Othermindswereatwork。Watt，whenonlytwenty-threeyearsold，attheinstigationofhisfriendRobison，madeamodellocomotive，providedwithtwocylindersoftinplate；buttheprojectwaslaidaside，andwasneveragaintakenupbytheinventor。Yet，inhispatentof1784，Wattincludedanarrangementbymeansofwhichsteam-powermightbeemployedforthepurposesoflocomotion。Butnofurthermodelofthecontrivancewasmade。
Meanwhile，Cugnot，ofParis，hadalreadymadearoadengineworkedbysteampower。ItwasfirsttriedattheArsenalin1769；and，beingsetinmotion，itranagainstastonewallinitswayandthrewitdown。TheenginewasafterwardstriedinthestreetsofParis。Inoneoftheexperimentsitfelloverwithacrash，andwasthenceforwardlockedupintheArsenaltopreventitsdoingfurthermischief。ThisfirstlocomotiveisnowtobeseenattheConservatoiredesArtsetMetiersatParis。
MurdockhaddoubtlessheardofWatt’soriginalspeculations，andproceeded，whileatRedruth，duringhisleisurehours，toconstructamodellocomotiveafteradesignofhisown。Thismodelwasofsmalldimensions，standinglittlemorethanafootandahalfhigh，thoughitwassufficientlylargetodemonstratethesoundnessoftheprincipleonwhichitwasconstructed。Itwassupportedonthreewheels，andcarriedasmallcopperboiler，heatedbyaspiritlamp，withafluepassingobliquelythroughit。Thecylinder，of3/4inchdiameterand2-inchstroke，wasfixedinthetopoftheboiler，thepiston-rodbeingconnectedwiththevibratorybeamattachedtotheconnecting-rodwhichworkedthecrankofthedriving-wheel。Thislittleengineworkedbytheexpansiveforceofsteamonly，whichwasdischargedintotheatmosphereafterithaddoneitsworkofalternatelyraisinganddepressingthepistoninthecylinder。
Mr。Murdock’sson，whilelivingatHandsworth，informedthepresentwriterthatthismodelwasinventedandconstructedin1781；but，afterperusingthecorrespondenceofBoultonandWatt，weinferthatitwasnotreadyfortrialuntil1784。ThefirstexperimentwasmadeinMurdock’sownhouseatRedruth，whenthelittleenginesuccessfullyhauledamodelwaggonroundtheroom，——thesinglewheel，placedinfrontoftheengineandworkinginaswivelframe，enablingittorunroundinacircle。
Anotherexperimentwasmadeoutofdoors，onwhichoccasion，smallthoughtheenginewas，itfairlyoutranthespeedofitsinventor。Onenight，afterreturningfromhisdutiesatthemineatRedruth，Murdockwentwithhismodellocomotivetotheavenueleadingtothechurch，aboutamilefromthetown。Thewalkwasnarrow，straight，andlevel。Havinglitthelamp，thewatersoonboiled，andoffstartedtheenginewiththeinventorafterit。