darwin and modern science-第131章

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tive　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　itoften　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　gainedalike　for　biology　and　geologyby　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　chapterin　which　he　compares　the　record　of　the　rocks　to　the　much　mutilated　volumes　of　a　human　historyremains　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　lifewe　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　remarkableI　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　t