▁income ▁in ▁w age ▁units ▁Although ▁Ke yn es ▁needs ▁the ▁first ▁equation ▁in ▁order ▁to ▁get ▁a ▁solution , ▁he ▁presents ▁his ▁system ▁as ▁complete ▁except ▁for ▁details ▁as ▁soon ▁as ▁he ▁has ▁the ▁last ▁two ▁equations , ▁which ▁he ▁interpre ts ▁as ▁being ▁in ▁Y   ▁and ▁r   ▁alone . ▁ ▁This ▁creates ▁the ▁possibility ▁of ▁falling ▁into ▁a ▁certain ▁misunder standing . ▁Assuming ▁that ▁income ▁is ▁indeed ▁determined ▁in ▁w age ▁units ▁by ▁these ▁equations , ▁it ▁might ▁be ▁supposed ▁that ▁– ▁income ▁being ▁a ▁quantity ▁in ▁man - h ours ▁– ▁the ▁level ▁of ▁employ ment ▁is ▁like wise ▁determined . ▁But ▁the ▁expression ▁of ▁income ▁in ▁man - h ours ▁is ▁purely ▁artificial . ▁In ▁particular , ▁although ▁the ▁level ▁of ▁income ▁has ▁been ▁determined , ▁its ▁division ▁between ▁w ages ▁and ▁prof its ▁has ▁not , ▁so ▁the ▁level ▁of ▁employ ment ▁is ▁ind et erm inate . ▁ ▁Units ▁for ▁IS - LM ▁curves ▁John ▁H icks ▁presented ▁Ke yn esian ▁arguments ▁in ▁money ▁terms ▁in ▁“ Mr . ▁Ke yn es ▁and ▁the ▁" Class ics " ”. ▁He ▁supplies ▁income ▁as ▁an ▁argument ▁to ▁both ▁prop ens ity ▁to ▁save ▁and ▁liquid ity ▁preference , ▁imp lying ▁that ▁the ▁proportion ▁of ▁income ▁saved ▁is ▁a ▁function ▁of ▁income ▁in ▁money ▁rather ▁than ▁real ▁terms . ▁Ke yn es ▁himself ▁compla ined ▁that ▁H icks ▁made ▁‘ s aving ▁a ▁function ▁of ▁money ▁income '. ▁▁ ▁He ▁was ▁aware ▁that ▁there ▁were ▁difficulties ▁and