the age of invention-第32章

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says　Edison；　〃repudiated　his　contract　with　the　automatic　telegraph　people　and　they　never　received　a　cent　for　their　wires　or　patents；　and　I　lost　three　years　of　very　hard　labor。　But　I　never　had　any　grudge　against　him　because　he　was　so　able　in　his　line；　and　as　long　as　my　part　was　successful　the　money　with　me　was　a　secondary　consideration。　When　Gould　got　the　Western　Union　I　knew　no　further　progress　in　telegraphy　was　possible；　and　I　went　into　other　lines。〃*

*　Quoted　in　Dyer　and　Martin。　〃Edison〃；　vol。　1；　p。　164。


In　fact；　however；　the　need　of　money　forced　Edison　later　on　to　resume　his　work　for　the　Western　Union　Telegraph　Company；　both　in　telegraphy　and　telephony。　His　connection　with　the　telephone　is　told　in　another　volume　of　this　series。*　He　invented　a　carbon　transmitter　and　sold　it　to　the　Western　Union　for　one　hundred　thousand　dollars；　payable　in　seventeen　annual　installments　of　six　thousand　dollars。　He　made　a　similar　agreement　for　the　same　sum　offered　him　for　the　patent　of　the　electro…motograph。　He　did　not　realize　that　these　installments　were　only　simple　interest　upon　the　sums　due　him。　These　agreements　are　typical　of　Edison's　commercial　sense　in　the　early　years　of　his　career　as　an　inventor。　He　worked　only　upon　inventions　for　which　there　was　a　possible　commercial　demand　and　sold　them　for　a　trifle　to　get　the　money　to　meet　the　pay　rolls　of　his　different　shops。　Later　the　inventor　learned　wisdom　and　associated　with　himself　keen　business　men　to　their　common　profit。

*　Hendrick；　〃The　Age　of　Big　Business〃。


Edison　set　up　his　laboratories　and　factories　at　Menlo　Park；　New　Jersey；　in　1876；　and　it　was　there　that　he　invented　the　phonograph；　for　which　he　received　the　first　patent　in　1878。　It　was　there；　too；　that　he　began　that　wonderful　series　of　experiments　which　gave　to　the　world　the　incandescent　lamp。　He　had　noticed　the　growing　importance　of　open　arc　lighting；　but　was　convinced　that　his　mission　was　to　produce　an　electric　lamp　for　use　within　doors。　Forsaking　for　the　moment　his　newborn　phonograph；　Edison　applied　himself　in　earnest　to　the　problem　of　the　lamp。　His　first　search　was　for　a　durable　filament　which　would　burn　in　a　vacuum。　A　series　of　experiments　with　platinum　wire　and　with　various　refractory　metals　led　to　no　satisfactory　results。　Many　other　substances　were　tried；　even　human　hair。　Edison　concluded　that　carbon　of　some　sort　was　the　solution　rather　than　a　metal。　Almost　coincidently；　Swan；　an　Englishman；　who　had　also　been　wrestling　with　this　problem；　came　to　the　same　conclusion。　Finally；　one　day　in　October；　1879；　after　fourteen　months　of　hard　work　and　the　expenditure　of　forty　thousand　dollars；　a　carbonized　cotton　thread　sealed　in　one　of　Edison's　globes　lasted　forty　hours。　〃If　it　will　burn　forty　hours　now；〃　said　Edison；　〃I　know　I　can　make　it　burn　a　hundred。〃　And　so　he　did。　A　better　filament　was　needed。　Edison　found　it　in　carbonized　strips　of　bamboo。

Edison　developed　his　own　type　of　dynamo；　the　largest　ever　made　up　to　that　time；　and；　along　with　the　Edison　incandescent　lamps；　it　was　one　of　the　wonders　of　the　Paris　Electrical　Exposition　of　1881。　The　installation　in　Europe　and　America　of　plants　for　service　followed。　Edison's　first　great　central　station；　supplying　power　for　three　thousand　lamps；　was　erected　at　Holborn　Viaduct；　London；　in　1882；　and　in　September　of　that　year　the　Pearl　Street　Station　in　New　York　City；　the　first　central　station　in　America；　was　put　into　operation。

The　incandescent　lamp　and　the　central　power　station；　considered　together；　may　be　regarded　as　one　of　the　most　fruitful　conceptions　in　the　history　of　applied　electricity。　It　comprised　a　complete　generating；　distributing；　and　utilizing　system；　from　the　dynamo　to　the　very　lamp　at　the　fixture；　ready　for　use。　It　even　included　a　meter　to　determine　the　current　actually　consumed。　The　success　of　the　system　was　complete；　and　as　fast　as　lamps　and　generators　could　be　produced　they　were　installed　to　give　a　service　at　once　recognized　as　superior　to　any　other　form　of　lighting。　By　1885　the　Edison　lighting　system　was　commercially　developed　in　all　its　essentials；　though　still　subject　to　many　improvements　and　capable　of　great　enlargement；　and　soon　Edison。　sold　out　his　interests　in　it　and　turned　his　great　mind　to　other　inventions。

The　inventive　ingenuity　of　others　brought　in　time　better　and　more　economical　incandescent　lamps。　From　the　filaments　of　bamboo　fiber　the　next　step　was　to　filaments　of　cellulose　in　the　form　of　cotton；　duly　prepared　and　carbonized。　Later　（1905）　came　the　metalized　carbon　filament　and　finally　the　employment　of　tantalum　or　tungsten。　The　tungsten　lamps　first　made　were　very　delicate；　and　it　was　not　until　W。　D。　Coolidge；　in　the　research　laboratories　of　the　General　Electric　Company　at　Schenectady；　invented　a　process　for　producing　ductile　tungsten　that　they　became　available　for　general　use。

The　dynamo　and　the　central　power　station　brought　the　electric　motor　into　action。　The　dynamo　and　the　motor　do　precisely　opposite　things。　The　dynamo　converts　mechanical　energy　into　electric　energy。　The　motor　transforms　electric　energy　into　mechanical　energy。　But　the　two　work　in　partnership　and　without　the　dynamo　to　manufacture　the　power　the　motor　could　not　thrive。　Moreover；　the　central　station　was　needed　to　distribute　the　power　for　transportation　as　well　as　for　lighting。

The　first　motors　to　use　Edison　station　current　were　designed　by　Frank　J。　Sprague；　a　graduate　of　the　Naval　Academy；　who　had　worked　with　Edison；　as　have　many　of　the　foremost　electrical　engineers　of　America　and　Europe。　These　small　motors　possessed　several　advantages　over　the　big　steam　engine。　They　ran　smoothly　and　noiselessly　on　account　of　the　absence　of　reciprocating　parts。　They　consumed　current　only　when　in　use。　They　could　be　installed　and　connected　with　a　minimum　of　trouble　and　expense。　They　emitted　neither　smell　nor　smoke。　Edison　built　an　experimental　electric　railway　line　at　Menlo　Park　in　1880　and　proved　its　practicability。　Meanwhile；　however；　as　he　worked　on　his　motors　and　dynamos；　he　was　anticipated　by　others　in　some　of　his　inventions。　It　would　not　be　fair　to　say　that　Edison　and　Sprague　alone　developed　the　electric　railway；　for　there　were　several　others　who　made　important　contributions。　Stephen　D。　Field　of　Stockbridge；　Massachusetts；　had　a　patent　which　the　Edison　interests　found　it　necessary　to　acquire；　C。　J。　Van　Depoele　and　Leo　Daft　made　important　contributions　to　the　trolley　system。　In　Cleveland　in　1884　an　electric　railway　on　a　small　scale　was　opened　to　the　public。　But　Sprague's　first　electric　railway；　built　at　Richmond；　Virginia；　in　1887；　as　a　complete　system；　is　generally　hailed　as　the　true　pioneer　of　electric　transportation　in　the　United　States。　Thereafter　the　electric　railway　spread　quickly　over　the　land；　obliterating　the　old　horsecars　and　greatly　enlarging　the　circumference　of　the　city。　Moreover；　on　the　steam　roads；　at　all　the　great　terminals；　and　wherever　there　were　tunnels　to　be　passed　through；　the　old　giant　steam　engine　in　time　yielded　place　to　the　electric　motor。

The　application　of　the　electric　motor　to　the　〃vertical　railway；〃　or　elevator；　made　possible　the　steel　skyscraper。　The　elevator；　of　course；　is　an　old　device。　It　was　improved　and　developed　in　America　by　Elisha　Graves　Otis；　an　inventor　who　lived　and　died　before　the　Civil　War　and　whose　sons　afterward　erected　a　great　business　on　foundations　laid　by　him。　The　first　Otis　elevators　were　moved　by　steam　or　hydraulic　power。　They　were　slow；　noisy；　and　difficult　of　control。　After　the　electric　motor　came　in；　the　elevator　soon　changed　its　character　and　adapted　itself　to　the　imperative　demands　of　the　towering；　skeleton…framed　buildings　which　were　rising　in　every　city。

Edison；　already　famous　as　〃the　Wizard　of　Menlo　Park；〃　established　his　factories　and　laboratories　at　West　Orange；　New　Jersey；　in　1887；　whence　he　has　since　sent　forth　a　constant　stream　of　inventions；　some　new　and　startling；　others　improvements　on　old　devices。　The　achievements　of　several　other　inventors　in　the　electrical　field　have　been　only　less　noteworthy　than　his。　The　new　profession　of　electrical　engineering　called　to　its　service　great　numbers　of　able　men。　Manufacturers　of　electrical　machinery　established　research　departments　and　employed　inventors。　The　times　had　indeed　changed　sinc