heroes of the telegraph-第2章

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city；　and　Franklin　demonstrated　the　identity　of　electricity　and　lightning。

The　charge　from　a　Leyden　jar　was　frequently　sent　through　a　chain　of　persons　clasping　hands；　or　a　length　of　wire　with　the　earth　as　part　of　the　circuit。　　This　experiment　was　made　by　Joseph　Franz；　of　Vienna；　in　1746；　and　Dr。　Watson；　of　London；　in　1747；　while　Franklin　ignited　spirits　by　a　spark　which　had　been　sent　across　the　Schuylkill　river　by　the　same　means。　　But　none　of　these　men　seem　to　have　grasped　the　idea　of　employing　the　fleet　fire　as　a　telegraph。

The　first　suggestion　of　an　electric　telegraph　on　record　is　that　published　by　one　'C。　M。'　in　the　Scots　Magazine　for　February　17；　1753。　The　device　consisted　in　running　a　number　of　insulated　wires　between　two　places；　one　for　each　letter　of　the　alphabet。　　The　wires　were　to　be　charged　with　electricity　from　a　machine　one　at　a　time；　according　to　the　letter　it　represented。　　At　its　far　end　the　charged　wire　was　to　attract　a　disc　of　paper　marked　with　the　corresponding　letter；　and　so　the　message　would　be　spelt。　　'C。　M。'　also　suggested　the　first　acoustic　telegraph；　for　he　proposed　to　have　a　set　of　bells　instead　of　the　letters；　each　of　a　different　tone；　and　to　be　struck　by　the　spark　from　its　charged　wire。

The　identity　of　'C。　M。；'　who　dated　his　letter　from　Renfrew；　has　not　been　established　beyond　a　doubt。　　There　is　a　tradition　of　a　clever　man　living　in　Renfrew　at　that　time；　and　afterwards　in　Paisley；　who　could　'licht　a　room　wi'　coal　reek　（smoke）；　and　mak'　lichtnin'　speak　and　write　upon　the　wa'。'　By　some　he　was　thought　to　be　a　certain　Charles　Marshall；　from　Aberdeen；　but　it　seems　likelier　that　he　was　a　Charles　Morrison；　of　Greenock；　who　was　trained　as　a　surgeon；　and　became　connected　with　the　tobacco　trade　of　Glasgow。　　In　Renfrew　he　was　regarded　as　a　kind　of　wizard；　and　he　is　said　to　have　emigrated　to　Virginia；　where　he　died。

In　the　latter　half　of　the　eighteenth　century；　many　other　suggestions　of　telegraphs　based　on　the　known　properties　of　the　electric　fire　were　published；　for　example；　by　Joseph　Bozolus；　a　Jesuit　lecturer　of　Rome；　in　1767；　by　Odier；　a　Geneva　physicist；　in　1773；　who　states　in　a　letter　to　a　lady；　that　he　conceived　the　idea　on　hearing　a　casual　remark；　while　dining　at　Sir　John　Pringle's；　with　Franklin；　Priestley；　and　other　great　geniuses。　　'I　shall　amuse　you；　perhaps；　in　telling　you；'　he　says；'that　I　have　in　my　head　certain　experiments　by　which　to　enter　into　conversation　with　the　Emperor　of　Mogol　or　of　China；　the　English；　the　French；　or　any　other　people　of　Europe　。。。　You　may　intercommunicate　all　that　you　wish　at　a　distance　of　four　or　five　thousands　leagues　in　less　than　half　an　hour。　Will　that　suffice　you　for　glory？'

George　Louis　Lesage；　in　1782；　proposed　a　plan　similar　to　'C。　M。's；'　using　underground　wires。　　An　anonymous　correspondent　of　the　JOURNAL　DE　PARIS　for　May　30；　1782；　suggested　an　alarm　bell　to　call　attention　to　the　message。　　Lomond；　of　Paris；　devised　a　telegraph　with　only　one　wire；　the　signals　to　be　read　by　the　peculiar　movements　of　an　attracted　pith…ball；　and　Arthur　Young　witnessed　his　plan　in　action；　as　recorded　in　his　diary。　M。　Chappe；　the　inventor　of　the　semaphore；　tried　about　the　year　1790　to　introduce　a　synchronous　electric　telegraph；　and　failed。

Don　Francisco　Salva　y　Campillo；　of　Barcelona；　in　1795；　proposed　to　make　a　telegraph　between　Barcelona　and　Mataro；　either　overhead　or　underground；　and　he　remarks　of　the　wires；　'at　the　bottom　of　the　sea　their　bed　would　be　ready　made；　and　it　would　be　an　extraordinary　casualty　that　should　disturb　them。'　　In　Salva's　telegraph；　the　signals　were　to　be　made　by　illuminating　letters　of　tinfoil　with　the　spark。　　Volta's　great　invention　of　the　pile　in　1800　furnished　a　new　source　of　electricity；　better　adapted　for　the　telegraph；　and　Salva　was　apparently　the　first　to　recognise　this；　for；　in　the　same　year；　he　proposed　to　use　it　and　interpret　the　signals　by　the　twitching　of　a　frog's　limb；　or　the　decomposition　of　water。

In　1802；　Jean　Alexandre；　a　reputed　natural　son　of　Jean　Jacques　Rousseau；　brought　out　a　TELEGRAPHE　INTIME；　or　secret　telegraph；　which　appears　to　have　been　a　step…by…step　apparatus。　　The　inventor　concealed　its　mode　of　working；　but　it　was　believed　to　be　electrical；　and　there　was　a　needle　which　stopped　at　various　points　on　a　dial。　　Alexandre　stated　that　he　had　found　out　a　strange　matter　or　power　which　was；　perhaps　generally　diffused；　and　formed　in　some　sort　the　soul　of　the　universe。　　He　endeavoured　to　bring　his　invention　under　the　eye　of　the　First　Consul；　but　Napoleon　referred　the　matter　to　Delambre；　and　would　not　see　it。　Alexandre　was　born　at　Paris；　and　served　as　a　carver　and　gilder　at　Poictiers；　then　sang　in　the　churches　till　the　Revolution　suppressed　this　means　of　livelihood。　　He　rose　to　influence　as　a　Commissary…general；　then　retired　from　the　army　and　became　an　inventor。　　His　name　is　associated　with　a　method　of　steering　balloons；　and　a　filter　for　supplying　Bordeaux　with　water　from　the　Garonne。　　But　neither　of　these　plans　appear　to　have　been　put　in　practice；　and　he　died　at　Angouleme；　leaving　his　widow　in　extreme　poverty。

Sommering；　a　distinguished　Prussian　anatomist；　in　1809　brought　out　a　telegraph　worked　by　a　voltaic　battery；　and　making　signals　by　decomposing　water。　　Two　years　later　it　was　greatly　simplified　by　Schweigger；　of　Halle；　and　there　is　reason　to　believe　that　but　for　the　discovery　of　electro…magnetism　by　Oersted；　in　1824　the　chemical　telegraph　would　have　come　into　practical　use。

In　1806；　Ralph　Wedgwood　submitted　a　telegraph　based　on　frictional　electricity　to　the　Admiralty；　but　was　told　that　the　semaphore　was　sufficient　for　the　country。　　In　a　pamphlet　he　suggested　the　establishment　of　a　telegraph　system　with　public　offices　in　different　centres。　　Francis　Ronalds；　in　1816；　brought　a　similar　telegraph　of　his　invention　to　the　notice　of　the　Admiralty；　and　was　politely　informed　that　'telegraphs　of　any　kind　are　now　wholly　unnecessary。'

In　1826…7；　Harrison　Gray　Dyar；　of　New　York；　devised　a　telegraph　in　which　the　spark　was　made　to　stain　the　signals　on　moist　litmus　paper　by　decomposing　nitric　acid；　but　he　had　to　abandon　his　experiments　in　Long　Island　and　fly　the　country；　because　of　a　writ　which　charged　him　with　a　conspiracy　for　carrying　on　secret　communication。　　In　1830　Hubert　Recy　published　an　account　of　a　system　of　Teletatodydaxie；　by　which　the　electric　spark　was　to　ignite　alcohol　and　indicate　the　signals　of　a　code。

But　spark　or　frictional　electric　telegraphs　were　destined　to　give　way　to　those　actuated　by　the　voltaic　current；　as　the　chemical　mode　of　signalling　was　superseded　by　the　electro…magnet。　　In　1820　the　separate　courses　of　electric　and　magnetic　science　were　united　by　the　connecting　discovery　of　Oersted；　who　found　that　a　wire　conveying　a　current　had　the　power　of　moving　a　compass…needle　to　one　side　or　the　other　according　to　the　direction　of　the　current。

La　Place；　the　illustrious　mathematician；　at　once　saw　that　this　fact　could　be　utilised　as　a　telegraph；　and　Ampere；　acting　on　his　suggestion；　published　a　feasible　plan。　　Before　the　year　was　out；　Schweigger；　of　Halle；　multiplied　the　influence　of　the　current　on　the　needle　by　coiling　the　wire　about　it。　　Ten　years　later；　Ritchie　improved　on　Ampere's　method；　and　exhibited　a　model　at　the　Royal　Institution；　London。　　About　the　same　time；　Baron　Pawel　Schilling；　a　Russian　nobleman；　still　further　modified　it；　and　the　Emperor　Nicholas　decreed　the　erection　of　a　line　from　Cronstadt　to　St。　Petersburg；　with　a　cable　in　the　Gulf　of　Finland　but　Schilling　died　in　1837；　and　the　project　was　never　realised。

In　1833…5　Professors　Gauss　and　Weber　constructed　a　telegraph　between　the　physical　cabinet　and　the　Observatory　of　the　University　of　Gottingen。　At　first　they　used　the　voltaic　pile；　but　abandoned　it　in　favour　of　Faraday's　recent　discovery　that　electricity　could　be　generated　in　a　wire　by　the　motion　of　a　magnet。　　The　magnetic　key　with　which　the　message　was　sent　Produced　by　its　action　an　electric　current　which；　after　traversing　the　line；　passed　through　a　coil　and　deflected　a　suspended　magnet　to　the　right　or　left；　according　to　the　direction　of　the　current。　　A　mirror　attached　to　the　suspension　magnified　the　movement　of　the　needle；　and　indicated　the　signals　after　the　manner　of　the　Thomson　mirror　galva