heroes of the telegraph-第4部分

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　to　the　work　of　introducing　the　telegraph。　　He　returned　to　London　soon　after；　and　was　able　to　exhibit　a　telegraph　with　three　needles　in　January；　1837。　　Feeling　his　want　of　scientific　knowledge；　he　consulted　Faraday　and　Dr。　Roget；　the　latter　of　whom　sent　him　to　Wheatstone。

At　a　second　interview；　Mr。　Cooke　told　Wheatstone　of　his　intention　to　bring　out　a　working　telegraph；　and　explained　his　method。　　Wheatstone；　according　to　his　own　statement；　remarked　to　Cooke　that　the　method　would　not　act；　and　produced　his　own　experimental　telegraph。　　Finally；　Cooke　proposed　that　they　should　enter　into　a　partnership；　but　Wheatstone　was　at　first　reluctant　to　comply。　　He　was　a　well…known　man　of　science；　and　had　meant　to　publish　his　results　without　seeking　to　make　capital　of　them。　　Cooke；　on　the　other　hand；　declared　that　his　sole　object　was　to　make　a　fortune　from　the　scheme。　　In　May　they　agreed　to　join　their　forces；　Wheatstone　contributing　the　scientific；　and　Cooke　the　administrative　talent。　　The　deed　of　partnership　was　dated　November　19；　1837。　　A　joint　patent　was　taken　out　for　their　inventions；　including　the　five…needle　telegraph　of　Wheatstone；　and　an　alarm　worked　by　a　relay；　in　which　the　current；　by　dipping　a　needle　into　mercury；　completed　a　local　circuit；　and　released　the　detent　of　a　clockwork。

The　five…needle　telegraph；　which　was　mainly；　if　not　entirely；　due　to　Wheatstone；　was　similar　to　that　of　Schilling；　and　based　on　the　principle　enunciated　by　Amperethat　is　to　say；　the　current　was　sent　into　the　line　by　completing　the　circuit　of　the　battery　with　a　make　and　break　key；　and　at　the　other　end　it　passed　through　a　coil　of　wire　surrounding　a　magnetic　needle　free　to　turn　round　its　centre。　　According　as　one　pole　of　the　battery　or　the　other　was　applied　to　the　line　by　means　of　the　key；　the　current　deflected　the　needle　to　one　side　or　the　other。　　There　were　five　separate　circuits　actuating　five　different　needles。　　The　latter　were　pivoted　in　rows　across　the　middle　of　a　dial　shaped　like　a　diamond；　and　having　the　letters　of　the　alphabet　arranged　upon　it　in　such　a　way　that　a　letter　was　literally　pointed　out　by　the　current　deflecting　two　of　the　needles　towards　it。

An　experimental　line；　with　a　sixth　return　wire；　was　run　between　the　Euston　terminus　and　Camden　Town　station　of　the　London　and　North　Western　Railway　on　July　25；　1837。　　The　actual　distance　was　only　one　and　a　half　mile；　but　spare　wire　had　been　inserted　in　the　circuit　to　increase　its　length。　　It　was　late　in　the　evening　before　the　trial　took　place。　　Mr。　Cooke　was　in　charge　at　Camden　Town；　while　Mr。　Robert　Stephenson　and　other　gentlemen　looked　on；　and　Wheatstone　sat　at　his　instrument　in　a　dingy　little　room；　lit　by　a　tallow　candle；　near　the　booking…office　at　Euston。　　Wheatstone　sent　the　first　message；　to　which　Cooke　replied；　and　'never；'　said　Wheatstone；　'did　I　feel　such　a　tumultuous　sensation　before；　as　when；　all　alone　in　the　still　room；　I　heard　the　needles　click；　and　as　I　spelled　the　words；　I　felt　all　the　magnitude　of　the　invention　pronounced　to　be　practicable　beyond　cavil　or　dispute。'

In　spite　of　this　trial；　however；　the　directors　of　the　railway　treated　the　'new…fangled'　invention　with　indifference；　and　requested　its　removal。　　In　July；　1839；　however；　it　was　favoured　by　the　Great　Western　Railway；　and　a　line　erected　from　the　Paddington　terminus　to　West　Drayton　station；　a　distance　of　thirteen　miles。　　Part　of　the　wire　was　laid　underground　at　first；　but　subsequently　all　of　it　was　raised　on　posts　along　the　line。　　Their　circuit　was　eventually　extended　to　Slough　in　1841；　and　was　publicly　exhibited　at　Paddington　as　a　marvel　of　science；　which　could　transmit　fifty　signals　a　distance　of　280；000　miles　in　a　minute。　The　price　of　admission　was　a　shilling。

Notwithstanding　its　success；　the　public　did　not　readily　patronise　the　new　invention　until　its　utility　was　noised　abroad　by　the　clever　capture　of　the　murderer　Tawell。　　Between　six　and　seven　o'clock　one　morning　a　woman　named　Sarah　Hart　was　found　dead　in　her　home　at　Salt　Hill；　and　a　man　had　been　observed　to　leave　her　house　some　time　before。　　The　police　knew　that　she　was　visited　from　time　to　time　by　a　Mr。　John　Tawell；　from　Berkhampstead；　where　he　was　much　respected；　and　on　inquiring　and　arriving　at　Slough；　they　found　that　a　person　answering　his　description　had　booked　by　a　slow　train　for　London；　and　entered　a　first…class　carriage。　　The　police　telegraphed　at　once　to　Paddington；　giving　the　particulars；　and　desiring　his　capture。　　'He　is　in　the　garb　of　a　Quaker；'　ran　the　message；　'with　a　brown　coat　on；　which　reaches　nearly　to　his　feet。'　There　was　no　'Q'　in　the　alphabet　of　the　five…needle　instrument；　and　the　clerk　at　Slough　began　to　spell　the　word　'Quaker'　with　a　'kwa'；　but　when　he　had　got　so　far　he　was　interrupted　by　the　clerk　at　Paddington；　who　asked　him　to　'repent。'　The　repetition　fared　no　better；　until　a　boy　at　Paddington　suggested　that　Slough　should　be　allowed　to　finish　the　word。　　'Kwaker'　was　understood；　and　as　soon　as　Tawell　stepped　out　on　the　platform　at　Paddington　he　was　'shadowed'　by　a　detective；　who　followed　him　into　a　New　Road　omnibus；　and　arrested　him　in　a　coffee　tavern。

Tawell　was　tried　for　the　murder　of　the　woman；　and　astounding　revelations　were　made　as　to　his　character。　　Transported　in　1820　for　the　crime　of　forgery；　he　obtained　a　ticket…of…leave；　and　started　as　a　chemist　in　Sydney；　where　he　flourished；　and　after　fifteen　years　left　it　a　rich　man。　Returning　to　England；　he　married　a　Quaker　lady　as　his　second　wife。　　He　confessed　to　the　murder　of　Sarah　Hart；　by　prussic　acid；　his　motive　being　a　dread　of　their　relations　becoming　known。

Tawell　was　executed；　and　the　notoriety　of　the　case　brought　the　telegraph　into　repute。　　Its　advantages　as　a　rapid　means　of　conveying　intelligence　and　detecting　criminals　had　been　signally　demonstrated；　and　it　was　soon　adopted　on　a　more　extensive　scale。

In　1845　Wheatstone　introduced　two　improved　forms　of　the　apparatus；　namely；　the　'single'　and　the　'double'　needle　instruments；　in　which　the　signals　were　made　by　the　successive　deflections　of　the　needles。　　Of　these；　the　single…needle　instrument；　requiring　only　one　wire；　is　still　in　use。

In　1841　a　difference　arose　between　Cooke　and　Wheatstone　as　to　the　share　of　each　in　the　honour　of　inventing　the　telegraph。　　The　question　was　submitted　to　the　arbitration　of　the　famous　engineer；　Marc　Isambard　Brunel；　on　behalf　of　Cooke；　and　Professor　Daniell；　of　King's　College；　the　inventor　of　the　Daniell　battery；　on　the　part　of　Wheatstone。　　They　awarded　to　Cooke　the　credit　of　having　introduced　the　telegraph　as　a　useful　undertaking　which　promised　to　be　of　national　importance；　and　to　Wheatstone　that　of　having　by　his　researches　prepared　the　public　to　receive　it。　　They　concluded　with　the　words：　　'It　is　to　the　united　labours　of　two　gentlemen　so　well　qualified　for　mutual　assistance　that　we　must　attribute　the　rapid　progress　which　this　important　invention　has　made　during　five　years　since　they　have　been　associated。'　The　decision；　however　vague；　pronounces　the　needle　telegraph　a　joint　production。　　If　it　was　mainly　invented　by　Wheatstone；　it　was　chiefly　introduced　by　Cooke。　Their　respective　shares　in　the　undertaking　might　be　compared　to　that　of　an　author　and　his　publisher；　but　for　the　fact　that　Cooke　himself　had　a　share　in　the　actual　work　of　invention。

In　1840　Wheatstone　had　patented　an　alphabetical　telegraph；　or；　'Wheatstone　A　B　C　instrument；'　which　moved　with　a　step…by…step　motion；　and　showed　the　letters　of　the　message　upon　a　dial。　　The　same　principle　was　utilised　in　his　type…printing　telegraph；　patented　in　1841。　　This　was　the　first　apparatus　which　printed　a　telegram　in　type。　　It　was　worked　by　two　circuits；　and　as　the　type　revolved　a　hammer；　actuated　by　the　current；　pressed　the　required　letter　on　the　paper。　　in　1840　Wheatstone　also　brought　out　his　magneto…electrical　machine　for　generating　continuous　currents；　and　his　chronoscope；　for　measuring　minute　intervals　of　time；　which　was　used　in　determining　the　speed　of　a　bullet　or　the　passage　of　a　star。　　In　this　apparatus　an　electric　current　actuated　an　electro…magnet；　which　noted　the　instant　of　an　occurrence　by　means　of　a　pencil　on　a　moving　paper。　　It　is　said　to　have　been　capable　of　distinguishing　1/7300　part　of　a　second；　and　the　time　a　body　took　to　fall　from　a　height　of　one　inch。

The　same　year　he　was　awarded　the　Royal　Medal　of　the　Royal　Society　for　his　explanation　of　binocular　vision；　a　research　which　led　him　to　construct　the　stereoscope。　　He　showed　that　our　impression　of　solidity　is　gained　by　the　combination　in　the　mind　of　two　separate　pictures　of　an　object　taken　by　both　of　our　eyes　from　different　points　of　view。　　Thus；　in　the　stereoscope；　an　arrangement　of　lenses　and　mirrors；　two　photographs　of　the　same　object　taken　from　different　points　are　so　combined　as　to　make　the　object　stand　out　with　a　solid　aspect。　　Sir　David　Brewster　improved　the　stereoscope　by　dispensing　with　the　mirrors；　and　bringing　it　into　its　existing　form。

The　'pseudoscope'　（Wheatstone　was　partial　to　exotic　forms　of　speech）　was　introduced　by　its　professor　in　1850；　and　is　in　some　sort　the　reverse　of　the　stereoscope；　since　it　causes　a　solid　object　to　seem　hollow；　and　a　nearer　one　to　be　farther　off；　thus；　a　bust　appears　to　be　a　mask；　and　a　tree　growing　outside　of　a　window　looks　as　if　it　were　growing　inside　the　room。

On　November　26；　1840；　he　exhibited　his　electro…magnetic　clock　in　the　library　of　the　Royal　Society；　and　propounded　a　plan　for　distributing　the　correct　time　from　a　standard　clock　to　a　number　of　local　timepieces。　The　circuits　of　these　were　to　be　electrified　by　a　key　or　contact…maker　actuated　by　the　arbour　of　the　standard；　and　their　hands　corrected　by　electro…magnetism。　　The　following　January　Alexander　Bain　took　out　a　patent　for　an　electro…magnetic　clock；　and　he　subsequently　charged　Wheatstone　with　appropriating　his　ideas。　　It　appears　that　Bain　worked　as　a　mechanist　to　Wheatstone　from　August　to　December；　1840；　and　he　asserted　that　he　had　communicated　the　idea　of　an　electric　clock　to　Wheatstone　during　that　period；　but　Wheatstone　maintained　that　he　had　experimented　in　that　direction　during　May。　　Bain　further　accused　Wheatstone　of　stealing　his　idea　of　the　electro…magnetic　printing　telegraph；　but　Wheatstone　showed　that　the　instrument　was　only　a　modification　of　his　own　electro…magnetic　tele