the age of invention-第2部分

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ER　GETTING　THE　FIRST　HUNDRED　POUND；　IT　IS　MORE　EASY　TO　GET　THE　SECOND；　money　itself　being　of　a　prolific　nature。〃　He　gave　much　unpaid　public　service　and　subscribed　generously　to　public　purposes；　yet　he　was　able；　at　the　early　age　of　forty…two；　to　turn　over　his　printing　office　to　one　of　his　journeymen；　and　to　retire　from　active　business；　intending　to　devote　himself　thereafter　to　such　public　employment　as　should　come　his　way；　to　philosophical　or　scientific　studies；　and　to　amusements。

From　boyhood　Franklin　had　been　interested　in　natural　phenomena。　His　〃Journal　of　a　Voyage　from　London　to　Philadelphia〃；　written　at　sea　as　he　returned　from　his　first　stay　in　London；　shows　unusual　powers　of　exact　observation　for　a　youth　of　twenty。　Many　of　the　questions　he　propounded　to　the　Junto　had　a　scientific　bearing。　He　made　an　original　and　important　invention　in　1749；　the　〃Pennsylvania　fireplace；〃　which；　under　the　name　of　the　Franklin　stove；　is　in　common　use　to　this　day；　and　which　brought　to　the　ill…made　houses　of　the　time　increased　comfort　and　a　great　saving　of　fuel。　But　it　brought　Franklin　no　pecuniary　reward；　for　he　never　deigned　to　patent　any　of　his　inventions。

His　active；　inquiring　mind　played　upon　hundreds　of　questions　in　a　dozen　different　branches　of　science。　He　studied　smoky　chimneys；　he　invented　bifocal　spectacles；　he　studied　the　effect　of　oil　upon　ruffled　water；　he　identified　the　〃dry　bellyache〃　as　lead　poisoning；　he　preached　ventilation　in　the　days　when　windows　were　closed　tight　at　night；　and　upon　the　sick　at　all　times；　he　investigated　fertilizers　in　agriculture。　Many　of　his　suggestions　have　since　borne　fruit；　and　his　observations　show　that　he　foresaw　some　of　the　great　developments　of　the　nineteenth　century。

His　fame　in　science　rests　chiefly　upon　his　discoveries　in　electricity。　On　a　visit　to　Boston　in　1746　he　saw　some　electrical　experiments　and　at　once　became　deeply　interested。　Peter　Collinson　of　London；　a　Fellow　of　the　Royal　Society；　who　had　made　several　gifts　to　the　Philadelphia　Library；　sent　over　some　of　the　crude　electrical　apparatus　of　the　day；　which　Franklin　used；　as　well　as　some　contrivances　he　had　purchased　in　Boston。　He　says　in　a　letter　to　Collinson：　〃For　my　own　part；　I　never　was　before　engaged　in　any　study　that　so　engrossed　my　attention　and　my　time　as　this　has　lately　done。〃

Franklin's　letters　to　Collinson　tell　of　his　first　experiments　and　speculations　as　to　the　nature　of　electricity。　Experiments　made　by　a　little　group　of　friends　showed　the　effect　of　pointed　bodies　in　drawing　off　electricity。　He　decided　that　electricity　was　not　the　result　of　friction；　but　that　the　mysterious　force　was　diffused　through　most　substances；　and　that　nature　is　always　alert　to　restore　its　equilibrium。　He　developed　the　theory　of　positive　and　negative　electricity；　or　plus　and　minus　electrification。　The　same　letter　tells　of　some　of　the　tricks　which　the　little　group　of　experimenters　were　accustomed　to　play　upon　their　wondering　neighbors。　They　set　alcohol　on　fire；　relighted　candles　just　blown　out；　produced　mimic　flashes　of　lightning；　gave　shocks　on　touching　or　kissing；　and　caused　an　artificial　spider　to　move　mysteriously。

Franklin　carried　on　experiments　with　the　Leyden　jar；　made　an　electrical　battery；　killed　a　fowl　and　roasted　it　upon　a　spit　turned　by　electricity；　sent　a　current　through　water　and　found　it　still　able　to　ignite　alcohol；　ignited　gunpowder；　and　charged　glasses　of　wine　so　that　the　drinkers　received　shocks。　More　important；　perhaps；　he　began　to　develop　the　theory　of　the　identity　of　lightning　and　electricity；　and　the　possibility　of　protecting　buildings　by　iron　rods。　By　means　of　an　iron　rod　he　brought　down　electricity　into　his　house；　where　he　studied　its　effect　upon　bells　and　concluded　that　clouds　were　generally　negatively　electrified。　In　June；　1752；　he　performed　the　famous　experiment　with　the　kite；　drawing　down　electricity　from　the　clouds　and　charging　a　Leyden　jar　from　the　key　at　the　end　of　the　string。

Franklin's　letters　to　Collinson　were　read　before　the　Royal　Society　but　were　unnoticed。　Collinson　gathered　them　together；　and　they　were　published　in　a　pamphlet　which　attracted　wide　attention。　Translated　into　French；　they　created　great　excitement；　and　Franklin's　conclusions　were　generally　accepted　by　the　scientific　men　of　Europe。　The　Royal　Society；　tardily　awakened；　elected　Franklin　a　member　and　in　1753　awarded　him　the　Copley　medal　with　a　complimentary　address。*

*　It　may　be　useful　to　mention　some　of　the　scientific　facts　and　mechanical　principles　which　were　known　to　Europeans　at　this　time。　More　than　one　learned　essay　has　been　written　to　prove　the　mechanical　indebtedness　of　the　modern　world　to　the　ancient；　particularly　to　the　works　of　those　mechanically　minded　Greeks：　Archimedes；　Aristotle；　Ctesibius；　and　Hero　of　Alexandria。　The　Greeks　employed　the　lever；　the　tackle；　and　the　crane；　the　force…pump；　and　the　suction…pump。　They　had　discovered　that　steam　could　be　mechanically　applied；　though　they　never　made　any　practical　use　of　steam。　In　common　with　other　ancients　they　knew　the　principle　of　the　mariner's　compass。　The　Egyptians　had　the　water…wheel　and　the　rudimentary　blast…furnace。　The　pendulum　clock　appears　to　have　been　an　invention　of　the　Middle　Ages。　The　art　of　printing　from　movable　type；　beginning　with　Gutenberg　about　1450；　helped　to　further　the　Renaissance。　The　improved　mariner's　compass　enabled　Columbus　to　find　the　New　world；　gunpowder　made　possible　its　conquest。　The　compound　microscope　and　the　first　practical　telescope　came　from　the　spectacle　makers　of　Middelburg；　Holland；　the　former　about　1590　and　the　latter　about　1608。　Harvey；　an　English　physician；　had　discovered　the　circulation　of　the　blood　in　1628；　and　Newton；　an　English　mathematician；　the　law　of　gravitation　in　1685。


If　Franklin's　desire　to　continue　his　scientific　researches　had　been　gratified；　it　is　possible　that　he　might　have　discovered　some　of　the　secrets　for　which　the　world　waited　until　Edison　and　his　contemporaries　revealed　them　more　than　a　century　later。　Franklin's　scientific　reputation　has　grown　with　the　years；　and　some　of　his　views　seem　in　perfect　accord　with　the　latest　developments　in　electricity。　But　he　was　not　to　be　permitted　to　continue　his　experiments。　He　had　shown　his　ability　to　manage　men　and　was　to　be　called　to　a　wider　field。

Franklin's　influence　among　his　fellow　citizens　in　Philadelphia　was　very　great。　Always　ostensibly　keeping　himself　in　the　background　and　working　through　others；　never　contradicting；　but　carrying　his　point　by　shrewd　questions　which　showed　the　folly　of　the　contrary　position；　he　continued　to　set　on　foot　and　carry　out　movements　for　the　public　good。　He　established　the　first　circulating　library　in　Philadelphia；　and　one　of　the　first　in　the　country；　and　an　academy　which　grew　into　the　University　of　Pennsylvania。　He　was　instrumental　in　the　foundation　of　a　hospital。　〃I　am　often　ask'd　by　those　to　whom　I　propose　subscribing；〃　said　one　of　the　doctors　who　had　made　fruitless　attempts　to　raise　money　for　the　hospital；　〃Have　you　consulted　Franklin　upon　this　business？〃　Other　public　matters　in　which　the　busy　printer　was　engaged　were　the　paving　and　cleaning　of　the　streets；　better　street　lighting；　the　organization　of　a　police　force　and　of　a　fire　company。　A　pamphlet　which　he　published；　〃Plain　Truth〃；　showing　the　helplessness　of　the　colony　against　the　French　and　Indians；　led　to　the　organization　of　a　volunteer　militia；　and　funds　were　raised　for　arms　by　a　lottery。　Franklin　himself　was　elected　colonel　of　the　Philadelphia　regiment；　〃but　considering　myself　unfit；　I　declined　the　station　and　recommended　Mr。　Lawrence；　a　fine　person　and　man　of　influence；　who　was　accordingly　appointed。〃　In　spite　of　his　militarism；　Franklin　retained　the　position　which　he　held　as　Clerk　of　the　Assembly；　though　the　majority　of　the　members　were　Quakers　opposed　to　war　on　principle。

The　American　Philosophical　Society　owes　its　origin　to　Franklin。　It　was　formally　organized　on　his　motion　in　1743；　but　the　society　has　accepted　the　organization　of　the　Junto　in　1727　as　the　actual　date　of　its　birth。　From　the　beginning　the　society　has　had　among　its　members　many　leading　men　of　scientific　attainments　or　tastes；　not　only　of　Philadelphia；　but　of　the　world。　In　1769　the　original　society　was　consolidated　with　another　of　similar　aims；　and　Franklin；　who　was　the　first　secretary　of　the　society；　was　elected　president　and　served　until　his　death。　The　first　important　undertaking　was　the　successful　observation　of　the　transit　of　Venus　in　1769；　and　many　important　scientific　discoveries　have　since　been　made　by　its　members　and　first　given　to　the　world　at　its　meetings。

Franklin's　appointment　as　one　of　the　two　Deputy　Postmasters　General　of　the　colonies　in　1753　enlarged　his　experience　and　his　reputation。　He　visited　nearly　all　the　post　offices　in　the　colonies　and　introduced　many　improvements　into　the　service。　In　none　of　his　positions　did　his　transcendent　business　ability　show　to　better　advantage。　He　established　new　postal　routes　and　shortened　others。　There　were　no　good　roads　in　the　colonies；　but　his　post　riders　made　what　then　seemed　wonderful　speed。　The　bags　were　opened　to　newspapers；　the　carrying　of　which　had　previously　been　a　private　and　unlawful　perquisite　of　the　riders。　Previously　there　had　been　one　mail　a　week　in　summer　between　New　York　and　Philadelphia　and　one　a　month　in　winter。　The　service　was　increased　to　three　a　week　in　summer　and　one　in　winter。

The　main　post　road　ran　from　northern　New　England　to　Savannah；　closely　hugging　the　seacoast　for　the　greater　part　of　the　way。　Some　of　the　milestones　set　by　Franklin　to　enable　the　postmasters　to　compute　the　postage；　which　was　fixed　according　to　distance；　are　still　standing。　Crossroads　connected　some　of　the　larger　communities　away　from　the　seacoast　with　the　main　road；　but　when　Franklin　died；　after　serving　also　as　Postmaster　General　of　the　United　States；　there　were　only　seventy…five　post　offices　in　the　entire　country。

Franklin　took　a　hand　in　the　final　struggle　between　France　and　England　in　America。　On　the　eve　of　the　conflict；　in　1754；　commissioners　from　the　several　colonies　were　ordered　to　convene　at　Albany　for　a　conference　with　the　Six　Nations　of　the　Iroquois；　and　Franklin　was　one　of　the　deputies　from　Pennsylvania。　On　his　way　to　Albany　he　〃projected　and　drew　a　plan　for　the　union　of　all