TheTimeTraveller(forsoitwillbeconvenienttospeakofhim)wasexpoundingareconditemattertous. Hisgreyeyesshoneandtwinkled,andhisusuallypalefacewasflushedandanimated. Thefireburnedbrightly,andthesoftradianceoftheincandescentlightsintheliliesofsilvercaughtthebubblesthatflashedandpassedinourglasses. Ourchairs,beinghispatents,embracedandcaressedusratherthansubmittedtobesatupon,andtherewasthatluxuriousafter–dinneratmospherewhenthoughtroamsgracefullyfreeofthetrammelsofprecision. Andheputittousinthisway—markingthepointswithaleanforefinger—aswesatandlazilyadmiredhisearnestnessoverthisnewparadox(aswethoughtit)andhisfecundity. 'Youmustfollowmecarefully.Ishallhavetocontrovertoneortwoideasthatarealmostuniversallyaccepted.Thegeometry,forinstance,theytaughtyouatschoolisfoundedonamisconception.' 'Isnotthatratheralargethingtoexpectustobeginupon?'saidFilby,anargumentativepersonwithredhair. 'Idonotmeantoaskyoutoacceptanythingwithoutreasonablegroundforit. YouwillsoonadmitasmuchasIneedfromyou. Youknowofcoursethatamathematicalline,alineofthicknessnil,hasnorealexistence.Theytaughtyouthat?Neitherhasamathematicalplane.Thesethingsaremereabstractions.' 'Thatisallright,'saidthePsychologist. 'Nor,havingonlylength,breadth,andthickness,canacubehavearealexistence.' 'ThereIobject,'saidFilby.'Ofcourseasolidbodymayexist.Allrealthings—' 'Somostpeoplethink.Butwaitamoment.Cananinstantaneouscubeexist?' 'Don'tfollowyou,'saidFilby. 'Canacubethatdoesnotlastforanytimeatall,havearealexistence?' Filbybecamepensive.'Clearly,'theTimeTravellerproceeded,'anyrealbodymusthaveextensioninfourdirections:itmusthaveLength,Breadth,Thickness,and—Duration. Butthroughanaturalinfirmityoftheflesh,whichIwillexplaintoyouinamoment,weinclinetooverlookthisfact. Therearereallyfourdimensions,threewhichwecallthethreeplanesofSpace,andafourth,Time. Thereis,however,atendencytodrawanunrealdistinctionbetweentheformerthreedimensionsandthelatter,becauseithappensthatourconsciousnessmovesintermittentlyinonedirectionalongthelatterfromthebeginningtotheendofourlives.' 'That,'saidaveryyoungman,makingspasmodiceffortstorelighthiscigaroverthelamp;'that...veryclearindeed.' 'Now,itisveryremarkablethatthisissoextensivelyoverlooked,'continuedtheTimeTraveller,withaslightaccessionofcheerfulness. 'ReallythisiswhatismeantbytheFourthDimension,thoughsomepeoplewhotalkabouttheFourthDimensiondonotknowtheymeanit. ItisonlyanotherwayoflookingatTime. ThereisnodifferencebetweenTimeandanyofthethreedimensionsofSpaceexceptthatourconsciousnessmovesalongit. Butsomefoolishpeoplehavegotholdofthewrongsideofthatidea. YouhaveallheardwhattheyhavetosayaboutthisFourthDimension?' 'Ihavenot,'saidtheProvincialMayor. 'Itissimplythis.ThatSpace,asourmathematicianshaveit,isspokenofashavingthreedimensions,whichonemaycallLength,Breadth,andThickness,andisalwaysdefinablebyreferencetothreeplanes,eachatrightanglestotheothers. Butsomephilosophicalpeoplehavebeenaskingwhythreedimensionsparticularly—whynotanotherdirectionatrightanglestotheotherthree? —andhaveeventriedtoconstructaFour–Dimensiongeometry. ProfessorSimonNewcombwasexpoundingthistotheNewYorkMathematicalSocietyonlyamonthorsoago. Youknowhowonaflatsurface,whichhasonlytwodimensions,wecanrepresentafigureofathree–dimensionalsolid,andsimilarlytheythinkthatbymodelsofthreedimensionstheycouldrepresentoneoffour—iftheycouldmastertheperspectiveofthething.See?' 'Ithinkso,'murmuredtheProvincialMayor;and,knittinghisbrows,helapsedintoanintrospectivestate,hislipsmovingasonewhorepeatsmysticwords. 'Yes,IthinkIseeitnow,'hesaidaftersometime,brighteninginaquitetransitorymanner. 'Well,IdonotmindtellingyouIhavebeenatworkuponthisgeometryofFourDimensionsforsometime.Someofmyresultsarecurious. Forinstance,hereisaportraitofamanateightyearsold,anotheratfifteen,anotheratseventeen,anotherattwenty–three,andsoon. Alltheseareevidentlysections,asitwere,Three–DimensionalrepresentationsofhisFour–Dimensionedbeing,whichisafixedandunalterablething. 'Scientificpeople,'proceededtheTimeTraveller,afterthepauserequiredfortheproperassimilationofthis,'knowverywellthatTimeisonlyakindofSpace. Hereisapopularscientificdiagram,aweatherrecord. ThislineItracewithmyfingershowsthemovementofthebarometer. Yesterdayitwassohigh,yesterdaynightitfell,thenthismorningitroseagain,andsogentlyupwardtohere. SurelythemercurydidnottracethislineinanyofthedimensionsofSpacegenerallyrecognized? Butcertainlyittracedsuchaline,andthatline,therefore,wemustconcludewasalongtheTime–Dimension.' 'But,'saidtheMedicalMan,staringhardatacoalinthefire,'ifTimeisreallyonlyafourthdimensionofSpace,whyisit,andwhyhasitalwaysbeen,regardedassomethingdifferent? AndwhycannotwemoveinTimeaswemoveaboutintheotherdimensionsofSpace?' TheTimeTravellersmiled.'AreyousurewecanmovefreelyinSpace? Rightandleftwecango,backwardandforwardfreelyenough,andmenalwayshavedoneso. Iadmitwemovefreelyintwodimensions.Buthowaboutupanddown?Gravitationlimitsusthere.' 'Notexactly,'saidtheMedicalMan.'Thereareballoons.' 'Butbeforetheballoons,saveforspasmodicjumpingandtheinequalitiesofthesurface,manhadnofreedomofverticalmovement.' 'Stilltheycouldmovealittleupanddown,'saidtheMedicalMan. 'Easier,fareasierdownthanup.' 'AndyoucannotmoveatallinTime,youcannotgetawayfromthepresentmoment.' 'Mydearsir,thatisjustwhereyouarewrong. Thatisjustwherethewholeworldhasgonewrong. Wearealwaysgettingawayfromthepresentmoment. Ourmentalexistences,whichareimmaterialandhavenodimensions,arepassingalongtheTime–Dimensionwithauniformvelocityfromthecradletothegrave. Justasweshouldtraveldownifwebeganourexistencefiftymilesabovetheearth'ssurface.' 'Butthegreatdifficultyisthis,'interruptedthePsychologist.'YoucanmoveaboutinalldirectionsofSpace,butyoucannotmoveaboutinTime.' 'Thatisthegermofmygreatdiscovery. ButyouarewrongtosaythatwecannotmoveaboutinTime. Forinstance,ifIamrecallinganincidentveryvividlyIgobacktotheinstantofitsoccurrence:Ibecomeabsent–minded,asyousay.Ijumpbackforamoment. OfcoursewehavenomeansofstayingbackforanylengthofTime,anymorethanasavageorananimalhasofstayingsixfeetabovetheground. Butacivilizedmanisbetteroffthanthesavageinthisrespect. Hecangoupagainstgravitationinaballoon,andwhyshouldhenothopethatultimatelyhemaybeabletostoporacceleratehisdriftalongtheTime–Dimension,oreventurnaboutandtraveltheotherway?' 'Oh,this,'beganFilby,'isall—' 'Whynot?'saidtheTimeTraveller. 'It'sagainstreason,'saidFilby. 'Whatreason?'saidtheTimeTraveller. 'Youcanshowblackiswhitebyargument,'saidFilby,'butyouwillneverconvinceme.' 'Possiblynot,'saidtheTimeTraveller.'ButnowyoubegintoseetheobjectofmyinvestigationsintothegeometryofFourDimensions.LongagoIhadavagueinklingofamachine—' 'TotravelthroughTime!'exclaimedtheVeryYoungMan. 'ThatshalltravelindifferentlyinanydirectionofSpaceandTime,asthedriverdetermines.' Filbycontentedhimselfwithlaughter. 'ButIhaveexperimentalverification,'saidtheTimeTraveller. 'Itwouldberemarkablyconvenientforthehistorian,'thePsychologistsuggested.'OnemighttravelbackandverifytheacceptedaccountoftheBattleofHastings,forinstance!' 'Don'tyouthinkyouwouldattractattention?'saidtheMedicalMan.'Ourancestorshadnogreattoleranceforanachronisms.' 'Onemightgetone'sGreekfromtheverylipsofHomerandPlato,'theVeryYoungManthought. 'InwhichcasetheywouldcertainlyploughyoufortheLittle–go.TheGermanscholarshaveimprovedGreeksomuch.' 'Thenthereisthefuture,'saidtheVeryYoungMan.'Justthink!Onemightinvestallone'smoney,leaveittoaccumulateatinterest,andhurryonahead!' 'Todiscoverasociety,'saidI,'erectedonastrictlycommunisticbasis.' 'Ofallthewildextravaganttheories!'beganthePsychologist. 'Yes,soitseemedtome,andsoInevertalkedofituntil—' 'Experimentalverification!'criedI.'Youaregoingtoverifythat?' 'Theexperiment!'criedFilby,whowasgettingbrain–weary. 'Let'sseeyourexperimentanyhow,'saidthePsychologist,'thoughit'sallhumbug,youknow.' TheTimeTravellersmiledroundatus.Then,stillsmilingfaintly,andwithhishandsdeepinhistrouserspockets,hewalkedslowlyoutoftheroom,andweheardhisslippersshufflingdownthelongpassagetohislaboratory. ThePsychologistlookedatus.'Iwonderwhathe'sgot?' 'Somesleight–of–handtrickorother,'saidtheMedicalMan,andFilbytriedtotellusaboutaconjurerhehadseenatBurslem;butbeforehehadfinishedhisprefacetheTimeTravellercameback,andFilby'sanecdotecollapsed. ThethingtheTimeTravellerheldinhishandwasaglitteringmetallicframework,scarcelylargerthanasmallclock,andverydelicatelymade. Therewasivoryinit,andsometransparentcrystallinesubstance. AndnowImustbeexplicit,forthisthatfollows—unlesshisexplanationistobeaccepted—isanabsolutelyunaccountablething. Hetookoneofthesmalloctagonaltablesthatwerescatteredabouttheroom,andsetitinfrontofthefire,withtwolegsonthehearthrug.Onthistableheplacedthemechanism.Thenhedrewupachair,andsatdown. Theonlyotherobjectonthetablewasasmallshadedlamp,thebrightlightofwhichfelluponthemodel. Therewerealsoperhapsadozencandlesabout,twoinbrasscandlesticksuponthemantelandseveralinsconces,sothattheroomwasbrilliantlyilluminated. Isatinalowarm–chairnearestthefire,andIdrewthisforwardsoastobealmostbetweentheTimeTravellerandthefireplace. Filbysatbehindhim,lookingoverhisshoulder. TheMedicalManandtheProvincialMayorwatchedhiminprofilefromtheright,thePsychologistfromtheleft. TheVeryYoungManstoodbehindthePsychologist.Wewereallonthealert. Itappearsincredibletomethatanykindoftrick,howeversubtlyconceivedandhoweveradroitlydone,couldhavebeenplayeduponusundertheseconditions. TheTimeTravellerlookedatus,andthenatthemechanism.'Well?'saidthePsychologist. 'Thislittleaffair,'saidtheTimeTraveller,restinghiselbowsuponthetableandpressinghishandstogetherabovetheapparatus,'isonlyamodel. Itismyplanforamachinetotravelthroughtime. Youwillnoticethatitlookssingularlyaskew,andthatthereisanoddtwinklingappearanceaboutthisbar,asthoughitwasinsomewayunreal.'Hepointedtothepartwithhisfinger. 'Also,hereisonelittlewhitelever,andhereisanother.' TheMedicalMangotupoutofhischairandpeeredintothething.'It'sbeautifullymade,'hesaid. 'Ittooktwoyearstomake,'retortedtheTimeTraveller. Then,whenwehadallimitatedtheactionoftheMedicalMan,hesaid:'NowIwantyouclearlytounderstandthatthislever,beingpressedover,sendsthemachineglidingintothefuture,andthisotherreversesthemotion. Thissaddlerepresentstheseatofatimetraveller. PresentlyIamgoingtopressthelever,andoffthemachinewillgo. Itwillvanish,passintofutureTime,anddisappear.Haveagoodlookatthething. Lookatthetabletoo,andsatisfyyourselvesthereisnotrickery. Idon'twanttowastethismodel,andthenbetoldI'maquack.' Therewasaminute'spauseperhaps.ThePsychologistseemedabouttospeaktome,butchangedhismind. ThentheTimeTravellerputforthhisfingertowardsthelever.'No,'hesaidsuddenly.'Lendmeyourhand.' AndturningtothePsychologist,hetookthatindividual'shandinhisownandtoldhimtoputouthisforefinger. SothatitwasthePsychologisthimselfwhosentforththemodelTimeMachineonitsinterminablevoyage.Weallsawtheleverturn. Iamabsolutelycertaintherewasnotrickery. Therewasabreathofwind,andthelampflamejumped. Oneofthecandlesonthemantelwasblownout,andthelittlemachinesuddenlyswunground,becameindistinct,wasseenasaghostforasecondperhaps,asaneddyoffaintlyglitteringbrassandivory;anditwasgone—vanished!Saveforthelampthetablewasbare. Everyonewassilentforaminute.ThenFilbysaidhewasdamned. ThePsychologistrecoveredfromhisstupor,andsuddenlylookedunderthetable. AtthattheTimeTravellerlaughedcheerfully.'Well?' hesaid,withareminiscenceofthePsychologist. Then,gettingup,hewenttothetobaccojaronthemantel,andwithhisbacktousbegantofillhispipe. Westaredateachother.'Lookhere,'saidtheMedicalMan,'areyouinearnestaboutthis?Doyouseriouslybelievethatthatmachinehastravelledintotime?' 'Certainly,'saidtheTimeTraveller,stoopingtolightaspillatthefire. Thenheturned,lightinghispipe,tolookatthePsychologist'sface. (ThePsychologist,toshowthathewasnotunhinged,helpedhimselftoacigarandtriedtolightituncut.) 'Whatismore,Ihaveabigmachinenearlyfinishedinthere'—heindicatedthelaboratory—'andwhenthatisputtogetherImeantohaveajourneyonmyownaccount.' 'Youmeantosaythatthatmachinehastravelledintothefuture?'saidFilby. 'Intothefutureorthepast—Idon't,forcertain,knowwhich.' AfteranintervalthePsychologisthadaninspiration.'Itmusthavegoneintothepastifithasgoneanywhere,'hesaid. 'Why?'saidtheTimeTraveller. 'BecauseIpresumethatithasnotmovedinspace,andifittravelledintothefutureitwouldstillbehereallthistime,sinceitmusthavetravelledthroughthistime.' 'But,'Isaid,'Ifittravelledintothepastitwouldhavebeenvisiblewhenwecamefirstintothisroom;andlastThursdaywhenwewerehere;andtheThursdaybeforethat;andsoforth!' 'Seriousobjections,'remarkedtheProvincialMayor,withanairofimpartiality,turningtowardstheTimeTraveller. 'Notabit,'saidtheTimeTraveller,and,tothePsychologist:'Youthink.Youcanexplainthat.It'spresentationbelowthethreshold,youknow,dilutedpresentation.' 'Ofcourse,'saidthePsychologist,andreassuredus.'That'sasimplepointofpsychology.Ishouldhavethoughtofit. It'splainenough,andhelpstheparadoxdelightfully. Wecannotseeit,norcanweappreciatethismachine,anymorethanwecanthespokeofawheelspinning,orabulletflyingthroughtheair. Ifitistravellingthroughtimefiftytimesorahundredtimesfasterthanweare,ifitgetsthroughaminutewhilewegetthroughasecond,theimpressionitcreateswillofcoursebeonlyone–fiftiethorone–hundredthofwhatitwouldmakeifitwerenottravellingintime.That'splainenough.' Hepassedhishandthroughthespaceinwhichthemachinehadbeen.'Yousee?'hesaid,laughing. Wesatandstaredatthevacanttableforaminuteorso.ThentheTimeTravelleraskeduswhatwethoughtofitall. 'Itsoundsplausibleenoughto–night,'saidtheMedicalMan;'butwaituntilto–morrow.Waitforthecommonsenseofthemorning.' 'WouldyouliketoseetheTimeMachineitself?'askedtheTimeTraveller. Andtherewith,takingthelampinhishand,heledthewaydownthelong,draughtycorridortohislaboratory. Iremembervividlytheflickeringlight,hisqueer,broadheadinsilhouette,thedanceoftheshadows,howweallfollowedhim,puzzledbutincredulous,andhowthereinthelaboratorywebeheldalargereditionofthelittlemechanismwhichwehadseenvanishfrombeforeoureyes. Partswereofnickel,partsofivory,partshadcertainlybeenfiledorsawnoutofrockcrystal. Thethingwasgenerallycomplete,butthetwistedcrystallinebarslayunfinisheduponthebenchbesidesomesheetsofdrawings,andItookoneupforabetterlookatit.Quartzitseemedtobe. 'Lookhere,'saidtheMedicalMan,'areyouperfectlyserious?Oristhisatrick—likethatghostyoushoweduslastChristmas?' 'Uponthatmachine,'saidtheTimeTraveller,holdingthelampaloft,'Iintendtoexploretime.Isthatplain?Iwasnevermoreseriousinmylife.' Noneofusquiteknewhowtotakeit. IcaughtFilby'seyeovertheshoulderoftheMedicalMan,andhewinkedatmesolemnly.