lightly over; and how, step by step, one was led to the grand conclusion of wide oceanic subsidence. No more admirable example of scientific method was ever given to the world, and even if he had written nothing else, the treatise alone would have placed Darwin in the very front of investigators of nature."

It is interesting to see in the following extract from one of Lyell's letters* how warmly and readily he embraced the theory. The extract also gives incidentally some idea of the theory itself.

"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 cost me a pang at first, for it accounted for so much, the annular form, the central lagoon, the sudden rising of an isolated mountain in a deep sea; all went so well with the notion of submerged, crateriform, and conical volcanoes, . and then the fact that in the South Pacific we had scarcely any rocks in the regions of coral islands, save two kinds, coral limestone and volcanic! Yet spite of all this, the whole theory is knocked on the head, and the annular shape and central lagoon have nothing to do with volcanoes, nor even with a crateriform bottom. Perhaps Darwin told you when at the Cape what he considers the true cause? Let any mountain be submerged gradually, and coral grow in the sea in which it is sinking, and there will be a ring of coral, and finally only a lagoon in the centre. Why? For the same reason that a barrier reef of coral grows along certain coasts: Australia, &c. Coral islands are the last efforts of drowning continents to lift their heads above water. Regions of elevation and subsidence in the ocean may be traced by the state of the coral reefs." There is little to be said as to published contemporary criticism. The book was not reviewed in the 'Quarterly Review' till 1847, when a favourable notice was

*To Sir John Herschel, May 24, 1837. Life of Sir Charles Lyell,' vol. ii. p. 12.

given. The reviewer speaks of the "bold and startling" character of the work, but seems to recognize the fact that the views are generally accepted by geologists. By that time the minds of men were becoming more ready to receive geology of this type. Even ten years before, in 1837, Lyell * says, "people are now much better prepared to believe Darwin when he advances proofs of the slow rise of the Andes, than they were in 1830, when I first startled them with that doctrine." This sentence refers to the theory elaborated in my father's geological observations on South America (1846), but the gradual change in receptivity of the geological mind must have been favourable to all his geological work. Nevertheless, Lyell seems at first not to have expected any ready acceptance of the Coral theory; thus he wrote to my father in 1837-"I could think of nothing for days after your lesson on coral reefs, but of the tops of submerged continents. It is all true, but do not flatter yourself that you will be believed till you are growing bald like me, with hard work and vexation at the incredulity of the world."

The second part of the 'Geology of the Voyage of the Beagle,' i. e. the volume on Volcanic Islands, which specially concerns us now, cannot be better described than by again quoting from Professor Geikie (p. 18):—

"Full of detailed observations, this work still remains the best authority on the general geological structure of most of the regions it describes. At the time it was written the 'crater of elevation theory,' though opposed by Constant Prévost, Scrope, and Lyell, was generally accepted, at least on the Continent. Darwin, however, could not receive it as a valid explanation of the facts; and though he did not share the view of its chief opponents, but ventured to propose a hypothesis of his own, the observations impartially made and described by him in this volume must be regarded as having contributed towards the final solution of the difficulty." Professor Geikie continues (p. 21): "He is one of the earliest

*Life of Sir Charles Lyell,' vol. ii. p. 6.

writers to recognize the magnitude of the denudation to which even recent geological accumulations have been subjected. One of the most impressive lessons to be learnt from his account of 'Volcanic Islands' is the prodigious extent to which they have been denuded. . . . He was disposed to attribute more of this work to the sea than most geologists would now admit; but he lived himself to modify his original views, and on this subject his latest utterances are quite abreast of the time."

An extract from a letter of my father's to Lyell shows his estimate of his own work. "You have pleased me much by saying that you intend looking through my 'Volcanic Islands' it cost me eighteen months! ! ! and I have heard of very few who have read it. Now I shall feel, whatever little (and little it is) there is confirmatory of old work, or new, will work its effect and not be lost."

The third of his geological books, 'Geological Observations on South America,' may be mentioned here, although it was not published until 1846. "In this work the author embodied all the materials collected by him for the illustration of South American Geology, save some which have been published elsewhere. One of the most important features of the book was the evidence which it brought forward to prove the slow interrupted elevation of the South American Continent during a recent geological period."*

Of this book my father wrote to Lyell :-" My volume will be about 240 pages, dreadfully dull, yet much condensed. I think whenever you have time to look through it, you will think the collection of facts on the elevation of the land and on the formation of terraces pretty good."

Of his special geological work as a whole, Professor Geikie, while pointing out that it was not "of the same epoch-making kind as his biological researches," remarks that he “gave a powerful impulse to" the general reception of Lyell's teaching "by the way in which he gathered from all parts of the world facts in its support."

Geikie, loc. cit.

1

WORK OF THE PERIOD 1842 TO 1854.

The work of these years may be roughly divided into a period of geology from 1842 to 1846, and one of zoology from 1846 onwards.

I extract from his diary notices of the time spent on his geological books and on his 'Journal.'

'Volcanic Islands.' Summer of 1842 to January, 1844. 'Geology of South America.' July, 1844, to April, 1845. Second Edition of 'The Journal,' October, 1845, to October, 1846.

The time between October, 1846, and October, 1854, was practically given up to working at the Cirripedia (Barnacles); the results were published in two volumes by the Ray Society in 1851 and 1854. His volumes on the Fossil Cirripedes were published by the Palæontographical Society in 1851 and 1854.

Some account of these volumes will be given later.

The minor works may be placed together, independently of subject matter.

"Observations on the Structure, &c., of the genus Sagitta," Ann. Nat. Hist. xiii., 1844, pp. 1-6.

"Brief Descriptions of several Terrestrial Planariæ, &c.," Ann. Nat. Hist. xiv., 1844, PP. 241-251.

"An Account of the Fine Dust* which often Falls on Vessels in the Atlantic Ocean," Geol. Soc. Journ. ii., 1846, pp.

26-30.

"On the Geology of the Falkland Islands," Geol. Soc. Journ. ii., 1846, pp. 267-274.

"On the Transportal of Erratic Boulders, &c.," Geol. Soc. Journ. iv., 1848, pp. 315-323.t

* A sentence occurs in this paper of interest, as showing that the author was alive to the importance of all means of distribution :-"The fact that particles of this size having been brought at least 330 miles from the land is interesting as bearing on the distribution of Cryptogamic plants."

An extract from a letter to Lyell, 1847, is of interest in connection with this essay :-" Would you be so good (if you know it) as to put Maclaren's

The article "Geology," in the Admiralty Manual of Scientific Enquiry (1849), pp. 156-195. This was written in the spring of 1848.

"On British Fossil Lepadidæ," 'Geol. Soc. Journ.' vi., 1850, pp. 439-440.

66 Analogy of the structure of some Volcanic Rocks with that of Glaciers," 'Edin. Roy. Soc. Proc.' ii., 1851, pp. 17-18. Professor Geikie has been so good as to give me (in a letter dated Nov. 1885) his impressions of my father's article in the Admiralty Manual.' He mentions the following

points as characteristic of the work:

"1. Great breadth of view. No one who had not practically studied and profoundly reflected on the questions discussed could have written it.

"2. The insight so remarkable in all that Mr. Darwin ever did. The way in which he points out lines of enquiry that would elucidate geological problems is eminently typical of him. Some of these lines have never yet been adequately followed; so with regard to them he was in advance of his time.

"3. 3. Interesting and sympathetic treatment. The author at once puts his readers into harmony with him. He gives them enough of information to show how delightful the field. is to which he invites them, and how much they might accomplish in it. There is a broad sketch of the subject

address on the enclosed letter and post it. It is chiefly to enquire in what paper he has described the Boulders on Arthur's Seat. Mr. D. Milne in the last Edinburgh 'New Phil. Journal' [1847], has a long paper on it. He says: Some glacialists have ventured to explain the transportation of boulders even in the situation of those now referred to, by imagining that they were transported on ice floes,' &c. He treats this view, and the scratching of rocks by icebergs, as almost absurd. . . he has finally stirred me up so, that (without you would answer him) I think I will send a paper in opposition to the same Journal. I can thus introduce some old remarks of mine, and some new, and will insist on your capital observations in N. America. It is a bore to stop one's work, but he has made me quite wroth."