万物简史英文版_比尔·布莱森-第11章

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stoically；　le　gentil　packed　up　his　instruments　and　set　off　for　the　nearest　port；　but　en　routehe　contracted　dysentery　and　was　laid　up　for　nearly　a　year。　still　weakened；　he　finally　made　itonto　a　ship。　it　was　nearly　wrecked　in　a　hurricane　off　the　african　coast。　when　at　last　hereached　home；　eleven　and　a　half　years　after　setting　off；　and　having　achieved　nothing；　hediscovered　that　his　relatives　had　had　him　declared　dead　in　his　absence　and　hadenthusiastically　plundered　his　estate。

in　parison；　the　disappointments　experienced　by　britain鈥檚　eighteen　scattered　observerswere　mild。　mason　found　himself　paired　with　a　young　surveyor　named　jeremiah　dixon　andapparently　they　got　along　well；　for　they　formed　a　lasting　partnership。　their　instructions　wereto　travel　to　sumatra　and　chart　the　transit　there；　but　after　just　one　night　at　sea　their　ship　wasattacked　by　a　french　frigate。　（although　scientists　were　in　an　internationally　cooperativemood；　nations　weren鈥檛。）　mason　and　dixon　sent　a　note　to　the　royal　society　observing　that　itseemed　awfully　dangerous　on　the　high　seas　and　wondering　if　perhaps　the　whole　thingoughtn鈥檛　to　be　called　off。　in　reply　they　received　a　swift　and　chilly　rebuke；　noting　that　they　hadalready　been　paid；　that　the　nation　and　scientific　munity　were　counting　on　them；　and　thattheir　failure　to　proceed　would　result　in　the　irretrievable　loss　of　their　reputations。　chastened；they　sailed　on；　but　en　route　word　reached　them　that　sumatra　had　fallen　to　the　french　and　sothey　observed　the　transit　inconclusively　from　the　cape　of　good　hope。　on　the　way　home　theystopped　on　the　lonely　atlantic　outcrop　of　st。　helena；　where　they　met　maskelyne；　whoseobservations　had　been　thwarted　by　cloud　cover。　mason　and　maskelyne　formed　a　solidfriendship　and　spent　several　happy；　and　possibly　even　mildly　useful；　weeks　charting　tidalflows。

soon　afterward；　maskelyne　returned　to　england　where　he　became　astronomer　royal；　andmason　and　dixon鈥攏ow　evidently　more　seasoned鈥攕et　off　for　four　long　and　often　perilousyears　surveying　their　way　through　244　miles　of　dangerous　american　wilderness　to　settle　aboundary　dispute　between　the　estates　of　william　penn　and　lord　baltimore　and　theirrespective　colonies　of　pennsylvania　and　maryland。　the　result　was　the　famous　mason　anddixon　line；　which　later　took　on　symbolic　importance　as　the　dividing　line　between　the　slaveand　free　states。　（although　the　line　was　their　principal　task；　they　also　contributed　severalastronomical　surveys；　including　one　of　the　century鈥檚　most　accurate　measurements　of　a　degreeof　meridian鈥攁n　achievement　that　brought　them　far　more　acclaim　in　england　than　the　settlingof　a　boundary　dispute　between　spoiled　aristocrats。）back　in　europe；　maskelyne　and　his　counterparts　in　germany　and　france　were　forced　to　theconclusion　that　the　transit　measurements　of　1761　were　essentially　a　failure。　one　of　theproblems；　ironically；　was　that　there　were　too　many　observations；　which　when　broughttogether　often　proved　contradictory　and　impossible　to　resolve。　the　successful　charting　of　avenusian　transit　fell　instead　to　a　little…known　yorkshire…born　sea　captain　named　james　cook；who　watched　the　1769　transit　from　a　sunny　hilltop　in　tahiti；　and　then　went　on　to　chart　andclaim　australia　for　the　british　crown。　upon　his　return　there　was　now　enough　information　forthe　french　astronomer　joseph　lalande　to　calculate　that　the　mean　distance　from　the　earth　tothe　sun　was　a　little　over　150　million　kilometers。　（two　further　transits　in　the　nineteenthcentury　allowed　astronomers　to　put　the　figure　at　149。59　million　kilometers；　where　it　hasremained　ever　since。　the　precise　distance；　we　now　know；　is　149。597870691　millionkilometers。）　the　earth　at　last　had　a　position　in　space。

as　for　mason　and　dixon；　they　returned　to　england　as　scientific　heroes　and；　for　reasonsunknown；　dissolved　their　partnership。　considering　the　frequency　with　which　they　turn　up　atseminal　events　in　eighteenth…century　science；　remarkably　little　is　known　about　either　man。　nolikenesses　exist　and　few　written　references。　of　dixon　the　dictionary　of　national　biographynotes　intriguingly　that　he　was　鈥渟aid　to　have　been　born　in　a　coal　mine；鈥潯�but　then　leaves　it　to　thereader鈥檚　imagination　to　supply　a　plausible　explanatory　circumstance；　and　adds　that　he　died　atdurham　in　1777。　apart　from　his　name　and　long　association　with　mason；　nothing　more　isknown。

mason　is　only　slightly　less　shadowy。　we　know　that　in　1772；　at　maskelyne鈥檚　behest；　heaccepted　the　mission　to　find　a　suitable　mountain　for　the　gravitational　deflectionexperiment；　at　length　reporting　back　that　the　mountain　they　needed　was　in　the　central　scottishhighlands；　just　above　loch　tay；　and　was　called　schiehallion。　nothing；　however；　wouldinduce　him　to　spend　a　summer　surveying　it。　he　never　returned　to　the　field　again。　his　nextknown　movement　was　in　1786　when；　abruptly　and　mysteriously；　he　turned　up　in　philadelphiawith　his　wife　and　eight　children；　apparently　on　the　verge　of　destitution。　he　had　not　been　backto　america　since　pleting　his　survey　there　eighteen　years　earlier　and　had　no　known　reasonfor　being　there；　or　any　friends　or　patrons　to　greet　him。　a　few　weeks　later　he　was　dead。

with　mason　refusing　to　survey　the　mountain；　the　job　fell　to　maskelyne。　so　for　four　monthsin　the　summer　of　1774；　maskelyne　lived　in　a　tent　in　a　remote　scottish　glen　and　spent　his　daysdirecting　a　team　of　surveyors；　who　took　hundreds　of　measurements　from　every　possibleposition。　to　find　the　mass　of　the　mountain　from　all　these　numbers　required　a　great　deal　oftedious　calculating；　for　which　a　mathematician　named　charles　hutton　was　engaged。　thesurveyors　had　covered　a　map　with　scores　of　figures；　each　marking　an　elevation　at　some　pointon　or　around　the　mountain。　it　was　essentially　just　a　confusing　mass　of　numbers；　but　huttonnoticed　that　if　he　used　a　pencil　to　connect　points　of　equal　height；　it　all　became　much　moreorderly。　indeed；　one　could　instantly　get　a　sense　of　the　overall　shape　and　slope　of　the　mountain。

he　had　invented　contour　lines。

extrapolating　from　his　schiehallion　measurements；　hutton　calculated　the　mass　of　the　earthat　5；000　million　million　tons；　from　which　could　reasonably　be　deduced　the　masses　of　all　theother　major　bodies　in　the　solar　system；　including　the　sun。　so　from　this　one　experiment　welearned　the　masses　of　the　earth；　the　sun；　the　moon；　the　other　planets　and　their　moons；　and　gotcontour　lines　into　the　bargain鈥攏ot　bad　for　a　summer鈥檚　work。

not　everyone　was　satisfied　with　the　results；　however。　the　shorting　of　the　schiehallionexperiment　was　that　it　was　not　possible　to　get　a　truly　accurate　figure　without　knowing　theactual　density　of　the　mountain。　for　convenience；　hutton　had　assumed　that　the　mountain　hadthe　same　density　as　ordinary　stone；　about　2。5　times　that　of　water；　but　this　was　little　more　thanan　educated　guess。

one　improbable…seeming　person　who　turned　his　mind　to　the　matter　was　a　country　parsonnamed　john　michell；　who　resided　in　the　lonely　yorkshire　village　of　thornhill。　despite　hisremote　and　paratively　humble　situation；　michell　was　one　of　the　great　scientific　thinkers　ofthe　eighteenth　century　and　much　esteemed　for　it。

among　a　great　deal　else；　he　perceived　the　wavelike　nature　of　earthquakes；　conducted　muchoriginal　research　into　magnetism　and　gravity；　and；　quite　extraordinarily；　envisioned　thepossibility　of　black　holes　two　hundred　years　before　anyone　else鈥攁　leap　of　intuitive　deductionthat　not　even　newton　could　make。　when　the　german…born　musician　william　herscheldecided　his　real　interest　in　life　was　astronomy；　it　was　michell　to　whom　he　turned　forinstruction　in　making　telescopes；　a　kindness　for　which　planetary　science　has　been　in　his　debtever　since。

4but　of　all　that　michell　acplished；　nothing　was　more　ingenious　or　had　greater　impactthan　a　machine　he　designed　and　built　for　measuring　the　mass　of　the　earth。　unfortunately；　hedied　before　he　could　conduct　the　experiments　and　both　the　idea　and　the　necessary　equipmentwere　passed　on　to　a　brilliant　but　magnificently　retiring　london　scientist　named　henrycavendish。

cavendish　is　a　book　in　himself。　born　into　a　life　of　sumptuous　privilege鈥攈is　grandfatherswere　dukes；　respectively；　of　devonshire　and　kent鈥攈e　was　the　most　gifted　english　scientistof　his　age；　but　also　the　strangest。　he　suffered；　in　the　words　of　one　of　his　few　biographers；from　shyness　to　a　鈥渄egree　bordering　on　disease。鈥潯�any　human　contact　was　for　him　a　source　ofthe　deepest　disfort。

once　he　opened　his　door　to　find　an　austrian　admirer；　freshly　arrived　from　vienna；　on　thefront　step。　excitedly　the　austrian　began　to　babble　out　praise。　for　a　few　moments　cavendishreceived　the　pliments　as　if　they　were　blows　from　a　blunt　object　and　then；　unable　to　takeany　more；　fled　down　the　path　and　out　the　gate；　leaving　the　front　door　wide　open。　it　was　somehours　before　he　could　be　coaxed　back　to　the　property。　even　his　housekeeper　municatedwith　him　by　letter。

although　he　did　sometimes　venture　into　society鈥攈e　was　particularly　devoted　to　the　weeklyscientific　soir茅es　of　the　great　naturalist　sir　joseph　banks鈥攊t　was　always　made　clear　to　theother　guests　that　cavendish　was　on　no　account　to　be　approached　or　even　looked　at。　thosewho　sought　his　views　were　advised　to　wander　into　his　vicinity　as　if　by　accident　and　to　鈥渢alk　as4in　1781　herschel　became　the　first　person　in　the　modern　era　to　discover　a　planet。　he　wanted　to　call　it　george；after　the　british　monarch；　but　was　overruled。　instead　it　became　uranus。

it　were　into　vacancy。鈥潯�if　their　remarks　were　scientifically　worthy　they　might　receive　amumbled　reply；　but　more　often　than　not　they　would　hear　a　peeved　squeak　（his　voice　appearsto　have　been　high　pitched）　and　turn　to　find　an　actual　vacancy　and　the　sight　of　cavendishfleeing　for　a　more　peaceful　corner。

his　wealth　and　solitary　inclinations　allowed　him　to　turn　his　house　in　clapham　into　a　largelaboratory　where　he　could　range　undisturbed　through　every　corner　of　the　physical　sciences鈥攅lectricity；　heat；　gravity；　gases；　anything　to　do　with　the　position　of　matter。　the　secondhalf　of　the　eighteenth　century　was　a　time　when　people　of　a　scientific　bent　grew　intenselyinterested　in　the　physical　properties　of　fundamental　things鈥攇ases　and　electricity　inparticular鈥攁nd　began　seeing　what　they　could　do　with　them；　often　with　more　enthusiasm　thansense。　in　america；　benjamin　franklin　famously　risked　his　life　by　flying　a　kite　in　an　electricalstorm。　in　france；　a　chemist　named　pilatre　de　rozier　tested　the　flammability　of　hydrogen　bygulping　a　mouthful　and　blowing　across　an　open　flame；　proving　at　a　stroke　that　hydrogen　isindeed　explosively　bustible　and　that　eyebrows　are　not　necessarily　a　permanent　feature　ofone鈥檚　face。　cavendish；　for　his　part；　conducted　experiments　in　which　he　subjected　himself　tograduated　jolts　of　electrical　current；　diligently　noting　the　increasing　levels　of　agony　until　hecould　keep　hold　of　his　quill；　and　sometimes　his　consciousness；　no　longer。

in　the　course　of　a　long　life　cavendish　made　a　string　of　signal　discoveries鈥攁mong　muchelse　he　was　the　first　person　to　isolate　hydrogen　and　the　first　to　bine　hydrogen　and　oxygento　form　water鈥攂ut　almost　nothing　he　did　was　entirely　divorced　from　strangeness。　to　thecontinuing　exasperation　of　his　fellow　scientists；　he　often　alluded　in　published　work　to　theresults　of　contingent　experiments　that　he　had　not　told　anyone　about。　in　his　secretiveness　hedidn�