heroes of the telegraph-第6章

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；　but　Wheatstone　showed　that　the　instrument　was　only　a　modification　of　his　own　electro…magnetic　telegraph。

In　1843　Wheatstone　communicated　an　important　paper　to　the　Royal　Society；　entitled　'An　Account　of　Several　New　Processes　for　Determining　the　Constants　of　a　Voltaic　Circuit。'　It　contained　an　exposition　of　the　well…　known　balance　for　measuring　the　electrical　resistance　of　a　conductor；　which　still　goes　by　the　name　of　Wheatstone's　Bridge　or　balance；　although　it　was　first　devised　by　Mr。　S。　W。　Christie；　of　the　Royal　Military　Academy；　Woolwich；　who　published　it　in　the　PHILOSOPHICAL　TRANSACTIONS　for　1833。　　The　method　was　neglected　until　Wheatstone　brought　it　into　notice。　　His　paper　abounds　with　simple　and　practical　formula：　　for　the　calculation　of　currents　and　resistances　by　the　law　of　Ohm。　　He　introduced　a　unit　of　resistance；　namely；　a　foot　of　copper　wire　weighing　one　hundred　grains；　and　showed　how　it　might　be　applied　to　measure　the　length　of　wire　by　its　resistance。　　He　was　awarded　a　medal　for　his　paper　by　the　Society。　　The　same　year　he　invented　an　apparatus　which　enabled　the　reading　of　a　thermometer　or　a　barometer　to　be　registered　at　a　distance　by　means　of　an　electric　contact　made　by　the　mercury。　　A　sound　telegraph；　in　which　the　signals　were　given　by　the　strokes　of　a　bell；　was　also　patented　by　Cooke　and　Wheatstone　in　May　of　that　year。

The　introduction　of　the　telegraph　had　so　far　advanced　that；　on　September　2；　1845；　the　Electric　Telegraph　Company　was　registered；　and　Wheatstone；　by　his　deed　of　partnership　with　Cooke；　received　a　sum　of　L33；000　for　the　use　of　their　joint　inventions。

》From　1836…7　Wheatstone　had　thought　a　good　deal　about　submarine　telegraphs；　and　in　1840　he　gave　evidence　before　the　Railway　Committee　of　the　House　of　Commons　on　the　feasibility　of　the　proposed　line　from　Dover　to　Calais。　　He　had　even　designed　the　machinery　for　making　and　laying　the　cable。　　In　the　autumn　of　1844；　with　the　assistance　of　Mr。　J。　D。　Llewellyn；　he　submerged　a　length　of　insulated　wire　in　Swansea　Bay；　and　signalled　through　it　from　a　boat　to　the　Mumbles　Lighthouse。　Next　year　he　suggested　the　use　of　gutta…percha　for　the　coating　of　the　intended　wire　across　the　Channel。

Though　silent　and　reserved　in　public；　Wheatstone　was　a　clear　and　voluble　talker　in　private；　if　taken　on　his　favourite　studies；　and　his　small　but　active　person；　his　plain　but　intelligent　countenance；　was　full　of　animation。　　Sir　Henry　Taylor　tells　us　that　he　once　observed　Wheatstone　at　an　evening　party　in　Oxford　earnestly　holding　forth　to　Lord　Palmerston　on　the　capabilities　of　his　telegraph。　　'You　don't　say　so！'　exclaimed　the　statesman。　　'I　must　get　you　to　tell　that　to　the　Lord　Chancellor。'　And　so　saying；　he　fastened　the　electrician　on　Lord　Westbury；　and　effected　his　escape。　　A　reminiscence　of　this　interview　may　have　prompted　Palmerston　to　remark　that　a　time　was　coming　when　a　minister　might　be　asked　in　Parliament　if　war　had　broken　out　in　India；　and　would　reply；　'Wait　a　minute；　I'll　just　telegraph　to　the　Governor…General；　and　let　you　know。'

At　Christchurch；　Marylebone；　on　February　12；　1847；　Wheatstone　was　married。　　His　wife　was　the　daughter　of　a　Taunton　tradesman；　and　of　handsome　appearance。　　She　died　in　1866；　leaving　a　family　of　five　young　children　to　his　care。　　His　domestic　life　was　quiet　and　uneventful。

One　of　Wheatstone's　most　ingenious　devices　was　the　'Polar　clock；'　exhibited　at　the　meeting　of　the　British　Association　in　1848。　　It　is　based　on　the　fact　discovered　by　Sir　David　Brewster；　that　the　light　of　the　sky　is　polarised　in　a　plane　at　an　angle　of　ninety　degrees　from　the　position　of　the　sun。　　It　follows　that　by　discovering　that　plane　of　polarisation；　and　measuring　its　azimuth　with　respect　to　the　north；　the　position　of　the　sun；　although　beneath　the　horizon；　could　be　determined；　and　the　apparent　solar　time　obtained。　　The　clock　consisted　of　a　spy…　glass；　having　a　nichol　or　double…image　prism　for　an　eye…piece；　and　a　thin　plate　of　selenite　for　an　object…glass。　　When　the　tube　was　directed　to　the　North　Polethat　is；　parallel　to　the　earth's　axisand　the　prism　of　the　eye…piece　turned　until　no　colour　was　seen；　the　angle　of　turning；　as　shown　by　an　index　moving　with　the　prism　over　a　graduated　limb；　gave　the　hour　of　day。　　The　device　is　of　little　service　in　a　country　where　watches　are　reliable；　but　it　formed　part　of　the　equipment　of　the　North　Polar　expedition　commanded　by　Captain　Nares。　　Wheatstone's　remarkable　ingenuity　was　displayed　in　the　invention　of　cyphers　which　have　never　been　unravelled；　and　interpreting　cypher　manuscripts　in　the　British　Museum　which　had　defied　the　experts。　　He　devised　a　cryptograph　or　machine　for　turning　a　message　into　cypher　which　could　only　be　interpreted　by　putting　the　cypher　into　a　corresponding　machine　adjusted　to　reproduce　it。

The　rapid　development　of　the　telegraph　in　Europe　may　be　gathered　from　the　fact　that　in　1855；　the　death　of　the　Emperor　Nicholas　at　St。　Petersburg；　about　one　o'clock　in　the　afternoon；　was　announced　in　the　House　of　Lords　a　few　hours　later；　and　as　a　striking　proof　of　its　further　progress；　it　may　be　mentioned　that　the　result　of　the　Oaks　of　1890　was　received　in　New　York　fifteen　seconds　after　the　horses　passed　the　winning…post。

Wheatstone's　next　great　invention　was　the　automatic　transmitter；　in　which　the　signals　of　the　message　are　first　punched　out　on　a　strip　of　paper；　which　is　then　passed　through　the　sending…key；　and　controls　the　signal　currents。　　By　substituting　a　mechanism　for　the　hand　in　sending　the　message；　he　was　able　to　telegraph　about　100　words　a　minute；　or　five　times　the　ordinary　rate。　　In　the　Postal　Telegraph　service　this　apparatus　is　employed　for　sending　Press　telegrams；　and　it　has　recently　been　so　much　improved；　that　messages　are　now　sent　from　London　to　Bristol　at　a　speed　of　600　words　a　minute；　and　even　of　400　words　a　minute　between　London　and　Aberdeen。　　On　the　night　of　April　8；　1886；　when　Mr。　Gladstone　introduced　his　Bill　for　Home　Rule　in　Ireland；　no　fewer　than　1；500；000　words　were　despatched　from　the　central　station　at　St。　Martin's…le…Grand　by　100　Wheatstone　transmitters。　　Were　Mr。　Gladstone　himself　to　speak　for　a　whole　week；　night　and　day；　and　with　his　usual　facility；　he　could　hardly　surpass　this　achievement。　　The　plan　of　sending　messages　by　a　running　strip　of　paper　which　actuates　the　key　was　originally　patented　by　Bain　in　1846；　but　Wheatstone；　aided　by　Mr。　Augustus　Stroh；　an　accomplished　mechanician；　and　an　able　experimenter；　was　the　first　to　bring　the　idea　into　successful　operation。

In　1859　Wheatstone　was　appointed　by　the　Board　of　Trade　to　report　on　the　subject　of　the　Atlantic　cables；　and　in　1864　he　was　one　of　the　experts　who　advised　the　Atlantic　Telegraph　Company　on　the　construction　of　the　successful　lines　of　1865　and　1866。　　On　February　4；　1867；　he　published　the　principle　of　reaction　in　the　dynamo…electric　machine　by　a　paper　to　the　Royal　Society；　but　Mr。　C。　W。　Siemens　had　communicated　the　identical　discovery　ten　days　earlier；　and　both　papers　were　read　on　the　same　day。　It　afterwards　appeared　that　Herr　Werner　Siemens；　Mr。　Samuel　Alfred　Varley；　and　Professor　Wheatstone　had　independently　arrived　at　the　principle　within　a　few　months　of　each　other。　　Varley　patented　it　on　December　24；　1866；　Siemens　called　attention　to　it　on　January　17；　1867；　and　Wheatstone　exhibited　it　in　action　at　the　Royal　Society　on　the　above　date。　　But　it　will　be　seen　from　our　life　of　William　Siemens　that　Soren　Hjorth；　a　Danish　inventor；　had　forestalled　them。

In　1870　the　electric　telegraph　lines　of　the　United　Kingdom；　worked　by　different　companies；　were　transferred　to　the　Post　Office；　and　placed　under　Government　control。

Wheatstone　was　knighted　in　1868；　after　his　completion　of　the　automatic　telegraph。　　He　had　previously　been　made　a　Chevalier　of　the　Legion　of　Honour。　　Some　thirty…four　distinctions　and　diplomas　of　home　or　foreign　societies　bore　witness　to　his　scientific　reputation。　　Since　1836　he　had　been　a　Fellow　of　the　Royal　Society；　and　in　1873　he　was　appointed　a　Foreign　Associate　of　the　French　Academy　of　Sciences。　　The　same　year　he　was　awarded　the　Ampere　Medal　by　the　French　Society　for　the　Encouragement　of　National　Industry。　　In　1875　he　was　created　an　honorary　member　of　the　Institution　of　Civil　Engineers。　　He　was　a　D。C。L。　of　Oxford　and　an　LL。D。