darwin and modern science-第110节

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ding　works　on　Osteology　by　Cuvier；　Desmarest　and　Lesson；　as　well　as　two　French　Encyclopaedias　of　Natural　History。　　As　a　sportsman；　he　would　obtain　specimens　of　recent　mammals　in　South　America；　and　would　thus　have　opportunities　of　studying　their　teeth　and　general　anatomy。　　Keen　observer；　as　he　undoubtedly　was；　we　need　not　then　be　surprised　that　he　was　able　to　make　out　the　resemblances　between　the　recent　and　fossil　forms。）

It　is　clear　that；　as　time　went　on；　Darwin　became　more　and　more　absorbed　in　his　geological　work。　　One　very　significant　fact　was　that　the　once　ardent　sportsman；　when　he　found　that　shooting　the　necessary　game　and　zoological　specimens　interfered　with　his　work　with　the　hammer；　gave　up　his　gun　to　his　servant。　　（〃L。L。〃　I。　page　63。）　　There　is　clear　evidence　that　Darwin　gradually　became　aware　how　futile　were　his　attempts　to　add　to　zoological　knowledge　by　dissection　and　drawing；　while　he　felt　ever　increasing　satisfaction　with　his　geological　work。

The　voyage　fortunately　extended　to　a　much　longer　period　（five　years）　than　the　two　originally　intended；　but　after　being　absent　nearly　three　years；　Darwin　wrote　to　his　sister　in　November；　1834；　〃Hurrah！　hurrah！　it　is　fixed　that　the　'Beagle'　shall　not　go　one　mile　south　of　Cape　Tres　Montes　（about　200　miles　south　of　Chiloe）；　and　from　that　point　to　Valparaiso　will　be　finished　in　about　five　months。　　We　shall　examine　the　Chonos　Archipelago；　entirely　unknown；　and　the　curious　inland　sea　behind　Chiloe。　　For　me　it　is　glorious。　　Cape　Tres　Montes　is　the　most　southern　point　where　there　is　much　geological　interest；　as　there　the　modern　beds　end。　　The　Captain　then　talks　of　crossing　the　Pacific；　but　I　think　we　shall　persuade　him　to　finish　the　coast　of　Peru；　where　the　climate　is　delightful；　the　country　hideously　sterile；　but　abounding　with　the　highest　interest　to　the　geologist。。。I　have　long　been　grieved　and　most　sorry　at　the　interminable　length　of　the　voyage　（though　I　never　would　have　quitted　it）。。。I　could　not　make　up　my　mind　to　return。　　I　could　not　give　up　all　the　geological　castles　in　the　air　I　had　been　building　up　for　the　last　two　years。〃　　（〃L。L。〃　I。　pages　257…58。）

In　April；　1835；　he　wrote　to　another　sister：　　〃I　returned　a　week　ago　from　my　excursion　across　the　Andes　to　Mendoza。　　Since　leaving　England　I　have　never　made　so　successful　a　journey。。。how　deeply　I　have　enjoyed　it；　it　was　something　more　than　enjoyment；　I　cannot　express　the　delight　which　I　felt　at　such　a　famous　winding…up　of　all　my　geology　in　South　America。　　I　literally　could　hardly　sleep　at　nights　for　thinking　over　my　day's　work。　　The　scenery　was　so　new；　and　so　majestic；　everything　at　an　elevation　of　12；000　feet　bears　so　different　an　aspect　from　that　in　the　lower　country。。。To　a　geologist；　also；　there　are　such　manifest　proofs　of　excessive　violence；　the　strata　of　the　highest　pinnacles　are　tossed　about　like　the　crust　of　a　broken　pie。〃　　（〃L。L。〃　I。　pages　259…60。）

Darwin　anticipated　with　intense　pleasure　his　visit　to　the　Galapagos　Islands。　　On　July　12th；　1835；　he　wrote　to　Henslow：　　〃In　a　few　days'　time　the　〃Beagle〃　will　sail　for　the　Galapagos　Islands。　　I　look　forward　with　joy　and　interest　to　this；　both　as　being　somewhat　nearer　to　England　and　for　the　sake　of　having　a　good　look　at　an　active　volcano。　　Although　we　have　seen　lava　in　abundance；　I　have　never　yet　beheld　the　crater。〃　　（〃M。L。〃　I。　page　26。）　　He　could　little　anticipate；　as　he　wrote　these　lines；　the　important　aid　in　the　solution　of　the　〃species　question〃　that　would　ever　after　make　his　visit　to　the　Galapagos　Islands　so　memorable。　　In　1832；　as　we　have　seen；　the　great　discovery　of　the　relations　of　living　to　extinct　mammals　in　the　same　area　had　dawned　upon　his　mind；　in　1835　he　was　to　find　a　second　key　for　opening　up　the　great　mystery；　by　recognising　the　variations　of　similar　types　in　adjoining　islands　among　the　Galapagos。

The　final　chapter　in　the　second　volume　of　the　〃Principles〃　had　aroused　in　Darwin's　mind　a　desire　to　study　coral…reefs；　which　was　gratified　during　his　voyage　across　the　Pacific　and　Indian　Oceans。　　His　theory　on　the　subject　was　suggested　about　the　end　of　1834　or　the　beginning　of　1835；　as　he　himself　tells　us；　before　he　had　seen　a　coral…reef；　and　resulted　from　his　work　during　two　years　in　which　he　had　〃been　incessantly　attending　to　the　effects　on　the　shores　of　South　America　of　the　intermittent　elevation　of　the　land；　together　with　denudation　and　the　deposition　of　sediment。〃　　（〃L。L。〃　I。　page　70。）

On　arriving　at　the　Cape　of　Good　Hope　in　July；　1836；　Darwin　was　greatly　gratified　by　hearing　that　Sedgwick　had　spoken　to　his　father　in　high　terms　of　praise　concerning　the　work　done　by　him　in　South　America。　　Referring　to　the　news　from　home；　when　he　reached　Bahia　once　more；　on　the　return　voyage　（August；　1836）；　he　says：　　〃The　desert；　volcanic　rocks；　and　wild　sea　of　Ascension。。。suddenly　wore　a　pleasing　aspect；　and　I　set　to　work　with　a　good…　will　at　my　old　work　of　Geology。〃　　（〃L。L。〃　I。　page　265。）　　Writing　fifty　years　later；　he　says：　　〃I　clambered　over　the　mountains　of　Ascension　with　a　bounding　step　and　made　the　volcanic　rocks　resound　under　my　geological　hammer！〃　　（〃L。L。〃　I。　page　66。）

That　his　determination　was　now　fixed　to　devote　his　own　labours　to　the　task　of　working　out　the　geological　results　of　the　voyage；　and　that　he　was　prepared　to　leave　to　more　practised　hands　the　study　of　his　biological　collections；　is　clear　from　the　letters　he　sent　home　at　this　time。　　From　St　Helena　he　wrote　to　Henslow　asking　that　he　would　propose　him　as　a　Fellow　of　the　Geological　Society；　and　his　Certificate；　in　Henslow's　handwriting；　is　dated　September　8th；　1836；　being　signed　from　personal　knowledge　by　Henslow　and　Sedgwick。　　He　was　proposed　on　November　2nd　and　elected　November　30th；　being　formally　admitted　to　the　Society　by　Lyell；　who　was　then　President；　on　January　4th；　1837；　on　which　date　he　also　read　his　first　paper。　　Darwin　did　not　become　a　Fellow　of　the　Linnean　Society　till　eighteen　years　later　（in　1854）。

An　estimate　of　the　value　and　importance　of　Darwin's　geological　discoveries　during　the　voyage　of　the　〃Beagle〃　can　best　be　made　when　considering　the　various　memoirs　and　books　in　which　the　author　described　them。　　He　was　too　cautious　to　allow　himself　to　write　his　first　impressions　in　his　Journal；　and　wisely　waited　till　he　could　study　his　specimens　under　better　conditions　and　with　help　from　others　on　his　return。　　The　extracts　published　from　his　correspondence　with　Henslow　and　others；　while　he　was　still　abroad；　showed；　nevertheless；　how　great　was　the　mass　of　observation；　how　suggestive　and　pregnant　with　results　were　the　reasonings　of　the　young　geologist。

Two　sets　of　these　extracts　from　Darwin's　letters　to　Henslow　were　printed　while　he　was　still　abroad。　　The　first　of　these　was　the　series　of　〃Geological　Notes　made　during　a　survey　of　the　East　and　West　Coasts　of　South　America；　in　the　years　1832；　1833；　1834　and　1835；　with　an　account　of　a　transverse　section　of　the　Cordilleras　of　the　Andes　between　Valparaiso　and　Mendoza〃。　　Professor　Sedgwick；　who　read　these　notes　to　the　Geological　Society　on　November　18th；　1835；　stated　that　〃they　were　extracted　from　a　series　of　letters　（addressed　to　Professor　Henslow）；　containing　a　great　mass　of　information　connected　with　almost　every　branch　of　natural　history；〃　and　that　he　（Sedgwick）　had　made　a　selection　of　the　remarks　which　he　thought　would　be　more　especially　interesting　to　the　Geological　Society。　　An　abstract　of　three　pages　was　published　in　the　〃Proceedings　of　the　Geological　Society〃　（Vol。　II。　pages　210…12。）；　but　so　unknown　was　the　author　at　this　time　that　he　was　described　as　F。　Darwin；　Esq。；　of　St　John's　College；　Cambridge〃！　　Almost　simultaneously　（on　November　16th；　1835）　a　second　set　of　extracts　from　these　lettersthis　time　of　a　general　characterwere　read　to　the　Philosophical　Society　at　Cambridge；　and　these　excited　so　much　interest　that　they　were　privately　printed　in　pamphlet　form　for　circulation　among　the　members。

Many　expeditions　and　〃scientific　missions〃　have　been　despatched　to　various　parts　of　the　world　since　the　return　of　the　〃Beagle〃　in　1836；　but　it　is　doubtful　whether　any；　even　the　most　richly　endowed　of　them；　has　brought　back　such　stores　of　new　information　and　fresh　discoveries　as　did　that　little　〃ten…gun　brig〃certainly　no　cabin　or　laboratory　was　the　birth…place　of　ideas　of　such　fruitful　character　as　was　that　narrow　end　of　a　chart…room；　where　the　solitary　naturalist　could　climb　into　his　hammock　and　indulge　in　meditation。

The　third　and　most　active　portion　of　Darwin's　career　as　a　geologist　was　the　period　which　followed　his　return　to　England　at　the　end　of　1836。　　His　immediate　admission　to　the　Geological　Society；　at　the　beginning　of　1837；　coincided　with　an　important　crisis　in　the　history　of　geological　science。

The　band　of　enthusiasts　who　nearly　thirty　years　before　had　inaugurated　the　Geological　Societyweary　of　the　fruitless　conflicts　between　〃Neptunists〃　and　〃Plutonists〃had　determined　to　eschew　theory　and　confine　their　labours　to　the　collection　of　facts；　their　publications　to　the　careful　record　of　observations。　　Greenough；　the　actual　founder　of　the　Society；　was　an　ardent　Wernerian；　and　nearly　all　his　fellow…workers　had　come；　more　or　less　directly；　under　the　Wernerian　teaching。　　Macculloch　alone　gave　valuable　support　to　the　Huttonian　doctrines；　so　far　as　they　re