"I replied, that most of the critics had attacked me for overrating Hutton, and that Playfair understood him as I did.

"Whewell concluded by considering Hopkins' mathematical calculations, to which Darwin had often referred. He also said that we ought not to try and make out what Hutton would have taught and thought, if he had known the facts which we now know."

It may be necessary to point out, in explanation of the above narrative, that while it was perfectly clear from Hutton's rather obscure and involved writings that he advocated slow and gradual change on the earth's surface, his frequent references to violent action and earthquakes led many—including Playfair, Lyell and Whewell—to believe that he held the changes going on in the earth's interior to be of a catastrophic nature. Fitton, however, maintained that Hutton was consistently uniformitarian. Before the idea of the actual "flowing" of solid bodies under intense pressure had been grasped by geologists, De la Beche, like Playfair before him, maintained that the bending and folding of rocks must have been effected before their complete consolidation.

In concluding his account of this memorable discussion, Lyell adds: "I was much struck with the different tone in which my gradual causes was treated by all, even including De la Beche, from that which they experienced in the same room four years ago, when Buckland, De la Beche(?), Sedgwick, Whewell, and some others treated them with as much ridicule as was consistent with politeness in my presence."

This important paper was, in spite of its theoretical character, published in full in the "Transactions of the Geological Society" (Ser. 2, Vol. V. pages 601-630). It did not however appear till 1840, and possibly some changes may have been made in it during the long interval between reading and printing. During the year 1839, Darwin continued his regular attendance at the Council meetings, but there is no record of any discussions in which he may have taken part, and he contributed no papers himself to the Society. At the beginning of 1840, he was re-elected for the third time as Secretary, but the results of failing health are indicated by the circumstance that, only at one meeting early in the session, was he able to attend the Council. At the beginning of the next session (Feb. 1841) Bunbury succeeded him as Secretary, Darwin still remaining on the Council. It may be regarded as a striking indication of the esteem in which he was held by his fellow geologists, that Darwin remained on the Council for 14 consecutive years down to 1849, though his attendances were in some years very few. In 1843 and 1844 he was a Vice-president, but after his retirement at the beginning of 1850, he never again accepted re-nomination. He continued, however, to contribute papers to the Society, as we shall see, down to the end of 1862.

Although Darwin early became a member of the Geological Dining Club, it is to be feared that he scarcely found himself in a congenial atmosphere at those somewhat hilarious gatherings, where the hardy wielders of the hammer not only drank port—and plenty of it—but wound up their meal with a mixture of Scotch ale and soda water, a drink which, as reminiscent of the "field," was regarded as especially appropriate to geologists. Even after the meetings, which followed the dinners, they reassembled for suppers, at which geological dainties, like "pterodactyle pie" figured in the bill of fare, and fines of bumpers were inflicted on those who talked the "ologies."

After being present at a fair number of meetings in 1837 and 1838, Darwin's attendances at the Club fell off to two in 1839, and by 1841 he had ceased to be a member. In a letter to Lyell on Dec. 2nd, 1841, Leonard Horner wrote that the day before "At the Council, I had the satisfaction of seeing Darwin again in his place and looking well. He tried the last evening meeting, but found it too much, but I hope before the end of the season he will find himself equal to that also. I hail Darwin's recovery as a vast gain to science." Darwin's probably last attendance, this time as a guest, was in 1851, when Horner again wrote to Lyell, "Charles Darwin was at the Geological Society's Club yesterday, where he had not been for ten years—remarkably well, and grown quite stout." ("Memoirs of Leonard Horner" (privately printed), Vol. II. pages 39 and 195.)

It may be interesting to note that at the somewhat less lively dining Club—the Philosophical—in the founding of which his friends Lyell and Hooker had taken so active a part, Darwin found himself more at home, and he was a frequent attendant—in spite of his residence being at Down—from 1853 to 1864. He even made contributions on scientific questions after these dinners. In a letter to Hooker he states that he was deeply interested in the reforms of the Royal Society, which the Club was founded to promote. He says also that he had arranged to come to town every Club day "and then my head, I think, will allow me on an average to go to every other meeting. But it is grievous how often any change knocks me up." ("L.L." II. pages 42, 43.)

Of the years 1837 and 1838 Darwin himself says they were "the most active ones which I ever spent, though I was occasionally unwell, and so lost some time... I also went a little into society." ("L.L." I. pages 67, 68.) But of the four years from 1839 to 1842 he has to confess sadly "I did less scientific work, though I worked as hard as I could, than during any other equal length of time in my life. This was owing to frequently recurring unwellness, and to one long and serious illness." ("L.L." I. page 69.)

Darwin's work at the Geological Society did not by any means engage the whole of his energies, during the active years 1837 and 1838. In June of the latter year, leaving town in somewhat bad health, he found himself at Edinburgh again, and engaged in examining the Salisbury Craigs, in a very different spirit to that excited by Jameson's discourse. ("L.L." I. page 290.) Proceeding to the Highlands he then had eight days of hard work at the famous "Parallel Roads of Glen Roy", being favoured with glorious weather.

He says of the writing of the paper on the subject—the only memoir contributed by Darwin to the Royal Society, to which he had been recently elected—that it was "one of the most difficult and instructive tasks I was ever engaged on." The paper extends to 40 quarto pages and is illustrated by two plates. Though it is full of the records of careful observation and acute reasoning, yet the theory of marine beaches which he propounded was, as he candidly admitted in after years ("M.L." II page 188.), altogether wrong. The alternative lake-theory he found himself unable to accept at the time, for he could not understand how barriers could be formed at successive levels across the valleys; and until the following year, when the existence of great glaciers in the district was proved by the researches of Agassiz, Buckland and others, the difficulty appeared to him an insuperable one. Although Darwin said of this paper in after years that it "was a great failure and I am ashamed of it"—yet he retained his interest in the question ever afterwards, and he says "my error has been a good lesson to me never to trust in science to the principle of exclusion." ("M.L." II. pages 171-93.)

Although Darwin had not realised in 1838 that large parts of the British Islands had been occupied by great glaciers, he had by no means failed while in South America to recognise the importance of ice-action. His observations, as recorded in his Journal, on glaciers coming down to the sea-level, on the west coast of South America, in a latitude corresponding to a much lower one than that of the British Islands, profoundly interested geologists; and the same work contains many valuable notes on the boulders and unstratified beds in South America in which they were included.

But in 1840 Agassiz read his startling paper on the evidence of the former existence of glaciers in the British Islands, and this was followed by Buckland's memoir on the same subject. On April 14, 1841, Darwin contributed to the Geological Society his important paper "On the Distribution of Erratic Boulders and the Contemporaneous Unstratified Deposits of South America", a paper full of suggestiveness for those studying the glacial deposits of this country. It was published in the "Transactions" in 1842.

The description of traces of glacial action in North Wales, by Buckland, appears to have greatly excited the interest of Darwin. With Sedgwick he had, in 1831, worked at the stratigraphy of that district, but neither of them had noticed the very interesting surface features. ("L.L." I. page 58.) Darwin was able to make a journey to North Wales in June, 1842 (alas! it was his last effort in field-geology) and as a result he published his most able and convincing paper on the subject in the September number of the "Philosophical Magazine" for 1842. Thus the mystery of the bell-stone was at last solved and Darwin, writing many years afterwards, said "I felt the keenest delight when I first read of the action of icebergs in transporting boulders, and I gloried in the progress of Geology." ("L.L." I. page 41.) To the "Geographical Journal" he had sent in 1839 a note "On a Rock seen on an Iceberg in 16 deg S. Latitude." For the subject of ice-action, indeed, Darwin retained the greatest interest to the end of his life. ("M.L." II. pages 148-71.)

In 1846, Darwin read two papers to the Geological Society "On the dust which falls on vessels in the Atlantic, and On the Geology of the Falkland Islands"; in 1848 he contributed a note on the transport of boulders from lower to higher levels; and in 1862 another note on the thickness of the Pampean formation, as shown by recent borings at Buenos Ayres. An account of the "British Fossil Lepadidae" read in 1850, was withdrawn by him.

At the end of 1836 Darwin had settled himself in lodgings in Fitzwilliam Street, Cambridge, and devoted three months to the work of unpacking his specimens and studying his collection of rocks. The pencilled notes on the Manuscript Catalogue in the Sedgwick Museum enable us to realise his mode of work, and the diligence with which it was carried on. The letters M and H, indicate the assistance he received from time to time from Professor Miller, the crystallographer, and from his friend Henslow. Miller not only measured many of the crystals submitted to him, but evidently taught Darwin to use the reflecting goniometer himself with considerable success. The "book of measurements" in which the records were kept, appears to have been lost, but the pencilled notes in the catalogue show how thoroughly the work was done. The letter R attached to some of the numbers in the catalogue evidently refers to the fact that they were submitted to Mr Trenham Reeks (who analysed some of his specimens) at the Geological Survey quarters in Craig's Court. This was at a later date when Darwin was writing the "Volcanic Islands" and "South America".

It was about the month of March, 1837, that Darwin completed this work upon his rocks, and also the unpacking and distribution of his fossil bones and other specimens. We have seen that November, 1832, must certainly be regarded as the date when he FIRST realised the important fact that the fossil mammals of the Pampean formation were all closely related to the existing forms in South America; while October, 1835, was, as undoubtedly, the date when the study of the birds and other forms of life in the several islands of the Galapagos Islands gave him his SECOND impulse towards abandoning the prevalent view of the immutability of species. When then in his pocket-book for 1837 Darwin wrote the often quoted passage: "In July opened first note-book on Transmutation of Species. Had been greatly struck from about the month of previous March on character of South American fossils, and species on Galapagos Archipelago. These facts (especially latter), origin of all my views" ("L.L." I. page 276.), it is clear that he must refer, not to his first inception of the idea of evolution, but to the flood of recollections, the reawakening of his interest in the subject, which could not fail to result from the sight of his specimens and the reference to his notes.

Except during the summer vacation, when he was visiting his father and uncle, and with the latter making his first observations upon the work of earthworms, Darwin was busy with his arrangements for the publication of the five volumes of the "Zoology of the 'Beagle'" and in getting the necessary financial aid from the government for the preparation of the plates. He was at the same time preparing his "Journal" for publication. During the years 1837 to 1843, Darwin worked intermittently on the volumes of Zoology, all of which he edited, while he wrote introductions to those by Owen and Waterhouse and supplied notes to the others.

Although Darwin says of his Journal that the preparation of the book "was not hard work, as my MS. Journal had been written with care." Yet from the time that he settled at 36, Great Marlborough Street in March, 1837, to the following November he was occupied with this book. He tells us that the account of his scientific observations was added at this time. The work was not published till March, 1839, when it appeared as the third volume of the "Narrative of the Surveying Voyages of H.M. Ships 'Adventure' and 'Beagle' between the years 1826 and 1836". The book was probably a long time in the press, for there are no less than 20 pages of addenda in small print. Even in this, its first form, the work is remarkable for its freshness and charm, and excited a great amount of attention and interest. In addition to matters treated of in greater detail in his other works, there are many geological notes of extreme value in this volume, such as his account of lightning tubes, of the organisms found in dust, and of the obsidian bombs of Australia.

Having thus got out of hand a number of preliminary duties, Darwin was ready to set to work upon the three volumes which were designed by him to constitute "The Geology of the Voyage of the 'Beagle'". The first of these was to be on "The Structure and Distribution of Coral-reefs". He commenced the writing of the book on October 5, 1838, and the last proof was corrected on May 6, 1842. Allowing for the frequent interruptions through illness, Darwin estimated that it cost him twenty months of hard work.

Darwin has related how his theory of Coral-reefs which was begun in a more "deductive spirit" than any of his other work, for in 1834 or 1835 it "was thought out on the west coast of South America, before I had seen a true coral-reef." ("L.L." I. page 70.) The final chapter in Lyell's second volume of the "Principles" was devoted to the subject of Coral-reefs, and a theory was suggested to account for the peculiar phenomena of "atolls." Darwin at once saw the difficulty of accepting the view that the numerous and diverse atolls all represent submerged volcanic craters. His own work had for two years been devoted to the evidence of land movements over great areas in South America, and thus he was led to announce his theory of subsidence to account for barrier and encircling reefs as well as atolls.

Fortunately, during his voyage across the Pacific and Indian Oceans, in his visit to Australia and his twelve days' hard work at Keeling Island, he had opportunities for putting his theory to the test of observation.

On his return to England, Darwin appears to have been greatly surprised at the amount of interest that his new theory excited. Urged by Lyell, he read to the Geological Society a paper on the subject, as we have seen, with as little delay as possible, but this paper was "withdrawn by permission of the Council." An abstract of three pages however appeared in the "Proceedings of the Geological Society". (Vol. II. pages 552-554 (May 31, 1837).) A full account of the observations and the theory was given in the "Journal" (1839) in the 40 pages devoted to Keeling Island in particular and to Coral formations generally. ("Journal" (1st edition), pages 439-69.)

It will be readily understood what an amount of labour the book on Coral reefs cost Darwin when we reflect on the number of charts, sailing directions, narratives of voyages and other works which, with the friendly assistance of the authorities at the Admiralty, he had to consult before he could draw up his sketch of the nature and distribution of the reefs, and this was necessary before the theory, in all its important bearings, could be clearly enunciated. Very pleasing is it to read how Darwin, although arriving at a different conclusion to Lyell, shows, by quoting a very suggestive passage in the "Principles" (1st edition Vol. II. page 296.), how the latter only just missed the true solution. This passage is cited, both in the "Journal" and the volume on Coral-reefs. Lyell, as we have seen, received the new theory not merely ungrudgingly, but with the utmost enthusiasm.

In 1849 Darwin was gratified by receiving the support of Dana, after his prolonged investigation in connection with the U.S. Exploring Expedition ("M.L." II. pages 226-8.), and in 1874 he prepared a second edition of his book, in which some objections which had been raised to the theory were answered. A third edition, edited by Professor Bonney, appeared in 1880, and a fourth (a reprint of the first edition, with introduction by myself) in 1890.

Although Professor Semper, in his account of the Pelew Islands, had suggested difficulties in the acceptance of Darwin's theory, it was not till after the return of the "Challenger" expedition in 1875 that a rival theory was propounded, and somewhat heated discussions were raised as to the respective merits of the two theories. While geologists have, nearly without exception, strongly supported Darwin's views, the notes of dissent have come almost entirely from zoologists. At the height of the controversy unfounded charges of unfairness were made against Darwin's supporters and the authorities of the Geological Society, but this unpleasant subject has been disposed of, once for all, by Huxley. ("Essays upon some Controverted Questions", London, 1892, pages 314-328 and 623-625.)

Darwin's final and very characteristic utterance on the coral-reef controversy is found in a letter which he wrote to Professor Alexander Agassiz, May 5th, 1881: less than a year before his death: "If I am wrong, the sooner I am knocked on the head and annihilated so much the better. It still seems to me a marvellous thing that there should not have been much, and long-continued, subsidence in the beds of the great oceans. I wish that some doubly rich millionaire would take it into his head to have borings made in some of the Pacific and Indian atolls, and bring home cores for slicing from a depth of 500 or 600 feet." ("L.L." III. page 184.)

Though the "doubly rich millionaire" has not been forthcoming, the energy, in England, of Professor Sollas, and in New South Wales of Professor Anderson Stuart served to set on foot a project, which, aided at first by the British Association for the Advancement of Science, and afterwards taken up jointly by the Royal Society, the New South Wales Government, and the Admiralty, has led to the most definite and conclusive results.

The Committee appointed by the Royal Society to carry out the undertaking included representatives of all the views that had been put forward on the subject. The place for the experiment was, with the consent of every member of the Committee, selected by the late Admiral Sir W.J. Wharton—who was not himself an adherent of Darwin's views—and no one has ventured to suggest that his selection, the splendid atoll of Funafuti, was not a most judicious one.

By the pluck and perseverance of Professor Sollas in the preliminary expedition, and of Professor T. Edgeworth David and his pupils, in subsequent investigations of the island, the rather difficult piece of work was brought to a highly satisfactory conclusion. The New South Wales Government lent boring apparatus and workmen, and the Admiralty carried the expedition to its destination in a surveying ship which, under Captain (now Admiral) A. Mostyn Field, made the most complete survey of the atoll and its surrounding seas that has ever been undertaken in the case of a coral formation.

After some failures and many interruptions, the boring was carried to the depth of 1114 feet, and the cores obtained were sent to England. Here the examination of the materials was fortunately undertaken by a zoologist of the highest repute, Dr G.J. Hinde—who has a wide experience in the study of organisms by sections—and he was aided at all points by specialists in the British Museum of Natural History and by other naturalists. Nor were the chemical and other problems neglected.

The verdict arrived at, after this most exhaustive study of a series of cores obtained from depths twice as great as that thought necessary by Darwin, was as follows:—"The whole of the cores are found to be built up of those organisms which are seen forming coral-reefs near the surface of the ocean—many of them evidently in situ; and not the slightest indication could be detected, by chemical or microscopic means, which suggested the proximity of non-calcareous rocks, even in the lowest portions brought up."

But this was not all. Professor David succeeded in obtaining the aid of a very skilful engineer from Australia, while the Admiralty allowed Commander F.C.D. Sturdee to take a surveying ship into the lagoon for further investigations. By very ingenious methods, and with great perseverance, two borings were put down in the midst of the lagoon to the depth of nearly 200 feet. The bottom of the lagoon, at the depth of 101 1/2 feet from sea-level, was found to be covered with remains of the calcareous, green sea-weed Halimeda, mingled with many foraminifera; but at a depth of 163 feet from the surface of the lagoon the boring tools encountered great masses of coral, which were proved from the fragments brought up to belong to species that live within AT MOST 120 feet from the surface of the ocean, as admitted by all zoologists. ("The Atoll of Funafuti; Report of the Coral Reef Committee of the Royal Society", London, 1904.)

Darwin's theory, as is well known, is based on the fact that the temperature of the ocean at any considerable depth does not permit of the existence and luxuriant growth of the organisms that form the reefs. He himself estimated this limit of depth to be from 120 to 130 feet; Dana, as an extreme, 150 feet; while the recent very prolonged and successful investigations of Professor Alexander Agassiz in the Pacific and Indian Oceans lead him also to assign a limiting depth of 150 feet; the EFFECTIVE, REEF-FORMING CORALS, however, flourishing at a much smaller depth. Mr Stanley Gardiner gives for the most important reef-forming corals depths between 30 and 90 feet, while a few are found as low as 120 feet or even 180 feet.

It will thus be seen that the verdict of Funafuti is clearly and unmistakeably in favour of Darwin's theory. It is true that some zoologists find a difficulty in realising a slow sinking of parts of the ocean floor, and have suggested new and alternative explanations: but geologists generally, accepting the proofs of slow upheaval in some areas—as shown by the admirable researches of Alexander Agassiz—consider that it is absolutely necessary to admit that this elevation is balanced by subsidence in other areas. If atolls and barrier-reefs did not exist we should indeed be at a great loss to frame a theory to account for their absence.

After finishing his book on Coral-reefs, Darwin made his summer excursion to North Wales, and prepared his important memoir on the glaciers of that district: but by October (1842) we find him fairly settled at work upon the second volume of his "Geology of the 'Beagle'—Geological Observations on the Volcanic Islands, visited during the Voyage of H.M.S. 'Beagle'". The whole of the year 1843 was devoted to this work, but he tells his friend Fox that he could "manage only a couple of hours per day, and that not very regularly." ("L.L." I. page 321.) Darwin's work on the various volcanic islands examined by him had given him the most intense pleasure, but the work of writing the book by the aid of his notes and specimens he found "uphill work," especially as he feared the book would not be read, "even by geologists." (Loc. cit.)

As a matter of fact the work is full of the most interesting observations and valuable suggestions, and the three editions (or reprints) which have appeared have proved a most valuable addition to geological literature. It is not necessary to refer to the novel and often very striking discoveries described in this well-known work. The subsidence beneath volcanic vents, the enormous denudation of volcanic cones reducing them to "basal wrecks," the effects of solfatarric action and the formation of various minerals in the cavities of rocks—all of these subjects find admirable illustration from his graphic descriptions. One of the most important discussions in this volume is that dealing with the "lamination" of lavas as especially well seen in the rocks of Ascension. Like Scrope, Darwin recognised the close analogy between the structure of these rocks and those of metamorphic origin—a subject which he followed out in the volume "Geological Observations on South America".

Of course in these days, since the application of the microscope to the study of rocks in thin sections, Darwin's nomenclature and descriptions of the petrological characters of the lavas appear to us somewhat crude. But it happened that the "Challenger" visited most of the volcanic islands described by Darwin, and the specimens brought home were examined by the eminent petrologist Professor Renard. Renard was so struck with the work done by Darwin, under disadvantageous conditions, that he undertook a translation of Darwin's work into French, and I cannot better indicate the manner in which the book is regarded by geologists than by quoting a passage from Renard's preface. Referring to his own work in studying the rocks brought home by the "Challenger" (Renard's descriptions of these rocks are contained in the "Challenger Reports". Mr Harker is supplementing these descriptions by a series of petrological memoirs on Darwin's specimens, the first of which appeared in the "Geological Magazine" for March, 1907.), he says:

"Je dus, en me livrant a ces recherches, suivre ligne par ligne les divers chapitres des "Observations geologiques" consacrees aux iles de l'Atlantique, oblige que j'etais de comparer d'une maniere suivie les resultats auxquels j'etais conduit avec ceux de Darwin, qui servaient de controle a mes constatations. Je ne tardai pas a eprouver une vive admiration pour ce chercheur qui, sans autre appareil que la loupe, sans autre reaction que quelques essais pyrognostiques, plus rarement quelques mesures au goniometre, parvenait a discerner la nature des agregats mineralogiques les plue complexes et les plus varies. Ce coup d'oeil qui savait embrasser de si vastes horizons, penetre ici profondement tous les details lithologiques. Avec quelle surete et quelle exactitude la structure et la composition des roches ne sont'elles pas determinees, l'origne de ces masses minerales deduite et confirmee par l'etude comparee des manifestations volcaniques d'autres regions; avec quelle science les relations entre les faits qu'il decouvre et ceux signales ailleurs par ses devanciers ne sont'elles pas etablies, et comme voici ebranlees les hypotheses regnantes, admises sans preuves, celles, par exemple, des crateres de soulevement et de la differenciation radicale des phenomenes plutoniques et volcaniques! Ce qui acheve de donner a ce livre un incomparable merite, ce sont les idees nouvelles qui s'y trouvent en germe et jetees la comme au hasard ainsi qu'un superflu d'abondance intellectuelle inepuisable." ("Observations Geologiques sur les Iles Volcaniques... ", Paris, 1902, pages vi., vii.)

While engaged in his study of banded lavas, Darwin was struck with the analogy of their structure with that of glacier ice, and a note on the subject, in the form of a letter addressed to Professor J.D. Forbes, was published in the "Proceedings of the Royal Society of Edinburgh". (Vol. II. (1844-5), pages 17, 18.)

From April, 1832, to September, 1835, Darwin had been occupied in examining the coast or making inland journeys in the interior of the South American continent. Thus while eighteen months were devoted, at the beginning and end of the voyage to the study of volcanic islands and coral-reefs, no less than three and a half years were given to South American geology. The heavy task of dealing with the notes and specimens accumulated during that long period was left by Darwin to the last. Finishing the "Volcanic Islands" on February 14th, 1844, he, in July of the same year, commenced the preparation of two important works which engaged him till near the end of the year 1846. The first was his "Geological Observations on South America", the second a recast of his "Journal", published under the short title of "A Naturalist's Voyage round the World".

The first of these works contains an immense amount of information collected by the author under great difficulties and not unfrequently at considerable risk to life and health. No sooner had Darwin landed in South America than two sets of phenomena powerfully arrested his attention. The first of these was the occurrence of great masses of red mud containing bones and shells, which afforded striking evidence that the whole continent had shared in a series of slow and gradual but often interrupted movements. The second related to the great masses of crystalline rocks which, underlying the muds, cover so great a part of the continent. Darwin, almost as soon as he landed, was struck by the circumstance that the direction, as shown by his compass, of the prominent features of these great crystalline rock-masses—their cleavage, master-joints, foliation and pegmatite veins—was the same as the orientation described by Humboldt (whose works he had so carefully studied) on the west of the same great continent.

The first five chapters of the book on South America were devoted to formations of recent date and to the evidence collected on the east and west coasts of the continent in regard to those grand earth-movements, some of which could be shown to have been accompanied by earthquake-shocks. The fossil bones, which had given him the first hint concerning the mutability of species, had by this time been studied and described by comparative anatomists, and Darwin was able to elaborate much more fully the important conclusion that the existing fauna of South America has a close analogy with that of the period immediately preceding our own.

The remaining three chapters of the book dealt with the metamorphic and plutonic rocks, and in them Darwin announced his important conclusions concerning the relations of cleavage and foliation, and on the close analogy of the latter structure with the banding found in rock-masses of igneous origin. With respect to the first of these conclusions, he received the powerful support of Daniel Sharpe, who in the years 1852 and 1854 published two papers on the structure of the Scottish Highlands, supplying striking confirmation of the correctness of Darwin's views. Although Darwin's and Sharpe's conclusions were contested by Murchison and other geologists, they are now universally accepted. In his theory concerning the origin of foliation, Darwin had been to some extent anticipated by Scrope, but he supplied many facts and illustrations leading to the gradual acceptance of a doctrine which, when first enunciated, was treated with neglect, if not with contempt.

The whole of this volume on South American geology is crowded with the records of patient observations and suggestions of the greatest value; but, as Darwin himself saw, it was a book for the working geologist and "caviare to the general." Its author, indeed, frequently expressed his sense of the "dryness" of the book; he even says "I long hesitated whether I would publish it or not," and he wrote to Leonard Horner "I am astonished that you should have had the courage to go right through my book." ("M.L." II. page 221.)

Fortunately the second book, on which Darwin was engaged at this time, was of a very different character. His "Journal", almost as he had written it on board ship, with facts and observations fresh in his mind, had been published in 1839 and attracted much attention. In 1845, he says, "I took much pains in correcting a new edition," and the work which was commenced in April, 1845, was not finished till August of that year. The volume contains a history of the voyage with "a sketch of those observations in Natural History and Geology, which I think will possess some interest for the general reader." It is not necessary to speak of the merits of this scientific classic. It became a great favourite with the general public—having passed through many editions—it was, moreover, translated into a number of different languages. Darwin was much gratified by these evidences of popularity, and naively remarks in his "Autobiography", "The success of this my first literary child tickles my vanity more than that of any of my other books" ("L.L." I. page 80.)—and this was written after the "Origin of Species" had become famous!

In Darwin's letters there are many evidences that his labours during these ten years devoted to the working out of the geological results of the voyage often made many demands on his patience and indomitable courage. Most geologists have experience of the contrast between the pleasures felt when wielding the hammer in the field, and the duller labour of plying the pen in the study. But in Darwin's case, innumerable interruptions from sickness and other causes, and the oft-deferred hope of reaching the end of his task were not the only causes operating to make the work irksome. The great project, which was destined to become the crowning achievement of his life, was now gradually assuming more definite shape, and absorbing more of his time and energies.

Nevertheless, during all this period, Darwin so far regarded his geological pursuits as his PROPER "work," that attention to other matters was always spoken of by him as "indulging in idleness." If at the end of this period the world had sustained the great misfortune of losing Darwin by death before the age of forty—and several times that event seemed only too probable—he might have been remembered only as a very able geologist of most advanced views, and a traveller who had written a scientific narrative of more than ordinary excellence!

The completion of the "Geology of the 'Beagle'" and the preparation of a revised narrative of the voyage mark the termination of that period of fifteen years of Darwin's life during which geological studies were his principal occupation. Henceforth, though his interest in geological questions remained ever keen, biological problems engaged more and more of his attention to the partial exclusion of geology.

The eight years from October, 1846, to October, 1854, were mainly devoted to the preparation of his two important monographs on the recent and fossil Cirripedia. Apart from the value of his description of the fossil forms, this work of Darwin's had an important influence on the progress of geological science. Up to that time a practice had prevailed for the student of a particular geological formation to take up the description of the plant and animal remains in it—often without having anything more than a rudimentary knowledge of the living forms corresponding to them. Darwin in his monograph gave a very admirable illustration of the enormous advantage to be gained—alike for biology and geology—by undertaking the study of the living and fossil forms of a natural group of organisms in connection with one another. Of the advantage of these eight years of work to Darwin himself, in preparing for the great task lying before him, Huxley has expressed a very strong opinion indeed. ("L.L." II. pages 247-48.)

But during these eight years of "species work," Darwin found opportunities for not a few excursions into the field of geology. He occasionally attended the Geological Society, and, as we have already seen, read several papers there during this period. His friend, Dr Hooker, then acting as botanist to the Geological Survey, was engaged in studying the Carboniferous flora, and many discussions on Palaezoic plants and on the origin of coal took place at this period. On this last subject he felt the deepest interest and told Hooker, "I shall never rest easy in Down churchyard without the problem be solved by some one before I die." ("M.L." I. pages 63, 64.)

As at all times, conversations and letters with Lyell on every branch of geological science continued with unabated vigour, and in spite of the absorbing character of the work on the Cirripedes, time was found for all. In 1849 his friend Herschel induced him to supply a chapter of forty pages on Geology to the Admiralty "Manual of Scientific Inquiry" which he was editing. This is Darwin's single contribution to books of an "educational" kind. It is remarkable for its clearness and simplicity and attention to minute details. It may be read by the student of Darwin's life with much interest, for the directions he gives to an explorer are without doubt those which he, as a self-taught geologist, proved to be serviceable during his life on the "Beagle".

On the completion of the Cirripede volumes, in 1854, Darwin was able to grapple with the immense pile of MS. notes which he had accumulated on the species question. The first sketch of 35 pages (1842), had been enlarged in 1844 into one of 230 pages ([The first draft of the "Origin" is being prepared for Press by Mr Francis Darwin and will be published by the Cambridge University Press this year (1909). A.C.S.]); but in 1856 was commenced the work (never to be completed) which was designed on a scale three or four times more extensive than that on which the "Origin of Species" was in the end written.

In drawing up those two masterly chapters of the "Origin", "On the Imperfection of the Geological Record," and "On the Geological Succession of Organic Beings", Darwin had need of all the experience and knowledge he had been gathering during thirty years, the first half of which had been almost wholly devoted to geological study. The most enlightened geologists of the day found much that was new, and still more that was startling from the manner of its presentation, in these wonderful essays. Of Darwin's own sense of the importance of the geological evidence in any presentation of his theory a striking proof will be found in a passage of the touching letter to his wife, enjoining the publication of his sketch of 1844. "In case of my sudden death," he wrote, "... the editor must be a geologist as well as a naturalist." ("L.L." II. pages 16, 17.)

In spite of the numerous and valuable palaeontological discoveries made since the publication of "The Origin of Species", the importance of the first of these two geological chapters is as great as ever. It still remains true that "Those who believe that the geological record is in any degree perfect, will at once reject the theory"—as indeed they must reject any theory of evolution. The striking passage with which Darwin concludes this chapter—in which he compares the record of the rocks to the much mutilated volumes of a human history—remains as apt an illustration as it did when first written.

And the second geological chapter, on the Succession of Organic Beings—though it has been strengthened in a thousand ways, by the discoveries concerning the pedigrees of the horse, the elephant and many other aberrant types, though new light has been thrown even on the origin of great groups like the mammals, and the gymnosperms, though not a few fresh links have been discovered in the chains of evidence, concerning the order of appearance of new forms of life—we would not wish to have re-written. Only the same line of argument could be adopted, though with innumerable fresh illustrations. Those who reject the reasonings of this chapter, neither would they be persuaded if a long and complete succession of "ancestral forms" could rise from the dead and pass in procession before them.

Among the geological discussions, which so frequently occupied Darwin's attention during the later years of his life, there was one concerning which his attitude seemed somewhat remarkable—I allude to his views on "the permanence of Continents and Ocean-basins." In a letter to Mr Mellard Reade, written at the end of 1880, he wrote: "On the whole, I lean to the side that the continents have since Cambrian times occupied approximately their present positions. But, as I have said, the question seems a difficult one, and the more it is discussed the better." ("M.L." II. page 147.) Since this was written, the important contribution to the subject by the late Dr W.T. Blanford (himself, like Darwin, a naturalist and geologist) has appeared in an address to the Geological Society in 1890; and many discoveries, like that of Dr Woolnough in Fiji, have led to considerable qualifications of the generalisation that all the islands in the great ocean are wholly of volcanic or coral origin.

I remember once expressing surprise to Darwin that, after the views which he had originated concerning the existence of areas of elevation and others of subsidence in the Pacific Ocean, and in face of the admitted difficulty of accounting for the distribution of certain terrestrial animals and plants, if the land and sea areas had been permanent in position, he still maintained that theory. Looking at me with a whimsical smile, he said: "I have seen many of my old friends make fools of themselves, by putting forward new theoretical views or revising old ones, AFTER THEY WERE SIXTY YEARS OF AGE; so, long ago, I determined that on reaching that age I would write nothing more of a speculative character."

Though Darwin's letters and conversations on geology during these later years were the chief manifestations of the interest he preserved in his "old love," as he continued to call it, yet in the sunset of that active life a gleam of the old enthusiasm for geology broke forth once more. There can be no doubt that Darwin's inability to occupy himself with field-work proved an insuperable difficulty to any attempt on his part to resume active geological research. But, as is shown by the series of charming volumes on plant-life, Darwin had found compensation in making patient and persevering experiment take the place of enterprising and exact observation; and there was one direction in which he could indulge the "old love" by employment of the new faculty.

We have seen that the earliest memoir written by Darwin, which was published in full, was a paper "On the Formation of Mould" which was read at the Geological Society on November 1st, 1837, but did not appear in the "Transactions" of the Society till 1840, where it occupied four and a half quarto pages, including some supplementary matter, obtained later, and a woodcut. This little paper was confined to observations made in his uncle's fields in Staffordshire, where burnt clay, cinders, and sand were found to be buried under a layer of black earth, evidently brought from below by earthworms, and to a recital of similar facts from Scotland obtained through the agency of Lyell. The subsequent history of Darwin's work on this question affords a striking example of the tenacity of purpose with which he continued his enquiries on any subject that interested him.

In 1842, as soon as he was settled at Down, he began a series of observations on a foot-path and in his fields, that continued with intermissions during his whole life, and he extended his enquiries from time to time to the neighbouring parks of Knole and Holwood. In 1844 we find him making a communication to the "Gardener's Chronicle" on the subject. About 1870, his attention to the question was stimulated by the circumstance that his niece (Miss L. Wedgwood) undertook to collect and weigh the worm-casts thrown up, during a whole year, on measured squares selected for the purpose, at Leith Hill Place. He also obtained information from Professor Ramsay concerning observations made by him on a pavement near his house in 1871. Darwin at this time began to realise the great importance of the action of worms to the archaeologist. At an earlier date he appears to have obtained some information concerning articles found buried on the battle-field of Shrewsbury, and the old Roman town of Uriconium, near his early home; between 1871 and 1878 Mr (afterwards Lord) Farrer carried on a series of investigations at the Roman Villa discovered on his land at Abinger; Darwin's son William examined for his father the evidence at Beaulieu Abbey, Brading, Stonehenge and other localities in the neighbourhood of his home; his sons Francis and Horace were enlisted to make similar enquiries at Chideock and Silchester; while Francis Galton contributed facts noticed in his walks in Hyde Park. By correspondence with Fritz Muller and Dr Ernst, Darwin obtained information concerning the worm-casts found in South America; from Dr Kreft those of Australia; and from Mr Scott and Dr (afterwards Sir George) King, those of India; the last-named correspondent also supplied him with much valuable information obtained in the South of Europe. Help too was obtained from the memoirs on Earthworms published by Perrier in 1874 and van Hensen in 1877, while Professor Ray Lankester supplied important facts with regard to their anatomy.

When therefore the series of interesting monographs on plant-life had been completed, Darwin set to work in bringing the information that he had gradually accumulated during forty-four years to bear on the subject of his early paper. He also utilised the skill and ingenuity he had acquired in botanical work to aid in the elucidation of many of the difficulties that presented themselves. I well remember a visit which I paid to Down at this period. At the side of the little study stood flower-pots containing earth with worms, and, without interrupting our conversation, Darwin would from time to time lift the glass plate covering a pot to watch what was going on. Occasionally, with a humorous smile, he would murmur something about a book in another room, and slip away; returning shortly, without the book but with unmistakeable signs of having visited the snuff-jar outside. After working about a year at the worms, he was able at the end of 1881 to publish the charming little book—"The Formation of Vegetable Mould through the Action of Worms, with Observations on their Habits". This was the last of his books, and its reception by reviewers and the public alike afforded the patient old worker no little gratification. Darwin's scientific career, which had begun with geological research, most appropriately ended with a return to it.

It has been impossible to sketch the origin and influence of Darwin's geological work without, at almost every step, referring to the part played by Lyell and the "Principles of Geology". Haeckel, in the chapters on Lyell and Darwin in his "History of Creation", and Huxley in his striking essay "On the Reception of the Origin of Species" ("L.L." II. pages 179-204.) have both strongly insisted on the fact that the "Origin" of Darwin was a necessary corollary to the "Principles" of Lyell.

It is true that, in an earlier essay, Huxley had spoken of the doctrine of Uniformitarianism as being, in a certain sense, opposed to that of Evolution (Huxley's Address to the Geological Society, 1869. "Collected Essays", Vol. VIII. page 305, London, 1896.); but in his later years he took up a very different and more logical position, and maintained that "Consistent uniformitarianism postulates evolution as much in the organic as in the inorganic world. The origin of a new species by other than ordinary agencies would be a vastly greater 'catastrophe' than any of those which Lyell success fully eliminated from sober geological speculation." ("L.L." II. page 190.)

Huxley's admiration for the "Principles of Geology", and his conviction of the greatness of the revolution of thought brought about by Lyell, was almost as marked as in the case of Darwin himself. (See his Essay on "Science and Pseudo Science". "Collected Essays", Vol. V. page 90, London, 1902.) He felt, however, as many others have done, that in one respect the very success of Lyell's masterpiece has been the reason why its originality and influence have not been so fully recognised as they deserved to be. Written as the book was before its author had arrived at the age of thirty, no less than eleven editions of the "Principles" were called for in his lifetime. With the most scrupulous care, Lyell, devoting all his time and energies to the task of collecting and sifting all evidence bearing on the subjects of his work, revised and re-revised it; and as in each edition, eliminations, modifications, corrections, and additions were made, the book, while it increased in value as a storehouse of facts, lost much of its freshness, vigour and charm as a piece of connected reasoning.

Darwin undoubtedly realised this when he wrote concerning the "Principles", "the first edition, my old true love, which I never deserted for the later editions." ("M.L." II. page 222.) Huxley once told me that when, in later life, he read the first edition, he was both surprised and delighted, feeling as if it were a new book to him. (I have before me a letter which illustrates this feeling on Huxley's part. He had lamented to me that he did not possess a copy of the first edition of the "Principles", when, shortly afterwards, I picked up a dilapidated copy on a bookstall; this I had bound and sent to my old teacher and colleague. His reply is characteristic:

October 8, 1884.

My Dear Judd,

You could not have made me a more agreeable present than the copy of the first edition of Lyell, which I find on my table. I have never been able to meet with the book, and your copy is, as the old woman said of her Bible, "the best of books in the best of bindings."

Ever yours sincerely,

T.H. Huxley.

(I cannot refrain from relating an incident which very strikingly exemplifies the affection for one another felt by Lyell and Huxley. In his last illness, when confined to his bed, Lyell heard that Huxley was to lecture at the Royal Institution on the "Results of the 'Challenger' expedition": he begged me to attend the lecture and bring him an account of it. Happening to mention this to Huxley, he at once undertook to go to Lyell in my place, and he did so on the morning following his lecture. I shall never forget the look of gratitude on the face of the invalid when he told me, shortly afterwards, how Huxley had sat by his bedside and "repeated the whole lecture to him.")

Darwin's generous nature seems often to have made him experience a fear lest he should do less than justice to his "dear old master," and to the influence that the "Principles of Geology" had in moulding his mind. In 1845 he wrote to Lyell, "I have long wished, not so much for your sake, as for my own feelings of honesty, to acknowledge more plainly than by mere reference, how much I geologically owe you. Those authors, however, who like you, educate people's minds as well as teach them special facts, can never, I should think, have full justice done them except by posterity, for the mind thus insensibly improved can hardly perceive its own upward ascent." ("L.L." I. pages 337-8.) In another letter, to Leonard Horner, he says: "I always feel as if my books came half out of Lyell's brain, and that I never acknowledge this sufficiently." ("M.L." II. page 117.) Darwin's own most favourite book, the "Narrative of the Voyage", was dedicated to Lyell in glowing terms; and in the "Origin of Species" he wrote of "Lyell's grand work on the "Principles of Geology", which the future historian will recognise as having produced a revolution in Natural Science." "What glorious good that work has done" he fervently exclaims on another occasion. ("L.L." I. page 342.)

To the very end of his life, as all who were in the habit of talking with Darwin can testify, this sense of his indebtedness to Lyell remained with him. In his "Autobiography", written in 1876, the year after Lyell's death, he spoke in the warmest terms of the value to him of the "Principles" while on the voyage and of the aid afforded to him by Lyell on his return to England. ("L.L." I. page 62.) But the year before his own death, Darwin felt constrained to return to the subject and to place on record a final appreciation—one as honourable to the writer as it is to his lost friend:

"I saw more of Lyell than of any other man, both before and after my marriage. His mind was characterised, as it appeared to me, by clearness, caution, sound judgment, and a good deal of originality. When I made any remark to him on Geology, he never rested until he saw the whole case clearly, and often made me see it more clearly than I had done before. He would advance all possible objections to my suggestion, and even after these were exhausted would remain long dubious. A second characteristic was his hearty sympathy with the work of other scientific men... His delight in science was ardent, and he felt the keenest interest in the future progress of mankind. He was very kind-hearted... His candour was highly remarkable. He exhibited this by becoming a convert to the Descent theory, though he had gained much fame by opposing Lamarck's views, and this after he had grown old."

"THE SCIENCE OF GEOLOGY IS ENORMOUSLY INDEBTED TO LYELL—MORE SO, AS I BELIEVE, THAN TO ANY OTHER MAN WHO EVER LIVED." ("L.L." I. pages 71-2 (the italics are mine.))

Those who knew Lyell intimately will recognise the truth of the portrait drawn by his dearest friend, and I believe that posterity will endorse Darwin's deliberate verdict concerning the value of his labours.

It was my own good fortune, to be brought into close contact with these two great men during the later years of their life, and I may perhaps be permitted to put on record the impressions made upon me during friendly intercourse with both.

In some respects, there was an extraordinary resemblance in their modes and habits of thought, between Lyell and Darwin; and this likeness was also seen in their modesty, their deference to the opinion of younger men, their enthusiasm for science, their freedom from petty jealousies and their righteous indignation for what was mean and unworthy in others. But yet there was a difference. Both Lyell and Darwin were cautious, but perhaps Lyell carried his caution to the verge of timidity. I think Darwin possessed, and Lyell lacked, what I can only describe by the theological term, "faith—the substance of things hoped for, the evidence of things not seen." Both had been constrained to feel that the immutability of species could not be maintained. Both, too, recognised the fact that it would be useless to proclaim this conviction, unless prepared with a satisfactory alternative to what Huxley called "the Miltonic hypothesis." But Darwin's conviction was so far vital and operative that it sustained him while working unceasingly for twenty-two years in collecting evidence bearing on the question, till at last he was in the position of being able to justify that conviction to others.

And yet Lyell's attitude—and that of Hooker, which was very similar—proved of inestimable service to science, as Darwin often acknowledged. One of the greatest merits of the "Origin of Species" is that so many difficulties and objections are anticipated and fairly met; and this was to a great extent the result of the persistent and very candid—if always friendly—criticism of Lyell and Hooker.

I think the divergence of mental attitude in Lyell and Darwin must be attributed to a difference in temperament, the evidence of which sometimes appears in a very striking manner in their correspondence. Thus in 1838, while they were in the thick of the fight with the Catastrophists of the Geological Society, Lyell wrote characteristically: "I really find, when bringing up my Preliminary Essays in "Principles" to the science of the present day, so far as I know it, that the great outline, and even most of the details, stand so uninjured, and in many cases they are so much strengthened by new discoveries, especially by yours, that we may begin to hope that the great principles there insisted on will stand the test of new discoveries." (Lyell's "Life, Letters and Journals", Vol. II. page 44.) To which the more youthful and impetuous Darwin replies: "BEGIN TO HOPE: why the POSSIBILITY of a doubt has never crossed my mind for many a day. This may be very unphilosophical, but my geological salvation is staked on it... it makes me quite indignant that you should talk of HOPING." ("L.L." I. page 296.)

It was not only Darwin's "geological salvation" that was at stake, when he surrendered himself to his enthusiasm for an idea. To his firm faith in the doctrine of continuity we owe the "Origin of Species"; and while Darwin became the "Paul" of evolution, Lyell long remained the "doubting Thomas."

Many must have felt like H.C. Watson when he wrote: "How could Sir C. Lyell... for thirty years read, write, and think, on the subject of species AND THEIR SUCCESSION, and yet constantly look down the wrong road!" ("L.L." II. page 227.) Huxley attributed this hesitation of Lyell to his "profound antipathy" to the doctrine of the "pithecoid origin of man." ("L.L." II. page 193.) Without denying that this had considerable influence (and those who knew Lyell and his great devotion to his wife and her memory, are aware that he and she felt much stronger convictions concerning such subjects as the immortality of the soul than Darwin was able to confess to) yet I think Darwin had divined the real characteristics of his friend's mind, when he wrote: "He would advance all possible objections... AND EVEN AFTER THESE WERE EXHAUSTED, WOULD REMAIN LONG DUBIOUS."

Very touching indeed was the friendship maintained to the end between these two leaders of thought—free as their intercourse was from any smallest trace of self-seeking or jealousy. When in 1874 I spent some time with Lyell in his Forfarshire home, a communication from Darwin was always an event which made a "red-letter day," as Lyell used to say; and he gave me many indications in his conversation of how strongly he relied upon the opinion of Darwin—more indeed than on the judgment of any other man—this confidence not being confined to questions of science, but extending to those of morals, politics, and religion.

I have heard those who knew Lyell only slightly, speak of his manners as cold and reserved. His complete absorption in his scientific work, coupled with extreme short-sightedness, almost in the end amounting to blindness, may have permitted those having but a casual acquaintance with him to accept such a view. But those privileged to know him intimately recognised the nobleness of his character and can realise the justice and force of Hooker's words when he heard of his death: "My loved, my best friend, for well nigh forty years of my life. The most generous sharer of my own and my family's hopes, joys and sorrows, whose affection for me was truly that of a father and brother combined."

But the strongest of all testimonies to the grandeur of Lyell's character is the lifelong devotion to him of such a man as Darwin. Before the two met, we find Darwin constantly writing of facts and observations that he thinks "will interest Mr Lyell"; and when they came together the mutual esteem rapidly ripened into the warmest affection. Both having the advantage of a moderate independence, permitting of an entire devotion of their lives to scientific research, they had much in common, and the elder man—who had already achieved both scientific and literary distinction—was able to give good advice and friendly help to the younger one. The warmth of their friendship comes out very strikingly in their correspondence. When Darwin first conceived the idea of writing a book on the "species question," soon after his return from the voyage, it was "by following the example of Lyell in Geology" that he hoped to succeed ("L.L." I. page 83.); when in 1844, Darwin had finished his first sketch of the work, and, fearing that his life might not be spared to complete his great undertaking, committed the care of it in a touching letter to his wife, it was his friend Lyell whom he named as her adviser and the possible editor of the book ("L.L." II. pages 17-18.); it was Lyell who, in 1856, induced Darwin to lay the foundations of a treatise ("L.L." I. page 84.) for which the author himself selected the "Principles" as his model; and when the dilemma arose from the receipt of Wallace's essay, it was to Lyell jointly with Hooker that Darwin turned, not in vain, for advice and help.

During the later years of his life, I never heard Darwin allude to his lost friend—and he did so very often—without coupling his name with some term of affection. For a brief period, it is true, Lyell's excessive caution when the "Origin" was published, seemed to try even the patience of Darwin; but when "the master" was at last able to declare himself fully convinced, he was the occasion of more rejoicing on the part of Darwin, than any other convert to his views. The latter was never tired of talking of Lyell's "magnanimity" and asserted that, "To have maintained in the position of a master, one side of a question for thirty years, and then deliberately give it up, is a fact to which I much doubt whether the records of science offer a parallel." ("L.L." II. pages 229-30.)

Of Darwin himself, I can safely affirm that I never knew anyone who had met him, even for the briefest period, who was not charmed by his personality. Who could forget the hearty hand-grip at meeting, the gentle and lingering pressure of the palm at parting, and above all that winning smile which transformed his countenance—so as to make portraits, and even photographs, seem ever afterwards unsatisfying! Looking back, one is indeed tempted to forget the profoundness of the philosopher, in recollection of the loveableness of the man.