heroes of the telegraph-第22部分

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uld　steam　forwards　or　backwards　with　equal　ease；　it　became　unnecessary　to　pass　the　cable　forward　before　hauling　it　in；　if　a　fault　were　discovered　in　the　part　submerged：　　the　motion　of　the　ship　had　only　to　be　reversed；　the　stern　rudder　fixed；　and　the　bow　rudder　turned；　while　a　small　engine　was　employed　to　haul　the　cable　back　over　the　stern　drum；　which　had　been　used　a　few　minutes　before　to　pay　it　out。

The　first　expedition　of　the　Faraday　was　the　laying　of　the　Direct　United　States　cable　in　the　winter　of　1874　a　work　which；　though　interrupted　by　stormy　weather；　was　resumed　and　completed　in　the　summer　of　1875。　　She　has　been　engaged　in　laying　several　Atlantic　cables　since；　and　has　been　fitted　with　the　electric　light；　a　resource　which　has　proved　of　the　utmost　service；　not　only　in　facilitating　the　night　operations　of　paying…out；　but　in　guarding　the　ship　from　collision　with　icebergs　in　foggy　weather　off　the　North　American　coast。

Mention　of　the　electric　light　brings　us　to　an　important　act　of　the　inventor；　which；　though　done　on　behalf　of　his　brother　Werner；　was　pregnant　with　great　consequences。　　This　was　his　announcement　before　a　meeting　of　the　Royal　Society；　held　on　February　14；　1867；　of　the　discovery　of　the　principle　of　reinforcing　the　field　magnetism　of　magneto…electric　generators　by　part　or　the　whole　of　the　current　generated　in　the　revolving　armaturea　principle　which　has　been　applied　in　the　dynamo…electric　machines；　now　so　much　used　for　producing　electric　light　and　effecting　the　transmission　of　power　to　a　distance　by　means　of　the　electric　current。　　By　a　curious　coincidence　the　same　principle　was　enunciated　by　Sir　Charles　Wheatstone　at　the　very　same　meeting；　while　a　few　months　previously　Mr。　S。　A。　Varley　had　lodged　an　application　for　a　British　patent；　in　which　the　same　idea　was　set　forth。　　The　claims　of　these　three　inventors　to　priority　in　the　discovery　were；　however；　anticipated　by　at　least　one　other　investigator；　Herr　Soren　Hjorth；　believed　to　be　a　Dane　by　birth；　and　still　remembered　by　a　few　living　electricians；　though　forgotten　by　the　scientific　world　at　large；　until　his　neglected　specification　was　unexpectedly　dug　out　of　the　musty　archives　of　the　British　Patent　Office　and　brought　into　the　light。

The　announcement　of　Siemens　and　Wheatstone　came　at　an　apter　time　than　Hjorth's；　and　was　more　conspicuously　made。　　Above　all；　in　the　affluent　and　enterprising　hands　of　the　brothers　Siemens；　it　was　not　suffered　to　lie　sterile；　and　the　Siemens　dynamo…electric　　machine　was　its　offspring。　This　dynamo；　as　is　well　known；　differs　from　those　of　Gramme　and　Paccinotti　chiefly　in　the　longitudinal　winding　of　the　armature；　and　it　is　unnecessary　to　describe　it　here。　　It　has　been　adapted　by　its　inventors　to　all　kinds　of　electrical　work；　electrotyping；　telegraphy；　electric　lighting；　and　the　propulsion　of　vehicles。

The　first　electric　tramway　run　at　Berlin　in　1879　was　followed　by　another　at　Dusseldorf　in　1880；　and　a　third　at　Paris　in　1881。　　With　all　of　these　the　name　of　Werner　Siemens　was　chiefly　associated；　but　William　Siemens　had　also　taken　up　the　matter；　and　established　at　his　country　house　of　Sherwood；　near　Tunbridge　Wells；　an　arrangement　of　dynamos　and　water…wheel；　by　which　the　power　of　a　neighbouring　stream　was　made　to　light　the　house；　cut　chaff　turn　washing…machines；　and　perform　other　household　duties。　　More　recently　the　construction　of　the　electric　railway　from　Portrush　to　Bushmills；　at　the　Giant's　Causeway；　engaged　his　attention；　and　this；　the　first　work　of　its　kind　in　the　United　Kingdom；　and　to　all　appearance　the　pioneer　of　many　similar　lines；　was　one　of　his　very　last　undertakings。

In　the　recent　development　of　electric　lighting；　William　Siemens；　whose　fame　had　been　steadily　growing；　was　a　recognised　leader；　although　he　himself　made　no　great　discoveries　therein。　　As　a　public　man　and　a　manufacturer　of　great　resources　his　influence　in　assisting　the　introduction　of　the　light　has　been　immense。　　The　number　of　Siemens　machines　and　Siemens　electric　lamps；　together　with　measuring　instruments　such　as　the　Siemens　electro…dynamometer；　which　has　been　supplied　to　different　parts　of　the　world　by　the　firm　of　which　he　was　the　head；　is　very　considerable；　and　probably　exceeds　that　of　any　other　manufacturer；　at　least　in　this　country。

Employing　a　staff　of　skilful　assistants　to　develop　many　of　his　ideas；　Dr。　Siemens　was　able　to　produce　a　great　variety　of　electrical　instruments　for　measuring　and　other　auxiliary　purposes；　all　of　which　bear　the　name　of　his　firm；　and　have　proved　exceedingly　useful　in　a　practical　sense。

Among　the　most　interesting　of　Siemens's　investigations　were　his　experiments　on　the　influence　of　the　electric　light　in　promoting　the　growth　of　plants；　carried　out　during　the　winter　of　1880　in　the　greenhouses　of　Sherwood。　　These　experiments　showed　that　plants　do　not　require　a　period　of　rest；　but　continue　to　grow　if　light　and　other　necessaries　are　supplied　to　them。　　Siemens　enhanced　the　daylight；　and；　as　it　were；　prolonged　it　through　the　night　by　means　of　arc　lamps；　with　the　result　of　forcing　excellent　fruit　and　flowers　to　their　maturity　before　the　natural　time　in　this　climate。

While　Siemens　was　testing　the　chemical　and　life…promoting　influence　of　the　electric　arc　light；　he　was　also　occupied　in　trying　its　temperature　and　heating　power　with　an　'electric　furnace；'　consisting　of　a　plumbago　crucible　having　two　carbon　electrodes　entering　it　in　such　a　manner　that　the　voltaic　arc　could　be　produced　within　it。　　He　succeeded　in　fusing　a　variety　of　refractory　metals　in　a　comparatively　short　time：　thus；　a　pound　of　broken　files　was　melted　in　a　cold　crucible　in　thirteen　minutes；　a　result　which　is　not　surprising　when　we　consider　that　the　temperature　of　the　voltaic　arc；　as　measured　by　Siemens　and　Rosetti；　is　between　2；000　and　3；000　Deg。　Centigrade；　or　about　one…third　that　of　the　probable　temperature　of　the　sun。　　Sir　Humphry　Davy　was　the　first　to　observe　the　extraordinary　fusing　power　of　the　voltaic　arc；　but　Siemens　first　applied　it　to　a　practical　purpose　in　his　electric　furnace。

Always　ready　to　turn　his　inventive　genius　in　any　direction；　the　introduction　of　the　electric　light；　which　had　given　an　impetus　to　improvement　in　the　methods　of　utilising　gas；　led　him　to　design　a　regenerative　gas　lamp；　which　is　now　employed　on　a　small　scale　in　this　country；　either　for　street　lighting　or　in　class…rooms　and　public　halls。　In　this　burner；　as　in　the　regenerative　furnace；　the　products　of　combustion　are　made　to　warm　up　the　air　and　gas　which　go　to　feed　the　flame；　and　the　effect　is　a　full　and　brilliant　light　with　some　economy　of　fuel。　　The　use　of　coal…gas　for　heating　purposes　was　another　subject　which　he　took　up　with　characteristic　earnestness；　and　he　advocated　for　a　time　the　use　of　gas　stoves　and　fires　in　preference　to　those　which　burn　coal；　not　only　on　account　of　their　cleanliness　and　convenience；　but　on　the　score　of　preventing　fogs　in　great　cities；　by　checking　the　discharge　of　smoke　into　the　atmosphere。　　He　designed　a　regenerative　gas　and　coke　fireplace；　in　which　the　ingoing　air　was　warmed　by　heat　conducted　from　the　back　part　of　the　grate；　and　by　practical　trials　in　his　own　office；　calculated　the　economy　of　the　system。　　The　interest　in　this　question；　however；　died　away　after　the　close　of　the　Smoke　Abatement　Exhibition；　and　the　experiments　of　Mr。　Aiken；　of　Edinburgh；　showed　how　futile　was　the　hope　that　gas　fires　would　prevent　fogs　altogether。　　They　might　indeed　ameliorate　the　noxious　character　of　a　fog　by　checking　the　discharge　of　soot　into　the　atmosphere；　but　Mr。　Aiken's　experiments　showed　that　particles　of　gas　were　in　themselves　capable　of　condensing　the　moisture　of　the　air　upon　them。　　The　great　scheme　of　Siemens　for　making　London　a　smokeless　city；　by　manufacturing　gas　at　the　coal…pit　and　leading　it　in　pipes　from　street　to　street；　would　not　have　rendered　it　altogether　a　fogless　one；　though　the　coke　and　gas　fires　would　certainly　have　reduced　the　quantity　of　soot　launched　into　the　air。　　Siemens's　scheme　was　rejected　by　a　Committee　of　the　House　of　Lords　on　the　somewhat　mistaken　ground　that　if　the　plan　were　as　profitable　as　Siemens　supposed；　it　would　have　been　put　in　practice　long　ago　by　private　enterprise。

》From　the　problem　of　heating　a　room；　the　mind　of　Siemens　also　passed　to　the　maintenance　of　solar　fires；　and　occupied　itself　with　the　supply　of　fuel　to　the　sun。　　Some　physicists　have　attributed　the　continuance　of　solar　heat　to　the　contraction　of　the　solar　mass；　and　others　to　the　impact　of　cometary　matter。　　Imbued　with　the　idea　of　regeneration；　and　seeking　in　nature　for　that　thrift　of　power　which　he；　as　an　inventor；　had　always　aimed　at；　Siemens　suggested　a　hypothesis　on　which　the　sun　conserves　its　heat　by　a　circulation　of　its　fuel　in　space。　　The　elements　dissociated　in　the　intense　heat　of　the　glowing　orb　rush　into　the　cooler　regions　of　space；　and　recombine　to　stream　again　towards　the　sun；　where　the　self…same　process　is　renewed。　　The　hypothesis　was　a　daring　one；　and　evoked　a　great　deal　of　discussion；　to　which　the　author　replied　with　interest；　afterwards　reprinting　the　controversy　in　a　volume；　ON　THE　CONSERVATION　OF　SOLAR　ENERGY。　　Whether　true　or　notand　time　will　probably　decidethe　solar　hypothesis　of　Siemens　revealed　its　author　in　a　new　light。　　Hitherto　he　had　been　the　ingenious