Howwilltheresultingstrainaffecttherelationsofthetworemainingclasses，thelabourersandthecapitalists?Theultimateevilofprotectionisthebaddistributionofcapital。Butcapitalalwaysactsbyemployinglabour。Thefarmer’scapitaldoesnotactbyitself，butbyenablinghismentowork，Hence，tounderstandtheworkingoftheindustrialmachinery，wehavetosettletherelationofwagesandprofits。Ricardostatesthisemphaticallyinhispreface。Rent，profit，andwages，hesays，representthethreepartsintowhichthewholeproduceoftheearthisdivided。’Todeterminethelawswhichregulatethisdistributionistheprincipalprobleminpoliticaleconomy’；andone，headds，whichhasbeenleftinobscuritybypreviouswriters。7Hisinvestigationsareespeciallydirectedbythepurposethusdefined。Hewasthefirstwriterwhofairlybroughtunderdistinctconsiderationwhatheheld，withreason，tobethemostimportantbranchofeconomicalinquiry。
TherewasclearlyagapintheeconomicdoctrinerepresentedbytheWealthofNations。AdamSmithwasprimarilyconcernedwiththetheoryofthe’market。’Heassumestheexistenceofthesocialarrangementwhichisindicatedbythatphrase。
Themarketimpliesaconstitutionofindustrialagenciessuchthat，withinit，onlyonepriceispossibleforagivencommodity，or，rather，suchthatadifferenceofpricecannotbepermanent。Accordingtotheacceptedillustration，theseaisnotabsolutelylevel。butitisalwaystendingtoalevel。8Apermanentelevationatonepointisimpossible。
Theagencybywhichthislevellingorequilibratingprocessiscarriedoutiscompetition，involvingwhatSmithcalledthe’higglingofthemarket。’
Themomentaryfluctuation，again，supposestheactionof’supplyanddemand’