Thecoal，therefore，hasvalue，mustbepaidforbyanequivalent，andhasacost。Thewaterfallisanaturalproductionagentintheproductionofwhichnolabourenters。
　　Butthisisnotall。Themanufacturerwhooperateswithsteamalsoemploysnaturalforceswhichcosthimnothingyetmakethelabourmoreproductiveandincreasethesurplus-valueandtherebytheprofit，inasmuchastheythuscheapenthemanufactureofthemeansofsubsistencerequiredforthelabourers。Thesenaturalforcesarethusquiteasmuchmonopolisedbycapitalasthesocialnaturalforcesoflabourarisingfromco-operation，divisionoflabour，etc。Themanufacturerpaysforcoal，butnotforthecapacityofwatertoalteritsphysicalstate，toturnintosteam，notfortheelasticityofthesteam，etc。Thismonopolisationofnaturalforces，thatis，oftheincreaseinlabour-powerproducedbythem，iscommontoallcapitaloperatingwithsteam-engines。Itmayincreasethatportionoftheproductoflabourwhichrepresentssurplus-valueinrelationtothatportionwhichistransformedintowages。Insofarasitdoesthis，itraisesthegeneralrateofprofit，butitdoesnotcreateanysurplus-profit，forthisconsistsoftheexcessofindividualprofitoveraverageprofit。Thefactthattheapplicationofanaturalforce，awaterfall，createssurplus-profitinthiscase，cannotthereforebeduesolelytothecircumstancethattheincreasedproductivityoflabourhereresultsfromtheapplicationofanaturalforce。Othermodifyingcircumstancesarenecessary。
　　Conversely。Themereapplicationofnaturalforcesinindustrymayinfluencethelevelofthegeneralrateofprofitbecauseitaffectsthequantityoflabourrequiredtoproducethenecessarymeansofsubsistence。
　　Butinitselfitdoesnotcreateanydeviationfromthegeneralrateofprofit，andthisispreciselythepointinwhichweareinterestedhere。
　　Furthermore，thesurplus-profitwhichsomeindividualcapitalotherwiserealisesinaparticularsphereofproduction-fordeviationsoftheratesofprofitinvariousspheresofproductionarecontinuallybalancedoutintoanaveragerate-isdue，asidefromfortuitousdeviations，toareductionincost-price，inproductioncosts。Thisreductionariseseitherfromthefactthatcapitalisusedingreaterthanaveragequantities，sothatfauxfraisofproductionarereduced，whilethegeneralcausesincreasingtheproductivenessoflabourcooperation，divisionoflabour，etc。canbecomeeffectivetoahigherdegree，withmoreintensity，becausetheirfieldofactivityhasbecomelarger；oritmayarisefromthefactthat，asidefromtheamountoffunctioningcapital，bettermethodsoflabour，newinventions，improvedmachinery，chemicalmanufacturingsecrets，etc。，inshort，newandimproved，betterthanaveragemeansofproductionandmethodsofproductionareused。Thereductionincost-priceandthesurplus-profitarisingfromitareheretheresultofthemannerinwhichthefunctioningcapitalisinvested。Theyresulteitherfromthefactthatthecapitalisconcentratedinthehandsofonepersoninextraordinarilylargequantitiesaconditionthatiscancelledoutassoonasequalmagnitudesofcapitalareusedontheaverage，orfromthefactthatacertainmagnitudeofcapitalfunctionsinaparticularlyproductivemanneraconditionthatdisappearsassoonastheexceptionalmethodofproductionbecomesgeneralorissurpassedbyastillmoredevelopedone。
　　Thecauseofthesurplus-profit，then，arisesherefromthecapitalitselfwhichincludesthelaboursetinmotionbyitwhetheritbeduetothegreatermagnitudeofcapitalemployedortoitsmoreefficientapplication；
　　and，asamatteroffact，thereisnoparticularreasonwhyallcapitalinthesameproductionsphereshouldnotbeinvestedinthesamemanner。
　　Onthecontrary，thecompetitionbetweencapitalstendstocancelthesedifferencesmoreandmore。Thedeterminationofvaluebythesociallynecessarylabour-timeassertsitselfthroughthecheapeningofcommoditiesandthecompulsiontoproducecommoditiesunderthesamefavourableconditions。
　　Butmattersaredifferentwiththesurplus-profitofanindustrialcapitalistwhomakesuseofthewaterfall。Theincreasedproductivenessofthelabourusedbyhimcomesneitherfromthecapitalandlabouritself，norfromthemereapplicationofsomenaturalforcedifferentfromcapitalandlabourbutincorporatedinthecapital。ItarisesfromthegreaternaturalproductivenessoflabourboundupwiththeapplicationofaforceofNature，butnotaforceofNaturethatisatthecommandofallcapitalinthesamesphereofproduction，asforexampletheelasticityofsteam。Inotherwords，itsapplicationisnottobetakenforgrantedwhenevercapitalisgenerallyinvestedinthissphereofproduction。Onthecontrary，itisamonopolisableforceofNaturewhich，likethewaterfall，isonlyatthecommandofthosewhohaveattheirdisposalparticularportionsoftheearthanditsappurtenances。
　　Itisbynomeanswithinthepowerofcapitaltocallintoexistencethisnaturalpremiseforagreaterproductivityoflabourinthesamemannerasanycapitalmaytransformwaterintosteam。ItisfoundonlylocallyinNatureand，whereveritdoesnotexist，itcannotbeestablishedbyadefiniteinvestmentofcapital。Itisnotboundtogoodswhichlabourcanproduce，suchasmachinesandcoal，buttospecificnaturalconditionsprevailingincertainportionsofland。Thosemanufacturerswhoownwaterfallsexcludethosewhodonotfromusingthisnaturalforce，becauseland，andparticularlylandendowedwithwater-power，isscarce。Thisdoesnotpreventtheamountofwater-poweravailableforindustrialpurposesfrombeingincreased，eventhoughthenumberofnaturalwaterfallsinagivencountryislimited。Thewaterfallmaybeharnessedbymaninordertofullyexploititsmotiveforce。Ifsuchexists，thewater-wheelmaybeimprovedsoastomakeuseofasmuchofthewater-poweraspossible；wheretheordinarywheelisnotsuitableforthewater-supply，turbinesmaybeused，etc。
　　Thepossessionofthisnaturalforceconstitutesamonopolyinthehandsofitsowner；itisaconditionforanincreaseintheproductivenessoftheinvestedcapitalthatcannotbeestablishedbytheproductionprocessofthecapitalitself；[33]thisnaturalforce，whichcanbemonopolisedinthismanner，isalwaysboundtotheland。Suchanaturalforcedoesnotbelongtothegeneralconditionsofthesphereofproductioninquestion，nortothoseconditionsofthelatterwhichmaybegenerallyestablished。
　　Nowletusassumethatthewaterfalls，alongwiththelandtowhichtheybelong，areheldbyindividualswhoareregardedasownersoftheseportionsoftheearth，i。e。，whoarelandowners。Theseownerspreventtheinvestmentofcapitalinthewaterfallsandtheirexploitationbycapital。
　　Theycanpermitorforbidsuchutilisation。Butawaterfallcannotbecreatedbycapitaloutofitself。Therefore，thesurplus-profitwhicharisesfromtheemploymentofthiswaterfallisnotduetocapital，buttotheutilisationofanaturalforcewhichcanbemonopolised，andhasbeenmonopolised，bycapital。Underthesecircumstances，thesurplus-profitistransformedintoground-rent，thatis，itfallsintopossessionoftheownerofawaterfall。
　　Ifthemanufacturerpaystheownerofawaterfall£；10annually，thenhisprofitis£；15，thatis，15%onthe£；100whichthenmakeuphiscostofproduction；andheisjustaswellorpossiblybetteroffthanallothercapitalistsinhissphereofproductionwhooperatewithsteam。Itwouldnotaltermattersonebitifthecapitalisthimselfshouldbetheownerofawaterfall。Hewould，insuchacase，pocketasbeforethesurplus-profitof£；10inhiscapacityaswaterfallowner，andnotinhiscapacityascapitalist；andpreciselybecausethissurplusdoesnotstemfromhiscapitalassuch，butratherfromthecontrolofalimitednaturalforcedistinctfromhiscapitalwhichcanbemonopolised，isittransformedintoground-rent。
　　First，itisevidentthatthisrentisalwaysadifferentialrent，foritdoesnotenterasadeterminingfactorintothegeneralproductionpriceofcommodities，butratherisbasedonit。Itinvariablyarisesfromthedifferencebetweentheindividualproductionpriceofaparticularcapitalhavingcommandoverthemonopolisednaturalforce，ontheonehand，andthegeneralproductionpriceofthetotalcapitalinvestedinthesphereofproductionconcerned，ontheother。
　　Secondly，thisground-rentdoesnotarisefromtheabsoluteincreaseintheproductivenessofemployedcapital，orlabourappropriatedbyit，sincethiscanonlyreducethevalueofcommodities；itisduetothegreaterrelativefruitfulnessofspecificseparatecapitalsinvestedinacertainproductionsphere，ascomparedwithinvestmentsofcapitalwhichareexcludedfromtheseexceptionalandnaturalconditionsfavouringproductiveness。
　　Forinstance，iftheuseofsteamshouldofferoverwhelmingadvantagesnotofferedbytheuseofwater-power，despitethefactthatcoalhasvalueandthewater-powerhasnot，andiftheseadvantagesmorethancompensatedfortheexpense，then，thewater-powerwouldnotbeusedandcouldnotproduceanysurplus-profit，andthereforecouldnotproduceanyrent。
　　Thirdly，thenaturalforceisnotthesourceofsurplus-profit，butonlyitsnaturalbasis，becausethisnaturalbasispermitsanexceptionalincreaseintheproductivenessoflabour。Inthesameway，use-valueisingeneralthebearerofexchange-value，butnotitscause。Ifthesameuse-valuecouldbeobtainedwithoutlabour，itwouldhavenoexchange-value，yetitwouldretain，asbefore，thesamenaturalusefulnessasuse-value。
　　Ontheotherhand，nothingcanhaveexchange-valueunlessithasuse-value，i。e。，unlessitisanaturalbeareroflabour。Wereitnotforthefactthatthevariousvaluesareaveragedoutintopricesofproduction，andthevariousindividualpricesofproductionintoageneralpriceofproductionregulatingthemarket，themereincreaseinproductivityoflabourthroughutilisationofthewaterfallwouldmerelylowerthepriceofcommoditiesproducedwiththeaidofthiswaterfall，withoutincreasingtheshareofprofitcontainedinthesecommodities。Similarly，ontheotherhand，thisincreasedproductivityoflabouritselfwouldnotbeconvertedintosurplus-valuewereitnotforthefactthatcapitalappropriatesthenaturalandsocialproductivityofthelabourusedbyitasitsown。
　　Fourthly，theprivateownershipofthewaterfallinitselfhasnothingtodowiththecreationofthesurplus-valueprofitportion，andtherefore，ofthepriceofthecommodityingeneral，whichisproducedbymeansofthewaterfall。Thissurplus-profitwouldalsoexistiflandedpropertydidnotexist；forinstance，ifthelandonwhichthewaterfallissituatedwereusedbythemanufacturerasunclaimedland。Hencelandedpropertydoesnotcreatetheportionofvaluewhichistransformedintosurplus-profit，butmerelyenablesthelandowner，theownerofthewaterfall，tocoaxthissurplus-profitoutofthepocketofthemanufacturerandintohisown。Itisnotthecauseofthecreationofsuchsurplus-profit，butisthecauseofitstransformationintotheformofground-rent，andthereforeoftheappropriationofthisportionoftheprofit，orcommodity-price，bytheownerofthelandorwaterfall。
　　Fifthly，itisevidentthatthepriceofthewaterfall，thatis，thepricewhichthelandownerwouldreceivewerehetosellittoathirdpartyoreventothemanufacturerhimself，doesnotimmediatelyenterintotheproductionpriceofthecommodities，althoughitdoesenterintotheindividualcost-priceofthemanufacturer；becausetherentarisesherefromthepriceofproductionofsimilarcommoditiesproducedbysteammachinery，andthispriceisregulatedindependentlyofthewaterfall。Furthermore，thispriceofthewaterfallonthewholeisanirrationalexpression，butbehinditisbiddenarealeconomicrelationship。Thewaterfall，likelandingeneral，andlikeanynaturalforce，hasnovaluebecauseitdoesnotrepresentanymaterialisedlabour，andtherefore，ithasnoprice，whichisnormallynomorethantheexpressionofvalueinmoneyterms。Wherethereisnovalue，thereisalsoeoipsonothingtobeexpressedinmoney。
　　Thispriceisnothingmorethanthecapitalisedrent。Landownershipenablesthelandownertoappropriatethedifferencebetweentheindividualprofitandaverageprofit。Theprofitthusacquired，whichisrenewedeveryyear，maybecapitalised，andappearsthenasthepriceofthenaturalforceitself。Ifthesurplus-profitrealisedbythemanufacturerusingthewaterfallamountsto£；10peryear，andtheaverageinterestis5%，thenthese£；10representtheannualinterestonacapitalof£；200andthecapitalisationoftheannual£；10whichthewaterfallenablesitsownertoappropriatefromthemanufacturer，appearsthenasthecapital-valueofthewaterfallitself。Thatitisnotthewaterfallitselfwhichhasvalue，butthatitspriceisamerereflectionoftheappropriatedsurplus-profitcapitalisticallycalculated，becomesatonceevidentfromthefactthatthepriceof£；200representsmerelytheproductobtainedbymultiplyingasurplus-profitof£；10by20years，whereas，otherconditionsremainingequal，thesamewaterfallwillenableitsownertoappropriatethese£；10
　　everyyearforanindefinitenumberofyears-30years，100years，orxyears；and，whereas，ontheotherhand，shouldsomenewmethodofproductionnotapplicablewithwater-powerreducethecost-priceofcommoditiesproducedbysteammachineryfrom£；100to£；90，thesurplus-profit，andtherebytherent，andthusthepriceofthewaterfall，woulddisappear。
　　Nowthatwehavedescribedthegeneralconceptofdifferentialrent，weshallpassontoitsconsiderationinagricultureproper。Whatappliestoagriculturewillalsoapplyonthewholetomining。
　　NOTES
　　33。Concerningextraprofit，seetheInquiry[intothosePrinciples，RespectingtheNatureofDemandandtheNecessityofConsumption，latelyadvocatedbyMr。Malthus，London，1821-Ed。]againstMalthus。1894:CapitalIII——Chapter39KarlMarx’sCAPITAL
　　volumeIII
　　THEPROCESSOFCAPITALISTPRODUCTIONASAWHOLECHAPTERXXXIX
　　FIRSTFORMOFDIFFERENTIALRENTDIFFERENTIALRENTIRicardoisquiterightinthefollowingobservations:”Rentisalwaysthedifferencebetweentheproduceobtainedbytheemploymentoftwoequalquantitiesofcapitalandlabour”Principles，p。59。[Hemeansdifferentialrent，forheassumesthatnootherrentbutdifferentialrentexists。]Heshouldhaveadded，”onequalareasofland”insofarasitisamatterofground-rentandnotsurplus-profitingeneral。
　　Inotherwords，surplus-profit，ifnormalandnotduetoaccidentaloccurrencesinthecirculationprocess，isalwaysproducedasadifferencebetweentheproductsoftwoequalquantitiesofcapitalandlabour，andthissurplus-profitistransformedintogroundrentwhentwoequal。quantitiesofcapitalandlabourareemployedonequalareasoflandwithunequalresults。Moreover，itisbynomeansabsolutelynecessaryforthissurplus-profittoarisefromtheunequalresultsofequalquantitiesofinvestedcapital。
　　Thevariousinvestmentsmayalsoemployunequalquantitiesofcapital。
　　Indeed，thisisgenerallythecase。Butequalproportions，forinstance£；100ofeach，produceunequalresults；thatis，theirratesofprofitaredifferent。Thisisthegeneralprerequisitefortheexistenceofsurplus-profitinanysphereofcapitalinvestment。Thesecondprerequisiteisthetransformationofthissurplus-profitintotheformofground-rentofrentingeneralasaformdistinctfromprofit；itmustbeinvestigatedineachcasewhen，how，underwhatconditionsthistransformationtakesplace。
　　Ricardoisalsorightinthefollowingobservation，provideditislimitedtodifferentialrent:”Whateverdiminishestheinequalityintheproduceobtainedonthesameoronnewland，tendstolowerrent，andwhateverincreasesthatinequality，necessarilyproducesanoppositeeffectandtendstoraiseit”p。74。
　　However，amongthesecausesarenotmerelythegeneralonesfertilityandlocation，butalso1thedistributionoftaxes，dependingonwhetheritoperatesuniformlyornot；thelatterisalwaysthecasewhen，asinEngland，itisnotcentralisedandwhenthetaxisleviedonland，notonrent；2theinequalitiesarisingfromadifferenceinagriculturaldevelopmentindifferentpartsofthecountry，sincethislineofproduction，owingtoitstraditionalcharacter，evensoutwithmoredifficultythanmanufacture；and3theinequalityindistributionofcapitalamongcapitalisttenants。Sincetheinvasionofagriculturebythecapitalistmodeofproduction，transformationofindependentlyproducingpeasantsintowage-workers，isinfactthelastconquestofthismodeofproduction，theseinequalitiesaregreaterherethaninanyotherlineofproduction。
　　Havingmadethesepreliminaryremarks，IwillfirstpresentabriefsummaryofthecharacteristicfeaturesofmyanalysisincontradistinctiontothatofRicardo，etc。
　　Weshallfirstconsidertheunequalresultsofequalquantitiesofcapitalappliedtodifferentplotsoflandofequalsize；or，inthecaseofunequalsize，resultscalculatedonthebasisofequalareas。
　　Thetwogeneralcausesoftheseunequalresults-quiteindependentofcapital-aie:1Fertility。Withreferencetothisfirstpoint，itwillbenecessarytodiscusswhatismeantbynaturalfertilityoflandandwhatfactorsareinvolved。2Thelocationoftheland。Thisisadecisivefactorinthecaseofcoloniesandingeneraldeterminesthesequenceinwhichplotsoflandcanbecultivated。Furthermore，itisevidentthatthesetwodifferentcausesofdifferentialrent-fertilityandlocation-mayworkinoppositedirections。Acertainplotoflandmaybeveryfavourablylocatedandyetbeverypoorinfertility，andviceversa。Thiscircumstanceisimportant，foritexplainshowitispossiblethatbringingintocultivationthelandofacertaincountrymayequallywellproceedfromthebettertotheworselandasviceversa。Finally，itisclearthattheprogressofsocialproductioningeneralhas，ontheonehand，theeffectofeveningoutdifferencesarisingfromlocationasacauseofground-rent，bycreatinglocalmarketsandimprovinglocationsbyestablishingcommunicationandtransportationfacilities；ontheotherhand，itincreasesthedifferencesinindividuallocationsofplotsoflandbyseparatingagriculturefrommanufacturingandforminglargecentresofproduction，ontheonehand，whilerelativelyisolatingagriculturaldistricts，ontheother。
　　Forthepresent，however，weshallleavethispointconcerninglocationoutofconsiderationandconfineourselvestonaturalfertility。
　　Asidefromclimaticfactors，etc。，thedifferenceinnaturalfertilitydependsonthechemicalcompositionofthetopsoil，thatis，onitsdifferentplantnutritioncontent。However，assumingthechemicalcompositionandnaturalfertilityinthisrespecttobethesamefortwoplotsofland，theactualeffectivefertilitydiffersdependingonwhethertheseelementsofplantnutritionareinaformwhichmaybemoreorlesseasilyassimilatedandimmediatelyutilisedfornourishingthecrops。Hence，itwilldependpartlyuponchemicalandpartlyuponmechanicaldevelopmentsinagriculturetowhatextentthesamenaturalfertilitymaybemadeavailableonplotsoflandofsimilarnaturalfertility。Fertility，althoughanobjectivepropertyofthesoil，alwaysimpliesaneconomicrelation，arelationtotheexistingchemicalandmechanicallevelofdevelopmentinagriculture，and，therefore，changeswiththislevelofdevelopment。Whetherbychemicalmeanssuchastheuseofcertainliquidfertilisersonstiffclaysoilandcalcinationofheavyclayeysoilsormechanicalmeanssuchasspecialploughsforheavysoils，theobstacleswhichmadeasoilofequalfertilityactuallylessfertilecanbeeliminateddrainagealsobelongsunderthishead。Oreventhesequenceintypesofsoilstakenundercultivationmaybechangedthereby，aswasthecase，forinstance，withlightsandysoilandheavyclayeysoilatacertainperiodofdevelopmentinEnglishagriculture。
　　Thisshowsonceagainthathistorically，inthesequenceofsoilstakenundercultivation，onemaypassoverfrommorefertiletolessfertilesoilsaswellasviceversa。Thesameresultsmaybeobtainedbyanartificiallycreatedimprovementinsoilcompositionorbyamerechangeinagriculturalmethods。Finally，thesameresultmaybebroughtaboutbyachangeinthehierarchicalarrangementofthesoiltypesduetodifferentconditionsofthesubsoil，assoonasthelatterlikewisebeginstobetilledandturnedoverintotoplayers。Thisisinpartdependentontheemploymentofnewagriculturalmethodssuchasthecultivationoffodder-grassandinpartontheemploymentofmechanicalmeanswhicheitherturnthesubsoiloverintotoplayers，mixitwithtopsoil，orcultivatethesubsoilwithoutturningitup。
　　Alltheseinfluencesuponthedifferentialfertilityofvariousplotsoflandaresuchthatfromthestandpointofeconomicfertility，theleveloflabourproductivity，inthiscasethecapacityofagriculturetomakethenaturalsoilfertilityimmediatelyexploitable——acapacitywhichdiffersinvariousperiodsofdevelopment——isasmuchafactorinso-callednaturalsoilfertilityasitschemicalcompositionandothernaturalproperties。
　　Weassume，then，theexistenceofaparticularstageofdevelopmentinagriculture。Weassumefurthermorethatthehierarchicalarrangementofsoiltypesaccordswiththisstageofdevelopment，asis，ofcourse，alwaysthecaseforsimultaneouscapitalinvestmentsondifferentplotsofland。Differentialrentmaythenformeitheranascendingoradescendingsequence，foralthoughthesequenceisgivenforthetotalityofactuallycultivatedplotsofland，aseriesofmovementsleadingtoitsformationhasinvariablytakenplace。
　　Letusassumetheexistenceoffourkindsofsoil:A，B，C，D。
　　Letusfurthermoreassumethepriceofonequarterofwheat=£；3，or60shillings。Sincetherentissolelydifferentialrent，thispriceof60shillingsperquarterfortheworstsoilisequaltothepriceofproduction，thatis，equaltothecapitalplusaverageprofit。LetAhethisworstsoil，whichyieldsIquarter=60shillingsforeach50shillingsspent；hencetheprofitamountsto10shillings，or20%。
　　LetByield2quarters=120shillingsforthesameexpenditureThiswouldmean70shillingsofprofit，orasurplus-profitof60shillings。
　　LetCyield3quarters=180shillingsforthesameexpenditure；
　　totalprofit=130shillings；surplus-profit=120shillings。
　　LetDyield4quarters=240shillings=180shillingsofsurplus-profit。
　　Wewouldthenhavethefollowingsequence:
　　TABLEI
　　TypeofSoilProductCapitalAdvancedProfitRentQuar-tersShil-ingsQuar-tersShil-ingsQuar-tersShil-ingsABCD123460120180240505050501/611/621/631/61070130190——123——60120180
　　Total……10qrs600sh。6qrs360sh。Therespectiverentsare:D=190sh-l0sh。，orthedifferencebetweenDandA；C=130sh-l0sh。，orthedifferencebetweenCandA；B=7Osh-10sh。，orthedifferencebetweenBandA；andthetotalrentforB，C，D=6quarters=360
　　shillings，equaltothesumofthedifferencesbetweenDandA，CandA，BandA。
　　Thissequence，whichrepresentsagivenproductinagivenconditionmay，consideredabstractlywehavealreadyofferedthereasonswhythismayhethecaseinreality，descendfromDtoA，fromfertiletolessandlessfertilesoil，orrisefromAtoD，fromrelativelypoortomoreandmorefertilesoil，or，finally，mayfluctuate，i。e。，nowrising，nowdescending——forinstancefromDtoC，fromCtoA，andfromAtoB。
　　Theprocessinthecaseofadescendingsequencewasasfollows:
　　Thepriceofaquarterofwheatrosegraduallyfrom，say，15shillingsto60shillings。Assoonasthe4quartersproducedbyDwemayconsiderthese4quartersassomanymillionquartersnolongersufficed，thepriceofwheatrosetoapointwherethesupplyshortagecouldbeproducedbyC。Thatistosay，thepriceofwheatmusthaverisento20shillingsperquarter。Whenithadrisento30shillingsperquarter，Bcouldbetakenundercultivation，andwhenitreached60shillingsAcouldbetakenundercultivation；andthecapitalinvesteddidnothavetocontentitselfwitharateofprofitlowerthan20%。Inthismanner，arentwasestablishedforD，firstof5shillingsperquarter=20shillingsforthe4quartersproducedbyit；thenof15shillingsperquarter=60shillings，thenof45shillingsperquarter=180shillingsfor4quarters。
　　IftherateofprofitofDoriginallywassimilarly=20%，thenitstotalprofiton4quartersofwheatwasaJsobut10shillings，butthisrepresentedmoregrainwhenthepricewas15shillingsthanitdoeswhenthepriceis60shillings。Butsincethegrainentersintothereproductionoflabour-power，andpartofeachquarterhastomakegoodsomeportionofwagesandanotherconstantcapital，thesurplus-valueundertheseconditionswashigher，andthusotherthingsbeingequaltherateofprofittoo。Thematterofrateofprofitwillhavetobespeciallyanalysed，andingreaterdetail。
　　Ontheotherhand，ifthesequencewereinthereverseorder，thatis，iftheprocessinitiatedfromA，thenthepriceofwheatatfirstwouldriseabove60shillingsperquarterwhennewlandwouldhavetobetakenundercultivation。ButsincethenecessarysupplywouldbeproducedbyB，asupplyof2quarters，thepricewouldfallto60shillingsagain，forBproducedwheatatacostof30shillingsperquarter，butsolditat60shillingsbecausethesupplyjustsufficedtocoverthedemand。Thusarentwasformed，firstof60shillingsforB，andinthesamewayforCandD；itisassumedthroughoutthatthemarket-priceremainedat60
　　shillings，althoughCandDproducedwheathavinganactualvalueof20
　　and15shillingsperquarterrespectively，becausethesupplyoftheonequarterproducedbyAwasneededasmuchasevertosatisfythetotaldemand。
　　Inthiscase，theincreaseindemandabovesupply，whichwasfirstsatisfiedbyA，thenbyAandB，wouldnothavemadeitpossibletocultivateB，CandDsuccessivejy，butwouldmerelyhavecausedageneralextensionofthesphereofcultivation，andthemorefertilelandsmightonlylatercomeundercultivation。
　　Inthefirstsequence，anincreaseinpricewouldraisetherentanddecreasetherateofprofit。Suchadecreasemightbeentirelyorpartiallycheckedbycounteractingcircumstances。Thispointwillhavetobetreatedlaterinmoredetail。Itshouldnotbeforgottenthatthegeneralrateofprofitisnotdetermineduniformlyinallspheresofproductionbythesurplus-value。Itisnottheagriculturalprofitwhichdeterminesindustrialprofit，butviceversa。Butofthismoreanon。
　　Inthesecondsequencetherateofprofitoninvestedcapitalwouldremainthesame。Theamountofprofitwouldberepresentedbylessgrain；buttherelativepriceofgrain，comparedwiththatofothercommodities，wouldhaverisen。However，theincreaseinprofitwhereversuchanincreasetakesplace，becomesseparatedfromtheprofitintheformofrent，insteadofflowingintothepocketsofthecapitalisttenantfarmerandappearingasagrowingprofit。Thepriceofgrain，however，couldremainunchangedundertheconditionsassumedhere。
　　Thedevelopmentandgrowth，ofdifferentialrentwouldremainthesameforfixedaswellasforincreasingprices，andforacontinuousprogressionfromworsetobettersoilsaswellasforacontinuousretrogressionfrombettertoworsesoils。
　　Thusfarwehaveassumed:1thatthepricerisesinonesequenceandremainsstationaryintheother；2thatthereisacontinuousprogressionfrombettertoworsesoil，orfromworsetobettersoil。
　　Butnowletusassumethatthedemandforgrainrisesfromitsoriginalfigureof10to17quarters；furthermore，thattheworstsoilAisdisplacedbyanothersoilA，whichproduces11/3quartersatapriceofproductionof60shillings50sh。costpluslOsh。for20%profit，sothatitspriceofproductionperquarter=45shillings；or，perhaps，theoldsoilAmayhaveimprovedthroughcontinuousrationalcultivation，orbecultivatedmoreproductivelyatthesamecost，forinstancethroughtheintroductionofclover，etc。，sothatitsoutputwiththesameinvestmentofcapitalrisesto11/3quarters。LetusalsoassumethatsoiltypesB，CandDyieldthesameoutputaspreviously，butthatnewsoiltypeshavebeenintroduced，forinstance，A’withafertilitylyingbetweenA
　　andB，andalsoB’andB”withafertilitybetweenBandC。Weshouldthenobservethefollowingphenomena:
　　First:Thepriceofproductionofaquarterofwheat，oritsregulatingmarket-price，fallsfrom60shillingsto45shillings，orby25%。
　　Second:Thecultivationproceedssimultaneouslyfrommorefertiletolessfertilesoil，andfromlessfertiletomorefertilesoil。
　　SoilA’ismorefertilethanA，butlessfertilethanthehithertocultivatedsoilsB，CandD。B’andB”aremorefertilethanA’，A’andB，butlessfertilethanCandD。Thesequencethusproceedsincrisscrossfashion。
　　CultivationdoesnotproceedtosoilabsolutelylessfertilethanA，etc。，buttorelativelylessfertilesoilwithrespecttothehithertomostfertilesoiltypesCandontheotherhand，cultivationdoesnotproceedtosoilabsolutelymorefertile，buttorelativelymorefertilesoilwithrespecttothehithertoleastfertilesoilA，orAandB。
　　Thirdly:TherentonBfalls；likewisetherentonCandD；butthetotalrentalingrainrisesfrom6quartersto72/3；theamountofcultivatedandrent-yieldinglandincreases，andtheamountofproducerisesfrom10quartersto17。Theprofit，althoughitremainsthesameforA，risesifexpressedingrain，buttherateofprofititselfmightrise，becausetherelativesurplus-valuedoes。Inthiscase，thewage，i。e。，theinvestmentofvariablecapitalandthereforethetotaloutlay，isreducedbecauseoftbecheapeningofmeansofsubsistence。Thistotalrentalexpressedinmoneyfallsfrom360shillingsto345shillings。
　　TABLEII
　　TypeofSoilProductCapi-talInvest-mentProfitRentPriceofProductionperQuaterQuar-tersShil-ingsQuar-tersShil-ingsQuar-tersShil-ingsAA’BB’B”CD11/3
　　12/3
　　2
　　21/3
　　22/3
　　3
　　4607590105120135180505050505050502/95/98/912/915/918/928/9102540557085130——
　　1/3
　　2/3
　　1
　　11/3
　　12/3
　　22/3——153045607512045sh。
　　36sh。
　　30sh。
　　255/7*sh。
　　221/2sh。
　　20sh。
　　15sh。
　　Total……1772/3345*IntheGerman1894editionthisreads:252/7——Ed。
　　Letusdrawupthenewsequence。[Seep。655——Ed。J
　　Finally，ifonlysoiltypesA，B，CandDwerecultivatedasbefore，buttheirproductivenessroseinsuchawaythatAproduced2quartersinsteadof1quarter，B-4quartersinsteadof2，C-7quartersinsteadof3，andD-10quartersinsteadof4，sothatthesamecausesaffectthevarioustypesofsoildifferently，thetotalproductionincreasesfrom10quartersto23。Assumingthatdemandabsorbsthese23quartersthroughanincreaseinpopulationandafallinprices，weshouldobtainthefollowingresult:
　　TABLEIII
　　TypeofSoilProductCapitalInvestmentPriceofProductionperQuarterProfitRentQuar-tersShil-ingsQuar-tersShil-ingsQuar-tersShil-ingsABCD247106012021030050505050301584/761/321/351/381/310701602500258060150240
　　Total……2315450Thenumericalproportionsinthisandinothertablesarechosenatrandombuttheassumptionsarequiterational。
　　Thefirstandprincipalassumptionisthatanimprovementinagricultureactsdifferentlyupondifferentsoils，andinthiscaseaffectsthebesttypesofsoil，CandD，morethantypesAandB。Experiencehasshownthatthisisgenerallythecase，althoughtheoppositemayalsotakeplace。
　　Iftheimprovementaffectedthepoorersoilsmorethanthebetterones，rentonthelatterwouldhavefalleninsteadofrisen。Butinourtable，wehaveassumedthattheabsolutegrowthinfertilityofallsoiltypesissimultaneouslyaccompaniedbyanincreaseingreaterrelativefertilityofthebettersoiltypes，CandD；thismeansanincreaseinthedifferencebetweentheproductatthesamecapitalinvestment，andthusanincreaseindifferentialrent。
　　Thesecondassumptionisthattotaldemandkeepspacewiththeincreaseinthetotalproduct。First，oneneednotimaginesuchanincreasecomingaboutabruptly，butrathergradually-untilsequenceIIIisestablished。
　　Secondly，itisnottruethattheconsumptionofnecessitiesoflifedoesnotincreaseastheybecomecheaper。TheabolitionoftheCornLawsinEnglandprovedthereversetobethecaseF。Newman，LecturesonPoliticalEconomy，London，1851，p。158——Ed。；theoppositeviewstemssolelyfromthefactthatlargeandsuddendifferencesinharvests，whicharemereresultsofweather，bringaboutatonetimeanextraordinaryfall，atanotheranextraordinaryrise，ingrainprices。Whileinsuchacasethesuddenandshort-livedreductioninpricedoesnothavetimetoexertitsfulleffectupontheextensionofconsumption，theoppositeistruewhenareductionarisesfromtheloweringoftheregulatingpriceofproductionitself，i。e。，isofalong-termnature。Thirdly，apartofthegrainmaybeconsumedintheformofbrandyorbeer；andtheincreasingconsumptionofbothoftheseitemsisbynomeansconfinedwithinnarrowlimits。Fourthly，thematterdependsinpartupontheincreaseinpopulationandinpartonthefactthatthecountrymaybegrain-exporting，asEnglandstillwaslongafterthemiddleofthe18thcentury，sothatthedemandisnotsolelyregulatedwithintheconfinesofnationalconsumption。Finally，theincreaseandpricereductioninwheatproductionmayresultinmakingwheat，insteadofryeoroats，theprincipalarticleofconsumptionforthemasses，sothatthedemandforitmaygrowifonlyforthisreason，justastheoppositemaytakeplacewhenproductiondecreasesandpricesrise-Thus，undertheseassumptions，andwiththepreviouslyselectedratios，sequenceIIIyieldstheresultthatthepriceperquarterfallsfrom60
　　to30shillings，thatis，by50%；thatproduction，comparedtosequenceI，increasesfrom10to23quarters，i。e。，by130%；thattherentremainsfixedforsoilB，increasesby25%IntheGerman1894editionthisreads:
　　doubles——Ed。forC，andby331/3%Ibid。p22——Ed。
　　forD；andthatthetotalrentalincreasesfrom£；18to£；22
　　1/2，Ibid。22——Ed。，by25%。Ibid。:22
　　1/9%——Ed。
　　AcomparisonofthesethreetableswherebysequenceIistobetakentwice，risingfromAtoD，anddescendingfromDtoA，whichmaybeconsideredeitherasgivengradationsundersomestageofsociety，forinstance，asexistingsidebysideinthreedifferentcountries，orassucceedingoneanotherindifferentperiodsofdevelopmentwithinthesamecountry，shows:
　　1Thesequence，whencomplete，whateverthecourseofitsformativeprocessmayhavebeen，invariablyappearsasbeinginadescendingline；
　　forwhenanalysingrentthepointofdeparturewillalwaysbelandyieldingthemaximumrent，andonlyfinallydowecometolandyieldingnorent。
　　2Thepriceofproductionontheworstsoil，i。e。，whichyieldsnorent，isalwaystheoneregulatingthemarket-price，althoughthelatterinTableI，ifitssequencewereformedinanascendingline，onlyremainedfixedbecausebetterandbettersoilwasconstantlydrawnintocultivation。
　　Insuchacase，thepriceofgrainproducedonthebestsoilisaregulatingoneillsofarasitdependsuponthequantityproducedonsuchsoiltowhatextentsoiltypeAremainstheregulator。IfB，CandDshouldproducemorethandemandrequires，Awouldceasetobetheregulator。Storchhasthispointhazilyinmindwhenheadoptsthebestsoiltypeastheregulatingone。H。Storch，Coursd’econom’iepoilitique，ouExpositiondesprincipesqutdeterminentlaprosperitedesnations，TomeII，St-Petersbourg，1815，pp。78-79——Ed。Inthismanner，theAmericanpriceofgrainregulatestheEnglishprice。
　　3Differentialrentarisesfromdifferencesinthenaturalfertilityofthesoilwhichisgivenforeverygivenstageofagriculturaldevelopmentleavingasideforthepresentthequestionoflocation；inotherwords，fromthelimitedareaofthebestland，andfromthecircumstancethatequalamountsofcapitalmustbeinvestedonunequaltypesofsoil，sothatanunequalproductresultsfromthesameamountofcapital。
　　4Theexistenceofadifferentialrentandofagraduateddifferentialrentcandevelopequallywellinadescendingsequence，whichproceedsfrombettertoworsesoils，asinanascendingone，whichprogressesintheoppositedirectionfromworsetobettersoils；oritmaybebroughtaboutincheckeredfashionbyalternatingmovements。SequenceImaybeformedbyproceedingfromDtoA，orfromAtoD；sequenceIIcomprisesbothtypesofmovement。
　　5Dependingonitsmodeofformation，differentialrentmaydevelopalongwithastationary，risingorfallingpriceoftheproductsoftheland。Inthecaseofafallingprice，totalproductionandtotalrentalmayrise，andrentmaydeveloponhithertorentlessland，eventhoughtheworstsoilAmayhavebeendisplacedbyabetteroneormayitselfhaveimproved，andeventhoughtherentmaydecreaseonotherlandwhichisbetter，oreventhebestTableII；thisprocessmayalsobeconnectedwithafallintotalrentinmoney。Finally，atatimewhenpricesfallonaccountofageneralimprovementincultivation，sothattheproductoftheworstsoilanditspricedecrease，therentonsomeofthebettersoilsmayremainthesame，ormayfall，whileitmayriseonthebestones。
　　Nevertheless，thedifferentialrentofeverysoil，comparedwiththeworstsoil，depends，ifthedifferenceinquantityofproductsisgiven，upontheprice，say，ofaquarterofwheat。Butwhenthepriceisgiven，differentialrentdependsuponthemagnitudeofthedifferenceinquantityofproducts，andifwithanincreasingabsolutefertilityofallsoilsthatofthebetteronesgrowsrelativelymorethanthatoftheworseones，themagnitudeofthisdifferencegrowsproportionately。InthiswayseeTableI，whenthepriceis60shillings，therentonDisdeterminedbyitsdifferentialproductascomparedwithA；inotherwords，bythesurplusof3quarters。
　　Therentistherefore=3x60=l80shillings。ButinTableIII，wheretheprice=30
　　shillings，therentisdeterminedbythequantityofsurplus-productofDascomparedwithA=8quarters；wethereforeobtain8X30=240shillings。
　　Thistakescareofthefirstfalseassumptionregardingdifferentialrent-stillfoundamongWest，Malthus，andRicardo——narnely，thatitnecessarilypresupposesamovementtowardworseandworsesoil，oranever-decreasingfertilityofthesoil。[West]EssayontheApplication0fCapitaltoLand，London，1815。Maitbus，PrinciplesofPolittcalEconomy，London，4836。Maithus，AnInquiryintotheNatureandProgressofRent，andthePrinctplesbywhichitisregulated，London，1815。
　　Ricardo，OnthePrinciplesofPoliticalEconomy，andTaxation，Thirdedition，London，4824，Chap。11——Ed。Itcanbeformed，aswehaveseen，withamovementtowardbetterandbettersoil；itcanbeformedwhenabettersoiltakesthelowestpositionthatwasformerlyoccupiedbytheworstsoil；itcanbeconnectedwithaprogressiveimprovementinagriculture。
　　Thepreconditionismerelytheinequalityofdifferentkindsofsoil。Sofarastheincreaseinproductivityisconcerned，itassumesthattheincreaseinabsolutefertilityofthetotalareadoesnoteliminatethisinequality，buteitherincreasesit，leavesitunchanged，ormerelyreducesit。
　　Fromthebeginningtothemiddleofthe18thcentury，England’sgrainpricesconstantlyfellinspiteofthefallingpricesofgoldandsilver，whileatthesametimeviewingthisentireperiodasawhole
　　therewasanincreaseinrent，intheover-allamountofrent，intheareaofcultivatedland，inagriculturalproduction，andinpopulation。ThiscorrespondstoTableItakeninconjunctionwithTableIIinanascendingline，butinsuchawaythattheworstlandAiseitherimprovedoreliminatedfromthegrain-producingarea；however，thisdoesnotmeanthatitwasnotusedforotheragriculturalorindustrialpurposes。
　　Fromtheearly19thcenturydatetobespecifiedmoreprecisely
　　until1815thereisaconstantriseingrainprices，accompaniedbyasteadyincreaseinrent，intheover-allamountofrent，intheareaofcultivatedland，inagriculturalproduction，andinpopulation。ThiscorrespondstoTableIinadescendingline。Citesomesourceshereonthecultivationofinferiorlandinthatperiod。
　　InPetty’sandDavenant’stime，farmersandlandownerscomplainedaboutimprovementsandthebringingintocultivationofnewland；therentonbetterlandsdecreased，andthetotalamountofrentincreasedthroughtheextensionoftheareaoflandyieldingrent。
　　Thesethreepointsshouldbeillustratedlaterbyquotations；likewiseforthedifferenceinfertilityofvariouscultivatedsectionsoflandinaparticularcountry。
　　Regardingdifferentialrentingeneral，itistobenotedthatthemarket-valueisalwaysabovethetotalpriceofproductionofthetotalquantityofproducts。Asanexample，letustakeTableI。Tenqilartersoftotalproductaresoldfor600shillingsbecausethemarket-priceisdeterminedbythepriceofproductionofA，whichamountsto60shillingsperquarter。Buttheactualpriceofproductionis:
　　A……Iqr=60sh。Iqr=60sb。
　　B……2qrs=60sb。Iqr=30sh。
　　C……3qrs=60Sb。Iqr=20ahD……4qrs=60sh。Iqr=15ah。
　　10qrs=240sh。Average1qr=24sh。Theactualpriceofproductionofthese10quartersis240shillings；buttheyaresoldfor600shillings，i。e。，at250%ofthepriceofproduction。
　　TheactualaveragepriceforIquarteris24shillings；themarket-priceis60shillings，i。e。，also250%oftheproductionprice。
　　Thisisdeterminationbymarket-valueasitassertsitselfonthebasisofcapitalistproductionthroughcompetition；thelattercreatesafalsesocialvalue。Thisarisesfromthelawofmarketvalue，towhichtheproductsofthesoilaresubject。Thedeterminationofthemarket-valueofproducts，includingthereforeagriculturalproducts，isasocialact，albeitasociallyunconsciousandunintentionalone。Itisbasednecessarilyupontheexchange-valueoftheproduct，notuponthesoilandthedifferencesinitsfertility。Ifwesupposethecapitalistformofsocietytobeabolishedandsocietyorganisedasaconsciousandplannedassociation，thenthe10quarterswouldrepresentaquantityofindependentlabour-timeequaltothatcontainedin240shillings。Societywouldnotthenbuythisagriculturalproductattwoandahalftimestheactuallabour-timeembodiedinitandthebasisforaclassoflandownerswouldthusbedestroyed。Thiswouldhavethesameeffectasareductioninpriceoftheproducttothesameamountresultingfromforeignimports。Whileitis，therefore，truethat，byretainingthepresentmodeofproduction，butassumingthatthedifferentialrentispaidtothestate，pricesofagriculturalproductswould，everythingelsebeingequal，remainthesame，itisequallywrongtosaythatthevalueoftheproductswouldremainthesameifcapitalistproductionweresupersededbyassociation。Theidentityofthemarket-priceforcommoditiesofthesamekindisthemannerwherebythesocialcharacterofvalueassertsitselfonthebasisofcapitalistproductionand，ingeneral，anyproductionbasedontheexchangeofcommoditiesbetweenindividuals。Whatsocietyoverpaysforagriculturalproductsinitscapacityofconsumer，whatisaminusintherealisationofitslabour-timeinagriculturalproduction，isnowaplusforaportionofsociety，forthelandlords。
　　Asecondcircumstance，importantfortheanalysistobegivenunderIIofthenextchapter，isthefollowing:
　　Itisnotmerelyamatterofrentperacre，orperhectare，norgenerallyofadifferencebetweenthepriceofproductionandmarketprice，norbetweentheindividualandthegeneralpriceofproductionperacre，butitisalsoaquestionofhowmanyacresofeachtypeofsoilareundercultivation。Thepointofimportancehererelatesdirectlyonlytothemagnitudeoftherental，thatis，thetotalrentoftheentirecultivatedarea；butitservesusatthesametimeasastepping-stonetotheconsiderationofariseintherateo/rentalthoughthereisnoriseinprices，norincreaseinthedifferencesinrelativefertilityofthevarioustypesofsoilifpricesfall。
　　Wehadabove:
　　TABLEI
　　TypeofSoilAcresPriceofProductionProductRentinGrainRentinMoneyABCD1111£；3£；3£；3£；31qrs2qrs3qrs4qrs01qrs2qrs3qrs0£；3£；6£；9
　　Total……4acres10qrs6qrs£；18Nowletusassumethatthenumberofcultivatedacresisdoubledineverycategory。Wethenhave:
　　TABLEIaTypeofSoilAcresPriceofProductionProductRentinGrainRentinMoneyABCD2222£；6£；6£；6£；62qrs4qrs6qrs8qrs02qrs4qrs6qrs0£；6£；12£；18
　　Total……8acres20qrs12qrs£；36Letusassumetwomorecases。Supposeinthefirstcaseproductionexpandsonthetwopooresttypesofsoilinthefollowingmanner:
　　TABLEIbTypeofSoilAcresPriceofProductionProductRentinGrainRentinMoneyPerAcreTotalABCD4422£；3£；3£；3£；3£；3£；6£；15£；164qr8qrs6qrs8qrs04qrs4qrs6qrs£；0£；12£；12£；18
　　Total……12acres£；3626qrs14qrs£；42And，finally，letusassumeanunequalexpansionofproductionandcultivatedareaforthefoursoilcategories:
　　TABLEIcTypeofSoilAcresPriceofProductionProductRentinGrainRentinMoneyPerAcreTotalABCD1254£；3£；3£；3£；3£；3£；6£；15£；121qr4qrs15qrs16qrs02qrs10qrs12qrs£；0£；6£；30£；18
　　Total……12acres£；3636qrs24qrs£；72Inthefirstplace，therentperacreremainsthesameinallthesecases——I，Ia，lbandIc——for，infact，theresultofthesameinvestmentofcapitalperacreofthesamesoiltypehasremainedunchanged。Wehaveonlyassumedwhatistrueofanycountryatanygivenmoment；namely，thatvarioussoiltypesexistindefiniteratiostothetotalcultivatedarea。
　　Andwealsoassumedwhatisalwaystrueofanytwocountriesbeingcompared，orofthesamecountryatdifferentperiods，namely，thattheproportionsinwhichthetotalcultivatedareaisdistributedamongthedifferentsoiltypesvary。
　　IncomparingIawithIweseethatifthecultivationoflandinallfourcategoriesincreasesinthesameproportionadoublingofthecultivatedacreagedoublesthetotalproduction，andthatthesameappliestotherentingrainandmoney。
　　However，ifwecomparelbandthenIcwithI，weseethatinbothcasesatriplingoftheareaundercultivationoccurs。Itincreasesinbothcasesfrom4acresto12，butinlbclassesAandBcontributemosttotheincrease，withAyieldingnorentandByieldingthesmallestamountofdifferentialrent。Thus，outofthe8newlycultivatedacres，AandBaccountfor3each，i。e。，6together，whereasCandDaccountforIeach，i。e。，2together。Inotherwords，three-quartersoftheincreaseisaccountedforbyAandB，andonlyone-quarterbyCandD。Withthispremise，inlbcomparedwithIthetrebledareaofcultivationdoesnotresultinatrebledproduct，fortheproductdoesnotincreasefrom10to30，butonlyto26。Ontheotherhand，sinceaconsiderablepartoftheincreaseconcernsA，whichdoesnotyieldanyrent，andsincethemajorpartoftheincreaseonbettersoilsconcernsB，therentingrainrisesonlyfrom6to14quarters，andtherentinmoneyfrom£；18to£；42。
　　ButifwecompareIcwithI，wherethelandyieldingnorentdoesnotincreaseinareaandthelandyieldingaminimumrentincreasesbutslightly，whileCandDaccountforthemajorpartoftheincrease，wefindthatwhenthecultivatedareaistrebledproductionincreasesfrom10to36
　　quarters，i。e。，tomorethanthreetimesitsoriginalamount。Therentingrainincreasesfrom6to24quartersortofourtimesitsoriginalamount；andsimilarlymoney-rent，from£；18to£；72。
　　Inallthesecasesitisinthenatureofthingsthatthepriceoftheagriculturalproductremainsunchanged。Thetotalrentalincreasesinallcaseswiththeextensionofcultivation，unlessittakesplaceexclusivelyontheworstsoil，whichdoesnotyieldanyrent。Butthisincreasevaries。
　　Shouldthisextensioninvolvethebettersoiltypesandthetotaloutput，consequently，increasenotmerelyinproportiontotheexpansionofthearea，butrathermorerapidly，thentherentingrainandmoneyincreasestothesameextent。Shoulditbetheworstsoil，andthetypesofsoilclosetoit，thatareprincipallyinvolvedintheexpansionwherebyitisassumedthattheworstsoilrepresentsaconstanttype，thetotalrentaldoesnotincreaseinproportiontotheextensionofcultivation。Thus，giventwocountriesinwhichsoilA，yieldingnorent，isofthesamequality，therentalisinverselyproportionaltothealiquotpartrepresentedbytheworstsoilandtheinferiorsoiltypesinthetotalareaundercultivation，andthereforeinverselyproportionaltotheoutput，assumingequalcapitalinvestmentsonequaltotallandareas。Arelationshipbetweenthequantityoftheworstandthequantityofthebettercultivatedlandinthetotallandareaofagivencountrythushasanoppositeinfluenceonthetotalrentalthantherelationshipbetweenthequalityoftheworstcultivatedlandandthequalityofthebetterandbesthasontherentperacreand-othercircumstancesremainingthesame-onthetotalrental。Confusionbetweenthesetwopointshasgivenrisetoallkindsoferroneousobjectionsraisedagainstdifferentialrent。
　　Thetotalrental，then，increasesbythemereextensionofcultivation，andbytheconsequentgreaterinvestmentofcapitalandlabourintheland。
　　Butthemostimportantpointisthis:Althoughitisourassuniptionthattheratioofrentsperacreforthevariouskindsofsoilremainsthesame，andthereforealsotherateofrentconsideredwithreferencetocapitalinvestedineachacre，yetthefollowingistobeobserved:IfwecompareIawithI，thecaseinwhichthenumberofcultivatedacresandthecapitalinvestedinthemhavebeenproportionatelyincreased，wefindthatasthetotalproductionhasincreasedproportionatelytotheexpandedcultivatedarea，i。e。，asbothhavebeendoubled，sohastherental。Ithasrisenfrom£；18to£；36，justasthenumberofacreshasrisenfrom4to8。
　　Ifwetakethetotalareaof4acres，wefindthatthetotalrentalamountedto£；18andthustheaveragerent，includingthelandwhichdoesnotyieldanyrent，is£；4112。Suchacalculationmightbemade，say，byalandlordowningall4acres；andinthiswaytheaveragerentisstatisticallycomputedforawholecountry。Thetotalrentalof£；18
　　isobtainedbytheinvestmentofacapitalof£；10。Wecalltheratioofthesetwofigurestherateofrent；inthepresentcaseitistherefore180%。
　　ThesamerateofrentobtainsinIa，where8insteadof4acresarecultivated，butalltypesoflandhavecontributedtotheincreaseinthesameproportion。Thetotalrentalof£；36yieldsfor8acresandaninvestedcapitalof£；20anaveragerentof£；4112peracreandarateofrentof180%。
　　Butifweconsiderlb，wheretheincreasehastakenplacemainlyupontwoinferiorcategoriesofsoil，weobtainarentof£；42for12acres，oranaveragerentof£；3112peracre。Thetotalinvestedcapitalis£；30，andthereforetherateof’rent=140%。Theaveragerentperacrehasthusdecreasedby£；1，andtherateofrenthasfallenfrom180to140%。Herethenwehaveariseinthetotalrentalfrom£；18to£；42，butadropinaveragerentcalculatedperacreaswellasonthebasisofcapital；thedroptakesplaceparalleltoanincreaseinproduction，butnotproportionately。Thisoccurseventhoughtherentforalltypesofsoil，calculatedperacreaswellasonthebasisofcapitaloutlay，remainsthesame。Thisoccursbecausethree-quartersoftheincreaseisaccountedforbysoilA，whichdoesnotyieldanyrent，andsoilB，whichyieldsonlyminimumrent。
　　IfthetotalexpansioninCaselbhadtakenplacesolelyonsoilA，weshouldhave9acresonA，IacreonB，IacreonCandIacreonD。Thetotalrentalwouldbe£；18，thesameasbefore；theaveragerentforthe12acresthereforewouldbe£；1112peracre；andarentof£；18onaninvestedcapitalof£；30wouldgivearateofrentof60%。Theaveragerent，calculatedperacreaswellasonthebasisofinvestedcapital，wouldhavegreatlydecreased，whilethetotalrentalwouldnothaveincreased。
　　Finally，letuscompareIcwithIandIb。ComparedwithI，theareahasbeentrebled，andalsotheinvestedcapital。Thetotalrentalis£；72for12acres，or£；6peracre-asagainst£；4112
　　inCaseI。Therateofrentontheinvestedcapital£；72:£；30
　　is240%insteadof180%。Thetotaloutputhasrisenfrom10to36quarters。
　　Comparedwithlb，wherethetotalnumberofcultivatedacres，theinvestedcapital，andthedifferencesbetweenthecultivatedsoiltypesarethesame，butthedistributiondifferent，theoutputis36quartersinsteadof26quarters，theaveragerentperacreis£；6insteadof£；3112，andtherateofrentwithreferencetothesameinvestedtotalcapitalis240%insteadof140%。
　　NomatterwhetherweregardthevariousconditionsintablesIa，lbandIcasexistingsimultaneouslysidebysideindifferentcountries，orasexistingsuccessivelyinthesamecountry，wecometothefollowingconclusions:Solongasthepriceofgrainremainsunchangedbecausetheyieldontheworst，rentlesssoilremainsthesame；solongasthedifferenceinthefertilityofthevariouscultivatedtypesofsoilremainsthesame；
　　solongastherespectiveoutputsremainthesame，hence，givenequalcapitalinvestmentsonequalaliquotpartsacresofcultivatedareaineverytypeofsoil；solongastheratio，therefore，betweentherentsperacreoneachcategoryofsoilisconstant，andtherateofrentonthecapitalinvestedineachplotofthesamekindofsoilisconstant:First，therentalconstantlyincreaseswiththeextensionofcultivatedareaandwiththeconsequentincreasedcapitalinvestment，exceptforthecasewheretheentireincreaseisaccountedforbyrentlessland。Secondly，theaveragerentperacretotalrentaldividedbythetotalnumberofcultivatedacres
　　aswellastheaveragerateofrenttotalrentaldividedbytheinvestedtotalcapitalmayvaryveryconsiderably；and，indeed，bothchangeinthesamedirection，butindifferentproportionstoeachother。IfweleaveoutofconsiderationthecaseinwhichtheexpansiontakesplaceonlyontherentlesssoilA，wefindthattheaveragerentperacreandtheaveragerateofrentonthecapitalinvestedinagriculturedependontheproportionswhichthevariousclassesofsoilconstituteinthetotalcultivatedarea；
　　or，whatamountstothesamething，onthedistributionofthetotalemployedcapitalamongthekindsofsoilofvaryingfertility。Whethermuchorlittlelandiscultivated，andwhetherthetotalrentalisthereforelargerorsmallerwiththeexceptionofthecaseinwhichtheexpansionisconfinedtoA，theaveragerentperacre，ortheaveragerateofrentoninvestedcapital，remainsthesameaslongastheproportionsofthevariouscategoriesofsoilinthetotalcultivatedarearemainunchanged。Inspiteofanincrease，evenaveryconsiderableone，inthetotalrentalwiththeextensionofcultivationandexpansionofcapitalinvestment，theaveragerentperacreandtheaveragerateofrentoncapitaldecreasewhentheextensionofrentlessland，andlandyieldingonlylittledifferentialrent，isgreaterthantheextensionofthesuperioroneyieldinggreaterrent。Conversely，theaveragerentperacreandtheaveragerateofrentoncapitalincreaseproportionatelytotheextentthatbetterlandconstitutesarelativelygreaterpartofthetotalareaandthereforeemploysarelativelygreatershareoftheinvestedcapital。
　　Hence，ifweconsidertheaveragerentperacre，orhectare，ofthetotalcultivatedlandasisgenerallydoneinstatisticalworks，incomparingeitherdifferentcountriesinthesameperiod，ordifferentperiodsinthesamecountry，wefindthattheaveragelevelofrentperacre，andconsequentlytotalrental，correspondstoacertainextentalthoughbynomeansidentical，butratheramorerapidlyincreasingextenttotheabsolute，nottotherelative，fertilityofthesoilinagivencountry；
　　thatis，totheaverageamountofproducewhichityieldsfromthesamearea。Forthelargertheshareofsuperiorsoilsinthetotalcultivatedarea，thegreatertheoutputforequalcapitalinvestmentsonequallylargeareasofland；andthehighertheaveragerentperacre。Inthereversecasetheoppositetakesplace。Thus，rentdoesnotappeartobedeterminedbytheratioofdifferentialfertility，butbytheabsolutefertility，andthelawofdifferentialrentappearsinvalid。Forthisreasoncertainphenomenaaredisputed，oranattemptismadetoexplainthembynon-existingdifferencesinaveragepricesofgrainandinthedifferentialfertilityofcultivatedland，whereassuchphenomenaaremerelyduetothefactthattheratiooftotalrentaltototalareaofcultivatedlandortototalcapitalinvestedintheland-aslongasthefertilityoftherentlesssoilremainsthesameandthereforethepricesofproduction，andthedifferencesbetweenthevariouskindsofsoilremainunchanged-isdeterminednotmerelybytherentperacreortherateofrentoncapital，butquiteasmuchbytherelativenumberofacresofeachtypeofsoilinthetotalnumberofcultivatedacres；or，whatamountstothesamething，bythedistributionofthetotalinvestedcapitalamongthevarioustypesofsoil。Curiouslyenough，thisfacthasbeencompletelyoverlookedthusfar。Atanyrate，weseeandthisisimportantforourfurtheranalysisthattherelativeleveloftheaveragerentperacre，andtheaveragerateofrentortheratioofthetotalrentaltothetotalcapitalinvestedintheland，mayriseorfallbymerelyextensivelyexpandingcultivation，aslongaspricesremainthesame，thedifferentialfertilitiesofthevarioussoilsremainunaltered，andtherentperacre，orrateofrentforcapitalinvestedperacreineverytypeofsoilactuallyyieldingrent，i。e。，forallcapitalactuallyyieldingrent，remainsunchanged。
　　ItisnecessarytomakethefollowingadditionalpointswithreferencetotheformofdifferentialrentconsideredunderheadingI；theyalsoapplyinparttodifferentialrentII:
　　First，itwasseenthattheaveragerentperacre，ortheaveragerateofrentoncapital，mayincreasewithanextensionofcultivationwhenpricesarestationaryandthedifferentialfertilityofthecultivatedplotsoflandremainsunaltered。Assoonasallthelandinagivencountryhasbeenappropriated，andinvestmentsofcapitalinland，cultivation，andpopulationhavereachedadefinitelevel-allgivenconditionsassoonasthecapitalistmodeofproductionbecomestheprevailingoneandalsoencompassesagriculture-thepriceofuncultivatedlandofvaryingqualitymerelyassumingdifferentialrenttoexistisdeterminedbythepriceofthecultivatedplotsoflandofthesamequalityandequivalentlocation。
　　Thepriceisthesame-afterdeductingthecostofbringingthenewlandintocultivation-eventhoughthislanddoesnotyieldanyrent。Thepriceofthelandis，indeed，nothingbutthecapitalisedrent。Buteveninthecaseofcultivatedland，thepricepaysonlyforfuturerents，as，forinstance，whentheprevalentinterestrateis5%andtherentfortwentyyearsispaidatonetimeinadvance。Whenlandissold，itissoldaslandyieldingrent，andtheprospectivecharacteroftherentwhichishereconsideredasaproductofthesoil，butitonlyseemstobethat
　　doesnotdistinguishtheuncultivatedfromthecultivatedland。Thepriceoftheuncultivatedland，likeitsrentthepriceofwhichrepresentsthecontractedformofthelatterisquiteillusoryaslongasthelandisnotactuallyused。Butitisthusdeterminedaprioriandisrealisedassoonasapurchaserisfound。Hence，whiletheactualaveragerentinagivencountryisdeterminedbyitsactualaverageannualrentalandtherelationofthelattertothetotalcultivatedarea，thepriceoftheuncultivatedlandisdeterminedbythepriceofthecultivatedland，andisthereforebutareflectionofthecapitalinvestedinthecultivatedlandandtheresultsobtainedtherefrom。Sincealllandwiththeexceptionoftheworstyieldsrentandthisrent，asweshallseeundertheheadofdifferentialrentII，increaseswiththequantityofcapitalandcorrespondingintensityofcultivation，thenominalpriceofuncultivatedplotsoflandisthusformed，andtheythusbecomecommodities，asourceofwealthfortheirowners。Thisexplainsatthesametime，whythepriceoflandincreasesinawholeregion，evenintheuncultivatedpartOpdyke。Landspeculation，forinstance，intheUnitedStates，isbasedsolelyonthisreflectionthrownbycapitalandlabouronuncultivatedland。
　　Secondly，progressinextendingcultivatedlandgenerallytakesplaceeithertowardinferiorsoiloronthevariousgiventypesofsoilinvaryingproportions，dependingonthemannerinwhichtheyaremet。Extensiononinferiorsoilisnaturallynevermadevoluntarily，butcanonlyresultfromrisingprices，assumingacapitalistmodeofproduction，andcanonlyresultfromnecessityunderanyothermodeofproduction。However，thisisnotabsolutelyso。Poorsoilmaybepreferredtoarelativelybettersoilonaccountoflocation，whichisofdecisiveimportanceforeveryextensionofcultivationinyoungcountries；furthermore，eventhoughthesoilformationinacertainregionmaygenerallybeclassifiedasfertile，itmayneverthelessconsistofamotleyconfusionofbetterandworsesoils，sothattheinferiorsoilmayhavetobecultivatedifonlybecauseitisfoundintheimmediatevicinityofthesuperiorsoil。Ifinferiorsoilissurroundedbysuperiorsoil，thenthelattergivesittheadvantageoflocationincomparisonwithmorefertilesoilwhichisnotyet，orisabouttobecome，partofthecultivatedarea。
　　Thus，theStateofMichiganwasoneofthefirstWesternStatestobecomeanexporterofgrain。YetitsSoilonthewholeispoor。ButitsproximitytotheStateofNewYorkanditswater-waysviatheLakesandErieCanalinitiallygaveittheadvantageovertheStatesendowedbyNaturewithmorefertilesoil，butsituatedfarthertotheWest。TheexampleofthisState，ascomparedwiththeStateofNewYork，alsodemonstratesthetransitionfromsuperiortoinferiorsoil。ThesoiloftheStateofNewYork，particularlyitswesternpart，isincomparablymorefertile，especiallyforthecultivationofwheat。Thisfertilesoilwastransformedintoinfertilesoilbyrapaciousmethodsofcultivation，andnowthesoilofMichiganappearedasthemorefertile。”In1838，wheatenflourwasshippedatBuffalofortheWest；
　　andthewheat-regionofNewYork，withthatofUpperCanada，werethemainsourcesofitssupply。Now，afteronlytwelveyears，anenormoussupplyofwheatandflourisbroughtfromtheWest，alongLakeErie，andshippedupontheErieCanalfortheEast，atBuffaloandtheadjoiningportofBlackrock……TheeffectoftheselargearrivalsfromtheWesternStates-whichwereunnaturallystimulatedduringtheyearsofEuropeanfamine……hasbeentorenderwheatlessvaluableinwesternNewYork，tomakethewheatculturelessremunerative，andtoturntheattentionoftheNewYorkfarmersmoretograzinganddairyhusbandry，fruitculture，andotherbranchesofruraleconomy，inwhichtheythinktheNorth-Westwillbeunablesodirectlytocompetewiththem。”I。W。Johnston，NotesonNorthAmerica，London，1851，I，pp。220-23。
　　Thirdly，itisamistakenassumptionthatthelandincoloniesand，ingeneral，inyoungcountrieswhichcanexportgrainatcheaperprices，mustofnecessitybeofgreaternaturalfertility。Thegrainisnotonlysoldbelowitsvalueinsuchcases，butbelowitspriceofproduction，i。e。，belowthepriceofproductiondeterminedbytheaveragerateofprofitintheoldercountries。
　　Thefactthatwe，asJohnstonsaysp。223，”areaccustomedtoattachtheideaofgreatnaturalproductivenessandofboundlesstractsofrichland，tothosenewStatesfromwhichcomethelargesuppliesofwheatthatareannuallypouredintotheportofBuffalo，”isprimarilytheresultofeconomicconditions。TheentirepopulationofsuchanareaasMichigan，forinstance，isatfirstalmostexclusivelyengagedinfarming，andparticularlyinproducingagriculturalmassproducts，whichalonecanbeexchangedforindustrialproductsandtropicalgoods。Itsentiresurplusproductionappears，therefore，intheformofgrain。Thisfromtheoutsetsetsapartthecolonialstatesfoundedonthebasisofthemodernworld-marketfromthoseofearlier，particularlyancient，times。Theyreceivethroughtheworld-marketfinishedproducts，suchasclothingandtoolswhichtheywouldhavetoproducethemselvesunderothercircumstances。OnlyonsuchabasisweretheSouthernStatesoftheUnionenabledtomakecottontheirstaplecrop。Thedivisionoflabourontheworld-marketmakesthispossible。Hence，iftheyseemtohavealargesurplusproductionconsideringtheiryouthandrelativelysmallpopulation，thisisnotsomuchduetothefertilityoftheirsoil，northefruitfijlnessoftheirlabour，butrathertotheone-sidedformoftheirlabour，andthereforeofthesurplus-produceinwhichsuchlabourisincorporated。