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
