darwin and modern science-第93章

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ul　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