andwouldsorenderittothatextentheterogeneous。Takeapieceofred—hot
matter，andhoweverevenlyheateditmayatfirstbe，itwillquicklycease
tobeso:theexterior，coolingfasterthantheinteriorwillbecomedifferent
fromitintemperature。Andthelapseintoheterogeneityoftemperature，
soobvious。inthisextremecase，takesplacemoreorlessinthecasesof