to write upon." He strongly
advised the young man not to accept any official scientific place, but
to devote himself to his own line of work. But Darwin was overpersuaded,
and became a member of the Council of the Geological Society in the
following February, and secretary in February, 1838. This office he held
with success for three years. Lyell referred in considerable detail to
the young traveller's views in his presidential address to the Society
in 1837.
Darwin's geological papers soon became numerous. In 1837 he discussed in
succession the recent elevation of the coast of Chili, the deposits
containing extinct mammalia in the neighbourhood of the Plata, the areas
of elevation and subsidence in the Pacific and Indian Oceans, as deduced
from the study of coral formations, and the formation of mould (the
precursor of a work he issued more than forty years later). Papers on
the connection of certain volcanic phenomena, and on the formation of
mountain chains, and other geological notes on South America, were read
in 1838; the interesting Parallel Roads of Glen Roy, in Scotland, which
he believed to be of marine origin, were described in 1839; the erratic
(glacial) boulders of South America, in 1841; and coral reefs in 1842: a
full record, one would imagine, of busy years, occupied also with
secretarial work. Lyell, writing to Sir John Herschel (May 24, 1837),
says: "I am very full of Darwin's new theory of coral islands, and have
urged Whewell to make him read it at our next meeting. I must give up my
volcanic crater theory for ever, though it costs me a pang at first." In
March, 1838, Lyell describes the reception of the paper on volcanic
phenomena at the Geological Society. "He opened upon De la Beche,
Phillips, and others, his whole battery of the earthquakes and volcanoes
of the Andes; and argued that spaces of a thousand miles long were
simultaneously subject to earthquakes and volcanic eruptions, and that
the elevation of the Pampas, Patagonia, &c., all depended upon a common
cause." In fit acknowledgment of such services to science, he was
elected a Fellow of the Royal Society on January 24, 1839.
Early in 1839 Darwin married his cousin, Emma Wedgwood, daughter of his
uncle Josiah Wedgwood: a union which, though consanguineous, proved in
the highest degree congenial and fortunate. In succeeding years a
numerous family of sons and daughters surrounded the happy parents.
After considerable delays by the Admiralty, though it had long been
ready, the Journal appeared, in 1839, as the third volume of Fitzroy's
"Voyages of _The Adventure_ and _Beagle_." _The Quarterly Review_ (lxv.
224) said that there could be no two opinions of its merits. "We find
ample materials for deep thinking; we have the vivid description that
fills the mind's eye with brighter pictures than painter can present,
and the charm arising from the freshness of heart which is thrown over
these virgin pages of a strong intellectual man, and an acute and deep
observer." Its merits, however, were somewhat slow to become known to
the general public, owing to the original expensive form of publication;
and it was not till 1845, when the second and enlarged edition appeared
as "The Journal of Researches," that the popular ear was gained. Later,
under the title, "A Naturalist's Voyage Round the World," the book has
become very widely known and appreciated.
The publication of "The Zoology of the Voyage of _The Beagle_,"
commenced in 1838, under Darwin's superintendence, gave a fuller view of
the acquisitions to natural history which had been made than had
previously been possible. The Treasury, acting on the representations of
the presidents of the Linnean, Zoological, and Geological Societies, as
well as of the naturalist himself, in 1837 made a grant of £1000 towards
the expenses of publication of these memoirs. Owen's description of the
fossil mammalia, completed in 1840; G. Waterhouse's of the living
mammalia, in 1839; Gould's of the birds, in 1841; L. Jenyns's of the
fish, in 1842; and Thomas Bell's of the reptiles, in 1843--all in
quarto, with beautiful plates, were a solid testimony to a splendid
success. Darwin furnished an introduction to each part, and the portions
of the text referring to the habits and ranges of the living animals.
Three species of mastodon and the gigantic megatherium were the only
extinct mammalia known from South America previous to Darwin's voyage.
To these were now added the _Mylodon Darwinii_, a giant sloth; the
scelidotherium, a somewhat smaller form; the great camel-like, yet
odd-toed, macrauchenia; and the toxodon, as large as a hippopotamus, yet
having a strange resemblance to the little rodents. All these belonged
to geological deposits not far anterior to the present age. The
collections of living vertebrates were less profoundly interesting, but
the number of new species was large; and the habits and localities being
recorded by so good an observer, gave them additional value.
The fossil mammals were given by the generous traveller to the London
College of Surgeons, the mammals and birds to the Zoological Society,
the reptiles to the British Museum, and the fishes to the Cambridge
Philosophical Society. Nor was this all. The collections of insects,
shells, and crustacea were described by many able specialists in
scientific publications. The flowering plants were described by Hooker,
and the non-flowering by Berkeley; and, altogether, no expedition ever
yielded a more solid result to the scientific naturalist, while
furnishing a delightful narrative to the general reader, and laying the
foundation for generalisations of surpassing importance to all thinking
minds.
It was evident to many geologists that the greatest value would attach
to the full record of the geological observations made by the gifted
young secretary of the Geological Society. A year after the publication
of the Journal the first portion of these observations, dealing with
coral reefs, was almost ready, but the continued ill-health of the
author delayed the publication till 1842. When it appeared, under the
title of "The Structure and Distribution of Coral Reefs," its success
was immediate and complete.
Ever since their first description by voyagers, marvel had been
expressed at the strange and beautiful phenomena presented by coral
islands. Coral, as being built up by the tireless labours of innumerable
so-called "insects," or "worms," had become associated with romantic
ideas. It really consists of the internal skeletons of coral-polyps,
allied to the sea anemone. Captain Basil Hall, in his "Voyage to Loo
Choo," looking with the eyes of one ignorant of zoology, had credited
the building of coral reefs to all kinds of creatures which lived on and
near the coral after it had been made; and his erroneous views had been
amplified and developed by James Montgomery, in his "Pelican Island,"
into the most fantastically incorrect description that ever versifier
penned. Sad to relate, his lines were often quoted, as if correct, by
scientific men in pre-Darwinian times.
Nothing gives clearer evidence of the power of mind which Darwin had
already attained when voyaging round the world than the originality of
his views on coral reefs. The lagoon islands, or atolls, he describes as
"vast rings of coral rock, often many leagues in diameter, here and
there surmounted by a low verdant island, with dazzling white shores,
bathed on the outside by the foaming breakers of the ocean; and, on the
inside, surrounding a calm expanse of water which, from reflection, is
of a bright, but pale, green colour." Keeling atoll, outside which, at
less than a mile and a half distance, no bottom was found with a line
7,200 feet in length, having been fully described, and an account given
of all other known atoll systems, the peculiarities of the great barrier
reef of North-east Australia, and that of New Caledonia, were recounted.
Off the latter, no bottom was found, at two ships' length from the reef,
with a line 900 feet long. With these were linked the smaller reefs of
Tahiti and others, where considerable islands are more or less
completely surrounded by them. Next, the fringing or shore reefs, at
first sight only a variety of barrier reefs, were clearly distinguished
from them by the absence of an interior deep-water channel, and their
not growing up from an immense, but from a moderate depth of water.
The remarkable fact was pointed out by Darwin that all coral islands are
within a little more than 30 degrees of the Equator, but that, at the
same time, they are absent over certain larger areas within the tropical
seas. There are none on the West Coast of South America, nor on the West
Coast of Africa. In this portion of his work we have another significant
sentence bearing on the struggle for existence. In discussing the
apparently capricious distribution of coral reefs, he remarks that "the
study of the terrestrial and better-known half of the world must
convince every one that no station capable of supporting life is
lost--nay more, that there is a struggle for each station between the
different orders of nature." He describes the large fishes and the
trepangs (_holothuriæ_) preying upon the coral-polyps, and shows how
complex are the conditions which determine the formation of reefs on any
shore. Perhaps no part of his work is more important than that in which
he collects the evidence proving how rapidly coral masses grow, and that
they for the most part cannot flourish in a greater depth of water than
fifteen fathoms.
Reasoning upon the facts observed by himself and others Darwin now
proceeded to upset the received theory that atolls were based upon
submarine volcanic craters, and to substitute for it the view that there
has been a prolonged and gradual subsidence of the areas upon which the
atolls are based, and a corresponding upward growth of the reef-building
corals. Thus fringing-reefs in time become barrier-reefs; and
barrier-reefs, when they encircle islands, are converted into atolls, or
lagoon islands, as soon as the last pinnacle of land sinks beneath the
surface of the ocean. The whole matter is summed up thus: "A magnificent
and harmonious picture of the movements which the crust of the earth has
within a late period undergone is presented to us. We see vast areas
rising, with volcanic matter every now and then bursting forth through
the vents or fissures with which they are traversed. We see other wide
spaces slowly sinking without any volcanic outbursts; and we may feel
sure that this sinking must have been immense in amount as well as in
area, thus to have buried over the broad face of the ocean every one of
these mountains above which atolls now stand like monuments, marking the
place of their former existence." "No more admirable example of
scientific method was ever given to the world," says Professor A.
Geikie, "and even if he had written nothing else, this treatise alone
would have placed Darwin in the very front of investigators of nature."
After thirty-two years' interval, a second edition of "Coral Reefs"
appeared, in a cheaper form, in 1874. It is rare indeed for a scientific
treatise to attain at once and maintain so long a position of such
undisputed authority. The eminent German naturalist, Semper, in 1863,
criticised the general theory in consequence of his own careful
examination of the Pelew Islands; but Darwin easily answered him by
pointing to the cumulative evidence in favour of his own views. The only
really important work on the subject, after Darwin's, was that of
Professor J. D. Dana, the eminent American naturalist and geologist, on
"Corals and Coral Islands," published in 1872. Darwin, in the preface to
his second edition, candidly acknowledged that he had not previously
laid sufficient weight on the mean temperature of the sea in determining
the distribution of coral reefs; but this did not touch his main
conception. In fact, he maintained his ground undisturbed, and at the
same time admired greatly Dana's book, which was the result of personal
examination of more coral formations than perhaps any one man had ever
studied, and which accepted Darwin's fundamental proposition, that
lagoon islands or atolls and barrier-reefs have been formed during
periods of subsidence.[5]
No such strikingly original theory is propounded in the second part of
"The Geology of the _Beagle_" dealing chiefly with volcanic islands. St.
Jago, in the Cape de Verde Islands; Fernando Noronha, Terceira, Tahiti,
Mauritius, St. Paul's, Ascension, St. Helena, and the Galapagos are in
turn more or less fully described, according to the opportunities the
explorer had possessed. To some extent, as in the succeeding part,
Darwin adapts his views on mountain elevation too closely to those
enunciated by Elie de Beaumont. The third part of the geology of the
_Beagle_, entitled "Geological Observations on South America," was not
published till 1846. Even this did not exhaust the contributions to
geology made from the _Beagle_ voyage, for it did not include the papers
on the "Connection of certain Volcanic Phenomena in South America"
(1838); on the "Distribution of Erratic Boulders" (1841); on the "Fine
Dust which falls on Vessels" (1845); and on the "Geology of the
Falkland Islands" (1846). A second edition of the two latter parts of
"The Geology of the _Beagle_" was published in one volume in 1876.
Meanwhile, after spending a few years of his early married life in
London, during which he was often in ill-health, Darwin fixed his
residence in 1842 at Down House, near Beckenham, Kent. The little
village of Down, three or four miles from the Orpington railway station,
was near enough to London for convenient access, yet greatly secluded
and thoroughly rural. The traveller's roving days were over, and his
infirmity of health prevented him from undertaking very fatiguing
journeys. After the cessation of his active work for the Geological
Society, Darwin's chief public appearance was when he spoke at the
Oxford meeting of the British Association, in 1847, when, strange to
say, Ruskin was secretary of the Geological Section.
At Down then, situated some 400 feet above the sea level on a plateau of
chalk, interrupted by wavy hollows with beech woods on the slopes, about
forty years of Darwin's life were passed. Down House, one of the square
red brick mansions of the last century, to which have been since added a
gable-fronted wing on one side and a more squarely-built wing and
pillared portico on the other, is shut in and almost hidden from the
roadway by a high wall and belt of trees. On the south side a walled
garden opens into a quiet meadow, bounded by underwood, through which is
seen a delightful view of the narrow valley beyond, towards Westerham.
One of the most admirable chapters of the well-known "Manual of
Scientific Enquiry," published in 1849, for the use of the navy and
travellers generally, and edited by Sir John Herschel, was Darwin's, on
Geology. The explorer is here taught to make the most of his
opportunities upon the soundest principles. The habits which the author
had himself formed are inculcated upon the observer--copious collecting,
accurate recording, much thinking. Nothing is omitted. Number-labels
which can be read upside down must have a stop to indicate the right way
up; every specimen should be ticketed on the day of collection; diagrams
of all kinds should be made, as nearly as possible, to scale. "Acquire
the habit of always seeking an explanation of every geological point met
with." "No one can expect to solve the many difficulties which will be
encountered, and which for a long time will remain to perplex
geologists; _but a ray of light will occasionally be his reward, and the
reward is ample_." Truly an ample reward awaited the observer who could
thus speak of the value of "a ray of light;" he certainly did, to use
the concluding words of the essay, "enjoy the high satisfaction of
contributing to the perfection of the history of this wonderful world."
Meanwhile Darwin had been carrying on a great research on the very
peculiar order of crustacea, termed Cirripedia, better known as
barnacles and acorn shells. He had originally only intended to describe
a single abnormal member of the group, from South America, but was led,
for the sake of comparison, to examine the internal parts of as many as
possible. The British Museum collection was freely opened to him, and as
the importance of studying the anatomy of many specimens became
evident, the splendid collections of Messrs. Stutchbury, Cuming, and
others were placed at his disposal, and he was permitted to open and to
dissect unique specimens of great value. In fact, almost every
naturalist of note who had any knowledge of the subject freely aided
him, and the result was a masterly series of finely illustrated volumes;
two on the living Cirripedia, issued by the Ray Society in 1851 and
1854; and two on the fossil Cirripedia of Great Britain, by the
Palæontographical Society, published in the same years. There is
evidence in these volumes that careful observations on the growth of
these creatures had been made as far back as the visit to the Galapagos
Islands in 1835. In many respects these works are as masterly as any the
author ever wrote. Considering the previous obscurity of the subject,
the difficulties attending the research, the almost entire lack at that
time of any general microscopical knowledge of tissues, and especially
of those of embryos, Darwin's success is marvellous. The details are too
technical for statement here, but any one with a zoological training,
who studies the strange complication of the reproductive systems, and
the remarkable transformations which the young undergo, as told in these
volumes, will appreciate more than ever the breadth and the solidity of
the basis of patiently acquired knowledge which Charles Darwin had
accumulated while his "Origin of Species" was taking shape.
At the anniversary meeting of the Royal Society in November, 1853, a
royal medal was presented to the author of "Coral Reefs" and the "Memoir
on the Cirripedia," the president, the Earl of Rosse, eulogizing the
former as one of the most important contributions to modern geology, and
the latter as containing new facts and conclusions of first-rate
interest. Finally, this chapter of Darwin's life may be closed with the
tardy award of the Wollaston medal to him by the Geological Society, in
February, 1859, when Professor John Phillips spoke of him as combining
the rarest acquirements as a naturalist, with the qualifications of a
first-class geologist, and as having by his admirable monograph on the
fossil Cirripedia added much to a reputation already raised to the
highest rank.
Yet even such a reputation could not secure fair treatment and impartial
judgment for the coming book, the subject of which might be supposed to
require supreme gifts of the very kind Darwin possessed.
FOOTNOTES:
[5: Mr. John Murray's views, derived from the experience
acquired in the voyage of the _Challenger_, and published in 1880, tend
to modify Darwin's conclusions to some extent. Mr. Murray says that it
is now shown that many submarine mountains exist, which are usually
volcanic, and which, being built upon by various forms of shell-bearing
animals, could be raised to such a level that ordinary corals could
build upon them. He concludes that probably all atolls are seated on
submarine volcanoes, and thus it is not necessary to suppose such
extensive and long-continued subsidences as Darwin suggested. This view
is also in harmony with Dana's views of the great antiquity and
permanence of the great ocean basin. See "The Structure and Origin of
Reefs and Islands." By John Murray; Proc. Roy. Soc., Edin., x. 505-18
(abstract); also _Nature_, xxii. 351-5.]