Shouldthestorythatisabouttobeunfoldedbefoundtolackinterest，thewritersmuststandconvictedofunpardonablelackofart。Nothingbutdulnessinthetellingcouldmarthestory，forinitselfitistherecordofthegrowthofthoseideasthathavemadeourraceanditscivilizationwhattheyare；ofideasinstinctwithhumaninterest，vitalwithmeaningforourrace；
fundamentalintheirinfluenceonhumandevelopment；partandparcelofthemechanismofhumanthoughtontheonehand，andofpracticalcivilizationontheother。Suchaphraseas\"fundamentalprinciples\"mayseematfirstthoughtahardsaying，buttheideaitimpliesislessrepellentthanthephraseitself，forthefundamentalprinciplesinquestionaresocloselylinkedwiththepresentinterestsofeveryoneofusthattheyliewithinthegraspofeveryaveragemanandwoman——nay，ofeverywell-developedboyandgirl。Theseprinciplesarenotmerelythestepping-stonestoculture，theprerequisitesofknowledge——theyare，inthemselves，anessentialpartoftheknowledgeofeverycultivatedperson。
Itisourtask，notmerelytoshowwhattheseprinciplesare，buttopointouthowtheyhavebeendiscoveredbyourpredecessors。
Weshalltracethegrowthoftheseideasfromtheirfirstvaguebeginnings。Weshallseehowvaguenessofthoughtgavewaytoprecision；howageneraltruth，oncegraspedandformulated，wasfoundtobeastepping-stonetoothertruths。Weshallseethattherearenoisolatedfacts，noisolatedprinciples，innature；
thateachpartofourstoryislinkedbyindissolublebandswiththatwhichgoesbefore，andwiththatwhichcomesafter。Forthemostpartthediscoveryofthisprincipleorthatinagivensequenceisnoaccident。GalileoandKepplermustprecedeNewton。
CuvierandLyallmustcomebeforeDarwin；——Which，afterall，isnomorethansayingthatinourTempleofScience，asinanyotherpieceofarchitecture，thefoundationmustprecedethesuperstructure。
Weshallbestunderstandourstoryofthegrowthofscienceifwethinkofeachnewprincipleasastepping-stonewhichmustfitintoitsownparticularniche；andifwereflectthattheentirestructureofmoderncivilizationwouldbedifferentfromwhatitis，andlessperfectthanitis，hadnotthatparticularstepping-stonebeenfoundandshapedandplacedinposition。
Takenasawhole，ourstepping-stonesleadusupanduptowardsthealluringheightsofanacropolisofknowledge，onwhichstandstheTempleofModernScience。Thestoryofthebuildingofthiswonderfulstructureisinitselffascinatingandbeautiful。
I。PREHISTORICSCIENCE
Tospeakofaprehistoricsciencemayseemlikeacontradictionofterms。Thewordprehistoricseemstoimplybarbarism，whilescience，clearlyenough，seemstheoutgrowthofcivilization；butrightlyconsidered，thereisnocontradiction。For，ontheonehand，manhadceasedtobeabarbarianlongbeforethebeginningofwhatwecallthehistoricalperiod；and，ontheotherhand，science，ofakind，isnolessaprecursorandacauseofcivilizationthanitisaconsequent。Togetthisclearlyinmind，wemustaskourselves:What，then，isscience？Thewordrunsgliblyenoughuponthetongueofourevery-dayspeech，butitisnotoften，perhaps，thattheywhouseithabituallyaskthemselvesjustwhatitmeans。Yettheanswerisnotdifficult。A
littleattentionwillshowthatscience，asthewordiscommonlyused，impliesthesethings:first，thegatheringofknowledgethroughobservation；second，theclassificationofsuchknowledge，andthroughthisclassification，theelaborationofgeneralideasorprinciples。InthefamiliardefinitionofHerbertSpencer，scienceisorganizedknowledge。
Nowitispatentenough，atfirstglance，thattheveriestsavagemusthavebeenanobserverofthephenomenaofnature。Butitmaynotbesoobviousthathemustalsohavebeenaclassifierofhisobservations——anorganizerofknowledge。Yetthemoreweconsiderthecase，themoreclearitwillbecomethatthetwomethodsaretoocloselylinkedtogethertobedissevered。Toobserveoutsidephenomenaisnotmoreinherentinthenatureofthemindthantodrawinferencesfromthesephenomena。Adeerpassingthroughtheforestscentsthegroundanddetectsacertainodor。Asequenceofideasisgeneratedinthemindofthedeer。Nothinginthedeer’sexperiencecanproducethatodorbutawolf；thereforethescientificinferenceisdrawnthatwolveshavepassedthatway。
Butitisapartofthedeer’sscientificknowledge，basedonpreviousexperience，individualandracial；thatwolvesaredangerousbeasts，andso，combiningdirectobservationinthepresentwiththeapplicationofageneralprinciplebasedonpastexperience，thedeerreachestheverylogicalconclusionthatitmaywiselyturnaboutandruninanotherdirection。Allthisimplies，essentially，acomprehensionanduseofscientificprinciples；and，strangeasitseemstospeakofadeeraspossessingscientificknowledge，yetthereisreallynoabsurdityinthestatement。Thedeerdoespossessscientificknowledge；
knowledgedifferingindegreeonly，notinkind，fromtheknowledgeofaNewton。Noristheanimal，withintherangeofitsintelligence，lesslogical，lessscientificintheapplicationofthatknowledge，thanistheman。Theanimalthatcouldnotmakeaccuratescientificobservationsofitssurroundings，anddeduceaccuratescientificconclusionsfromthem，wouldsoonpaythepenaltyofitslackoflogic。
Whatistrueofman’sprecursorsintheanimalscaleis，ofcourse，trueinawiderandfullersenseofmanhimselfattheveryloweststageofhisdevelopment。Agesbeforethetimewhichthelimitationsofourknowledgeforceustospeakofasthedawnofhistory，manhadreachedahighstageofdevelopment。Asasocialbeing，hehaddevelopedalltheelementsofaprimitivecivilization。If，forconvenienceofclassification，wespeakofhisstateassavage，orbarbaric，weusetermswhich，afterall，arerelative，andwhichdonotshutoffourprimitiveancestorsfromatolerablycloseassociationwithourownideals。Weknowthat，evenintheStoneAge，manhadlearnedhowtodomesticateanimalsandmakethemusefultohim，andthathehadalsolearnedtocultivatethesoil。Lateron，doubtlessbyslowandpainfulstages，heattainedthosewonderfulelementsofknowledgethatenabledhimtosmeltmetalsandtoproduceimplementsofbronze，andthenofiron。EvenintheStoneAgehewasamechanicofmarvellousskill，asanyoneofto-daymaysatisfyhimselfbyattemptingtoduplicatesuchanimplementasachippedarrow-head。Andabarbarianwhocouldfashionanaxeoraknifeofbronzehadcertainlygonefarinhisknowledgeofscientificprinciplesandtheirpracticalapplication。Thepracticalapplicationwas，doubtless，theonlythoughtthatourprimitiveancestorhadinmind；quiteprobablythequestionastoprinciplesthatmightbeinvolvedtroubledhimnotatall。Yet，inspiteofhimself，heknewcertainrudimentaryprinciplesofscience，eventhoughhedidnotformulatethem。
Letusinquirewhatsomeoftheseprinciplesare。Suchaninquirywill，asitwere，clearthegroundforourstructureofscience。
Itwillshowtheplaneofknowledgeonwhichhistoricalinvestigationbegins。Incidentally，perhaps，itwillrevealtousunsuspectedaffinitiesbetweenourselvesandourremoteancestor。
Withoutattemptinganythinglikeafullanalysis，wemaynoteinpassing，notmerelywhatprimitivemanknew，butwhathedidnotknow；thatatleastavaguenotionmaybegainedofthefieldforscientificresearchthatlayopenforhistoricmantocultivate。
Itmustbeunderstoodthattheknowledgeofprimitiveman，asweareabouttooutlineit，isinferential。Wecannottracethedevelopmentoftheseprinciples，muchlesscanwesaywhodiscoveredthem。Someofthem，asalreadysuggested，areman’sheritagefromnon-humanancestors。Otherscanonlyhavebeengraspedbyhimafterhehadreachedarelativelyhighstageofhumandevelopment。Butalltheprinciplesherelistedmustsurelyhavebeenpartsofourprimitiveancestor’sknowledgebeforethoseearliestdaysofEgyptianandBabyloniancivilization，therecordsofwhichconstituteourfirstintroductiontotheso-calledhistoricalperiod。Takensomewhatintheorderoftheirprobablediscovery，thescientificideasofprimitivemanmayberoughlylistedasfollows:
1。Primitivemanmusthaveconceivedthattheearthisflatandoflimitlessextent。Bythisitisnotmeanttoimplythathehadadistinctconceptionofinfinity，but，forthatmatter，itcannotbesaidthatanyoneto-dayhasaconceptionofinfinitythatcouldbecalleddefinite。But，reasoningfromexperienceandthereportsoftravellers，therewasnothingtosuggesttoearlymanthelimitoftheearth。Hedid，indeed，findinhiswanderings，thatchangedclimaticconditionsbarredhimfromfartherprogress；butbeyondthefarthestreachesofhismigrations，theseeminglyflatland-surfacesandwater-surfacesstretchedawayunbrokenand，toallappearances，withoutend。Itwouldrequireareachofthephilosophicalimaginationtoconceivealimittotheearth，andwhilesuchimaginingsmayhavebeencurrentintheprehistoricperiod，wecanhavenoproofofthem，andwemaywellpostponeconsiderationofman’searlydreamingsastotheshapeoftheearthuntilweenterthehistoricalepochwherewestandonfirmground。
2。Primitivemanmust，fromaveryearlyperiod，haveobservedthatthesungivesheatandlight，andthatthemoonandstarsseemtogivelightonlyandnoheat。Itrequiredbutaslightextensionofthisobservationtonotethatthechangingphasesoftheseasonswereassociatedwiththeseemingapproachandrecessionofthesun。Thisobservation，however，couldnothavebeenmadeuntilmanhadmigratedfromthetropicalregions，andhadreachedastageofmechanicaldevelopmentenablinghimtoliveinsubtropicalortemperatezones。Eventhenitisconceivablethatalongperiodmusthaveelapsedbeforeadirectcausalrelationwasfelttoexistbetweentheshiftingofthesunandtheshiftingoftheseasons；because，aseveryoneknows，theperiodsofgreatestheatinsummerandgreatestcoldinwinterusuallycomesomeweeksafterthetimeofthesolstices。Yet，thefactthattheseextremesoftemperatureareassociatedinsomewaywiththechangeofthesun’splaceintheheavensmust，intime，haveimpresseditselfuponevenarudimentaryintelligence。
Itishardlynecessarytoaddthatthisisnotmeanttoimplyanydefiniteknowledgeoftherealmeaningof，theseemingoscillationsofthesun。Weshallseethat，evenatarelativelylateperiod，thevaguestnotionswerestillinvogueastothecauseofthesun’schangesofposition。
Thatthesun，moon，andstarsmoveacrosstheheavensmustobviouslyhavebeenamongtheearliestscientificobservations。
Itmustnotbeinferred，however，thatthisobservationimpliedanecessaryconceptionofthecompleterevolutionofthesebodiesabouttheearth。Itisunnecessarytospeculatehereastohowtheprimitiveintelligenceconceivedthetransferofthesunfromthewesterntotheeasternhorizon，tobeeffectedeachnight，forweshallhaveoccasiontoexaminesomehistoricalspeculationsregardingthisphenomenon。Wemayassume，however，thattheideaofthetransferoftheheavenlybodiesbeneaththeearthwhatevertheconceptionastotheformofthatbodymustearlyhavepresenteditself。
Itrequiredarelativelyhighdevelopmentoftheobservingfaculties，yetadevelopmentwhichmanmusthaveattainedagesbeforethehistoricalperiod，tonotethatthemoonhasasecondarymotion，whichleadsittoshiftitsrelativepositionintheheavens，asregardsthestars；thatthestarsthemselves，ontheotherhand，keepafixedrelationasregardsoneanother，withthenotableexceptionoftwoorthreeofthemostbrilliantmembersofthegalaxy，thelatterbeingthebodieswhichcametobeknownfinallyasplanets，orwanderingstars。ThewanderingpropensitiesofsuchbrilliantbodiesasJupiterandVenuscannotwellhaveescapeddetection。Wemaysafelyassume，however，thattheseanomalousmotionsofthemoonandplanetsfoundnoexplanationthatcouldbecalledscientificuntilarelativelylateperiod。
3。Turningfromtheheavenstotheearth，andignoringsuchprimitiveobservationsasthatofthedistinctionbetweenlandandwater，wemaynotethattherewasonegreatscientificlawwhichmusthaveforceditselfupontheattentionofprimitiveman。Thisisthelawofuniversalterrestrialgravitation。ThewordgravitationsuggeststhenameofNewton，anditmayexcitesurprisetohearaknowledgeofgravitationascribedtomenwhoprecededthatphilosopherby，say，twenty-fiveorfiftythousandyears。Yettheslightestconsiderationofthefactswillmakeitclearthatthegreatcentrallawthatallheavybodiesfalldirectlytowardstheearth，cannothaveescapedtheattentionofthemostprimitiveintelligence。Thearborealhabitsofourprimitiveancestorsgaveopportunitiesforconstantobservationofthepracticalitiesofthislaw。And，sosoonasmanhaddevelopedthementalcapacitytoformulateideas，oneoftheearliestideasmusthavebeentheconception，howevervaguelyphrasedinwords，thatallunsupportedbodiesfalltowardstheearth。Thesamephenomenonbeingobservedtooperateonwater-surfaces，andnoalterationbeingobservedinitsoperationindifferentportionsofman’shabitat，themostprimitivewanderermusthavecometohavefullfaithintheuniversalactionoftheobservedlawofgravitation。Indeed，itisinconceivablethathecanhaveimaginedaplaceontheearthwherethislawdoesnotoperate。Ontheotherhand，ofcourse，henevergraspedtheconceptionoftheoperationofthislawbeyondthecloseproximityoftheearth。Toextendthereachofgravitationouttothemoonandtothestars，includingwithinitscompasseveryparticleofmatterintheuniverse，wastheworkofNewton，asweshallseeinduecourse。Meantimeweshallbetterunderstandthatworkifwerecallthatthemerelocalfactofterrestrialgravitationhasbeenthefamiliarknowledgeofallgenerationsofmen。ItmayfurtherhelptoconnectusinsympathywithourprimevalancestorifwerecallthatintheattempttoexplainthisfactofterrestrialgravitationNewtonmadenoadvance，andweofto-dayarescarcelymoreenlightenedthanthemanoftheStoneAge。LikethemanoftheStoneAge，weknowthatanarrowshotintotheskyfallsbacktotheearth。Wecancalculate，ashecouldnotdo，thearcitwilldescribeandtheexactspeedofitsfall；butastowhyitreturnstoearthatall，thegreatestphilosopherofto-dayisalmostasmuchinthedarkaswasthefirstprimitivebowmanthatevermadetheexperiment。
Otherphysicalfactsgoingtomakeupanelementaryscienceofmechanics，thatweredemonstrativelyknowntoprehistoricman，weresuchasthese:therigidityofsolidsandthemobilityofliquids；thefactthatchangesoftemperaturetransformsolidstoliquidsandviceversa——thatheat，forexample，meltscopperandeveniron，andthatcoldcongealswater；andthefactthatfriction，asillustratedintherubbingtogetheroftwosticks，mayproduceheatenoughtocauseafire。Therationaleofthislastexperimentdidnotreceiveanexplanationuntilaboutthebeginningofthenineteenthcenturyofourownera。Buttheexperimentalfactwassowellknowntoprehistoricmanthatheemployedthismethod，asvarioussavagetribesemployittothisday，forthealtogetherpracticalpurposeofmakingafire；justasheemployedhispracticalknowledgeofthemutabilityofsolidsandliquidsinsmeltingores，inalloyingcopperwithtintomakebronze，andincastingthisalloyinmoldstomakevariousimplementsandweapons。Here，then，werethegermsofanelementaryscienceofphysics。Meanwhilesuchobservationsasthatofthesolutionofsaltinwatermaybeconsideredasgivingafirstlessoninchemistry，butbeyondsuchaltogetherrudimentaryconceptionschemicalknowledgecouldnothavegone——unless，indeed，thepracticalobservationoftheeffectsoffirebeincluded；norcanthiswellbeoverlooked，sincescarcelyanothersinglelineofpracticalobservationhadamoredirectinfluenceinpromotingtheprogressofmantowardstheheightsofcivilization。
4。Inthefieldofwhatwenowspeakofasbiologicalknowledge，primitivemanhadobviouslythewidestopportunityforpracticalobservation。Wecanhardlydoubtthatmanattained，atanearlyday，tothatconceptionofidentityandofdifferencewhichPlatoplacesattheheadofhismetaphysicalsystem。Weshallurgepresentlythatitispreciselysuchgeneralideasasthesethatwereman’searliestinductionsfromobservation，andhencethatcametoseemthemostuniversaland\"innate\"ideasofhismentality。Itisquiteinconceivable，forexample，thateventhemostrudimentaryintelligencethatcouldbecalledhumancouldfailtodiscriminatebetweenlivingthingsand，letussay，therocksoftheearth。Themostprimitiveintelligence，then，musthavemadeatacitclassificationofthenaturalobjectsaboutitintothegranddivisionsofanimateandinanimatenature。
Doubtlessthenascentscientistmayhaveimaginedlifeanimatingmanybodiesthatweshouldcallinanimate——suchasthesun，wanderingplanets，thewinds，andlightning；and，ontheotherhand，hemayquitelikelyhaverelegatedsuchobjectsastreestotheranksofthenon-living；butthatherecognizedafundamentaldistinctionbetween，letussay，awolfandagranitebowlderwecannotwelldoubt。Astepbeyondthis——astep，however，thatmayhaverequiredcenturiesormillenniumsinthetaking——musthavecarriedmantoaplaneofintelligencefromwhichaprimitiveAristotleorLinnaeuswasenabledtonotedifferencesandresemblancesconnotingsuchgroupsofthingsasfishes，birds，andfurrybeasts。Thisconception，tobesure，isanabstractionofarelativelyhighorder。Weknowthattherearesavageracesto-daywhoselanguagecontainsnowordforsuchanabstractionasbirdortree。Weareboundtobelieve，then，thattherewerelongagesofhumanprogressduringwhichthehighestmanhadattainednosuchstageofabstraction；but，ontheotherhand，itisequallylittleinquestionthatthisdegreeofmentaldevelopmenthadbeenattainedlongbeforetheopeningofourhistoricalperiod。Theprimevalman，then，whosescientificknowledgeweareattemptingtopredicate，hadbecome，throughhisconceptionoffishes，birds，andhairyanimalsasseparateclasses，ascientificzoologistofrelativelyhighattainments。
Inthepracticalfieldofmedicalknowledge，acertainstageofdevelopmentmusthavebeenreachedataveryearlyday。Evenanimalspickandchooseamongthevegetablesaboutthem，andattimesseekoutcertainherbsquitedifferentfromtheirordinaryfood，practisingasortofinstinctivetherapeutics。Thecat’sfondnessforcatnipisacaseinpoint。Themostprimitiveman，then，musthaveinheritedaracialorinstinctiveknowledgeofthemedicinaleffectsofcertainherbs；inparticularhemusthavehadsuchelementaryknowledgeoftoxicologyaswouldenablehimtoavoideatingcertainpoisonousberries。Perhaps，indeed，weareplacingtheeffectbeforethecausetosomeextent；for，afterall，theanimalsystempossessesmarvellouspowersofadaption，andthereisperhapshardlyanypoisonousvegetablewhichmanmightnothavelearnedtoeatwithoutdeleteriouseffect，providedtheexperimentweremadegradually。Toacertainextent，then，theobservedpoisonouseffectsofnumerousplantsuponthehumansystemaretobeexplainedbythefactthatourancestorshaveavoidedthisparticularvegetable。Certainfruitsandberriesmighthavecometohavebeenapartofman’sdiet，hadtheygrownintheregionsheinhabitedatanearlyday，whichnowarepoisonoustohissystem。Thisthought，however，carriesustoofarafield。Forpracticalpurposes，itsufficesthatcertainroots，leaves，andfruitspossessprinciplesthatarepoisonoustothehumansystem，andthatunlessmanhadlearnedinsomewaytoavoidthese，ourracemusthavecometodisaster。Inpointoffact，hedidlearntoavoidthem；andsuchevidenceimplied，ashasbeensaid，anelementaryknowledgeoftoxicology。
Coupledwiththisknowledgeofthingsdangeroustothehumansystem，theremusthavegrownup，ataveryearlyday，abeliefintheremedialcharacterofvariousvegetablesasagentstocombatdisease。Here，ofcourse，wasarudimentarytherapeutics，acrudeprincipleofanempiricalartofmedicine。Asjustsuggested，thelowerorderofanimalshaveaninstinctiveknowledgethatenablesthemtoseekoutremedialherbsthoughweprobablyexaggeratetheextentofthisinstinctiveknowledge；
andifthisbetrue，manmusthaveinheritedfromhisprehumanancestorsthisinstinctalongwiththeothers。Thatheextendedthisknowledgethroughobservationandpractice，andcameearlytomakeextensiveuseofdrugsinthetreatmentofdisease，isplacedbeyondcavilthroughtheobservationofthevariousexistingbarbarictribes，nearlyallofwhompracticeelaboratesystemsoftherapeutics。Weshallhaveoccasiontoseethatevenwithinhistorictimestheparticulartherapeuticmeasuresemployedwereoftencrude，and，asweareaccustomedtosay，unscientific；buteventhecrudestofthemarereallybaseduponscientificprinciples，inasmuchastheirapplicationimpliesthedeductionofprinciplesofactionfrompreviousobservations。
Certaindrugsareappliedtoappeasecertainsymptomsofdiseasebecauseinthebeliefofthemedicine-mansuchdrugshaveprovedbeneficialinprevioussimilarcases。
Allthis，however，impliesanappreciationofthefactthatmanissubjectto\"natural\"diseases，andthatifthesediseasesarenotcombated，deathmayresult。Butitshouldbeunderstoodthattheearliestmanprobablyhadnosuchconceptionasthis。
Throughoutalltheagesofearlydevelopment，whatwecall\"natural\"diseaseand\"natural\"deathmeanttheonslaughtofatangibleenemy。Astudyofthisquestionleadsustosomeverycuriousinferences。Themorewelookintothematterthemorethethoughtforcesitselfhometousthattheideaofnaturaldeath，aswenowconceiveit，cametoprimitivemanasarelativelylatescientificinduction。Thisthoughtseemsalmoststartling，soaxiomatichastheconception\"manismortal\"cometoappear。Yetastudyoftheideasofexistingsavages，combinedwithourknowledgeofthepointofviewfromwhichhistoricalpeoplesregarddisease，makeitmoreprobablethattheprimitiveconceptionofhumanlifedidnotincludetheideaofnecessarydeath。WearetoldthattheAustraliansavagewhofallsfromatreeandbreakshisneckisnotregardedashavingmetanaturaldeath，butashavingbeenthevictimofthemagicalpracticesofthe\"medicine-man\"ofsomeneighboringtribe。Similarly，weshallfindthattheEgyptianandtheBabylonianoftheearlyhistoricalperiodconceivedillnessasbeingalmostinvariablytheresultofthemachinationsofanenemy。OneneedbutrecallthesuperstitiousobservancesoftheMiddleAges，andtheyetmorerecentbeliefinwitchcraft，torealizehowgenerallydiseasehasbeenpersonifiedasamaliciousagentinvokedbyanunfriendlymind。Indeed，thephraseologyofourpresent-dayspeechisstillreminiscentofthis；aswhen，forexample，wespeakofan\"attackoffever，\"andthelike。
When，followingoutthisidea，wepicturetoourselvestheconditionsunderwhichprimitivemanlived，itwillbeevidentatoncehowrelativelyinfrequentmusthavebeenhisobservationofwhatweusuallytermnaturaldeath。Hisworldwasaworldofstrife；helivedbythechase；hesawanimalskilloneanother；
hewitnessedthedeathofhisownfellowsatthehandsofenemies。Naturallyenough，then，whenamemberofhisfamilywas\"struckdown\"byinvisibleagents，heascribedthisdeathalsotoviolence，eventhoughtheoffensiveagentwasconcealed。
Moreover，havingverylittleideaofthelapseoftime——beingquiteunaccustomed，thatis，toreckoneventsfromanyfixedera——primitivemancannothavegainedatonceaclearconceptionofageasappliedtohisfellows。Untilarelativelylatestageofdevelopmentmadetriballifepossible，itcannothavebeenusualformantohaveknowledgeofhisgrandparents；asarulehedidnotknowhisownparentsafterhehadpassedtheadolescentstageandhadbeenturnedoutupontheworldtocareforhimself。
If，then，certainofhisfellow-beingsshowedthoseevidencesofinfirmitywhichweascribetoage，itdidnotnecessarilyfollowthathesawanyassociationbetweensuchinfirmitiesandthelengthoftimewhichthosepersonshadlived。Theveryfactthatsomebarbaricnationsretainthecustomofkillingtheagedandinfirm，initselfsuggeststhepossibilitythatthiscustomarosebeforeaclearconceptionhadbeenattainedthatsuchdragsuponthecommunitywouldberemovedpresentlyinthenaturalorderofthings。Toapersonwhohadnoclearconceptionofthelapseoftimeandnopreconceptionastothelimitedperiodofman’slife，theinfirmitiesofagemightverynaturallybeascribedtotherepeatedattacksofthoseinimicalpowerswhichwereunderstoodsoonerorlatertocarryoffmostmembersoftherace。Andcoupledwiththisthoughtwouldgotheconceptionthatinasmuchassomepeoplethroughluckhadescapedthevengeanceofalltheirenemiesforlongperiods，thesesameindividualsmightcontinuetoescapeforindefiniteperiodsofthefuture。Therewerenowrittenrecordstotellprimevalmanofeventsoflongago。Helivedinthepresent，andhissweepofideasscarcelycarriedhimbackbeyondthelimitsofhisindividualmemory。Butmemoryisobservedtobefallacious。Itmustearlyhavebeennotedthatsomepeoplerecalledeventswhichotherparticipantsinthemhadquiteforgotten，anditmayreadilyenoughhavebeeninferredthatthosemembersofthetribewhospokeofeventswhichotherscouldnotrecallweremerelytheoneswhoweregiftedwiththebestmemories。Ifthesereachedaperiodwhentheirmemoriesbecamevague，itdidnotfollowthattheirrecollectionshadcarriedthembacktothebeginningsoftheirlives。Indeed，itiscontrarytoallexperiencetobelievethatanymanremembersallthethingshehasonceknown，andtheobservedfallaciousnessandevanescenceofmemorywouldthustendtosubstantiateratherthantocontroverttheideathatvariousmembersofatribehadbeenaliveforanindefiniteperiod。
Withoutfurtherelaboratingtheargument，itseemsajustifiableinferencethatthefirstconceptionprimitivemanwouldhaveofhisownlifewouldnotincludethethoughtofnaturaldeath，butwould，conversely，connotethevagueconceptionofendlesslife。
Ourownancestors，afewgenerationsremoved，hadnotgotridofthisconception，astheperpetualquestofthespringofeternalyouthamplytestifies。Anaturalistofourowndayhassuggestedthatperhapsbirdsneverdieexceptbyviolence。Thethought，then，thatmanhasatermofyearsbeyondwhich\"inthenatureofthings，\"asthesayinggoes，hemaynotlive，wouldhavedawnedbutgraduallyuponthedevelopingintelligenceofsuccessivegenerationsofmen；andwecannotfeelsurethathewouldfullyhavegraspedtheconceptionofa\"natural\"terminationofhumanlifeuntilhehadshakenhimselffreefromtheideathatdiseaseisalwaystheresultofthemagicpracticeofanenemy。Ourobservationofhistoricalmaninantiquitymakesitsomewhatdoubtfulwhetherthisconceptionhadbeenattainedbeforethecloseoftheprehistoricperiod。Ifithad，thisconceptionofthemortalityofmanwasoneofthemoststrikingscientificinductionstowhichprehistoricmanattained。Incidentally，itmaybenotedthattheconceptionofeternallifeforthehumanbodybeingamoreprimitiveideathantheconceptionofnaturaldeath，theideaoftheimmortalityofthespiritwouldbethemostnaturalofconceptions。Theimmortalspirit，indeed，wouldbebutacorrelativeoftheimmortalbody，andtheideawhichweshallseeprevalentamongtheEgyptiansthatthesoulpersistsonlyaslongasthebodyisintact——theideauponwhichthepracticeofmummifyingthedeaddepended——findsareadyexplanation。Butthisphaseofthesubjectcarriesussomewhatafield。Forourpresentpurposeitsufficestohavepointedoutthattheconceptionofman’smortality——aconceptionwhichnowseemsofallothersthemostnaturaland\"innate\"——wasinallprobabilityarelativelylatescientificinductionofourprimitiveancestors。
5。Turningfromtheconsiderationofthebodytoitsmentalcomplement，weareforcedtoadmitthathere，also，ourprimitivemanmusthavemadecertainelementaryobservationsthatunderliesuchsciencesaspsychology，mathematics，andpoliticaleconomy。
Theelementaryemotionsassociatedwithhungerandwithsatiety，withloveandwithhatred，musthaveforcedthemselvesupontheearliestintelligencethatreachedtheplaneofconsciousself-observation。Thecapacitytocount，atleasttothenumberfourorfive，iswithintherangeofevenanimalintelligence。
Certainsavageshavegonescarcelyfartherthanthis；butourprimevalancestor，whowasforgingontowardscivilization，hadlearnedtocounthisfingersandtoes，andtonumberobjectsabouthimbyfivesandtensinconsequence，beforebepassedbeyondtheplaneofnumerousexistingbarbarians。Howmuchbeyondthishehadgoneweneednotattempttoinquire；buttherelativelyhighdevelopmentofmathematicsintheearlyhistoricalperiodsuggeststhatprimevalmanhadattainedanotinconsiderableknowledgeofnumbers。Thehumdrumvocationoflookingafteranumerousprogenymusthavetaughtthemothertherudimentsofadditionandsubtraction；andtheelementsofmultiplicationanddivisionareimpliedinthecapacitytocarryoneventherudestformofbarter，suchasthevarioustribesmusthavepractisedfromanearlyday。
Astopoliticalideas，eventhecrudesttriballifewasbasedoncertainconceptionsofownership，atleastoftribalownership，andtheapplicationoftheprincipleoflikenessanddifferencetowhichwehavealreadyreferred。Eachtribe，ofcourse，differedinsomeregardfromothertribes，andtherecognitionofthesedifferencesimpliedinitselfapoliticalclassification。A
certaintribetookpossessionofaparticularhunting-ground，whichbecame，forthetimebeing，itshome，andoverwhichitcametoexercisecertainrights。Aninvasionofthisterritorybyanothertribemightleadtowar，andthebandingtogetherofthemembersofthetribetorepeltheinvaderimpliedbotharecognitionofcommunalunityandaspeciesofprejudiceinfavorofthatcommunitythatconstitutedaprimitivepatriotism。Butthisunityofactioninopposinganothertribewouldnotpreventacertainrivalryofinterestbetweenthemembersofthesametribe，whichwouldshowitselfmoreandmoreprominentlyasthetribeincreasedinsize。Theassociationoftwoormorepersonsimplies，always，theascendencyofsomeandthesubordinationofothers。Leadershipandsubordinationarenecessarycorrelativesofdifferenceofphysicalandmentalendowment，andrivalrybetweenleaderswouldinevitablyleadtotheformationofprimitivepoliticalparties。Withtheultimatesuccessandascendencyofoneleader，whosecureseitherabsolutepowerorpowermodifiedinaccordancewiththeadviceofsubordinateleaders，wehavethegermsofanelaboratepoliticalsystem——anembryoscienceofgovernment。
Meanwhile，theveryexistenceofsuchacommunityimpliestherecognitiononthepartofitsmembersofcertainindividualrights，therecognitionofwhichisessentialtocommunalharmony。Therightofindividualownershipofthevariousarticlesandimplementsofevery-daylifemustberecognized，orallharmonywouldbeatanend。Certainrulesofjustice——
primitivelaws——must，bycommonconsent，giveprotectiontotheweakestmembersofthecommunity。Herearetherudimentsofasystemofethics。Itmayseemanomaloustospeakofthisprimitivemorality，thisearlyrecognitionoftheprinciplesofrightandwrong，ashavinganyrelationtoscience。Yet，rightlyconsidered，thereisnoincongruityinsuchacitation。Therecannotwellbeadoubtthattheadoptionofthosebroadprinciplesofrightandwrongwhichunderlietheentirestructureofmoderncivilizationwasduetoscientificinduction，——inotherwords，tothebelief，basedonobservationandexperience，thattheprinciplesimpliedwereessentialtocommunalprogress。Hewhohasscannedthepageantofhistoryknowshowoftentheseprinciplesseemtobeabsentintheintercourseofmenandnations。Yettheidealisalwaysthereasastandardbywhichalldeedsarejudged。
Itwouldappear，then，thattheentiresuperstructureoflatersciencehaditsfoundationintheknowledgeandpracticeofprehistoricman。Thecivilizationofthehistoricalperiodcouldnothaveadvancedasithashadtherenotbeencountlessgenerationsofculturebackofit。Thenewprinciplesofsciencecouldnothavebeenevolvedhadtherenotbeengreatbasalprincipleswhichagesofunconsciousexperimenthadimpresseduponthemindofourrace。Duemeedofpraisemustbegiven，then，toourprimitiveancestorforhisscientificaccomplishments；butjusticedemandsthatweshouldlookalittlefartherandconsiderthereversesideofthepicture。Wehavehadtodo，thusfar，chieflywiththepositivesideofaccomplishment。Wehavepointedoutwhatourprimitiveancestorknew，intimating，perhaps，thelimitationsofhisknowledge；butwehavehadlittletosayofoneall-importantfeatureofhisscientifictheorizing。Thefeatureinquestionisbasedonthehighlyscientificdesireandpropensitytofindexplanationsforthephenomenaofnature。Withoutsuchdesirenoprogresscouldbemade。Itis，aswehaveseen，thegeneralizingfromexperiencethatconstitutesrealscientificprogress；andyet，justasmostothergoodthingscanbeoverdone，thisscientificpropensitymaybecarriedtoadisastrousexcess。
Primevalmandidnotescapethisdanger。Heobserved，hereasoned，hefoundexplanations；buthedidnotalwaysdiscriminateastothelogicalityofhisreasonings。Hefailedtorecognizethelimitationsofhisknowledge。Theobserveduniformityinthesequenceofcertaineventsimpressedonhismindtheideaofcauseandeffect。Proximatecausesknown，hesoughtremotercauses；childlike，hisinquiringmindwasalwaysasking，Why？and，childlike，hedemandedanexplicitanswer。Iftheforcesofnatureseemedtocombathim，ifwindandrainopposedhisprogressandthunderandlightningseemedtomenacehisexistence，hewasledirrevocablytothinkofthosehumanfoeswhowarredwithhim，andtosee，backofthewarfareoftheelements，aninscrutablemalevolentintelligencewhichtookthismethodtoexpressitsdispleasure。Buteveryotherlineofscientificobservationleadsequally，followingbackasequenceofevents，toseeminglycauselessbeginnings。Modernsciencecanexplainthelightning，asitcanexplainagreatnumberofthemysterieswhichtheprimevalintelligencecouldnotpenetrate。
Buttheprimordialmancouldnotwaitfortherevelationsofscientificinvestigation:hemustvaultatoncetoafinalsolutionofallscientificproblems。Hefoundhissolutionbypeoplingtheworldwithinvisibleforces，anthropomorphicintheirconception，likehimselfintheirthoughtandaction，differingonlyinthelimitationsoftheirpowers。Hisowndreamexistencegavehimseemingproofoftheexistenceofanalterego，aspiritualportionofhimselfthatcoulddisseveritselffromhisbodyandwanderatwill；hisscientificinductionsseemedtotellhimofaworldofinvisiblebeings，capableofinfluencinghimforgoodorill。Fromthescientificexerciseofhisfacultiesheevolvedtheall-encompassinggeneralizationsofinvisibleandall-powerfulcausesbackofthephenomenaofnature。Thesegeneralizations，earlydevelopedandseeminglysupportedbytheobservationsofcountlessgenerations，cametobeamongthemostfirmlyestablishedscientificinductionsofourprimevalancestor。Theyobtainedaholduponthementalityofourracethatledsubsequentgenerationstothinkofthem，sometimestospeakofthem，as\"innate\"ideas。Theobservationsuponwhichtheywerebasedarenow，forthemostpart，susceptibleofotherinterpretations；buttheoldinterpretationshaveprecedentandprejudicebackofthem，andtheyrepresentideasthataremoredifficultthanalmostanyotherstoeradicate。Always，andeverywhere，superstitionsbaseduponunwarrantedearlyscientificdeductionshavebeenthemostimplacablefoestotheprogressofscience。Menhavebuiltsystemsofphilosophyaroundtheirconceptionofanthropomorphicdeities；theyhavelinkedtothesesystemsofphilosophythealliedconceptionoftheimmutabilityofman’sspirit，andtheyhaveaskedthatscientificprogressshouldstopshortatthebrinkofthesesystemsofphilosophyandaccepttheirdictatesasfinal。Yetthereisnotto-dayinexistence，andthereneverhasbeen，onejotofscientificevidencefortheexistenceoftheseintangibleanthropomorphicpowersbackofnaturethatisnotsusceptibleofscientificchallengeandofmorelogicalinterpretation。Indespiteofwhichthesuperstitiousbeliefsarestillasfirmlyfixedinthemindsofalargemajorityofourraceastheywereinthemindofourprehistoricancestor。Thefactofthisbalefulheritagemustnotbeforgotteninestimatingthedebtofgratitudewhichhistoricmanowestohisbarbaricpredecessor。
Inthepreviouschapterwehavepurposelyrefrainedfromreferringtoanyparticulartribeorraceofhistoricalman。Now，however，weareatthebeginningsofnationalexistence，andwehavetoconsidertheaccomplishmentsofanindividualrace；orrather，perhaps，oftwoormoreracesthatoccupiedsuccessivelythesamegeographicalterritory。Butevennowourstudiesmustforatimeremainverygeneral；weshallseelittleornothingofthedeedsofindividualscientistsinthecourseofourstudyofEgyptianculture。Wearestill，itmustbeunderstood，atthebeginningsofhistory；indeed，wemustfirstbridgeoverthegapfromtheprehistoricbeforewemayfindourselvesfairlyonthelineofmarchofhistoricalscience。
Attheveryoutsetwemaywellaskwhatconstitutesthedistinctionbetweenprehistoricandhistoricepochs——adistinctionwhichhasbeenconstantlyimpliedinmuchthatwehavesaid。Thereplysavorssomewhatofvagueness。Itisadistinctionhavingtodo，notsomuchwithfactsofhumanprogressaswithourinterpretationofthesefacts。Whenwespeakofthedawnofhistorywemustnotbeunderstoodtoimplythat，attheperiodinquestion，therewasanysuddenchangeintheintellectualstatusofthehumanraceorinthestatusofanyindividualtribeornationofmen。Whatwemeanisthatmodernknowledgehaspenetratedthemistsofthepastfortheperiodwetermhistoricalwithsomethingmoreofclearnessandprecisionthanithasbeenabletobringtobearuponyetearlierperiods。
Newaccessionsofknowledgemaythusshiftfromtimetotimetheboundsoftheso-calledhistoricalperiod。TheclearestillustrationofthisisfurnishedbyourinterpretationofEgyptianhistory。UntilrecentlythebiblicalrecordsoftheHebrewcaptivityorservice，togetherwiththesimilaraccountofJosephus，furnishedaboutallthatwasknownofEgyptianhistoryevenofsocomparativelyrecentatimeasthatofRamsesII。
fifteenthcenturyB。C。，andfromthatperiodontherewasalmostacompletegapuntilthestorywastakenupbytheGreekhistoriansHerodotusandDiodorus。Itistruethattheking-listsoftheAlexandrianhistorian，Manetho，wereallalongaccessibleinsomewhatgarbledcopies。Butatbesttheyseemedtosupplyunintelligiblelistsofnamesanddateswhichnoonewasdisposedtotakeseriously。Thattheywere，broadlyspeaking，truehistoricalrecords，andmostimportanthistoricalrecordsatthat，wasnotrecognizedbymodernscholarsuntilfreshlighthadbeenthrownonthesubjectfromaltogethernewsources。
Thesenewsourcesofknowledgeofancienthistorydemandamoment’sconsideration。Theyareall-importantbecausetheyhavebeenthemeansofextendingthehistoricalperiodofEgyptianhistoryusingthewordhistoryinthewayjustexplainedbythreeorfourthousandyears。Asjustsuggested，thathistoricalperiodcarriedthescholarshipoftheearlynineteenthcenturyscarcelybeyondthefifteenthcenturyB。C。，butto-day’svisionextendswithtolerableclearnesstoaboutthemiddleofthefifthmillenniumB。C。ThischangehasbeenbroughtaboutchieflythroughstudyoftheEgyptianhieroglyphics。Thesehieroglyphicsconstitute，aswenowknow，ahighlydevelopedsystemofwriting；
asystemthatwaspractisedforsomethousandsofyears，butwhichfellutterlyintodisuseinthelaterRomanperiod，andtheknowledgeofwhichpassedabsolutelyfromthemindofman。Forabouttwothousandyearsnoonewasabletoread，withanydegreeofexplicitness，asinglecharacterofthisstrangescript，andtheideabecameprevalentthatitdidnotconstitutearealsystemofwriting，butonlyamoreorlessbarbaricsystemofreligioussymbolism。ThefalsityofthisviewwasshownearlyinthenineteenthcenturywhenDr。ThomasYoungwasled，throughstudyofthefamoustrilingualinscriptionoftheRosettastone，tomakethefirstsuccessfulattemptatclearingupthemysteriesofthehieroglyphics。
Thisisnottheplacetotellthestoryofhisfascinatingdiscoveriesandthoseofhissuccessors。Thatstorybelongstonineteenth-centuryscience，nottothescienceoftheEgyptians。
SufficeitherethatYounggainedthefirstclewtoafewofthephoneticvaluesoftheEgyptiansymbols，andthattheworkofdiscoverywascarriedonandvastlyextendedbytheFrenchmanChampollion，alittlelater，withtheresultthatthefirmfoundationsofthemodernscienceofEgyptologywerelaid。
SubsequentlysuchstudentsasRosellinitheItalian，LepsiustheGerman，andWilkinsontheEnglishman，enteredthefield，whichinduecoursewascultivatedbyDeRougeinFranceandBirchinEngland，andbysuchdistinguishedlatter-dayworkersasChabas，Mariette，Maspero，Amelineau，andDeMorganamongtheFrenchmen；
ProfessorPetrieandDr。BudgeinEngland；andBrugschPashaandProfessorErmaninGermany，nottomentionalargecoterieofsomewhatlessfamiliarnames。Thesemenworking，someoftheminthefieldofpracticalexploration，someasstudentsoftheEgyptianlanguageandwriting，haverestoredtousatolerablypreciseknowledgeofthehistoryofEgyptfromthetimeofthefirsthistoricalking，Mena，whosedateisplacedataboutthemiddleofthefifthcenturyB。C。Weknownotmerelythenamesofmostofthesubsequentrulers，butsomethingofthedeedsofmanyofthem；and，whatisvastlymoreimportant，weknow，thankstothemoderninterpretationoftheoldliterature，manythingsconcerningthelifeofthepeople，andinparticularconcerningtheirhighestculture，theirmethodsofthought，andtheirscientificattainments，whichmightwellhavebeensupposedtobepastfindingout。Norhasmoderninvestigationhaltedwiththetimeofthefirstkings；therecentexplorationsofsucharchaeologistsasAmelineau，DeMorgan，andPetriehavebroughttolightnumerousremainsofwhatisnowspokenofasthepredynasticperiod——aperiodwhentheinhabitantsoftheNileValleyusedimplementsofchippedstone，whentheirpotterywasmadewithouttheuseofthepotter’swheel，andwhentheyburiedtheirdeadincuriouslycrampedattitudeswithoutattemptatmummification。TheseaboriginalinhabitantsofEgyptcannotperhapswithstrictproprietybespokenofaslivingwithinthehistoricalperiod，sincewecannotdatetheirrelicswithanyaccuracy。ButtheygiveusglimpsesoftheearlystagesofcivilizationuponwhichtheEgyptiansofthedynasticperiodweretoadvance。
ItisheldthatthenascentcivilizationoftheseEgyptiansoftheNeolithic，orlateStoneAge，wasoverthrownbytheinvadinghostsofamorehighlycivilizedracewhichprobablycamefromtheEast，andwhichmayhavebeenofaSemiticstock。Thepresumptionisthatthisinvadingpeoplebroughtwithitaknowledgeoftheartsofwarandpeace，developedoradoptedinitsoldhome。Theintroductionoftheseartsservedtobridgesomewhatsuddenly，sofarasEgyptisconcerned，thatgapbetweentheprehistoricandthehistoricstageofculturetowhichwehaveallalongreferred。Theessentialstructureofthatbridge，letitnowbeclearlyunderstood，consistedofasingleelement。
Thatelementisthecapacitytomakewrittenrecords:aknowledgeoftheartofwriting。Clearlyunderstood，itisthiselementofknowledgethatformsthelineboundingthehistoricalperiod。
Numberlessmementosareinexistencethattelloftheintellectualactivitiesofprehistoricman；suchmementosasflintimplements，piecesofpottery，andfragmentsofbone，inscribedwithpicturesthatmayfairlybespokenofasworksofart；butsolongasnowrittenwordaccompaniestheserecords，solongasnonameofkingorscribecomesdowntous，wefeelthattheserecordsbelongtothedomainofarchaeologyratherthantothatofhistory。Yetitmustbeunderstoodallalongthatthesetwodomainsshadeoneintotheotherand，ithasalreadybeenurged，thatthedistinctionbetweenthemisonethatpertainsrathertomodernscholarshipthantothedevelopmentofcivilizationitself。Bearingthisdistinctionstillinmind，andrecallingthatthehistoricalperiod，whichistobethefieldofourobservationthroughouttherestofourstudies，extendsforEgyptwellbackintothefifthmillenniumB。C。，letusbrieflyreviewthepracticalphasesofthatcivilizationtowhichtheEgyptianhadattainedbeforethebeginningofthedynasticperiod。Sincetheoreticalscienceiseverywherelinkedwiththemechanicalarts，thissurveywillgiveusaclearcomprehensionofthefieldthatliesopenfortheprogressofscienceinthelongstagesofhistoricaltimeuponwhichwearejustentering。
Wemaypassoversuchrudimentaryadvancesinthedirectionofcivilizationasareimpliedintheuseofarticulatelanguage，theapplicationoffiretotheusesofman，andthesystematicmakingofdwellingsofonesortoranother，sinceallofthesearestagesofprogressthatwerereachedveryearlyintheprehistoricperiod。WhatmoredirectlyconcernsusistonotethatareallyhighstageofmechanicaldevelopmenthadbeenreachedbeforethedawningsofEgyptianhistoryproper。Allmannerofhouseholdutensilswereemployed；thepotter’swheelaidedintheconstructionofagreatvarietyofearthenvessels；
weavinghadbecomeafineart，andweaponsofbronze，includingaxes，spears，knives，andarrow-heads，wereinconstantuse。
Animalshadlongbeendomesticated，inparticularthedog，thecat，andtheox；thehorsewasintroducedlaterfromtheEast。
ThepracticalartsofagriculturewerepractisedalmostastheyareatthepresentdayinEgypt，therebeing，ofcourse，thesamedependencethenasnowupontheinundationsoftheNile。
Astogovernment，theEgyptianofthefirstdynastyregardedhiskingasademi-godtobeactuallydeifiedafterhisdeath，andthispointofviewwasnotchangedthroughoutthestagesoflaterEgyptianhistory。Inpointofart，marvellousadvancesupontheskilloftheprehistoricmanhadbeenmade，probablyinpartunderAsiaticinfluences，andthatuniquestyleofstiltedyetexpressivedrawinghadcomeintovogue，whichwastoberememberedinaftertimesastypicallyEgyptian。Moreimportantthanallelse，ourEgyptianoftheearliesthistoricalperiodwasinpossessionoftheartofwriting。HehadbeguntomakethosespecificrecordswhichwereimpossibletothemanoftheStoneAge，andthushehadenteredfullyuponthewayofhistoricalprogresswhich，asalreadypointedout，hasitsveryfoundationinwrittenrecords。Fromnowonthedeedsofindividualkingscouldfindspecificrecord。Itbegantobepossibletofixthechronologyofremoteeventswithsomeaccuracy；andwiththissamefixingofchronologiescametheadventoftruehistory。TheperiodwhichprecedeswhatisusuallyspokenofasthefirstdynastyinEgyptisoneintowhichthepresent-daysearcherisstillabletoseebutdarkly。TheevidenceseemstosuggestthananinvasionofrelativelyculturedpeoplefromtheEastoverthrew，andintimesupplanted，theNeolithiccivilizationoftheNileValley。Itisimpossibletodatethisinvasionaccurately，butitcannotwellhavebeenlaterthantheyear5000
B。C。，anditmayhavebeenagreatmanycenturiesearlierthanthis。Betheexactdateswhattheymay，wefindtheEgyptianofthefifthmillenniumB。C。infullpossessionofahighlyorganizedcivilization。
Allsubsequentageshavemarvelledatthepyramids，someofwhichdatefromabouttheyear4000B。C。，thoughwemaynoteinpassingthatthesedatesmustnotbetakentooliterally。ThechronologyofancientEgyptcannotasyetbefixedwithexactaccuracy，butthedisagreementsbetweenthevariousstudentsofthesubjectneedgiveuslittleconcern。Forourpresentpurposeitdoesnotintheleastmatterwhetherthepyramidswerebuiltthreethousandorfourthousandyearsbeforethebeginningofourera。
ItsufficesthattheydatebacktoaperiodlongantecedenttothebeginningsofcivilizationinWesternEurope。TheyprovethattheEgyptianofthatearlydayhadattainedaknowledgeofpracticalmechanicswhich，evenfromthetwentieth-centurypointofview，isnottobespokenoflightly。Ithassometimesbeensuggestedthatthesemightypyramids，builtastheyareofgreatblocksofstone，speakforanalmostmiraculousknowledgeonthepartoftheirbuilders；butasanerviewoftheconditionsgivesnowarrantforthisthought。Diodoras，theSicilian，inhisfamousWorld’sHistory，writtenaboutthebeginningofourera，explainsthebuildingofthepyramidsbysuggestingthatgreatquantitiesofearthwerepiledagainstthesideoftherisingstructuretoformaninclinedplaneupwhichtheblocksofstoneweredragged。Hegivesuscertainfigures，based，doubtless，onreportsmadetohimbyEgyptianpriests，whointurndrewuponthetraditionsoftheircountry，perhapsevenuponwrittenrecordsnolongerpreserved。Hesaysthatonehundredandtwentythousandmenwereemployedintheconstructionofthelargestpyramid，andthat，notwithstandingthesizeofthishostofworkers，thetaskoccupiedtwentyyears。Wemustnotplacetoomuchdependenceuponsuchfiguresasthese，fortheancienthistoriansarenotoriouslygiventoexaggerationinrecordingnumbers；yetweneednotdoubtthatthereportgivenbyDiodorusissubstantiallyaccurateinitsmainoutlinesastothemethodthroughwhichthepyramidswereconstructed。Ahostofmenputtingtheiraddedweightandstrengthtothetask，withtheaidofropes，pulleys，rollers，andlevers，andutilizingtheprincipleoftheinclinedplane，couldundoubtedlymoveandelevateandplaceinpositionthelargestblocksthatenterintothepyramidsor——whatseemsevenmorewonderful——themostgiganticobelisks，withouttheaidofanyotherkindofmechanismorofanymoreoccultpower。Thesamehandscould，asDiodorussuggests，removealltraceofthedebrisofconstructionandleavethepyramidsandobelisksstandinginweirdisolation，asifsprungintobeingthroughamiracle。
IthasbeennecessarytobearinmindthesephasesofpracticalcivilizationbecausemuchthatweknowofthepurelyscientificattainmentsoftheEgyptiansisbaseduponmodernobservationoftheirpyramidsandtemples。Itwasearlyobserved，forexample，thatthepyramidsareobviouslyorientedasregardsthedirectioninwhichtheyface，instrictaccordancewithsomeastronomicalprinciple。EarlyinthenineteenthcenturytheFrenchmanBiotmadeinterestingstudiesinregardtothissubject，andahundredyearslater，inourowntime，SirJosephNormanLockyer，followinguptheworkofvariousintermediaryobservers，hasgiventhesubjectmuchattention，makingitthecentralthemeofhisworkonTheDawnofAstronomy。[1]Lockyer’sresearchesmakeitclearthatinthemainthetemplesofEgyptwereorientedwithreferencetothepointatwhichthesunrisesonthedayofthesummersolstice。ThetimeofthesolsticehadpeculiarinterestfortheEgyptians，becauseitcorrespondedrathercloselywiththetimeoftherisingoftheNile。Thefloodsofthatriverappearwithverygreatregularity；theon-rushingtidereachestheregionofHeliopolisandMemphisalmostpreciselyonthedayofthesummersolstice。Thetimevariesatdifferentstagesoftheriver’scourse，butasthecivilizationoftheearlydynastiescentredatMemphis，observationsmadeatthisplacehadwidestvogue。
Consideringtheall-essentialcharacteroftheNilefloods-withoutwhichcivilizationwouldbeimpossibleinEgypt——itisnotstrangethatthetimeoftheirappearanceshouldbetakenasmarkingthebeginningofanewyear。Thefactthattheircomingcoincideswiththesolsticemakessuchadivisionofthecalendarperfectlynatural。Inpointoffact，fromtheearliestperiodsofwhichrecordshavecomedowntous，thenewyearoftheEgyptiansdatesfromthesummersolstice。ItiscertainthatfromtheearliesthistoricalperiodstheEgyptianswereawareoftheapproximatelengthoftheyear。Itwouldbestrangewereitotherwise，consideringtheeasewithwhicharecordofdayscouldbekeptfromNilefloodtoNileflood，orfromsolsticetosolstice。Butthis，ofcourse，appliesonlytoanapproximatecount。ThereissomereasontobelievethatintheearliestperiodtheEgyptiansmadethiscountonly360days。Thefactthattheiryearwasdividedintotwelvemonthsofthirtydayseachlendscolortothisbelief；but，inanyevent，themistakewasdiscoveredinduetimeandapartialremedywasappliedthroughtheinterpolationofa\"littlemonth\"offivedaysbetweentheendofthetwelfthmonthandthenewyear。Thisnearlybutnotquiteremediedthematter。Whatitobviouslyfailedtodowastotakeaccountofthatadditionalquarterofadaywhichreallyroundsouttheactualyear。
Itwouldhavebeenavastlyconvenientthingforhumanityhaditchancedthattheearthhadsoaccommodateditsrotarymotionwithitsspeedoftransitaboutthesunastomakeitsannualflightinprecisely360days。Twelvelunarmonthsofthirtydayseachwouldthenhavecoincidedexactlywiththesolaryear，andmostofthecomplexitiesofthecalendar，whichhavesopuzzledhistoricalstudents，wouldhavebeenavoided；but，ontheotherhand，perhapsthisverysimplicitywouldhaveproveddetrimentaltoastronomicalsciencebypreventingmenfromsearchingtheheavensascarefullyastheyhavedone。Bethatasitmay，thecomplexityexists。Theactualyearofthreehundredandsixty-fiveandaboutone-quarterdayscannotbedividedevenlyintomonths，andsomesuchexpedientastheintercalationofdayshereandthereisessential，elsethecalendarwillbecomeabsolutelyoutofharmonywiththeseasons。
InthecaseoftheEgyptians，theattemptatadjustmentwasmade，asjustnoted，bytheintroductionofthefivedays，constitutingwhattheEgyptiansthemselvestermed\"thefivedaysoverandabovetheyear。\"Theseso-calledepagomenaldayswereundoubtedlyintroducedataveryearlyperiod。MasperoholdsthattheywereinusebeforethefirstThinitedynasty，citinginevidencethefactthatthelegendofOsirisexplainsthesedaysashavingbeencreatedbythegodThotinordertopermitNuittogivebirthtoallherchildren；thisexpedientbeingnecessarytoovercomeabanwhichhadbeenpronouncedagainstNuit，accordingtowhichshecouldnotgivebirthtochildrenonanydayoftheyear。But，ofcourse，thefiveadditionaldaysdonotsufficefullytorectifythecalendar。Thereremainstheadditionalquarterofadaytobeaccountedfor。This，ofcourse，amountstoafulldayeveryfourthyear。WeshallseethatlaterAlexandriansciencehitupontheexpedientofaddingadaytoeveryfourthyear；anexpedientwhichtheJuliancalendaradoptedandwhichstillgivesusourfamiliarleap-year。But，unfortunately，theancientEgyptianfailedtorecognizetheneedofthisadditionalday，orifhedidrecognizeithefailedtoactonhisknowledge，andsoithappenedthat，startingsomewherebackintheremotepastwithanewyear’sdaythatcoincidedwiththeinundationoftheNile，therewasaconstantlyshiftingmaladjustmentofcalendarandseasonsastimewenton。
TheEgyptianseasons，itshouldbeexplained，werethreeinnumber:theseasonoftheinundation，theseasonoftheseed-time，andtheseasonoftheharvest；eachseasonbeing，ofcourse，fourmonthsinextent。Originally，asjustmentioned，theseasonoftheinundationsbeganandcoincidedwiththeactualtimeofinundation。Themoreprecisefixingofnewyear’sdaywasaccomplishedthroughobservationofthetimeoftheso-calledheliacalrisingofthedog-star，Sirius，whichboretheEgyptiannameSothis。Itchancesthat，asviewedfromabouttheregionofHeliopolis，thesunatthetimeofthesummersolsticeoccupiesanapparentpositionintheheavensclosetothedog-star。Now，asiswellknown，theEgyptians，seeingdivinitybackofalmosteveryphenomenonofnature，verynaturallypaidparticularreverencetosoobviouslyinfluentialapersonageasthesun-god。
InparticulartheythoughtitfittingtodohomagetohimjustashewasstartingoutonhistourofEgyptinthemorning；andthattheymightknowtheprecisemomentofhiscoming，theEgyptianastronomerpriests，perchedonthehill-topsneartheirtemples，werewonttoscantheeasternhorizonwithreferencetosomestarwhichhadbeenobservedtoprecedethesolarluminary。Ofcoursetheprecessionoftheequinoxes，duetothataxialwobbleinwhichourclumsyearthindulges，wouldchangetheapparentpositionofthefixedstarsinreferencetothesun，sothatthesamestarcouldnotdoserviceasheliacalmessengerindefinitely；but，ontheotherhand，thesechangesaresoslowthatobservationsbymanygenerationsofastronomerswouldberequiredtodetecttheshifting。ItisbelievedbyLockyer，thoughtheevidenceisnotquitedemonstrative，thattheastronomicalobservationsoftheEgyptiansdatebacktoaperiodwhenSothis，thedog-star，wasnotincloseassociationwiththesunonthemorningofthesummersolstice。Yet，accordingtothecalculationsofBiot，theheliacalrisingofSothisatthesolsticewasnotedasearlyastheyear3285B。C。，anditiscertainthatthisstarcontinuedthroughoutsubsequentcenturiestokeepthispositionofpeculiarprestige。HenceitwasthatSothiscametobeassociatedwithIsis，oneofthemostimportantdivinitiesofEgypt，andthatthedayinwhichSothiswasfirstvisibleinthemorningskymarkedthebeginningofthenewyear；
thatdaycoinciding，asalreadynoted，withthesummersolsticeandwiththebeginningoftheNileflow。
Butnowforthedifficultiesintroducedbythatunreckonedquarterofaday。Obviouslywithacalendarof365daysonly，attheendoffouryears，thecalendaryear，orvagueyear，astheEgyptianscametocallit，hadgainedbyonefulldayupontheactualsolaryear——thatistosay，theheliacalrisingofSothis，thedog-star，wouldnotoccuronnewyear’sdayofthefaultycalendar，butadaylater。Andwitheachsucceedingperiodoffouryearsthedayofheliacalrising，whichmarkedthetruebeginningoftheyear——andwhichstill，ofcourse，coincidedwiththeinundation——wouldhavefallenanotherdaybehindthecalendar。Inthecourseof120yearsanentiremonthwouldbelost；andin480yearssogreatwouldbecometheshiftingthattheseasonswouldbealtogethermisplaced；theactualtimeofinundationscorrespondingwithwhatthecalendarregisteredastheseed-time，andtheactualseed-timeinturncorrespondingwiththeharvest-timeofthecalendar。
Atfirstthoughtthisseemsveryawkwardandconfusing，butinallprobabilitytheeffectswerebynomeanssomuchsoinactualpractice。Weneedgonofartherthantoourownexperiencetoknowthatthenamesofseasons，asofmonthsanddays，cometohaveinthemindsofmostofusapurelyconventionalsignificance。FewofusstoptogiveathoughttothemeaningofthewordsJanuary，February，etc。，exceptastheyconnotecertainclimaticconditions。If，then，ourowncalendarweresodefectivethatinthecourseof120yearsthemonthofFebruaryhadshiftedbacktooccupythepositionoftheoriginalJanuary，thechangewouldhavebeensogradual，coveringtheperiodoftwolife-timesoroffourorfiveaveragegenerations，thatitmightwellescapegeneralobservation。
EachsucceedinggenerationofEgyptians，then，maynotimprobablyhaveassociatedthenamesoftheseasonswiththecontemporaryclimaticconditions，troublingthemselveslittlewiththethoughtthatinanearlieragetheclimaticconditionsforeachperiodofthecalendarwerequitedifferent。Wecannotwellsuppose，however，thattheastronomerpriestswereoblivioustothetruestateofthings。UponthemdevolvedthedutyofpredictingthetimeoftheNileflood；adutytheywereenabledtoperformwithoutdifficultythroughobservationoftherisingofthesolstitialsunanditsSothicmessenger。Totheseobserversitmustfinallyhavebeenapparentthattheshiftingoftheseasonswasattherateofonedayinfouryears；thisknown，itrequirednogreatmathematicalskilltocomputethatthisshiftingwouldfinallyeffectacompletecircuitofthecalendar，sothatafter4X365=1460yearsthefirstdayofthecalendaryearwouldagaincoincidewiththeheliacalrisingofSothisandwiththecomingoftheNileflood。Inotherwords，1461vagueyearsorEgyptiancalendaryearsOf365dayseachcorrespondto1460
actualsolaryearsof3651/4dayseach。Thisperiod，measuredthusbytheheliacalrisingofSothis，isspokenofastheSothiccycle。
Touswhoaretrainedfromchildhoodtounderstandthattheyearconsistsofapproximately3651/4days，andtoknowthatthecalendarmayberegulatedapproximatelybytheintroductionofanextradayeveryfourthyear，thisrecognitionoftheSothiccycleseemssimpleenough。Yetiftheaveragemanofuswillreflecthowlittleheknows，ofhisownknowledge，oftheexactlengthoftheyear，itwillsoonbecomeevidentthattheappreciationofthefaultsofthecalendarandtheknowledgeofitsperiodicaladjustmentconstitutedarelativelyhighdevelopmentofscientificknowledgeonthepartoftheEgyptianastronomer。ItmaybeaddedthatvariouseffortstoreformthecalendarweremadebytheancientEgyptians，butthattheycannotbecreditedwithasatisfactorysolutionoftheproblem；for，ofcourse，theAlexandrianscientistsofthePtolemaicperiodwhoseworkweshallhaveoccasiontoreviewpresentlywerenotEgyptiansinanypropersenseoftheword，butGreeks。
Sincesomuchofthetimeoftheastronomerpriestswasdevotedtoobservationoftheheavenlybodies，itisnotsurprisingthattheyshouldhavemappedouttheapparentcourseofthemoonandthevisibleplanetsintheirnightlytouroftheheavens，andthattheyshouldhavedividedthestarsofthefirmamentintomoreorlessarbitrarygroupsorconstellations。Thattheydidsoisevidencedbyvarioussculpturedrepresentationsofconstellationscorrespondingtosignsofthezodiacwhichstillornamenttheceilingsofvariousancienttemples。Unfortunatelythedecorativesense，whichwasalwayspredominantwiththeEgyptiansculptor，ledhimtotakevariouslibertieswiththedistributionoffiguresintheserepresentationsoftheconstellations，sothattheinferencesdrawnfromthemastotheexactmapoftheheavensastheEgyptiansconceiveditcannotbefullyreliedupon。Itappears，however，thattheEgyptianastronomerdividedthezodiacintotwenty-fourdecani，orconstellations。Thearbitrarygroupingsoffigures，withtheaidofwhichthesearedelineated，bearacloseresemblancetotheequallyarbitraryoutlineswhichwearestillaccustomedtouseforthesamepurpose。