Thenight-watchman，AlfredSwanson，tookcareofthiscuriousplant，whichconsistedofabatteryofpetroleumlampsthatwereforcedtoburntothesootingpoint。DuringhisroundsinthenightSwansonwouldfindtimetocollectfromthechimneysthesootthatthelampsgave。Itwasthenweighedoutintoverysmallportions，whichwerepressedintocakesorbuttonsbymeansofahand-press。Theselittlecakesweredelicatelypackedawaybetweenlayersofcottoninsmall，lightboxesandshippedtoBergmanninNewYork，bywhomthetelephonetransmitterswerebeingmade。AlittlelatertheEdisonelectricrailwaywasbuiltontheconfinesofthepropertyoutthroughthewoods，atfirstonlyathirdofamileinlength，butreachingultimatelytoPumptown，almostthreemilesaway。
Mr。Edison'sownwordsmaybequotedastothemenwithwhomhesurroundedhimselfhereanduponwhoseserviceshedependedprincipallyforhelpintheaccomplishmentofhisaims。InanautobiographicalarticleintheElectricalWorldofMarch5，1904，hesays：“ItisinterestingtonotethatinadditiontothosementionedaboveCharlesBatchelorandFrankUpton，Ihadaroundmeothermenwhoeversincehaveremainedactiveinthefield，suchasMessrs。FrancisJehl，WilliamJ。Hammer，MartinForce，LudwigK。Boehm，notforgettingthatgoodfriendandco-worker，thelateJohnKruesi。Theyfoundplentytodointhevariousdevelopmentsoftheart，andasInowlookbackIsometimeswonderhowwedidsomuchinsoshortatime。“Mr。Jehlinhisreminiscencesaddsanothernametotheabove——namely，thatofJohnW。Lawson，andthengoesontosay：“Thesearethenamesofthepioneersofincandescentlighting，whowerecontinuouslyatthesideofEdisondayandnightforsomeyears，andwho，underhisguidance，workeduponthecarbon-filamentlampfromitsbirthtoripematurity。Thesemenallhadcompletefaithinhisabilityandstoodbyhimasonarock，guardingtheirworkwiththesecretivenessofaburglar-proofsafe。WheneveritleakedoutintheworldthatEdisonwassucceedinginhisworkontheelectriclight，spiesandotherscametothePark；
soitwasoftheutmostimportancethattheexperimentsandtheirresultsshouldbekeptasecretuntilEdisonhadsecuredtheprotectionofthePatentOffice。“WiththisstaffwasassociatedfromthefirstMr。E。H。Johnson，whoseworkwithMr。Edisonlaychiefly，however，outsidethelaboratory，takinghimtoallpartsofthecountryandtoEurope。TherewerealsotoberegardedasdetachedmembersofittheBergmannbrothers，manufacturingforMr。EdisoninNewYork，andincessantlyexperimentingforhim。
InadditiontheremustbeincludedMr。SamuelInsull，whoseactivitiesformanyyearsasprivatesecretaryandfinancialmanagerweredevotedsolelytoMr。
Edison'sinterests，withMenloParkasacentreandmainsourceofanxietyastopay-rollsandotherconstantlyrecurringobligations。Thenamesofyetotherassociatesoccurfromtimetotimeinthisnarrative——“Edisonmen“whohavebeenveryproudoftheircloserelationshiptotheinventorandhisworkatoldMenlo。“TherewasalsoMr。CharlesL。
Clarke，whodevotedhimselfmainlytoengineeringmatters，andlateronactedaschiefengineeroftheEdisonElectricLightCompanyforsomeyears。
ThentherewereWilliamHolzerandJamesHipple，bothofwhomtookanactivepartinthepracticaldevelopmentoftheglass-blowingdepartmentofthelaboratory，and，subsequently，atthefirstEdisonlampfactoryatMenloPark。LateronMessrs。Jehl，Hipple，andForceassistedMr。Batchelortoinstallthelamp-worksoftheFrenchEdisonCompanyatIvry-sur-Seine。ThentherewereMessrs。CharlesT。
Hughes，SamuelD。Mott，andCharlesT。Mott，whodevotedtheirtimechieflytocommercialaffairs。Mr。
Hughesconductedmostofthiswork，andlaterontookaprominentpartinEdison'selectric-railwayexperiments。Hisbusinessabilitywasonahighlevel，whilehispersonalcharacterendearedhimtousall。
Amongothernowwell-knownmenwhocametousandassistedinvariouskindsofworkwereMessrs。
Acheson，Worth，Crosby，Herrick，andHill，whileDoctorHaidwasplacedbyMr。Edisoninchargeofaspecialchemicallaboratory。Dr。E。L。Nicholswasalsowithusforashorttimeconductingaspecialseriesofexperiments。TherewasalsoMr。Isaacs，whodidagreatdealofphotographicwork，andtowhomwemustbethankfulforthepicturesofMenloParkinconnectionwithEdison'swork。
“AmongotherswhowereaddedtoMr。Kruesi'sstaffinthemachine-shopwereMessrs。J。H。VailandW。S。Andrews。Mr。Vailhadchargeofthedynamo-
room。Hehadagoodgeneralknowledgeofmachinery，andverysoonacquiredsuchfamiliaritywiththedynamosthathecouldskipaboutamongthemwithastonishingagilitytoregulatetheirbrushesortothrowrosinonthebeltswhentheybegantosqueal。
LateronhetookanactivepartintheaffairsandinstallationsoftheEdisonLightCompany。Mr。
AndrewsstayedonMr。Kruesi'sstaffaslongasthelaboratorymachine-shopwaskeptopen，afterwhichhewentintotheemployoftheEdisonElectricLightCompanyandbecameactivelyengagedinthecommercialandtechnicalexploitationofthesystem。
AnothermanwhowaswithusatMenloParkwasMr。
HermanClaudius，anAustrian，whoatonetimewasemployedinconnectionwiththeStateTelegraphsofhiscountry。TohimMr。EdisonassignedthetaskofmakingacompletemodelofthenetworkofconductorsforthecontemplatedfirststationinNewYork。“
Mr。FrancisR。Upton，whowasearlyemployedbyMr。Edisonashismathematician，furnishesapleasant，vividpictureofhischiefassociatesengagedonthememorableworkatMenloPark。Hesays：“Mr。
CharlesBatchelorwasMr。Edison'sprincipalassistantatthattime。HewasanEnglishman，andcametothiscountrytosetupthethread-weavingmachineryfortheClarkthread-works。Hewasamostintelligent，patient，competent，andloyalassistanttoMr。Edison。Irememberdistinctlyseeinghimworkmanyhourstomountasmallfilament；andhishandwouldbeassteadyandhispatienceasunyieldingattheendofthosemanyhoursasitwasatthebeginning，inspiteofrepeatedfailures。Hewasawonderfulmechanic；thecontrolthathehadofhisfingerswasmarvellous，andhiseyesightwassharp。Mr。
Batchelor'sjudgmentandgoodsensewerealwaysinevidence。
“Mr。Kruesiwasthesuperintendent，aSwisstrainedinthebestSwissideasofaccuracy。Hewasasplendidmechanicwithavigoroustemper，andwonderfulabilitytoworkcontinuouslyandtogetworkoutofmen。Itwasanidealcombination，thatofEdison，Batchelor，andKruesi。Mr。Edisonwithhiswonderfulflowofideaswhichweresharplydefinedinhismind，ascanbeseenbyanyofthesketchesthathemade，asheevidentlyalwaysthinksinthreedimensions；
Mr。Kruesi，willingtotaketheideas，andcapableofcomprehendingthem，woulddistributetheworksoastogetitdonewithmarvellousquicknessandgreataccuracy。Mr。Batchelorwasalwaysreadyforanyspecialfineexperimentingorobserva-
tion，andcouldholdtowhateverhewasataslongasMr。Edisonwished；andalwaysbroughttobearonwhathewasatthegreatestskill。“
WhileEdisondependeduponUptonforhismathematicalwork，hewaswonttocheckitupinaverypracticalmanner，asevidencedbythefollowingincidentdescribedbyMr。Jehl：“IwasoncewithMr。
Uptoncalculatingsometableswhichhehadputmeon，whenMr。Edisonappearedwithaglassbulbhavingapear-shapedappearanceinhishand。Itwasthekindthatweweregoingtouseforourlampexperiments；andMr。EdisonaskedMr。Uptontopleasecalculateforhimitscubiccontentsincentimetres。
NowMr。Uptonwasaveryablemathematician，who，afterhefinishedhisstudiesatPrinceton，wenttoGermanyandgothisfinalglossunderthatgreatmaster，Helmholtz。Whateverhedidandworkedonwasexecutedinapuremathematicalmanner，andanywrangleratOxfordwouldhavebeendelightedtoseehimjugglewithintegralanddifferentialequations，withadexteritythatwassurprising。
Hedrewtheshapeofthebulbexactlyonpaper，andgottheequationofitslineswithwhichhewasgoingtocalculateitscontents，whenMr。Edisonagainappearedandaskedhimwhatitwas。HeshowedEdisontheworkhehadalreadydoneonthesubject，andtoldhimthathewouldverysoonfinishcalculatingit。`Why，'saidEdison，`Iwouldsimplytakethatbulbandfillitwithmercuryandweighit；andfromtheweightofthemercuryanditsspecificgravityI'llgetitinfiveminutes，anduselessmentalenergythanisnecessaryinsuchafatiguingoperation。'“
MenloParkbecameultimatelythecentreofEdison'sbusinesslifeasitwasofhisinventing。Aftertheshortdistastefulperiodduringtheintroductionofhislightingsystem，whenhespentalargepartofhistimeattheofficesat65FifthAvenue，NewYork，orontheactualworkconnectedwiththeNewYorkEdisoninstallation，hesettledbackagaininMenloParkaltogether。Mr。SamuelInsulldescribesthebusinessmethodswhichprevailedthroughouttheearlierMenloParkdaysof“stormandstress，“andthecuriousconditionswithwhichhehadtodealasprivatesecretary：“IneverattemptedtosystematizeEdison'sbusinesslife。Edison'swholemethodofworkwouldupsetthesystemofanyoffice。Hewasjustaslikelytobeatworkinhislaboratoryatmidnightasmidday。Hecarednotforthehoursofthedayorthedaysoftheweek。Ifhewasexhaustedhemightmorelikelybeasleepinthemiddleofthedaythaninthemiddleofthenight，asmostofhisworkinthewayofinventionswasdoneatnight。I
usedtorunhisofficeonasclosebusinessmethodsasmyexperienceadmitted；andIwouldgetathimwheneveritsuitedhisconvenience。Sometimeshewouldnotgooverhismailfordaysatatime；butothertimeshewouldgoregularlytohisofficeinthemorning。AtothertimesmyengagementsusedtobewithhimtogooverhisbusinessaffairsatMenloParkatnight，ifIwasoccupiedinNewYorkduringtheday。Infact，asamatterofconvenienceIusedmoreoftentogetathimatnight，asitleftmydaysfreetotransacthisaffairs，andenabledme，probablyatamidnightluncheon，togetafewminutesofhistimetolookoverhiscorrespondenceandgethisdirectionsastowhatIshoulddoinsomeparticularnegotiationormatteroffinance。WhileitwasamatterofsuitingEdison'sconvenienceastowhenI
shouldtransactbusinesswithhim，italsosuitedmyownideas，asitenabledmeaftergettingthroughmybusinesswithhimtoenjoytheprivilegeofwatchinghimathiswork，andtolearnsomethingaboutthetechnicalsideofmatters。WhateverknowledgeI
mayhaveoftheelectriclightandpowerindustryI
feelIoweittothetuitionofEdison。Hewasaboutthemostwillingtutor，andImustconfessthathehadtobeapatientone。“
Hereagainoccursthereferencetotheincessantnight-workatMenloPark，anotethatisstruckineveryreminiscenceandineveryrecordofthetime。
ButitisnottobeinferredthattheatmosphereofgrimdeterminationandpersistentpursuitofthenewinventioncharacteristicofthisperiodmadelifeaburdentothesmallfamilyoflaborersassociatedwithEdison。Manyatimeduringthelong，wearynightsofexperimentingEdisonwouldcallahaltforrefreshments，whichhehadorderedalwaystobesentinwhennight-workwasinprogress。Everythingwouldbedropped，allpresentwouldjoininthemeal，andthelastgoodstoryorjokewouldpassaround。
InhisnotesMr。Jehlsays：“Ourlunchalwaysendedwithacigar，andImaymentionherethatalthoughEdisonwasneverfastidiousineating，healwaysrelishedagoodcigar，andseemedtofindinitconsolationandsolace……Itoftenhappenedthatwhilewewereenjoyingthecigarsafterourmidnightre-
past，oneoftheboyswouldstartupatuneontheorganandwewouldallsingtogether，oroneoftheotherswouldgiveasolo。Anotheroftheboyshadavoicethatsoundedlikesomethingbetweentheringofanoldtomatocanandapewterjug。Hehadonesongthathewouldsingwhileweroaredwithlaughter。
Hewasalsogreatinimitatingthetin-foilphonograph……WhenBoehmwasingood-humorhewouldplayhiszithernowandthen，andamuseusbysingingprettyGermansongs。Onmanyoftheseoccasionsthelaboratorywastherendezvousofjollyandconvivialvisitors，mostlyoldfriendsandacquaintancesofMr。Edison。Someoftheofficeemployeeswouldalsodropinonceinawhile，andaseverybodypresentwasalwayswelcometopartakeofthemidnightmeal，weallenjoyedthesegatherings。Afterawhile，whenwewerereadytoresumework，ourvisitorswouldintimatethattheyweregoinghometobed，butwefellowscouldstayupandwork，andtheywoulddepart，generallysingingsomesonglikeGood-night，ladies！……ItoftenhappenedthatwhenEdisonhadbeenworkinguptothreeorfouro'clockinthemorning，hewouldliedownononeofthelaboratorytables，andwithnothingbutacoupleofbooksforapillow，wouldfallintoasoundsleep。
Hesaiditdidhimmoregoodthanbeinginasoftbed，whichspoilsaman。Someofthelaboratoryassistantscouldbeseennowandthensleepingonatableintheearlymorninghours。Iftheirsnoringbecameobjectionabletothosestillatwork，the`calmer'wasapplied。ThismachineconsistedofaBabbitt'ssoapboxwithoutacover。Uponitwasmountedabroadratchet-wheelwithacrank，whileintotheteethofthewheelthereplayedastout，elasticslabofwood。Theboxwouldbeplacedonthetablewherethesnorerwassleepingandthecrankturnedrapidly。Theracketthusproducedwassomethingterrible，andthesleeperwouldjumpupasthoughatyphoonhadstruckthelaboratory。Theirrepressiblespiritofhumorintheolddays，althoughsomewhatstrenuousattimes，causedmanyamomentofhilaritywhichseemedtorefreshtheboys，andenabledthemtoworkwithrenewedvigorafteritsmanifestation。“Mr。Uptonremarksthatoftenduringtheperiodoftheinventionoftheincandescentlamp，whenundergreatstrainandfatigue，Edisonwouldgototheorganandplaytunesinaprimitiveway，andcomebacktocrackjokeswiththestaff。
“ButIhaveoftenfeltthatMr。Edisonnevercouldcomprehendthelimitationsofthestrengthofothermen，ashisownphysicalandmentalstrengthhavealwaysseemedtobewithoutlimit。Hecouldworkcontinuouslyaslongashewished，andhadsleepathiscommand。Hissleepwasalwaysinstant，profound，andrestful。Hehastoldmethatheneverdreamed。IhaveknownMr。Edisonnowforthirty-oneyears，andfeelthathehasalwayskepthisminddirectandsimple，goingstraighttotherootoftroubles。
OneofthepeculiaritiesIhavenoticedisthatIhaveneverknownhimtobreakintoaconversationgoingonaroundhim，andaskwhatpeopleweretalkingabout。Thenearesthewouldevercometoitwaswhentherehadevidentlybeensomestorytold，andhisfacewouldexpressadesiretojoininthelaugh，whichwouldimmediatelyinvitetellingthestorytohim。“
NexttothosewhoworkedwithEdisonatthelaboratoryandwerewithhimconstantlyatMenloParkwerethevisitors，someofwhomwerehisbusinessassociates，someofthemscientificmen，andsomeofthemhero-worshippersandcuriosity-hunters。ForemostinthefirstcategorywasMr。E。H。Johnson，whowasinrealityEdison'smostintimatefriend，andwasrequiredforconstantconsultation；butwhoseintenseactivity，remarkablegraspofelectricalprinciples，andunusualpowersofexposition，ledtohisfrequentdetachmentforlongtrips，includingthosewhichresultedintheintroductionofthetelephone，phonograph，andelectriclightinEnglandandontheContinent。AlessfrequentvisitorwasMr。S。
Bergmann，whohadallheneededtooccupyhistimeinexperimentingandmanufacturing，andwhosecontemporaneousWoosterStreetletter-headsadvertisedEdison'sinventionsasbeingmadethere，AmongthescientistswereProf。GeorgeF。Barker，ofPhiladelphia，abig，good-naturedphilosopher，whosevaluableadviceEdisonesteemedhighly。Insharpcontrasttohimwastheearnest，seriousRowland，ofJohnsHopkinsUniversity，afterwardtheleadingAmericanphysicistofhisday。Profs。C。F。BrackettandC。F。Young，ofPrincetonUniversity，wereoftenreceived，alwaysinterestedinwhatEdisonwasdoing，andproudthatoneoftheirownstudents，Mr。Upton，wastakingsuchaprominentpartinthedevelopmentofthework。
SoonafterthesuccessofthelightingexperimentsandtheinstallationatMenloParkbecameknown，Edisonwasbesiegedbypersonsfromallpartsoftheworldanxioustosecurerightsandconcessionsfortheirrespectivecountries。AmongthesewasMr。
LouisRau，ofParis，whoorganizedtheFrenchEdisonCompany，thepioneerEdisonlightingcorporationinEurope，andwho，withtheaidofMr。Batchelor，establishedlamp-worksandamachine-shopatIvrysur-Seine，nearParis，in1882。ItwastherethatMr。
NikolaTeslamadehisentreeintothefieldoflightandpower，andbeganhisowncareerasaninventor；
andtherealsoMr。EtienneFodor，generalmanageroftheHungarianGeneralElectricCompanyatBudapest，receivedhisearlytraining。ItwashewhoerectedatAthensthefirstEuropeanEdisonstationonthenowuniversalthree-wiresystem。AnothervisitorfromEurope，alittlelater，wasMr。EmilRathenau，thepresentdirectorofthegreatAllgemeineElektricitaetsGesellschaftofGermany。Hesecuredtherightsfortheempire，andorganizedtheBerlinEdisonsystem，nowoneofthelargestintheworld。Throughhisextraordinaryenergyandenterprisethebusinessmadeenormousstrides，andMr。
Rathenauhasbecomeoneofthemostconspicuousindustrialfiguresinhisnativecountry。FromItalycameProfessorColombo，lateracabinetminister，withhisfriendSignorBuzzi，ofMilan。Therightsweresecuredforthepeninsula；ColomboandhisfriendsorganizedtheItalianEdisonCompany，anderectedatMilanthefirstcentralstationinthatcountry。Mr。JohnW。Lieb，Jr。，nowavice-presidentoftheNewYorkEdisonCompany，wassentoverbyMr。Edisontosteertheenterprisetechnically，andspenttenyearsinbuildingitup，withsuchbrilliantsuccessthathewaslaterdecoratedasCommanderoftheOrderoftheCrownofItalybyKingVictor。AnotheryoungAmericanenlistedintoEuropeanservicewasMr。E。G。Acheson，theinventorofcarborundum，whobuiltanumberofplantsinItalyandFrancebeforehereturnedhome。Mr。LiebhassincebecomePresidentoftheAmericanInstituteofElectricalEngineersandtheAssociationofEdisonIlluminatingCompanies，whileDoctorAchesonhasbeenPresidentoftheAmericanElectrochemicalSociety。
SwitzerlandsentMessrs。Turrettini，Biedermann，andThury，alldistinguishedengineers，tonegotiateforrightsintherepublic；andsoitwentwithregardtoalltheothercountriesofEurope，aswellasthoseofSouthAmerica。ItwasaquestionofkeepingsuchvisitorsawayratherthanofinvitingthemtotakeuptheexploitationoftheEdisonsystem；forwhattimewasnotspentinpersonalinterviewswasrequiredforthemassesoflettersfromeverycountryunderthesun，allmakinginquiries，offeringsuggestions，proposingterms。Norwerethevisitorsmerelythoseonbusinessbent。Therewerethelion-huntersandcelebrities，ofwhomSarahBernhardtmayserveasatype。OnevisitofnotewasthatpaidbyLieut。
G。W。DeLong，whohadanearnestandprotractedconversationwithEdisonovertheArcticexpeditionhewasundertakingwiththeaidofMr。JamesGordonBennett，oftheNewYorkHerald。TheJeannettewasbeingfittedout，andEdisontoldDeLongthathewouldmakeandpresenthimwithasmalldynamomachine，someincandescentlamps，andanarclamp。
Whilethelittledynamowasbeingbuiltallthemeninthelaboratorywrotetheirnamesonthepaperinsulationthatwaswoundupontheironcoreofthearmature。AstheJeannettehadnosteam-engineonboardthatcouldbeusedforthepurpose，EdisondesignedthedynamosothatitcouldbeworkedbymanpowerandtoldLieutenantDeLong“itwouldkeeptheboyswarmupintheArctic，“whentheygeneratedcurrentwithit。Theill-fatedshipneverreturnedfromhervoyage，butwentdownintheicywatersoftheNorth，theretoremainuntilsomefuturecataclysmofnature，tenthousandyearshence，shallrevealtheshipandthefirstmarinedynamoascuriousrelicsofaremotecivilization。
EdisonalsofurnishedDeLongwithasetoftelephonesprovidedwithextensiblecircuits，sothatpartiesontheice-floescouldgolongdistancesfromtheshipandstillkeepincommunicationwithher。
Sofarasthewriterscanascertainthisisthefirstexampleof“fieldtelephony。“Anothernauticalexperimentthathemadeatthistime，suggestedprobablybytherequirementsoftheArcticexpedition，wasabuoythatwasfloatedinNewYorkharbor，andwhichcontainedasmallEdisondynamoandtwoorthreeincandescentlamps。Thedynamowasdrivenbythewaveortidemotionthroughintermediatemechanism，andthusthelampswerelitupfromtimetotime，servingassignals。Theseweretheprototypesofthelightedbuoyswhichhavesincebecomefamiliar，asinthechanneloffSandyHook。
OnenotableafternoonwasthatonwhichtheNewYorkboardofaldermentookaspecialtrainouttoMenloParktoseethelightingsystemwithitsconductorsundergroundinoperation。TheEdisonElectricIlluminatingCompanywasapplyingforafranchise，andthealdermen，forlackofscientifictrainingandspecificpracticalinformation，wereveryscepticalonthesubject——asindeedtheymightwellbe。“Mr。
Edisondemonstratedpersonallythedetailsandmeritsofthesystemtothem。Thevoltagewasincreasedtoahigherpressurethanusual，andalltheincandescentlampsatMenloParkdidtheirbesttowintheapprobationoftheNewYorkCityfathers。
AfterEdisonhadfinishedexhibitingallthegoodpointsofhissystem，heconductedhisguestsupstairsinthelaboratory，wherealongtablewasspreadwiththebestthingsthatoneofthemostprominentNewYorkcatererscouldfurnish。Thelaboratorywitnessedhightimesthatnight，forallwereinthebestofhumor，andmanyabottlewasdrainedintoastingthehealthofEdisonandthealdermen。“ThiswasoneoftheextremelyrareoccasionsonwhichEdisonhasaddressedanaudience；
butthestakewasworththeeffort。TherepresentativesofNewYorkcouldwithjusticedrinkthehealthoftheyounginventor，whosesystemisoneofthegreatestboonsthecityhaseverhadconferreduponit。
AmongotherfrequentvisitorswasMr，Edison'sfather，“oneofthoseamiable，patriarchalcharacterswithaHoraceGreeleybeard，typicalAmericansoftheoldschool，“whowouldsometimescomeintothelaboratorywithhistwograndchildren，alittleboyandgirlcalled“Dash“and“Dot。“Hepreferredtositandwatchhisbrilliantsonatwork“withanexpressionofsatisfactiononhisfacethatindicatedasenseofhappinessandcontentthathisboy，borninthatdistant，humblehomeinOhio，hadrisentofameandbroughtsuchhonoruponthename。Itwas，indeed，apatheticsighttoseeafatherveneratehissonastheelderEdisondid。“NotlessathomewasMr。Mackenzie，theMt。Clemensstationagent，thelifeofwhosechildEdisonhadsavedwhenatrainnewsboy。TheoldScotchmanwasoneoftheinnocent，charteredlibertinesoftheplace，withanunlimitedstockofgoodjokesandstories，butseldomofanypracticaluse。Ononeoccasion，however，wheneverythingpossibleandimpossibleunderthesunwasbeingcarbonizedforlampfilaments，heallowedahandfulofhisbushyredbeardtobetakenforthepurpose；andhislaughwastheloudestwhentheEdison-Mackenziehairlampswerebroughtuptoincandescence——theirrichnessinredraysbeingslylyattributedtothenatureofthefilamentarymaterial！
Oddlyenough，afewyearslater，someinventoractuallytookoutapatentformakingincandescentlampswithcarbonizedhairforfilaments！
Yetothervisitorsagainhauntedtheplace，andwiththefollowingreminiscenceofoneofthem，fromMr。Edisonhimself，thispartofthechaptermustclose：“AtMenloParkonecoldwinternighttherecameintothelaboratoryastrangemaninamostpitifulcondition。Hewasnearlyfrozen，andheaskedifhemightsitbythestove。Inafewmomentsheaskedfortheheadman，andIwasbroughtforward。
Hehadaheadofabnormalsize，withhighlyintellectualfeaturesandaverysmallandemaciatedbody。
Hesaidhewassufferingverymuch，andaskedifI
hadanymorphine。AsIhadabouteverythinginchemistrythatcouldbebought，ItoldhimIhad。
HerequestedthatIgivehimsome，soIgotthemorphinesulphate。Hepouredoutenoughtokilltwomen，whenItoldhimthatwedidn'tkeepahotelforsuicides，andhehadbettercutthequantitydown。
Hethenbaredhislegsandarms，andtheywereliterallypittedwithscars，duetotheuseofhypodermicsyringes。Hesaidhehadtakenitforyears，anditrequiredabigdosetohaveanyeffect。Ilethimgoahead。Inashortwhileheseemedlikeanothermanandbegantotellstories，andtherewereaboutfiftyofuswhosataroundlisteninguntilmorning。Hewasamanofgreatintelligenceandeducation。HesaidhewasaJew，buttherewasnodistinctivefeaturetoverifythisassertion。HecontinuedtostayarounduntilhefinishedeverycombinationofmorphinewithanacidthatIhad，probablytenouncesalltold。
Thenheaskedifhecouldhavestrychnine。Ihadanounceofthesulphate。Hetookenoughtokillahorse，andassertedithadasgoodaneffectasmorphine。Whenthiswasgone，theonlythingIhadleftwasachunkofcrudeopium，perhapstwoorthreepounds。Hechewedthisupanddisappeared。
Iwasgreatlydisappointed，becauseIwouldhavelaidinanotherstockofmorphinetokeephimatthelaboratory。AboutaweekafterwardhewasfounddeadinabarnatPerthAmboy。“
Returningtotheworkitself，noteofwhichhasal-
readybeenmadeinthisandprecedingchapters，wefindaninterestinganduniquereminiscenceinMr。
Jehl'snotesofthereversiontocarbonasafilamentinthelamps，followinganexhibitionofmetallic-
filamentlampsgiveninthespringof1879tothemeninthesyndicateadvancingthefundsfortheseexperiments：“TheycametoMenloParkonalateafternoontrainfromNewYork。Itwasalreadydarkwhentheywereconductedintothemachine-
shop，wherewehadseveralplatinumlampsinstalledinseries。WhenEdisonhadfinishedexplainingtheprinciplesanddetailsofthelamp，heaskedKruesitoletthedynamomachinerun。ItwasoftheGrammetype，asourfirstdynamooftheEdisondesignwasnotyetfinished。Edisonthenorderedthe`juice'
tobeturnedonslowly。To-dayIcanseethoselampsrisingtoacherryred，likeglowbugs，andhearMr。
Edisonsaying`alittlemorejuice，'andthelampsbegantoglow。`Alittlemore'isthecommandagain，andthenoneofthelampsemitsforaninstantalightlikeastarinthedistance，afterwhichthereisaneruptionandapuff；andthemachine-shopisintotaldarkness。Weknewinstantlywhichlamphadfailed，andBatchelorreplacedthatbyagoodone，havingafewinreservenearby。Theoperationwasrepeatedtwoorthreetimeswithaboutthesameresults，afterwhichthepartywentintothelibraryuntilitwastimetocatchthetrainforNewYork。“
Suchanexhibitionwasdecidedlydiscouraging，anditwasnotajubilantpartythatreturnedtoNewYork，but：“ThatnightEdisonremainedinthelaboratorymeditatingupontheresultsthattheplatinumlamphadgivensofar。Iwasengagedreadingabooknearatableinthefront，whileEdisonwasseatedinachairbyatableneartheorgan。Withhisheadturneddownward，andthatconspicuouslockofhairhanginglooselyononeside，helookedlikeNapoleoninthecelebratedpicture，OntheEveofaGreatBattle。Thosedayswereheroicones，forhethenbattledagainstmightyodds，andtheprospectsweredimandnotveryencouraging。IncasesofemergencyEdisonalwayspossessedakeenfacultyofdecidingimmediatelyandcorrectlywhattodo；
andthedecisionhethenarrivedatwaspredestinedtobetheturning-pointthatledhimontoultimatesuccess……Afterthatexhibitionwehadahouse-
cleaningatthelaboratory，andthemetallic-filamentlampswerestoredaway，whilepreparationsweremadeforourexperimentsoncarbonlamps。“
Thustheworkwenton。MenloParkhashithertobeenassociatedinthepublicthoughtwiththetelephone，phonograph，andincandescentlamp；butitwasthere，equally，thattheEdisondynamoandsystemofdistributionwerecreatedandappliedtotheirspecificpurposes。Whileallthisstudyofapossiblelampwasgoingon，Mr。Uptonwasbusycalculatingtheeconomyofthe“multiplearc“system，andmakingagreatmanytablestodeterminewhatresistancealampshouldhaveforthebestresults，andatwhatpointtheproposedgeneralsystemwouldfalloffineconomywhenthelampswereofthelowerresistancethatwasthengenerallyassumedtobenecessary。Theworldatthattimehadnottheshadowofanideaastowhattheprinciplesofamultiplearcsystemshouldbe，enablingmillionsoflampstobelightedoffdistributingcircuits，eachlampindependentofeveryother；butatMenloParkatthatremoteperiodintheseventiesMr。Edison'smathematicianwasformulatingtheinventor'sconceptioninclear，instructivefigures；“andtheworkthenexecutedhashelditsowneversince。“Fromthebeginningofhisexperimentsonelectriclight，Mr。Edisonhadawell-definedideaofproducingnotonlyapracticablelamp，butalsoaSYSTEMofcommercialelectriclighting。Suchaschemeinvolvedthecreationofanentirelynewart，fortherewasnothingonthefaceoftheearthfromwhichtodrawassistanceorprecedent，unlessweexcepttheelementaryformsofdynamostheninexistence。Itistrue，therewereseveraltypesofmachinesinuseforthethenverylimitedfieldofarclighting，buttheywereregardedasvaluelessasapartofagreatcomprehensiveschemewhichcouldsupplyeverybodywithlight。Suchmachineswereconfessedlyinefficient，althoughrepresentingthefarthestreachofayoungart。A
commissionappointedatthattimebytheFranklinInstitute，andincludingProf。ElihuThomson，investigatedthemeritsofexistingdynamosandreportedastothebestofthem：“TheGrammemachineisthemosteconomicalasameansofconvertingmotiveforceintoelectricity；itutilizesinthearcfrom38to41percent。ofthemotiveworkproduced，afterdeductionismadeforfrictionandtheresistanceoftheair。“TheyreportedalsothattheBrusharclightingmachine“producesintheluminousarcusefulworkequivalentto31percent。ofthemotivepoweremployed，orto381/2percent。afterthefrictionhasbeendeducted。“Commercialpossibilitiescouldnotexistinthefaceofsuchloweconomyasthis，andMr。Edisonrealizedthathewouldhavetoimprovethedynamohimselfifhewantedabettermachine。
Thescientificworldatthattimewasengagedinacontroversyregardingtheexternalandinternalresistanceofacircuitinwhichageneratorwassituated。
DiscussingthesubjectMr。Jehl，inhisbiographicalnotes，says：“Whilethiscontroversyragedinthescientificpapers，andcriticismandconfusionseemedatitsheight，EdisonandUptondiscussedthisquestionverythoroughly，andEdisondeclaredhedidnotintendtobuildupasystemofdistributioninwhichtheexternalresistancewouldbeequaltotheinternalresistance。Hesaidhewasjustaboutgoingtodotheopposite；hewantedalargeexternalresistanceandalowinternalone。Hesaidhewantedtoselltheenergyoutsideofthestationandnotwasteitinthedynamoandconductors，whereitbroughtnoprofits……Intheselaterdays，whentheseideasofEdisonareusedascommonproperty，andareappliedineverymodernsystemofdistribution，itisastonishingtorememberthatwhentheywerepropoundedtheymetwithmostvehementantagonismfromtheworldatlarge。“Edison，familiarwithbatteriesintelegraphy，couldnotbringhimselftobelievethatanysubstitutegeneratorofelectricalenergycouldbeefficientthatuseduphalfitsownpossibleoutputbeforedoinganequalamountofoutsidework。
Undauntedbythedictaofcontemporaneousscience，Mr。Edisonattackedthedynamoproblemwithhisaccustomedvigorandthoroughness。Hechosethedrumformforhisarmature，andexperimentedwithdifferentkindsofiron。Coresweremadeofcastiron，othersofforgediron；andstillothersofsheetsofironofvariousthicknessesseparatedfromeachotherbypaperorpaint。Thesecoreswerethenallowedtoruninanexcitedfield，andafteragiventimetheirtemperaturewasmeasuredandnoted。
BysuchpracticalmethodsEdisonfoundthatthethin，laminatedcoresofsheetirongavetheleastheat，andhadtheleastamountofwastefuleddycurrents。Hisexperimentsandideasonmagnetismatthatperiodwerefarinadvanceofthetime。HisworkandtestsregardingmagnetismwererepeatedlateronbyHopkinsonandKapp，whothenelucidatedthewholetheorymathematicallybymeansofformulaeandconstants。Beforethis，however，Edisonhadattainedtheseresultsbypioneerwork，foundedonhisoriginalreasoning，andutilizedthemintheconstructionofhisdynamo，thusrevolutionizingtheartofbuildingsuchmachines。
Afterthoroughinvestigationofthemagneticqualitiesofdifferentkindsofiron，Edisonbegantomakeastudyofwindingthecores，firstdeterminingtheelectromotiveforcegeneratedperturnofwireatvariousspeedsinfieldsofdifferentintensities。Healsoconsideredvariousformsandshapesforthearmature，andbymethodicalandsystematicresearchobtainedthedataandbestconditionsuponwhichhecouldbuildhisgenerator。Inthefieldmagnetsofhisdynamoheconstructedthecoresandyokeofforgedironhavingaverylargecross-section，whichwasanewthinginthosedays。Greatattentionwasalsopaidtoallthejoints，whichweresmootheddownsoastomakeaperfectmagneticcontact。TheEdisondynamo，withitslargemassesofiron，wasavividcontrasttothethenexistingtypeswiththeirmeagrequantitiesoftheferricelement。Edisonalsomadetestsonhisfieldmagnetsbyslowlyraisingthestrengthoftheexcitingcurrent，sothatheobtainedfiguressimilartothoseshownbyamagneticcurve，andinthiswayfoundwheresaturationcommenced，andwhereitwasuselesstoexpendmorecurrentonthefield。IfhehadaskedUptonatthetimetoformulatetheresultsofhisworkinthisdirection，forpublication，hewouldhaveanticipatedthehistoricworkonmagnetismthatwasexecutedbythetwootherinvestigators；HopkinsonandKapp，lateron。
Thelaboratorynote-booksoftheperiodbearabundantevidenceofthesystematicandsearchingnatureoftheseexperimentsandinvestigations，inthehundredsofpagesofnotes，sketches，calculations，andtablesmadeatthetimebyEdison，Upton，Batchelor，Jehl，andbyotherswhofromtimetotimewereintrustedwithspecialexperimentstoelucidatesomeparticularpoint。Mr。Jehlsays：“Theexperimentsonarmature-windingwerealsoveryinteresting。
Edisonhadanumberofsmallwoodencoresmade，atbothendsofwhichweinsertedlittlebrassnails，andwewoundthewoodencoreswithtwineasifitwerewireonanarmature。Inthiswaywestudiedarmature-winding，andhadmatcheswhereeachofushadacore，whilebetsweremadeastowhowouldbethefirsttofinishproperlyandcorrectlyacertainkindofwinding。Carehadtobetakenthatthewoundcorecorrespondedtothedirectionofthecurrent，supposingitwereplacedinafieldandrevolved。
AfterEdisonhaddecidedthisquestion，Uptonmadedrawingsandtablesfromwhichtherealarmatureswerewoundandconnectedtothecommutator。Toastudentofto-dayallthisseemssimple，butinthosedaystheartofconstructingdynamoswasaboutasdarkasairnavigationisatpresent……Edisonalsoimprovedthearmaturebydividingitandthecommutatorintoafargreaternumberofsectionsthanuptothattimehadbeenthepractice。Hewasalsothefirsttousemicaininsulatingthecommutatorsectionsfromeachother。“
Inthemeantime，duringtheprogressoftheinvestigationsonthedynamo，wordhadgoneouttotheworldthatEdisonexpectedtoinventageneratorofgreaterefficiencythananythatexistedatthetime。Againhewasassailedandridiculedbythetechnicalpress，forhadnottheforemostelectriciansandphysicistsofEuropeandAmericaworkedforyearsontheproductionofdynamosandarclampsastheythenexisted？EventhoughthisyoungmanatMenloParkhaddonesomewonderfulthingsfortelegraphyandtelephony；evenifhehadrecordedandreproducedhumanspeech，hehadhislimitations，andcouldnotupsetthesettleddictumofsciencethattheinternalresistancemustequaltheexternalresistance。
Suchwasthetrendofpublicopinionatthetime，but“afterMr。Kruesihadfinishedthefirstpracticaldynamo，andafterMr。Uptonhadtesteditthoroughlyandverifiedhisfiguresandresultsseveraltimes——
forhealsowassurprised——Edisonwasabletotelltheworldthathehadmadeageneratorgivinganefficiencyof90percent。“Ninetypercent。asagainst40percent。wasamightyhit，andtheworldwouldnotbelieveit。Criticismandargumentwereagainattheirheight，whileUpton，asEdison'sduellist，waskeptbusyreplyingtoprivateandpublicchallengesofthefact……“Thetremendousprogressoftheworldinthelastquarterofacentury，owingtotherevolutioncausedbytheall-conqueringmarchof`HeavyCurrentEngineering，'istheoutcomeofEdison'sworkatMenloParkthatraisedtheefficiencyofthedynamofrom40percent。to90percent。“
Mr。Uptonsumsitallupverypreciselyinhisremarksuponthisperiod：“Whathasnowbeenmadeclearbyaccuratenomenclaturewasthenveryfoggyinthetext-books。Mr。Edisonhadcompletelygraspedtheeffectofsubdivisionofcircuits，andtheinfluenceofwiresleadingtosuchsubdivisions，whenitwasmostdifficulttoexpresswhatheknewintechnicallanguage。IrememberdistinctlywhenMr。
Edisongavemetheproblemofplacingamotorincircuitinmultiplearcwithafixedresistance；andI
hadtoworkouttheproblementirely，asIcouldfindnopriorsolution。TherewasnothingIcouldfindbearinguponthecounterelectromotiveforceofthearmature，andtheeffectoftheresistanceofthearmatureontheworkgivenoutbythearmature。
Itwasawonderfulexperiencetohaveproblemsgivenmeoutoftheintuitionsofagreatmind，basedonenormousexperienceinpracticalwork，andapplyingtonewlinesofprogress。OneofthemainimpressionsleftuponmeafterknowingMr。Edisonformanyyearsisthemarvellousaccuracyofhisguesses。Hewillseethegeneralnatureofaresultlongbeforeitcanbereachedbymathematicalcalculation。Hisgreatnesswasalwaystobeclearlyseenwhendifficultiesarose。Theyalwaysmadehimcheerful，andstartedhimthinking；andverysoonwouldcomealineofsuggestionswhichwouldnotenduntilthedifficultywasmetandovercome，orfoundinsurmountable。IhaveoftenfeltthatMr。Edisongothimselfpurposelyintotroublebyprematurepublicationsandotherwise，sothathewouldhaveafullincentivetogethimselfoutofthetrouble。“
ThischaptermaywellendwithastatementfromMr。Jehl，shrewdandobservant，asaparticipatorinalltheearlyworkofthedevelopmentoftheEdisonlightingsystem：“ThosewhoweregatheredaroundhimintheoldMenloParklaboratoryenjoyedhisconfidence，andhetheirs。Norwasthisconfidenceeverabused。Hewasrespectedwitharespectwhichonlygreatmencanobtain，andhenevershowedbyanywordoractthathewastheiremployerinasensethatwouldhurtthefeelings，asisoftenthecaseintheordinarycourseofbusinesslife。Heconversed，argued，anddisputedwithusallasifhewereacolleagueonthesamefooting。Itwashiswinningwaysandmannersthatattachedusallsoloyallytohisside，andmadeuseverreadywithaboundlessdevotiontoexecuteanyrequestordesire。“Thusdoesagreatmagnet，runthroughaheapofsandandfilings，exertitslinesofforceandattractirresistiblytoitselftheironandsteelparticlesthatareitsaffinity，andhavingsiftedthemout，leavingtheuselessdustbehind，holdthemtoitselfwithresponsivetenacity。
CHAPTERXIII
AWORLD-HUNTFORFILAMENTMATERIAL
INwritingabouttheoldexperimentingdaysatMenloPark，Mr。F。R。Uptonsays：“Edison'sdayistwenty-fourhourslong，forhehasalwaysworkedwhenevertherewasanythingtodo，whetherdayornight，andcarriedaforceofnightworkers，sothathisexperimentscouldgooncontinually。Ifhewantedmaterial，healwaysmadeitaprincipletohaveitatonce，andneverhesitatedtousespecialmessengerstogetit。Irememberintheearlydaysoftheelectriclighthewantedamercurypumpforexhaustingthelamps。HesentmetoPrincetontogetit。IgotbacktoMetuchenlateintheday，andhadtocarrythepumpovertothelaboratoryonmybackthatevening，setitup，andworkallnightandthenextdaygettingresults。“
ThischaracteristicprincipleofobtainingdesiredmaterialinthequickestandmostpositivewaymanifesteditselfinthesearchthatEdisoninstitutedforthebestkindofbambooforlampfilaments，immediatelyafterthediscoveryrelatedinaprecedingchapter。Itisdoubtfulwhether，intheannalsofscientificresearchandexperiment，thereisanythingquiteanalogoustothestoryofthissearchandthevariousexpeditionsthatwentoutfromtheEdisonlaboratoryin1880andsubsequentyears，toscourtheearthforamaterialsoapparentlysimpleasahomogeneousstripofbamboo，orothersimilarfibre。
Prolongedandexhaustiveexperiment，microscopicexamination，andanintimateknowledgeofthenatureofwoodandplantfibres，however，hadledEdisontotheconclusionthatbambooorsimilarfibrousfilamentsweremoresuitablethananythingelsethenknownforcommercialincandescentlamps，andhewantedthemostperfectforthatpurpose。
Hence，thequickestwaywastosearchthetropicsuntilthepropermaterialwasfound。
ThefirstemissarychosenforthispurposewasthelateWilliamH。Moore，ofRahway，NewJersey，wholeftNewYorkinthesummerof1880，boundforChinaandJapan，thesebeingthecountriespre-
eminentlynotedfortheproductionofabundantspeciesofbamboo。OnarrivalintheEasthequicklyleftthecitiesbehindandproceededintotheinterior，extendinghissearchfarintothemoreremotecountrydistricts，collectingspecimensonhisway，anddevotingmuchtimetothestudyofthebamboo，andinroughlytestingtherelativevalueofitsfibreincanesofone，two，three，four，andfiveyeargrowths。
GreatbalesofsamplesweresenttoEdison，andaftercarefultestsacertainvarietyandgrowthofJapanesebamboowasdeterminedtobethemostsatisfactorymaterialforfilamentsthathadbeenfound。Mr。
Moore，whowascontinuinghissearchesinthatcountry，wasinstructedtoarrangeforthecultivationandshipmentofregularsuppliesofthisparticularspecies。ArrangementstothisendwereaccordinglymadewithaJapanesefarmer，whobegantomakeimmediateshipments，andwhosubsequentlydisplayedsomuchingenuityinfertilizingandcross-
fertilizingthatthehomogeneityoftheproductwasconstantlyimproved。TheuseofthisbambooforEdisonlampfilamentswascontinuedformanyyears。
AlthoughMr。Mooredidnotmeetwiththeexcitingadventuresofsomesubsequentexplorers，heencounterednumerousdifficultiesandnovelexperiencesinhismanymonthsoftravelthroughthehinterlandofJapanandChina。Theattitudetowardforeignersthirtyyearsagowasnotasfriendlyasithassincebecome，butEdison，asusual，hadmadeahappychoiceofmessengers，asMr。Moore'sgoodnatureanddiplomacyattested。Thesequalities，togetherwithhispersistenceandperseveranceandfacultyofintelligentdiscriminationinthematteroffibres，helpedtomakehismissionsuccessful，andgavetohimthehonorofbeingtheonewhofoundthebamboowhichwasadoptedforuseasfilamentsincommercialEdisonlamps。
AlthoughEdisonhadsatisfiedhimselfthatbamboofurnishedthemostdesirablematerialthusfardiscoveredforincandescent-lampfilaments，hefeltthatinsomepartoftheworldtheremightbefoundanaturalproductofthesamegeneralcharacterthatwouldfurnishastillmoreperfectandhomogeneousmaterial。Inhisstudyofthissubject，andduringtheprosecutionofvigorousandsearchinginquiriesinvariousdirections，helearnedthatMr。JohnC。
Brauner，thenresidinginBrooklyn，NewYork，hadanexpertknowledgeofindigenousplantsoftheparticularkinddesired。DuringthecourseofageologicalsurveywhichhehadmadefortheBrazilianGovernment，Mr。Braunerhadexaminedcloselythevariousspeciesofpalmswhichgrowplentifullyinthatcountry，andofthemtherewasonewhosefibreshethoughtwouldbejustwhatEdisonwanted。
Accordingly，Mr。BraunerwassentforanddispatchedtoBrazilinDecember，1880，tosearchforandsendsamplesofthisandsuchotherpalms，fibres，grasses，andcanesas，inhisjudgment，wouldbesuitablefortheexperimentsthenbeingcarriedonatMenloPark。LandingatPara，hecrossedoverintotheAmazonianprovince，andthenceproceededthroughtheheartofthecountry，makinghiswaybycanoeontheriversandtheirtributaries，andbyfootintotheforestsandmarshesofavastandalmostuntroddenwilderness。InthismannerMr。BraunertraversedabouttwothousandmilesofthecomparativelyunknowninteriorofSouthernBrazil，andprocuredalargevarietyoffibrousspecimens，whichheshippedtoEdisonafewmonthslater。WhenthesefibresarrivedintheUnitedStatestheywerecarefullytestedandafewofthemfoundsuitablebutnotsuperiortotheJapanesebamboo，whichwasthenbeingexclusivelyusedinthemanufactureofcommercialEdisonlamps。
LateronEdisonsentoutanexpeditiontoexplorethewildsofCubaandJamaica。Atwomonths'
investigationofthelatterislandrevealedavarietyofbamboogrowths，ofwhichagreatnumberofspecimenswereobtainedandshippedtoMenloPark；butoncarefultesttheywerefoundinferiortotheJap-
anesebamboo，andhencerejected。TheexplorationofthegladesandswampsofFloridabythreemenextendedoveraperiodoffivemonthsinaminutesearchforfibrouswoodsofthepalmettospecies。A
greatvarietywasfound，andoverfivehundredboxesofspecimenswereshippedtothelaboratoryfromtimetotime，butnoneofthemtestedoutwithentirelysatisfactoryresults。
TheuseofJapanesebambooforcarbonfilamentswasthereforecontinuedinthemanufactureoflamps，althoughanincessantsearchwasmaintainedforastillmoreperfectmaterial。Thespiritofprogress，sopervasiveinEdison'scharacter，ledhim，however，torenewhisinvestigationsfurtherafieldbysendingouttwoothermentoexaminethebambooandsimilargrowthsofthosepartsofSouthAmericanotcoveredbyMr。Brauner。ThesetwomenwereFrankMcGowanandC。F。Hanington，bothofwhomhadbeenfornearlysevenyearsintheemployoftheEdisonElectricLightCompanyinNewYork。Theformerwasastocky，ruggedIrishman，possessingthenativeshrewdnessandbuoyancyofhisrace，coupledwithundauntedcourageanddetermination；andthelatterwasaveteranoftheCivilWar，withsomeknowledgeofforestandfield，acquiredasasportsman。
TheyleftNewYorkinSeptember，1887，arrivinginduetimeatPara，proceedingthencetwenty-
threehundredmilesuptheAmazonRivertoIquitos。
Nothingofaneventfulnatureoccurredduringthistrip，butonarrivalatIquitosthetwomenseparated；
Mr。McGowantoexploreonfootandbycanoeinPeru，Ecuador，andColombia，whileMr。HaningtonreturnedbytheAmazonRivertoPara。ThenceHaningtonwentbysteamertoMontevideo，andbysimilarconveyanceuptheRiverdelaPlataandthroughUruguay，Argentine，andParaguaytothesouthernmostpartofBrazil，collectingalargenumberofspecimensofpalmsandgrasses。
TheadventuresofMr。McGowan，afterleavingIquitos，wouldfillabookifrelatedindetail。Theobjectofthepresentnarrativeandthespaceattheauthors'disposal，however，donotpermitofmorethanabriefmentionofhisexperiences。HisfirstobjectivepointwasQuito，aboutfivehundredmilesaway，whichheproposedtoreachonfootandbymeansofcanoeingontheNapoRiverthroughawildandcomparativelyunknowncountryteemingwithtribesofhostilenatives。Thedangersoftheexpeditionwerepicturedtohiminglowingcolors，butspurningpropheciesofdiredisaster，heengagedsomenativeIndiansandacanoeandstartedonhisexplorations，reachingQuitoineighty-sevendays，afterathoroughsearchofthecountryonbothsidesoftheNapoRiver。FromQuitohewenttoGuayaquil，fromtherebysteamertoBuenaventura，andthencebyrail，twelvemiles，toCordova。FromthispointhesetoutonfoottoexploretheCaucaValleyandtheCordilleras。
Mr。McGowanfoundintheseregionsagreatvarietyofbamboo，smallandlarge，somespeciesgrowingseventy-fivetoonehundredfeetinheight，andfromsixtonineinchesindiameter。Hecollectedalargenumberofspecimens，whichweresubsequentlysenttoOrangeforEdison'sexamination。Afteraboutfifteenmonthsofexplorationattendedbymuchhardshipandprivation，desertedsometimesbytreacherousguides，twicelaidlowbyfevers，occasionallyinperilfromIndianattacks，wildanimalsandpoisonousserpents，tormentedbyinsectpests，endangeredbyfloods，onehundredandnineteendayswithoutmeat，ninety-eightdayswithouttakingoffhisclothes，Mr。
McGowanreturnedtoAmerica，brokeninhealthbuthavingfaithfullyfulfilledthecommissionintrustedtohim。TheEveningSun，NewYork，obtainedaninterviewwithhimatthattime，andinitsissueofMay2，1889，gavemorethanapagetoabriefstoryofhisinterestingadventures，andthencommentededitoriallyuponthem，asfollows：
“AROMANCEOFSCIENCE“
“ThenarrativegivenelsewhereintheEveningSunofthewanderingsofEdison'smissionaryofscience，Mr。FrankMcGowan，furnishesanewproofthattheromancesofreallifesurpassanythattheimaginationcanframe。
“InpursuitofasubstancethatshouldmeettherequirementsoftheEdisonincandescentlamp，Mr。McGowanpenetratedthewildernessoftheAmazon，andforayeardefieditsfevers，beasts，reptiles，anddeadlyinsectsinhisquestofamaterialsopreciousthatjealousNaturehashiddenitinhermostsecretfastnesses。
“Noheroofmythologyorfableeverdaredsuchdragonstorescuesomecaptivegoddessasdidthisdauntlesschampionofcivilization。Theseus，orSiegfried，oranyknightofthefairybooksmightenvythevictoriesofEdison'sirresistiblelieutenant。
“Asasamplestoryofadventure，Mr。McGowan'snarrativeisamarvelfittobeclassedwiththehistoricjour-
neyingsofthegreatesttravellers。Butitgainsimmenselyininterestwhenweconsiderthatitsucceededinitsscientificpurpose。Themysteriousbamboowasdiscovered，andlargequantitiesofitwereprocuredandbroughttotheWizard'slaboratory，theretosufferanotherwondrouschangeandthentolightupourpleasure-
hauntsandourhomeswithagentleradiance。“
Afurther，thoughrathersad，interestattachestotheMcGowanstory，foronlyashorttimehadelapsedafterhisreturntoAmericawhenhedisappearedsuddenlyandmysteriously，andinspiteoflong-continuedandstrenuouseffortstoobtainsomelightonthesubject，noclewortraceofhimwaseverfound。HewasafavoriteamongtheEdison“oldtimers，“
andhismemoryisstillcherished，forwhensomeofthe“boys“happentogettogether，astheyoccasionallydo，someoneisalmostsureto“wonderwhatbecameofpoor`Mac。'“HewaslastseenatMouquin'sfamousoldFrenchrestaurantonFultonStreet，NewYork，wherehelunchedwithoneoftheauthorsofthisbookandthelateLutherStieringer。
Hesatwiththemfortwoorthreehoursdiscussinghiswonderfultrip，andtellingsomefascinatingstoriesofadventure。ThenthepartyseparatedattheAnnStreetdooroftherestaurant，aftermakingplanstosecurethenarrativeinmoredetailedformforsubsequentuse——andMcGowanhasnotbeenseenfromthathourtothis。ThetrailoftheexplorerwasmoreinstantlylostinNewYorkthaninthevastrecessesoftheAmazonswamps。
ThenextandlastexplorerwhomEdisonsentoutinsearchofnaturalfibreswasMr。JamesRicalton，ofMaplewood，NewJersey，aschool-principal，awell-
knowntraveller，andanardentstudentofnaturalscience。Mr。Ricalton'sownstoryofhismemorableexpeditionissointerestingastobeworthyofrepetitionhere：
“Avillageschoolmasterisnotunaccustomedtodoor-rappings；forthestepsofbelligerentmothersareoftenthitherwardbentseekingredressforconjuredwrongstotheirdarlingboobies。
“Itwasabewilderingmoment，therefore，totheMaplewoodteacherwhen，inansweringarapatthedooroneafternoon，hefound，insteadofaniratemother，amessengerfromthelaboratoryoftheworld'sgreatestinventorbearingaletterrequestinganaudienceafewhourslater。
“Beingtheteachertowhomreferenceismade，I
amnowquitewillingtoconfessthatfortheremainderofthatafternoon，lessthanaprobleminEuclidwouldhavebeensufficienttodisqualifymefortheremainingscholasticdutiesofthehour。Ifeltit，ofcourse，tobenosmallhonorforahumbleteachertobecalledtothesanctumofThomasA。Edison。Theletter，however，gavenointimationofthenatureoftheobjectforwhichIhadbeeninvitedtoappearbeforeMr。Edison……
“WhenIwaspresentedtoMr。Edisonhiswayofsettingforththemissionhehaddesignatedformewascharacteristicofhowagreatmindconceivesvastundertakingsandcommandsgreatthingsinfewwords。AtthistimeMr。Edisonhaddiscoveredthatthefibreofacertainbambooaffordedaverydesirablecarbonfortheelectriclamp，andthevarietyofbam-
boousedwasaproductofJapan。Itwashisbeliefthatinotherpartsoftheworldotherandsuperiorvarietiesmightbefound，andtothatendhehaddispatchedexplorerstobambooregionsinthevalleysofthegreatSouthAmericanrivers，wherespecimenswerefoundofextraordinaryquality；butthelocalityinwhichthesespecimenswerefoundwaslostinthelimitlessreachesofthosegreatriver-bottoms。ThegreatnecessityformoredurablecarbonsbecameadesideratumsourgentthatthetirelessinventordecidedtocommissionanotherexplorertosearchthetropicaljunglesoftheOrient。
“ThisbringsmethentothefirstmeetingofEdison，whenhesetforthsubstantiallyasfollows，asIrememberittwentyyearsago，thepurposeforwhichhehadcalledmefrommyscholasticduties。Withaquizzicalgleaminhiseye，hesaid：`IwantamantoransackallthetropicaljunglesoftheEasttofindabetterfibreformylamp；Iexpectittobefoundinthepalmorbamboofamily。Howwouldyoulikethatjob？'Suitingmyreplytohisloveofbrevityanddispatch，Isaid，`Thatwouldsuitme。'`Canyougoto-morrow？'washisnextquestion。`Well，Mr。Edison，ImustfirstofallgetaleaveofabsencefrommyBoardofEducation，andassisttheboardtosecureasubstituteforthetimeofmyabsence。Howlongwillittake，Mr。Edison？'`HowcanItell？
Maybesixmonths，andmaybefiveyears；nomatterhowlong，findit。'Hecontinued：`IsentamantoSouthAmericatofindwhatIwant；hefoundit；
butlosttheplacewherehefoundit，sohemightaswellneverhavefounditatall。'HereatIwasenjoinedtoproceedforthwithtocourttheBoardofEducationforaleaveofabsence，whichIdidsuccessfully，theboardconsideringthatacallsoimportantandhonorarywasentitledtotheirunqualifiedfavor，whichtheygenerouslygranted。
“IreportedtoMr。Edisononthefollowingday，whenheinstructedmetocometothelaboratoryatoncetolearnallthedetailsofdrawingandcarbonizingfibres，whichitwouldbenecessarytodointheOrientaljungles。ThisIdid，and，inthemeantime，asetofsuitabletoolsforthispurposehadbeenorderedtobemadeinthelaboratory。AssoonasI
learnedmynewtrade，whichIaccomplishedinafewdays，Mr。EdisondirectedmetothelibraryofthelaboratorytooccupyafewdaysinstudyingthegeographyoftheOrientand，particularly，indrawingmapsofthetributariesoftheGanges，theIrrawaddy，andtheBrahmaputrarivers，andotherregionswhichIexpectedtoexplore。
“ItwaswhilethusengagedthatMr。Edisoncametomeonedayandsaid：`Ifyouwillgouptothehouse'hispalatialhomenotfaraway`andlookbehindthesofainthelibraryyouwillfindajointofbamboo，aspecimenofthatfoundinSouthAmerica；
bringitdownandmakeastudyofit；ifyoufindsomethingequaltothatIwillbesatisfied。'AtthehomeIwasguidedtothelibrarybyanIrishservant-
woman，towhomIcommunicatedmyknowledgeofthedefinitelocalityofthesamplejoint。Sheplungedherarm，bareandherculean，behindtheaforementionedsofa，andholdingaloftasectionofwood，calledoutinamoodofdiscovery：`Isthatit？'
Replyingintheaffirmative，sheadded，underanimpulseofinnocentdivinationthatwhateverherwizardmasterlaidhandsuponcouldresultinnothingshortofaninvention，`Sure，sor，andwhat'shegoingtoinvintouto'that？'
“Mykitoftoolsmade，mymapsdrawn，myOrientalgeographyreviewed，Icometothepointwhenmattersofimmediatedeparturearediscussed；
andwhenItookoccasiontomentiontomychiefthat，onthesubjectoflifeinsurance，underwritersrefusetotakeanyrisksonanenterprisesohazardous，Mr。Edisonsaidthat，ifIdidnotplacetoohighavaluationonmyperson，hewouldtaketheriskhimself。IrepliedthatIwasbornandbredinNewYorkState，butnowthatIhadbecomeaJerseymanIdidnotvaluemyselfatabovefifteenhundreddollars。
Edisonlaughedandsaidthathewouldassumetherisk，andanotherpointwassettled。Thenextmatterwasthefinancingofthetrip，aboutwhichMr。EdisonaskedinatentativewayabouttheratestotheEast。Itoldhimtheexpenseofsuchatripcouldnotbedeterminedbeforehandindetail，butthatIhadestablishedsomewhatofareputationforeconomictravel，andthatIdidnotbelieveanytravellercouldsurpassmeinthatrespect。Hedesirednofurtherassuranceinthatdirection，andthereuponorderedaletterofcreditmadeoutwithauthorizationtoorderasecondwhenthefirstwasexhausted。
Hereinthenaresetforthinbriefestspacethepreliminariesofacircuitoftheglobeinquestoffibre。
“ItsohappenedthatthedayonwhichIsetoutfellonWashington'sBirthday，andIsuggestedtomyboysandgirlsatschoolthattheymakealineacrossthestationplatformneartheschoolatMaplewood，andfromthislineIwouldstarteastwardaroundtheworld，andifgood-fortuneshouldbringmebackIwouldmeetthemfromthewestwardatthesameline。AsIhadoftenmadethem`toethescratch，'
foroncetheywereonlytoowellpleasedtohavemetoethelineforthem。
“Thiswasdone，andIsailedviaEnglandandtheSuezCanaltoCeylon，thatfairisletowhichSindbadtheSailormadehissixthvoyage，picturesquelyreferredtoinhistoryasthe`brightestgemintheBritishColonialCrown。'IknewCeylontobeeminentlytropical；Iknewittoberichinmanyvarietiesofthebamboofamily，whichhasbeencalledthekingofthegrasses；andinthisfamilyhadImosthopeoffindingthedesiredfibre。Weekswerespentinthisparadisiacalisle。Everypartwasvisited。Nativewoodcraftsmenwereofferedapremiumoneverynewspeciesbroughtin，andinthiswaynearlyahundredspeciesweretested，agreaternumberthanwasfoundinanyothercountry。OneofthebestspecimenstestedduringtheentiretriparoundtheworldwasfoundfirstinCeylon，althoughlaterinBurmah，itbeingindigenoustothelattercountry。Itisagigantictree-grassorreedgrowinginclumpsoffromonetotwohundred，oftentwelveinchesindiameter，andonehundredandfiftyfeethigh，andknownasthegiantbambooBambusagigantia。Thisgiantgrassstoodthehighesttestasacarbon，andonaccountofitsextraordinarysizeandqualitiesIextenditthisspecialmention。Withotherswhohavegivenmuchattentiontothisremarkablereed，Ibelievethatinitsmanifoldusesthebambooistheworld'sgreatestdendralbenefactor。
“FromCeylonIproceededtoIndia，touchingthegreatpeninsulafirstatCapeComorin，andcontinuingnorthwardbywayofPondicherry，Madura，andMadras；andthencetothetablelandofBangaloreandtheWesternGhauts，testingmanykindsofwoodateverypoint，butparticularlythepalmandbamboofamilies。FromtherangeoftheWesternGhautsIwenttoBombayandthennorthbythewayofDelhitoSimla，thesummercapitaloftheHimalayas；
thenceagainnorthwardtotheheadwatersoftheSutlejRiver，testingeverywhereonmywayeverythinglikelytoaffordthedesiredcarbon。
“OnreturningfromthemountainsIfollowedthevalleysoftheJumnaandtheGangestoCalcutta，whenceIagainascendedtheSub-HimalayastoDarjeeling，wherethenumerousriver-bottomsweresprinkledplentifullywithmanyvarietiesofbamboo，fromthelargersizestodwarfedspeciescoveringthemountainslopes，andnotlongerthanthegrassofmeadows。AgaindescendingtotheplainsIpassedeastwardtotheBrahmaputraRiver，whichIascendedtothefoot-hillsinAssam；butfindingnothingofsuperiorqualityinallthisnorthernregionIreturnedtoCalcuttaandsailedthencetoRangoon，inBurmah；
andthere，findingnosamplesgivingmoreexcellenttestsinthelowerreachesoftheIrrawaddy，IascendedthatrivertoMandalay，where，throughBurmesebamboowiseacres，IgatheredinfromroundaboutandtestedallthattheunusuallyrichBurmesefloracouldfurnish。InBurmahthegiantbamboo，asalreadymentioned，isfoundindigenous；butbesideitnosuperiorvarietieswerefound。SamplestestedatseveralpointsontheMalayPeninsulashowednonewspecies，exceptatapointnorthofSingapore，whereIfoundaspecieslargeandheavywhichgaveatestnearlyequaltothatofthegiantbambooinCeylon。
“AftercompletingtheMalayPeninsulaIhadplannedtovisitJavaandBorneo；buthavingfoundintheMalayPeninsulaandinCeylonabamboofibrewhichaveragedatestfromonetotwohundredpercent。betterthanthatinuseatthelampfactory，IdecideditwasunnecessarytovisitthesecountriesorNewGuinea，asmy`Eureka'hadalreadybeenestablished，andthatIwouldthereforesetforthoverthereturnhemisphere，searchingChinaandJapanontheway。TheriversinSouthernChinabroughtdowntoCantonbamboosofmanyspecies，wherethiswondrouslyutilitarianreedentersverylargelyintotheindustriallifeofthatpeople，andnotmerelyintotheindustriallife，butevenintotheculinaryarts，forbamboosproutsareauniversalvegetableinChina；butamongallthebamboosofChinaI
foundnoneofsuperexcellenceincarbonizingqualities。
Japancamenextinthesuccessionofcountriestobeexplored，buttheretheworkwasmuchsimplified，fromthefactthattheTokioMuseumcontainsacompleteclassifiedcollectionofallthedifferentspeciesintheempire，andtheresamplescouldbeobtainedandtested。
“Nowthelastoftheimportantbamboo-producingcountriesintheglobecircuithadbeendone，andthe`home-lap'wasinorder；thebroadPacificwasspannedinfourteendays；mynatalcontinentinsix；
andonthe22dofFebruary，onthesameday，atthesamehour，atthesameminute，oneyeartoasecond，`littleMaude，'asweetmaidoftheschool，ledmeacrossthelinewhichcompletedthecircuitoftheglobe，andwhereIwasgreetedbythecheersofmyboysandgirls。IatoncereportedtoMr。Edison，whosemannerofgreetingmyreturnwasascharacteristicofthemanashissummaryandmatter-of-
factmannerofmydispatch。HislittlecatechismofcuriousinquirywasembracedinfoursmallandintenselyAnglo-Saxonwords——withhisusualpleasantsmileheextendedhishandandsaid：`Didyougetit？'Thiswassurelyasummingofayear'sexplorationnotlesslaconicthanCaesar'sreviewofhisGalliccampaign。WhenIrepliedthatIhad，butthathemustbethefinaljudgeofwhatIhadfound，hesaidthatduringmyabsencehehadsucceededinmakinganartificialcarbonwhichwasmeetingtherequirementssatisfactorily；sowell，indeed，thatI
believenopracticalusewasevermadeofthebamboofibresthereafter。
“IhavehereingivenaverybriefresumeofmysearchforfibrethroughtheOrient；andduringmyconnectionwiththatmissionIwasatalltimesnotlessastonishedatMr。Edison'squickperceptionofconditionsandhisinstantdecisionandhisbignessofconceptions，thanIhadalwaysbeenwithhisprodigiousindustryandhisinventivegenius。
“Thinkingpersonsknowthatblatantmenneveraccomplishmuch，andEdison'smarvellousbrevityofspeechalongwithhismiraculousachievementsshoulddomuchtoputboresandgarrulityoutoffashion。“
AlthoughEdisonhadinstitutedsuchacostlyandexhaustivesearchthroughouttheworldforthemostperfectofnaturalfibres，hedidnotnecessarilyfeelcommittedforalltimetotheexclusiveuseofthatmaterialforhislampfilaments。Whiletheseexplorationswereinprogress，asindeedlongbefore，hehadgivenmuchthoughttotheproductionofsomeartificialcompoundthatwouldembracenotonlytherequiredhomogeneity，butalsomanyotherqualificationsnecessaryforthemanufactureofanimprovedtypeoflampwhichhadbecomedesirablebyreasonoftherapidadoptionofhislightingsystem。
AttheverytimeMr。McGowanwasmakinghisexplorationsdeepinSouthAmerica，andMr。Ricaltonhisswifttriparoundtheworld，Edison，aftermuchinvestigationandexperiment，hadproducedacompoundwhichpromisedbetterresultsthanbamboofibres。Aftersomechangesdictatedbyexperience，thisartificialfilamentwasadoptedinthemanufactureoflamps。Noradicalchangewasimmediatelymade，however，buttheproductofthelampfactorywasgraduallychangedover，duringthecourseofafewyears，fromtheuseofbambootothe“squirted“filament，asthenewmaterialwascalled。
Anartificialcompoundofonekindoranotherhasindeedbeenuniversallyadoptedforthepurposebyallmanufacturers；hencetheincandescingconductorsinallcarbon-filamentlampsofthepresentdayaremadeinthatway。Thefactremains，however，thatfornearlynineyearsallEdisonlampsmanymillionsintheaggregateweremadewithbamboofilaments，andmanyofthemforseveralyearsafterthat，untilbamboowasfinallyabandonedintheearlynineties，exceptforuseinafewspecialtypeswhichweresomadeuntilabouttheendof1908。Thelastfewyearshavewitnessedaremarkableadvanceinthemanufactureofincandescentlampsinthesubstitutionofmetallicfilamentsforthoseofcarbon。Itwillberememberedthatmanyoftheearlierexperimentswerebasedontheuseofstripsofplatinum；whileotherraremetalswerethesubjectofcasualtrial。Norealsuccesswasattainedinthatdirection，andformanyyearsthecarbon-filamentlampreignedsupreme。
Duringthelastfourorfiveyearslampswithfilamentsmadefromtantalumandtungstenhavebeenproducedandplacedonthemarketwithgreatsuccess，andarenowlargelyused。Theirpriceisstillveryhigh，however，ascomparedwiththatofthecarbonlamp，whichhasbeenvastlyimprovedinmethodsofconstruction，andwhoseaveragepriceoffifteencentsisonlyone-tenthofwhatitwaswhenEdisonfirstbroughtitout。
WiththecloseofMr。McGowan'sandMr。Ricalton'sexpeditions，thereendedthehistoricworld-huntfornaturalfibres。FromstarttofinishtheinvestigationsandsearchesmadebyEdisonhimself，andcarriedonbyothersunderhisdirection，areremarkablenotonlyfromthefactthattheyentailedatotalexpenditureofabout$100，000，disbursedunderhissupervisionbyMr。Upton，butalsobecauseoftheiruniqueinceptionandthoroughnesstheyillustrateoneofthestrongesttraitsofhischaracter——aninvincibledeterminationtoleavenostoneunturnedtoacquirethatwhichhebelievestobeinexistence，andwhich，whenfound，willanswerthepurposethathehasinmind。