Apartfromnaturalconditions，suchasfertilityofthesoil，&C。，andfromtheskillofindependentandisolatedproducers（shownratherqualitativelyinthegoodnessthanquantitativelyinthemassoftheirproducts），thedegreeofproductivityoflabour，inagivensociety，isexpressedintherelativeextentofthemeansofproductionthatonelabourer，duringagiventime，withthesametensionoflabour—power，turnsintoproducts。Themassofthemeansofproductionwhichhethustransforms，increaseswiththeproductivenessofhislabour。Butthosemeansofproductionplayadoublepart。Theincreaseofsomeisaconsequence，thatoftheothersaconditionoftheincreasingproductivityoflabour。E。g。，withthedivisionoflabourinmanufacture，andwiththeuseofmachinery，morerawmaterialisworkedupinthesametime，and，therefore，agreatermassofrawmaterialandauxiliarysubstancesenterintothelabour—process。
Thatistheconsequenceoftheincreasingproductivityoflabour。Ontheotherhand，themassofmachinery，beastsofburden，mineralmanures，drain—pipes，&c。，isaconditionoftheincreasingproductivityoflabour。Soalsoisitwiththemeansofproductionconcentratedinbuildings，furnaces，meansoftransport，&c。Butwhetherconditionorconsequence，thegrowingextentofthemeansofproduction，ascomparedwiththelabour—powerincorporatedwiththem，isanexpressionofthegrowingproductivenessoflabour。Theincreaseofthelatterappears，therefore，inthediminutionofthemassoflabourinproportiontothemassofmeansofproductionmovedbyit，orinthediminutionofthesubjectivefactorofthelabour—processascomparedwiththeobjectivefactor。
Thischangeinthetechnicalcompositionofcapital，thisgrowthinthemassofmeansofproduction，ascomparedwiththemassofthelabour—powerthatvivifiesthem，isreflectedagaininitsvalue—composition，bytheincreaseoftheconstantconstituentofcapitalattheexpenseofitsvariableconstituent。Theremaybe，e。g。，originally50percent。ofacapitallaidoutinmeansofproduction，and50percent。inlabour—power;lateron，withthedevelopmentoftheproductivityoflabour，80percent。inmeansofproduction，20percent。inlabour—power，andsoon。Thislawoftheprogressiveincreaseinconstantcapital，inproportiontothevariable，isconfirmedateverystep（asalreadyshown）bythecomparativeanalysisofthepricesofcommodities，whetherwecomparedifferenteconomicepochsordifferentnationsinthesameepoch。Therelativemagnitudeoftheelementofprice，whichrepresentsthevalueofthemeansofproductiononly，ortheconstantpartofcapitalconsumed，isindirect，therelativemagnitudeoftheotherelementofpricethatpayslabour（thevariablepartofcapital）
isininverseproportiontotheadvanceofaccumulation。
Thisdiminutioninthevariablepartofcapitalascomparedwiththeconstant，orthealteredvalue—compositionofthecapital，however，onlyshowsapproximatelythechangeinthecompositionofitsmaterialconstituents。