TellProfessorSedgwickhedoesnotknowhowmuchIamindebtedtohimfortheWelshExpedition;ithasgivenmeaninterestinGeologywhichIwouldnotgiveupforanyconsideration。IdonotthinkIeverspentamoredelightfulthreeweeksthanpoundingtheNorth—westMountains。IlookforwardtothegeologyaboutMonteVideoasIhearthereareslatesthere，soIpresumeinthatdistrictIshallfindthejunctionsofthePampas，andtheenormousgraniteformationofBrazils。AtBahiathepegmatiteandgneissinbedshadthesamedirection，asobservedbyHumboldt，prevailingoverColumbia，distant1300miles——isitnotwonderful？MonteVideowillbeforalongtimemydirection。Ihopeyouwillwriteagaintome，thereisnobodyfromwhomIlikereceivingadvicesomuchasfromyou……Excusethisalmostunintelligibleletter，andbelieveme，mydearHenslow，withthewarmestfeelingsofrespectandfriendship，Yoursaffectionately，CHAS。DARWIN。
CHARLESDARWINTOJ。M。HERBERT。
BotofogoBay，RiodeJaneiro，June1832。
MydearoldHerbert，YourletterarrivedherewhenIhadgivenupallhopesofreceivinganother，itgaveme，therefore，anadditionaldegreeofpleasure。Atsuchanintervaloftimeandspaceonedoeslearntofeeltrulyobligedtothosewhodonotforgetone。Thememorywhenrecallingscenespastby，affordstousEXILESoneofthegreatestpleasures。OftenandoftenwhilstwanderingamongstthesehillsdoIthinkofBarmouth，and，Imayadd，asoftenwishforsuchacompanion。Whatacontrastdoesawalkinthesetwoplacesafford;hereabruptandstonypeaksaretotheverysummitenclosedbyluxuriantwoods;thewholesurfaceofthecountry，exceptingwhereclearedbyman，isoneimpenetrableforest。HowdifferentfromWales，withitsslopinghillscoveredwithturf，anditsopenvalleys。Iwasnotpreviouslyawarehowintimatelywhatmaybecalledthemoralpartisconnectedwiththeenjoymentofscenery。Imeansuchideas，asthehistoryofthecountry，theutilityoftheproduce，andmoreespeciallythehappinessofthepeoplelivingwiththem。ChangetheEnglishlabourerintoapoorslave，workingforanother，andyouwillhardlyrecognisethesameview。Iamsureyouwillbegladtohearhowverywelleverypart（Heavenforefend，exceptsea—sickness）oftheexpeditionhasanswered。WehavealreadyseenTeneriffeandtheGreatCanary;St。JagowhereIspentthreemostdelightfulweeks，revellinginthedelightsoffirstnaturalisingatropicalvolcanicisland，andbesidesotherislands，thetwocelebratedportsintheBrazils，viz。BahiaandRio。
IwasinmyhammocktillwearrivedattheCanaries，andIshallneverforgetthesublimeimpressionthefirstviewofTeneriffemadeonmymind。