ABSTRACT
NowwhenEy>l,theshareofconsumptionincreases, whenEy<l,thesharedecreases:Engel'sLaw.A typicalprosperityphenomenonariseswhenEy<O (withincomerising).However,wecanhardlysay anythingwithanyforceofargumentaboutinferiorityandGiffengoods,unlesswehavemoredetailed statisticalmaterial. 12Thesameistrueofa specialstudyofthedevelopmentintheperiodof incomeelasticitieswithregardtocertainarticles ofconsumption,theso-calledEngelcurves.l3We lookupontheseriesofincomeelasticitiesmet withmerelyasaroughindicationofconsumerbehaviourrelativetofood.
