riginal geological work； he declares； 〃showed me clearly the wonderful superiority of Lyell's manner of treating geology； compared with that of any other author； whose works I had with me or ever afterwards read。〃 （〃L。L。〃 I。 page 62。）
At St Jago Darwin first experienced the joy of making new discoveries； and his delight was unbounded。 Writing to his father he says； 〃Geologising in a volcanic country is most delightful； besides the interest attached to itself； it leads you into most beautiful and retired spots。〃 （〃L。L。〃 I。 page 228。） To Henslow he wrote of St Jago： 〃Here we spent three most delightful weeks。。。St Jago is singularly barren； and produces few plants or insects； so that my hammer was my usual companion； and in its company most delightful hours I spent。〃 〃The geology was pre…eminently interesting； and I believe quite new； there are some facts on a large scale of upraised coast （which is an excellent epoch for all the volcanic rocks to date from）； that would interest Mr Lyell。〃 （〃L。L。〃 I。 page 235。） After more than forty years the memory of this； his first geological work； seems as fresh as ever； and he wrote in 1876； 〃The geology of St Jago is very striking； yet simple： a stream of lava formerly flowed over the bed of the sea； formed of triturated recent shells and corals； which it has baked into a hard white rock。 Since then the whole island has been upheaved。 But the line of white rock revealed to me a new and important fact； namely； that there had been afterwards subsidence round the craters； which had since been in action； and had poured forth lava。〃 （〃L。L。〃 I。 page 65。）
It was at this time； probably； that Darwin made his first attempt at drawing a sketch…map and section to illustrate the observations he had made （see his 〃Volcanic Islands〃； pages 1 and 9）。 His first important geological discovery； that of the subsidence of strata around volcanic vents （which has since been confirmed by Mr Heaphy in New Zealand and other authors） awakened an intense enthusiasm； and he writes： 〃It then first dawned on me that I might perhaps write a book on the geology of the various countries visited； and this made me thrill with delight。 That was a memorable hour to me； and how distinctly I can call to mind the low cliff of lava beneath which I rested； with the sun glaring hot； a few strange desert plants growing near； and with living corals in the tidal pools at my feet。〃 （〃L。L。〃 I。 page 66。）
But it was when the 〃Beagle〃； after touching at St Paul's rock and Tristan d'Acunha （for a sufficient time only to collect specimens）； reached the shores of South America； that Darwin's real work began； and he was able； while the marine surveys were in progress； to make many extensive journeys on land。 His letters at this time show that geology had become his chief delight； and such exclamations as 〃Geology carries the day；〃 〃I find in Geology a never failing interest；〃 etc。 abound in his correspondence。
Darwin's time was divided between the study of the great deposits of red mudthe Pampean formationwith its interesting fossil bones and shells affording proofs of slow and constant movements of the land； and the underlying masses of metamorphic and plutonic rocks。 Writing to Henslow in March； 1834； he says： 〃I am quite charmed with Geology； but； like the wise animal between two bundles of hay； I do not know which to like best； the old crystalline groups of rocks； or the softer and fossiliferous beds。 When puzzling about stratification； etc。； I feel inclined to cry 'a fig for your big oysters； and your bigger megatheriums。' But then when digging out some fine bones； I wonder how any man can tire his arms with hammering granite。〃 （〃L。L。〃 I。 page 249。） We are told by Darwin that he loved to reason about and attempt to predict the nature of the rocks in each new district before he arrived at it。
This love of guessing as to the geology of a district he was about to visit is amusingly expressed by him in a letter （of May； 1832） to his cousin and old college…friend； Fox。 After alluding to the beetles he had been collectinga taste his friend had in common with himselfhe writes of geology that 〃It is like the pleasure of gambling。 Speculating on first arriving； what the rocks may be； I often mentally cry out 3 to 1 tertiary against primitive； but the latter have hitherto won all the bets。〃 （〃L。L。〃 I。 page 233。）
Not the least important of the educational results of the voyage to Darwin was the acquirement by him of those habits of industry and method which enabled him in after life to accomplish so muchin spite of constant failures of health。 From the outset； he daily undertook and resolutely accomplished； in spite of sea…sickness and other distractions； four important tasks。 In the first place he regularly wrote up the pages of his Journal； in which； paying great attention to literary style and composition； he recorded only matters that would be of general interest； such as remarks on scenery and vegetation； on the peculiarities and habits of animals； and on the characters； avocations and political institutions of the various races of men with whom he was brought in contact。 It was the freshness of these observations that gave his 〃Narrative〃 so much charm。 Only in those cases in which his ideas had become fully crystallised； did he attempt to deal with scientific matters in this journal。 His second task was to write in voluminous note…books facts concerning animals and plants； collected on sea or land； which could not be well made out from specimens preserved in spirit； but he tells us that； owing to want of skill in dissecting and drawing； much of the time spent in this work was entirely thrown away； 〃a great pile of MS。 which I made during the voyage has proved almost useless。〃 （〃L。L。〃 I。 page 62。） Huxley confirmed this judgment on his biological work； declaring that 〃all his zeal and industry resulted； for the most part； in a vast accumulation of useless manuscript。〃 （〃Proc。 Roy。 Soc。〃 Vol。 XLIV。 （1888）； page IX。） Darwin's third task was of a very different character and of infinitely greater value。 It consisted in writing notes of his journeys on landthe notes being devoted to the geology of the districts visited by him。 These formed the basis； not only of a number of geological papers published on his return； but also of the three important volumes forming 〃The Geology of the voyage of the 'Beagle'〃。 On July 24th； 1834； when little more than half of the voyage had been completed； Darwin wrote to Henslow； 〃My notes are becoming bulky。 I have about 600 small quarto pages full； about half of this is Geology。〃 （〃M。L。〃 I。 page 14。） The last； and certainly not the least important of all his duties； consisted in numbering； cataloguing； and packing his specimens for despatch to Henslow； who had undertaken the care of them。 In his letters he often expresses the greatest solicitude lest the value of these specimens should be impaired by the removal of the numbers corresponding to his manuscript lists。 Science owes much to Henslow's patient care of the collections sent to him by Darwin。 The latter wrote in Henslow's biography； 〃During the five years' voyage； he regularly corresponded with me and guided my efforts； he received； opened； and took care of all the specimens sent home in many large boxes。〃 （〃Life of Henslow〃； by L。 Jenyns （Blomefield）； London； 1862； page 53。）
Darwin's geological specimens are now very appropriately lodged for the most part in the Sedgwick Museum； Cambridge； his original Catalogue with subsequent annotations being preserved with them。 From an examination of these catalogues and specimens we are able to form a fair notion of the work done by Darwin in his little cabin in the 〃Beagle〃； in the intervals between his land journeys。
Besides writing up his notes； it is evident that he was able to accomplish a considerable amount of study of his specimens； before they were packed up for despatch to Henslow。 Besides hand…magnifiers and a microscope； Darwin had an equipment for blowpipe…analysis； a contact…goniometer and magnet； and these were in constant use by him。 His small library of reference （now included in the Collection of books placed by Mr F。 Darwin in the Botany School at Cambridge （〃Catalogue of the Library of Charles Darwin now in the Botany School； Cambridge〃。 Compiled by H。W。 Rutherford； with an introduction by Francis Darwin。 Cambridge； 1908。）） appears to have been admirably selected； and in all probability contained （in addition to a good many works relating to South America） a fair number of excellent books of reference。 Among those relating to mineralogy； he possessed the manuals of Phillips； Alexander Brongniart； Beudant； von Kobell and Jameson： all the 〃Cristallographie〃 of Brochant de Villers and； for blowpipe work； Dr Children's translation of the book of Berzelius on the subject。 In addition to these； he had Henry's 〃Experimental Chemistry〃 and Ure's 〃Dictionary〃 （of Chemistry）。 A work； he evidently often employed； was P。 Syme's book on 〃Werner's Nomenclature of Colours〃； while； for Petrology； he used Macculloch's 〃Geological Classification of Rocks〃。 How diligently and well he employed his instruments and books is shown by the valuable observations recorded in the annotated Catalogues drawn up on board ship。
These catalogues have on the right…hand pages numbers and descriptions of the specimens； and on the opposite pages notes on the specimensthe result of experiments made at the time and written in a very small hand。 Of the subsequently made pencil notes； I shall have to speak later。 （I am greatly indebted to my friend Mr A。 Harker； F。R。S。； for his assistance in examining these specimens and catalogues。 He has also arranged the specimens in the Sedgwick Museum； so as to make reference to them easy。 The specimens from Ascension and a few others are however in the Museum at Jermyn Street。）
It is a question of great interest to determine the period and the occasion of Darwin's first awakening to the great problem of the transmutation of species。 He tells us himself that his grandfather's 〃Zoonomia〃 had been read by him 〃but without producing any effect；〃 and that his friend Grant's rhapsodies on Lamarck and his views on evolution only gave ri