Bythesideofindependentproducerswhocarryontheirhandicraftsandagricultureinthetraditionalold—fashionedway，therestandstheusurerorthemerchant，withhisusurer’scapitalormerchant’scapital，feedingonthemlikeaparasite。Thepredominance，inasociety，ofthisformofexploitationexcludesthecapitalistmodeofproduction;towhichmode，however，thisformmayserveasatransition，asitdidtowardsthecloseoftheMiddleAges。Finally，asisshownbymodern"domesticindustry，"
　　someintermediateformsarehereandtherereproducedinthebackgroundofModernIndustry，thoughtheirphysiognomyistotallychanged。
　　If，ontheonehand，themereformalsubjectionoflabourtocapitalsufficesfortheproductionofabsolutesurplus—value，if，e。g。，itissufficientthathandicraftsmanwhopreviouslyworkedontheirownaccount，orasapprenticesofamaster，shouldbecomewagelabourersunderthedirectcontrolofacapitalist;so，ontheotherhand，wehaveseen，howthemethodsofproducingrelativesurplus—value，are，atthesametime，methodsofproducingabsolutesurplus—value。Nay，more，theexcessiveprolongationoftheworking—dayturnedouttobethepeculiarproductofModernIndustry。
　　Generallyspeaking，thespecificallycapitalistmodeofproductionceasestobeameremeansofproducingrelativesurplus—value，sosoonasthatmodehasconqueredanentirebranchofproduction;andstillmoreso，sosoonasithasconqueredalltheimportantbranches。Itthenbecomesthegeneral，sociallypredominantformofproduction。Asaspecialmethodofproducingrelativesurplus—value，itremainseffectiveonly，first，insofarasitseizesuponindustriesthatpreviouslywereonlyformallysubjecttocapital，thatis，sofarasitispropagandist;secondly，insofarastheindustriesthathavebeentakenoverbyit，continuetoberevolutionisedbychangesinthemethodsofproduction。
　　Fromonestandpoint，anydistinctionbetweenabsoluteandrelativesurplus—valueappearsillusory。Relativesurplus—valueisabsolute，sinceitcompelstheabsoluteprolongationoftheworking—daybeyondthelabour—timenecessarytotheexistenceofthelabourerhimself。Absolutesurplus—valueisrelative，sinceitmakesnecessarysuchadevelopmentoftheproductivenessoflabour，aswillallowofthenecessarylabour—timebeingconfinedtoaportionoftheworking—day。Butifwekeepinmindthebehaviourofsurplus—value，thisappearanceofidentityvanishes。Oncethecapitalistmodeofproductionisestablishedandbecomegeneral，thedifferencebetweenabsoluteandrelativesurplus—valuemakesitselffelt，wheneverthereisaquestionofraisingtherateofsurplus—value。Assumingthatlabour—powerispaidforatitsvalue，weareconfrontedbythisalternative:giventheproductivenessoflabouranditsnormalintensity，therateofsurplus—valuecanberaisedonlybytheactualprolongationoftheworking—day;ontheotherhand，giventhelengthoftheworking—day，thatrisecanbeeffectedonlybyachangeintherelativemagnitudesofthecomponentsoftheworking—day，viz。，necessarylabourandsurplus—labour;achangewhich，ifthewagesarenottofallbelowthevalueoflabour—power，presupposesachangeeitherintheproductivenessorintheintensityofthelabour。
　　Ifthelabourerwantsallhistimetoproducethenecessarymeansofsubsistenceforhimselfandhisrace，hehasnotimeleftinwhichtoworkgratisforothers。Withoutacertaindegreeofproductivenessinhislabour，hehasnosuchsuperfluoustimeathisdisposal;withoutsuchsuperfluoustime，nosurplus—labour，andthereforenocapitalists，noslave—owners，nofeudallords，inoneword，noclassoflargeproprietors。[1]
　　Thuswemaysaythatsurplus—valuerestsonanaturalbasis;butthisispermissibleonlyintheverygeneralsense，thatthereisnonaturalobstacleabsolutelypreventingonemanfromdisburdeninghimselfofthelabourrequisiteforhisownexistence，andburdeninganotherwithit，anymore，forinstance，thanunconquerablenaturalobstaclepreventonemanfromeatingthefleshofanother。[2]Nomysticalideasmustinanywaybeconnected，assometimeshappens，withthishistoricallydevelopedproductivenessoflabour。Itisonlyaftermenhaveraisedthemselvesabovetherankofanimals，whenthereforetheirlabourhasbeentosomeextentsocialised，thatastateofthingsarisesinwhichthesurplus—labouroftheonebecomesaconditionofexistencefortheother。Atthedawnofcivilisationtheproductivenessacquiredbylabourissmall，butsotooarethewantswhichdevelopwithandbythemeansofsatisfyingthem。Further，atthatearlyperiod，theportionofsocietythatlivesonthelabourofothersisinfinitelysmallcomparedwiththemassofdirectproducers。Alongwiththeprogressintheproductivenessoflabour，thatsmallportionofsocietyincreasesbothabsolutelyandrelatively。[3]Besides，capitalwithitsaccompanyingrelationsspringsupfromaneconomicsoilthatistheproductofalongprocessofdevelopment。Theproductivenessoflabourthatservesasitsfoundationandstarting—point，isagift，notofnature，butofahistoryembracingthousandsofcenturies。
　　Apartfromthedegreeofdevelopment，greaterorless，intheformofsocialproduction，theproductivenessoflabourisfetteredbyphysicalconditions。Theseareallreferabletotheconstitutionofmanhimself（race，&c。），andtosurroundingnature。Theexternalphysicalconditionsfallintotwogreateconomicclasses，（1）Naturalwealthinmeansofsubsistence，i。e。，afruitfulsoil，watersteemingwithfish，&c。，and（2），naturalwealthintheinstrumentsoflabour，suchaswaterfalls，navigablerivers，wood，metal，coal，&c。Atthedawnofcivilisation，itisthefirstclassthatturnsthescale;atahigherstageofdevelopment，itisthesecond。Compare，forexample，EnglandwithIndia，orinancienttimes，AthensandCorinthwiththeshoresoftheBlackSea。
　　Thefewerthenumberofnaturalwantsimperativelycallingforsatisfaction，andthegreaterthenaturalfertilityofthesoilandthefavourablenessoftheclimate，somuchlessisthelabour—timenecessaryforthemaintenanceandreproductionoftheproducer。Somuchgreaterthereforecanbetheexcessofhislaboursforothersoverhislabourforhimself。DiodoruslongagoremarkedthisinrelationtotheancientEgyptians。"Itisaltogetherincrediblehowlittletroubleandexpensethebringingupoftheirchildrencausesthem。Theycookforthemthefirstsimplefoodathand;theyalsogivethemthelowerpartofthepapyrusstemtoeat，sofarasitcanberoastedinthefire，andtherootsandstalksofmarshplants，someraw，someboiledandroasted。Mostofthechildrengowithoutshoesandunclothed，fortheairissomild。Henceachild，untilheisgrownup，costshisparentsnotmore，onthewhole，thantwentydrachmas。Itisthis，chiefly，whichexplainswhythepopulationofEgyptissonumerous，and，therefore，whysomanygreatworkscanbeundertaken。"[4]NeverthelessthegrandstructuresofancientEgyptarelessduetotheextentofitspopulationthantothelargeproportionofitthatwasfreelydisposable。Justastheindividuallabourercandomoresurplus—labourinproportionashisnecessarylabour—timeisless，sowithregardtotheworkingpopulation。Thesmallerthepartofitwhichisrequiredfortheproductionofthenecessarymeansofsubsistence，somuchthegreateristhepartthatcanbesettodootherwork。
　　Capitalistproductiononceassumed，then，allothercircumstancesremainingthesame，andgiventhelengthoftheworkingday，thequantityofsurplus—labourwillvarywiththephysicalconditionsoflabour，especiallywiththefertilityofthesoil。Butitbynomeansfollowsfromthisthatthemostfruitfulsoilisthemostfittedforthegrowthofthecapitalistmodeofproduction。
　　Thismodeisbasedonthedominionofmanovernature。Wherenatureistoolavish，she"keepshiminhand，likeachildinleading—strings。"Shedoesnotimposeuponhimanynecessitytodevelophimself。[5]Itisnotthetropicswiththeirluxuriantvegetation，butthetemperatezone，thatisthemother—countryofcapital。Itisnotthemerefertilityofthesoil，butthedifferentiationofthesoil，thevarietyofitsnaturalproducts，thechangesoftheseasons，whichformthephysicalbasisforthesocialdivisionoflabour，andwhich，bychangesinthenaturalsurroundings，spurmanontothemultiplicationofhiswants，hiscapabilities，hismeansandmodesoflabour。Itisthenecessityofbringinganaturalforceunderthecontrolofsociety，ofeconomising，ofappropriatingorsubduingitonalargescalebytheworkofman’shand，thatfirstplaysthedecisivepartinthehistoryofindustry。Examplesare，theirrigationworksinEgypt，[6]Lombardy，Holland，orinIndiaandPersiawhereirrigationbymeansofartificialcanals，notonlysuppliesthesoilwiththewaterindispensabletoit，butalsocarriesdowntoit，intheshapeofsedimentfromthehills，mineralfertilisers。
　　ThesecretoftheflourishingstateofindustryinSpainandSicilyunderthedominionoftheArabslayintheirirrigationworks。[7]
　　Favourablenaturalconditionsalone，giveusonlythepossibility，neverthereality，ofsurplus—labour，nor，consequently，ofsurplus—valueandasurplus—product。Theresultofdifferenceinthenaturalconditionsoflabouristhis，thatthesamequantityoflaboursatisfies，indifferentcountries，adifferentmassofrequirements，[8]consequently，thatundercircumstancesinotherrespectsanalogous，thenecessarylabour—timeisdifferent。Theseconditionsaffectsurplus—labouronlyasnaturallimits，i。e。，byfixingthepointsatwhichlabourforotherscanbegin。Inproportionasindustryadvances，thesenaturallimitsrecede。InthemidstofourWestEuropeansociety，wherethelabourerpurchasestherighttoworkforhisownlivelihoodonlybypayingforitinsurplus—labour，theideaeasilytakesrootthatitisaninherentqualityofhumanlabourtofurnishasurplus—product。[9]Butconsider，forexample，aninhabitantoftheeasternislandsoftheAsiaticArchipelago，wheresagogrowswildintheforests。"Whentheinhabitantshaveconvincedthemselves，byboringaholeinthetree，thatthepithisripe，thetrunkiscutdownanddividedintoseveralpieces，thepithisextracted，mixedwithwaterandfiltered:itisthenquitefitforuseassago。Onetreecommonlyyields300lbs。，andoccasionally500to600
　　lbs。There，then，peoplegointotheforests，andcutbreadforthemselves，justaswithustheycutfire—wood。"[10]Supposenowsuchaneastembread—cutterrequires12workinghoursaweekforthesatisfactionofallhiswants。Nature’sdirectgifttohimisplentyofleisuretime。Beforehecanapplythisleisuretimeproductivelyforhimself，awholeseriesofhistoricaleventsisrequired;beforehespendsitinsurplus—labourforstrangers，compulsionisnecessary。Ifcapitalistproductionwereintroduced，thehonestfellowwouldperhapshavetoworksixdaysaweek，inordertoappropriatetohimselftheproductofoneworkingday。ThebountyofNaturedoesnotexplainwhyhewouldthenhavetowork6daysaweek，orwhyhemustfurnish5daysofsurplus—labour。
　　Itexplainsonlywhyhisnecessarylabour—timewouldbelimitedtoonedayaweek。Butinnocasewouldhissurplus—productarisefromsomeoccultqualityinherentinhumanlabour。
　　Thus，notonlydoesthehistoricallydevelopedsocialproductivenessoflabour，butalsoitsnaturalproductiveness，appeartobeproductivenessofthecapitalwithwhichthatlabourisincorporated。
　　Ricardoneverconcernshimselfabouttheoriginofsurplus—value。Hetreatsitasathinginherentinthecapitalistmodeofproduction，whichmode，inhiseyes，isthenaturalformofsocialproduction。Wheneverhediscussestheproductivenessoflabour，heseeksinit，notthecauseofsurplus—value，butthecausethatdeterminesthemagnitudeofthatvalue。
　　Ontheotherhand，hisschoolhasopenlyproclaimedtheproductivenessoflabourtobetheoriginatingcauseofprofit（read:Surplus—value）。
　　Thisatalleventsisaprogressasagainstthemercantilistswho，ontheirside，derivedtheexcessofthepriceoverthecostofproductionoftheproduct，fromtheactofexchange，fromtheproductbeingsoldaboveitsvalue。Nevertheless，Ricardo’sschoolsimplyshirkedtheproblem，theydidnotsolveit。Infactthesebourgeoiseconomistsinstinctivelysaw，andrightlyso，thatitisverydangeroustostirtoodeeplytheburningquestionoftheoriginofsurplus—value。ButwhatarewetothinkofJohnStuartMill，who，halfacenturyafterRicardo，solemnlyclaimssuperiorityoverthemercantilists，byclumsilyrepeatingthewretchedevasionsofRicardo’searliestvulgarisers？
　　Millsays:"Thecauseofprofitisthatlabourproducesmorethanisrequiredforitssupport。"Sofar，nothingbuttheoldstory;butMillwishingtoaddsomethingofhisown，proceeds:"Tovarytheformofthetheorem;thereasonwhycapitalyieldsaprofit，isbecausefood，clothing，materialsandtools，lastlongerthanthetimewhichwasrequiredtoproducethem。"Hehereconfoundsthedurationoflabour—timewiththedurationofitsproducts。Accordingtothisview，abakerwhoseproductlastsonlyaday，couldneverextractfromhisworkpeoplethesameprofit，asamachinemakerwhoseproductsendurefor20yearsandmore。Ofcourseitisverytrue，thatifabird’snestdidnotlastlongerthanthetimeittakesinbuilding，birdswouldhavetodowithoutnests。
　　Thisfundamentaltruthonceestablished，Millestablisheshisownsuperiorityoverthemercantilists。"Wethussee，"heproceeds，"thatprofitarises，notfromtheincidentofexchange，butfromtheproductivepoweroflabour;
　　andthegeneralprofitofthecountryisalwayswhattheproductivepoweroflabourmakesit，whetheranyexchangetakesplaceornot。Iftherewerenodivisionofemployments，therewouldbenobuyingorselling，buttherewouldstillbeprofit。"ForMillthen，exchange，buyingandselling，thosegeneralconditionsofcapitalistproduction，arebutanincident，andtherewouldalwaysbeprofitsevenwithoutthepurchaseandsaleoflabour—power！
　　"If，"hecontinues，"thelabourersofthecountrycollectivelyproducetwentypercentmorethantheirwages，profitswillbetwentypercent，whateverpricesmayormaynotbe。"Thisis，ontheonehand，ararebitoftautology;foriflabourersproduceasurplus—valueof20%forthecapitalist，hisprofitwillbetothetotalwagesofthelabourersas20:100。Ontheotherhand，itisabsolutelyfalsetosaythat"profitswillbe20%。"Theywillalwaysbeless，becausetheyarecalculateduponthesumtotalofthecapitaladvanced。If，forexample，thecapitalisthaveadvanced£500，ofwhich£4OOislaidoutinmeansofproductionand£100inwages，andiftherateofsurplus—valuebe20%，therateofprofitwillbe20:500，i。e。，4%andnot20%。
　　ThenfollowsasplendidexampleofMill’smethodofhandlingthedifferenthistoricalformsofsocialproduction。"Iassume，throughout，thestateofthingswhich，wherethelabourersandcapitalistsareseparateclasses，prevails，withfewexceptions，universally;namely，thatthecapitalistadvancesthewholeexpenses，includingtheentireremunerationofthelabourer。"
　　Strangeopticalillusiontoseeeverywhereastateofthingswhichasyetexistsonlyexceptionallyonourearth。[11]Butletusfinish？Milliswillingtoconcede，"thatheshoulddosoisnotamatterofinherentnecessity。"Onthecontrary:"thelabourermightwait，untiltheproductioniscomplete，forallthatpartofhiswageswhichexceedsmerenecessaries:andevenforthewhole，ifhehasfundsinhandsufficientforhistemporarysupport。Butinthelattercase，thelaboureristothatextentreallyacapitalistintheconcern，bysupplyingaportionofthefundsnecessaryforcarryingiton。"Millmighthavegonefurtherandhaveadded，thatthelabourerwhoadvancestohimselfnotonlythenecessariesoflifebutalsothemeansofproduction，isinrealitynothingbuthisownwage—labourer。HemightalsohavesaidthattheAmericanpeasantproprietorisbutaserfwhodoesenforcedlabourforhimselfinsteadofforhislord;
　　Afterthusprovingclearly，thatevenifcapitalistproductionhadnoexistence，stillitwouldalwaysexist，Millisconsistentenoughtoshow，onthecontrary，thatithasnoexistence，evenwhenitdoesexist。"Andevenintheformercase"（whentheworkmanisawagelabourertowhomthecapitalistadvancesallthenecessariesoflife，hethelabourer），"maybelookeduponinthesamelight，"（i。e。，asacapitalist），"since，contributinghislabouratlessthanthemarket—price，（！）hemayberegardedaslendingthedifference（？）tohisemployerandreceivingitbackwithinterest，&c。"[12]Inreality，thelaboureradvanceshislabourgratuitouslytothecapitalistduring，sayoneweek，inordertoreceivethemarketpriceattheendoftheweek，&c。，anditisthiswhich，accordingtoMill，transformshimintoacapitalist。Onthelevelplain，simplemoundslooklikehills;andtheimbecileflatnessofthepresentbourgeoisieistobemeasuredbythealtitudeofitsgreatintellects。
　　Footnotes[1]"Theveryexistenceofthemaster—capitalists，asadistinctclass，isdependentontheproductivenessofindustry。"（Ramsay，l。c。，p。206。）
　　"Ifeachman’slabourwerebutenoughtoproducehisownfood，therecouldbenoproperty。"（Ravenstone，l。c。p。14，15。）
　　[2]Accordingtoarecentcalculation，thereareyetatleast4，000，000cannibalsinthosepartsoftheearthwhichhavealreadybeenexplored。
　　[3]"AmongthewildIndiansinAmerica，almosteverythingisthelabourer’s，99partsofahundredaretobeputupontheaccountoflabour。InEngland，perhaps，thelabourerhasnot2/3。"（TheAdvantagesoftheEastIndiaTrade，&c。，p。73。）
　　[4]Diodorus，l。c。，l。I。，c。80。
　　[5]"Thefirst（naturalwealth）asitismostnobleandadvantageous，sodothitmakethepeoplecareless，proud，andgiventoallexcesses;whereasthesecondenforcethvigilancy，literature，artsandpolicy。"（England’sTreasurebyForeignTrade。OrtheBalanceofourForeignTradeistheRuleofourTreasure。WrittenbyThomasMunofLondon，merchant，andnowpublishedforthecommongoodbyhissonJohnMun。London，1669，p。181，182。）"NorcanIconceiveagreatercurseuponabodyofpeople，thantobethrownuponaspotofland，wheretheproductionsforsubsistenceandfoodwere，ingreatmeasure，spontaneous，andtheclimaterequiredoradmittedlittlecareforraimentandcovering……theremaybeanextremeontheotherside。
　　Asoilincapableofproducebylabourisquiteasbadasasoilthatproducesplentifullywithoutanylabour。"（AnInquiryintothePresentHighPriceofProvisions。Lond。1767，p。10。）
　　[6]ThenecessityforpredictingtheriseandfalloftheNilecreatedEgyptianastronomy，andwithitthedominionofthepriests，asdirectorsofagriculture。
　　"Lesolsticeestlemomentdel’annéeoucommencelacrueduNil，etceluiquelesEgyptiensontduobserveravecleplusd’attention……
　　C’étaitcetteannéetropiquequ’illeurimportaitdemarquerpoursedirigerdansleursopérationsagricoles。Ilsdurentdoncchercherdanslecielunsigneapparentdesonretour。"（Cuvier:Discourssurlesrévolutionsduglobe，ed。Hoefer，Paris，1863，p。141。）
　　[7]OneofthematerialbasesofthepowerofthestateoverthesmalldisconnectedproducingorganismsinIndia，wastheregulationofthewatersupply。TheMahometanrulersofIndiaunderstoodthisbetterthantheirEnglishsuccessors。
　　Itisenoughtorecalltomindthefamineof1866，whichcostthelivesofmorethanamillionHindusinthedistrictofOrissa，intheBengalpresidency。
　　[8]"Therearenotwocountrieswhichfurnishanequalnumberofthenecessariesoflifeinequalplenty，andwiththesamequantityoflabour。Men’swantsincreaseordiminishwiththeseverityortemperatenessoftheclimatetheylivein;consequently，theproportionoftradewhichtheinhabitantsofdifferentcountriesareobligedtocarryonthroughnecessitycannotbethesame，norisitpracticabletoascertainthedegreeofvariationfartherthanbythedegreesofHeatandCold;fromwhenceonemaymakethisgeneralconclusion，thatthequantityoflabourrequiredforacertainnumberofpeopleisgreatestincoldclimates，andleastinhotones;forintheformermennotonlywantmoreclothes，buttheearthmorecultivatingthaninthelatter。"（AnEssayontheGoverningCausesoftheNaturalRateofInterest。Lond。1750。p。60。）Theauthorofthisepoch—makinganonymousworkisJ。Massy。Humetookhistheoryofinterestfromit。
　　[9]"Chaquetravaildoit（thisappearsalsotobepartofthedroitsetdevoirsducitoyen）laisserunexcédant。"Proudhon。
　　[10]F。Schouw:"DieErde，diePflanzeundderMensch，"2。Ed。Leipz。1854，p。148。
　　[11]InearliereditionsofCapitalthequotationfromJohnStuartMill，"I
　　assumethroughout……ofthelabourer，"hadbeengivenincorrectly，thewords"wherethelabourersandcapitalistsareseparateclasses"havingbeenleftout。Marx，inaletterdatedNovember28，1878，pointedthisouttoDanielson，theRussiantranslatorofCapital，adding:
　　"Thenexttwosentences，viz。’Strangeopticalillusiontoseeeverywhereastateofthingswhichasyetexistsonlyexceptionallyonourearth。Butletusfinish’—shouldbedeletedandthefollowingsentencesubstituted:
　　"Mr。Millisgoodenoughtobelievethatthisstateofthingsisnotanabsolutenecessity，eveninthateconomicsysteminwhich’labourersandcapitalistsareseparateclasses。’"
　　ThesubstanceofthisnotehasbeentakenfromtheVolksaugabe。
　　ThequotationfromMillisfromhisPrinciplesofPoliticalEconomy，BookII，ChapXV，5。
　　[12]J。St。Mill。PrinciplesofPol。Econ。Lond。1868，p。252—53passim。
　　ChapterSeventeenKarlMarxCapitalVolumeOnePartV:
　　TheProductionofAbsoluteandofRelativeSurplus—ValueCHAPTERSEVENTEEN:
　　CHANGESOFMAGNITUDEINTHEPRICEOFLABOUR—POWERANDINSURPLUSVALUE
　　ContentsSection1—LengthoftheWorking—DayandIntensityofLabourConstant。ProductivenessofLabourVariableSection2—Working—DayConstant。ProductivenessofLabourConstant。IntensityofLabourVariableSection3—ProductivenessandIntensityofLabourConstant。
　　LengthoftheWorking—DayVariableSection4—SimultaneousVariationsintheDuration，Productiveness，andIntensityofLabourA。DiminishingProductivenessofLabourwithaSimultaneousLengtheningoftheWorking—DayB。IncreasingIntensityandProductivenessofLabourwithSimultaneousShorteningoftheWorking—DayThevalueoflabour—powerisdeterminedbythevalueofthenecessariesoflifehabituallyrequiredbytheaveragelabourer。Thequantityofthesenecessariesisknownatanygivenepochofagivensociety，andcanthereforebetreatedasaconstantmagnitude。Whatchanges，isthevalueofthisquantity。Thereare，besides，twootherfactorsthatenterintothedeterminationofthevalueoflabour—power。One，theexpensesofdevelopingthatpower，whichexpensesvarywiththemodeofproduction;theother，itsnaturaldiversity，thedifferencebetweenthelabour—powerofmenandwomen，ofchildrenandadults。Theemploymentofthesedifferentsortsoflabour—power，anemploymentwhichis，initsturn，madenecessarybythemodeofproduction，makesagreatdifferenceinthecostofmaintainingthefamilyofthelabourer，andinthevalueofthelabour—poweroftheadultmale。Boththesefactors，however，areexcludedinthefollowinginvestigation。[1]
　　Iassume（1）thatcommoditiesaresoldattheirvalue;（2）thatthepriceoflabour—powerrisesoccasionallyaboveitsvalue，butneversinksbelowit。
　　Onthisassumptionwehaveseenthattherelativemagnitudesofsurplus—valueandofpriceoflabour—poweraredeterminedbythreecircumstances;（1）
　　thelengthoftheworking—day，ortheextensivemagnitudeoflabour;（2）
　　thenormalintensityoflabour，itsintensivemagnitude，wherebyagivenquantityoflabourisexpendedinagiventime;（3）theproductivenessoflabour，wherebythesamequantumoflabouryields，inagiventime，agreaterorlessquantumofproduct，dependentonthedegreeofdevelopmentintheconditionsofproduction。Verydifferentcombinationsareclearlypossible，accordingasoneofthethreefactorsisconstantandtwovariable，ortwoconstantandonevariable，orlastly，allthreesimultaneouslyvariable。
　　Andthenumberofthesecombinationsisaugmentedbythefactthat，whenthesefactorssimultaneouslyvary，theamountanddirectionoftheirrespectivevariationsmaydiffer。Inwhatfollowsthechiefcombinationsaloneareconsidered。
　　SECTION1LENGTHOFTHEWORKING—DAYANDINTENSITYOFLABOURCONSTANT。PRODUCTIVENESS
　　OFLABOURVARIABLE。
　　Ontheseassumptionsthevalueoflabour—power，andthemagnitudeofsurplus—value，aredeterminedbythreelaws。
　　（1。）Aworkingdayofgivenlengthalwayscreatesthesameamountofvalue，nomatterhowtheproductivenessoflabour，and，withit，themassoftheproduct，andthepriceofeachsinglecommodityproduced，mayvary。
　　Ifthevaluecreatedbyaworking—dayof12hoursbe，say，sixshillings，then，althoughthemassofthearticlesproducedvarieswiththeproductivenessoflabour，theonlyresultisthatthevaluerepresentedbysixshillingsisspreadoveragreaterorlessnumberofarticles。
　　（2。）Surplus—valueandthevalueoflabour—powervaryinoppositedirections。Avariationintheproductivenessoflabour，itsincreaseordiminution，causesavariationintheoppositedirectioninthevalueoflabour—power，andinthesamedirectioninsurplus—value。
　　Thevaluecreatedbyaworkingdayof12hoursisaconstantquantity，say，sixshillings。Thisconstantquantityisthesumofthesurplus—valueplusthevalueofthelabour—power，whichlattervaluethelabourerreplacesbyanequivalent。Itisself—evident，thatifaconstantquantityconsistsoftwoparts，neitherofthemcanincreasewithouttheotherdiminishing。
　　Letthetwopartsatstartingbeequal;3shillingsvalueoflabour—power，3shillingssurplus—value。Thenthevalueofthelabour—powercannotrisefromthreeshillingstofour，withoutthesurplus—valuefallingfromthreeshillingstotwo;andthesurplus—valuecannotrisefromthreeshillingstofour，withoutthevalueoflabour—powerfallingfromthreeshillingstotwo。Underthesecircumstances，therefore，nochangecantakeplaceintheabsolutemagnitude，eitherofthesurplus—value，orofthevalueoflabour—power，withoutasimultaneouschangeintheirrelativemagnitudes，i。e。，relativelytoeachother。Itisimpossibleforthemtoriseorfallsimultaneously。
　　Further，thevalueoflabour—powercannotfall，andconsequentlysurplus—valuecannotrise，withoutariseintheproductivenessoflabour。Forinstance，intheabovecase，thevalueofthelabour—powercannotsinkfromthreeshillingstotwo，unlessanincreaseintheproductivenessoflabourmakesitpossibletoproducein4hoursthesamequantityofnecessariesaspreviouslyrequired6hourstoproduce。Ontheotherhand，thevalueofthelabour—powercannotrisefromthreeshillingstofour，withoutadecreaseintheproductivenessoflabour，wherebyeighthoursbecomerequisitetoproducethesamequantityofnecessaries，fortheproductionofwhichsixhourspreviouslysufficed。
　　Itfollowsfromthis，thatanincreaseintheproductivenessoflabourcausesafallinthevalueoflabour—powerandaconsequentriseinsurplus—value，while，ontheotherhand，adecreaseinsuchproductivenesscausesariseinthevalueoflabour—power，andafallinsurplus—value。
　　Informulatingthislaw，Ricardooverlookedonecircumstance;althoughachangeinthemagnitudeofthesurplus—valueorsurplus—labourcausesachangeintheoppositedirectioninthemagnitudeofthevalueoflabour—power，orinthequantityofnecessarylabour，itbynomeansfollowsthattheyvaryinthesameproportion。Theydoincreaseordiminishbythesamequantity。
　　Buttheirproportionalincreaseordiminutiondependsontheiroriginalmagnitudesbeforethechangeintheproductivenessoflabourtookplace。
　　Ifthevalueofthelabour—powerbe4shillings，orthenecessarylabour—time8hours，andthesurplus—valuebe2shillings，orthesurplus—labour4
　　hours，andif，inconsequenceofanincreaseintheproductivenessoflabour，thevalueofthelabour—powerfallto3shillings，orthenecessarylabourto6hours，thesurplus—valuewillriseto3shillings，orthesurplus—labourto6hours。Thesamequantity，1shillingor2hours，isaddedinonecaseandsubtractedintheother。Buttheproportionalchangeofmagnitudeisdifferentineachcase。Whilethevalueofthelabour—powerfallsfrom4shillingsto3，i。e。，by1/4or25%，thesurplus—valuerisesfrom2shillingsto3，i。e。，by1/2or50%。Itthereforefollowsthattheproportionalincreaseordiminutioninsurplus—value，consequentonagivenchangeintheproductivenessoflabour，dependsontheoriginalmagnitudeofthatportionoftheworkingdaywhichembodiesitselfinsurplus—value;
　　thesmallerthatportion，thegreateristheproportionalchange;thegreaterthatportion，thelessistheproportionalchange。
　　（3。）Increaseordiminutioninsurplus—valueisalwaysconsequenton，andneverthecauseof，thecorrespondingdiminutionorincreaseinthevalueoflabour—power。[2]
　　Sincetheworking—dayisconstantinmagnitude，andisrepresentedbyavalueofconstantmagnitude，since，toeveryvariationinthemagnitudeofsurplus—value，therecorrespondsaninversevariationinthevalueoflabour—power，andsincethevalueoflabour—powercannotchange，exceptinconsequenceofachangeintheproductivenessoflabour，itclearlyfollows，undertheseconditions，thateverychangeofmagnitudeinsurplus—valuearisesfromaninversechangeofmagnitudeinthevalueoflabour—power。
　　If，then，aswehavealreadyseen，therecanbenochangeofabsolutemagnitudeinthevalueoflabour—power，andinsurplus—value，unaccompaniedbyachangeintheirrelativemagnitudes，sonowitfollowsthatnochangeintheirrelativemagnitudesispossible，withoutapreviouschangeintheabsolutemagnitudeofthevalueoflabour—power。
　　Accordingtothethirdlaw，achangeinthemagnitudeofsurplus—value，presupposesamovementinthevalueoflabour—power，whichmovementisbroughtaboutbyavariationintheproductivenessoflabour。Thelimitofthischangeisgivenbythealteredvalueoflabour—power。Nevertheless，evenwhencircumstancesallowthelawtooperate，subsidiarymovementsmayoccur。Forexample:ifinconsequenceoftheincreasedproductivenessoflabour，thevalueoflabour—powerfallsfrom4shillingsto3，orthenecessarylabour—timefrom8hoursto6，thepriceoflabour—powermaypossiblynotfallbelow3s。8d。，3s。6d。，or3s。2d。，andthesurplus—valueconsequentlynotriseabove3s。4d。，3s。6d。，or3s。10d。Theamountofthisfall，thelowestlimitofwhichis3shillings（thenewvalueoflabour—power），dependsontherelativeweight，whichthepressureofcapitalontheoneside，andtheresistanceofthelabourerontheother，throwsintothescale。
　　Thevalueoflabour—powerisdeterminedbythevalueofagivenquantityofnecessaries。Itisthevalueandnotthemassofthesenecessariesthatvarieswiththeproductivenessoflabour。Itis，however，possiblethat，owingtoanincreaseofproductiveness，boththelabourerandthecapitalistmaysimultaneouslybeabletoappropriateagreaterquantityofthesenecessaries，withoutanychangeinthepriceoflabour—powerorinsurplus—value。Ifthevalueoflabour—powerbe3shillings，andthenecessarylabour—timeamountto6hours，ifthesurplus—valuelikewisebe3shillings，andthesurplus—labour6hours，theniftheproductivenessoflabourweredoubledwithoutalteringtheratioofnecessarylabourtosurplus—labour，therewouldbenochangeofmagnitudeinsurplus—valueandpriceoflabour—power。Theonlyresultwouldbethateachofthemwouldrepresenttwiceasmanyuse—valuesasbefore;theseuse—valuesbeingtwiceascheapasbefore。Althoughlabour—powerwouldbeunchangedinprice，itwouldbeaboveitsvalue。If，however，thepriceoflabour—powerhadfallen，notto1s。6d。，thelowestpossiblepointconsistentwithitsnewvalue，butto2s。10d。or2s。6d。，stillthislowerpricewouldrepresentanincreasedmassofnecessaries。Inthiswayitispossiblewithanincreasingproductivenessoflabour，forthepriceoflabour—powertokeeponfalling，andyetthisfalltobeaccompaniedbyaconstantgrowthinthemassofthelabourer’smeansofsubsistence。