Bythemid-nineteenthcentury,theterm"icebox"hadenteredtheAmericanlanguage,buticewasstillonlybeginningtoaffectthedietofordinarycitizensintheUnitedStates.Theicetradegrewwiththegrowthofcities.Icewasusedinhotels,taverns(酒馆),andhospitals,andbysomeforward-lookingcitydealersinfreshmeat,freshfish,andbutter.AftertheCivilWar(1861-1865),asicewasusedtorefrigeratefreightcars,italsocameintohouseholduse.Evenbefore1880,halfoftheicesoldinNewYork,Philadelphia,andBaltimore,andone-thirdofthatsoldinBostonandChicago,wenttofamiliesfortheirownuse.Thishadbecomepossiblebecauseanewhouseholdconvenience,theicebox,aprecursor(前身)ofthemodernfridge,hadbeeninvented.

Makinganefficienticeboxasnotaseasyaswemightnowsuppose.Intheearlynineteenthcentury,theknowledgeofthephysicsofheat,whichwasessentialtoascienceofrefrigeration,wasrudimentary(未发展的).Thecommonsensenotionthatthebesticeboxwasonethatpreventedtheicefrommeltingwasofcoursemistaken,foritwasthemeltingoftheicethatperformedthecooling.Nevertheless,earlyeffortstoeconomizeiceincludedwrappinguptheiceinblankets,whichkepttheicefromdoingitsjob.Notuntilneartheendofthenineteenthcenturydidinventorsachievethedelicatebalanceofinsulation(绝缘)andcirculationneededforanefficienticebox.

Butasearlyas1803,andingeniousMarylandfarmer,ThomasMoore,hadbeenontherighttrack.HeownedafarmabouttwentymilesoutsidethecityofWashington,forwhichthevillageofGeorgetownwasthemarketcenter.Whenheusedaniceboxofhisowndesigntotransporthisbuttertomarket,hefoundthatcustomerswouldpassuptherapidlymeltingstuffinthetubsofhiscompetitorstopayapremiumprice(高价)forhisbutter,stillfreshandhardinneat,one-poundbricks.Oneadvantageofhisicebox,Mooreexplained,wasthatfarmerswouldnolongerhavetotraveltomarketatnightinordertokeeptheirproducecool.

小题1:WherewasiceusedaftertheCivilWar?