letter dated December, 1836, only a few weeks after the Beagle returned, Lyell, writing to tell Darwin of the great pleasure which he had derived from a paper of his, and offering to go through it with him before it was read in public, says "The idea of the Pampas going up at the rate of an inch in a century, while the western coast and the Andes rise many feet, and unequally, has long been a dream of mine. What a splendid field you have to write upon." In another letter, in March, 1838, Lyell returns to the subject, and gives an account of the meeting of the Geological Society at which Darwin read his paper on the Connection of Volcanic Phenomena and the Elevation of Mountain Chains. "He opened upon De la Bêche, 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 on a common cause." So early had Mr. Darwin, then a young man of twenty-nine, taken his place among the leading geologists of his time.

In 1842 the first of three volumes by Mr. Darwin on the Geology of the Beagle was published under the title of the Structure and Distribution of Coral Reefs; in 1844 appeared Geological Observations on the Volcanic Islands visited during the Voyage of H. M. S. Beagle,

together with some Brief Notices on the Geology of Australia and the Cape of Good Hope"; and in 1846 the work was completed by "Geological Observations on South America." Each of these volumes was enough to make a considerable reputation for the writer, but the first was the most important. close was Mr. Darwin's observation, and so cogent was his reasoning, that in four or five years the theory which he set forth was "in progress of adoption by men of science in every country.' "This theory (says

1

Quarterly Review, LXXXI. (1847), p. 492.

So

the Director General of the Geological Survey1) for simplicity and grandeur strikes every reader with astonishment. It is pleasant after the lapse of many years to recall the delight with which one first read the Coral Reefs, how one watched the facts being marshalled into their places, nothing being ignored or passed lightly over, and how step by step one was led up to the grand conclusion of wide oceanic subsidences. No more admirable example of scientific method was ever given to the world, and even if he had written nothing else, this treatise alone would have placed Darwin in the very front of investigators of nature." We have mentioned the direct results of the voyage of the Beagle; the indirect results can neither be mentioned nor measured. They are to be seen, as we have said, in almost every work which Mr. Darwin wrote; and the sum of them is a revolution in scientific belief. For this reason it has seemed well to occupy so much of this paper with the early years of Mr. Darwin as a student and a discoverer.

Mr. Darwin, as we have seen, had not been long at home before his valuable services were recognized by men of science, and he was soon elected a Fellow of the Royal Society. In the letter from which we have already quoted, Lyell advises him to accept no official appointment if he can avoid it; but not long afterwards we find him Secretary to the Geological Society, an office which he filled when the Journal of Researches was published in 1839. Two years later he retired, and it was fortunate for the world that thenceforth he acted upon Lyell's advice, and "worked exclusively for science." It was before the Geological Society, on the 1st of November, 1837, that Mr. Darwin read a short paper on the " Formation of Mould "; and forty four years passed before he gave to the public the mature results of his investigations, in the interesting

Paper in Nature on "Mr. Darwin's work in Geology" by Archibald Geikie, LL.D., F.R.S., 1882.

book on the same subject published not many months before he died.

His uncle, Mr. Josiah Wedgwood of Maer Hall in Staffordshire, had suggested to him that the apparent sinking of superficial bodies was due to the action of earth-worms; and this suggestion started Mr. Darwin on the line of enquiry and experiment described in the latest work of his life. For the purposes of that enquiry a quantity of broken chalk was spread over part of a field at Down, in December, 1842, and after an interval of twenty nine years, at the end of November, 1871, a trench was dug to test the results. The book on Earth Worms will be mentioned again in order of date; but it is worth while recording here a fact which gives so vivid an illustration of Mr. Darwin's patient devotion to scientific truth. He seemed never to take a step forward until his footing was perfectly secure; and that is the reason, probably, why his writings have made so profound an impression and so quickly won the assent of his contemporaries.

In the early part of 1839 Mr. Darwin married his cousin, Miss Emma Wedgwood, daughter of Mr. Josiah Wedgwood of Maer Hall, and after a short residence in London he settled in 1842 at Down House,1 near Down, in Kent, for the rest of his days. Down is a quiet little village near the borders of Surrey, three or four miles from the Orpington Station on the South Eastern Railway, between London and Hastings. There, on the pleasant Kentish hills, in the seclusion which was necessary for his work, but near the metropolis, he spent his fruitful days; and, except the record of his published works, there is little to tell of the forty years passed in this quiet retreat. Happy in his home, with children growing up about him, with

1 For the engraving of Down House, and the Greenhouse (given further on), we are indebted to the publishers of The Century, in which they appeared (Vol. XXV., No. 3), to illustrate an interesting paper by Mr. Wallace.