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高中英语现代文背诵篇章30TheoriginofRefrigerators素材.doc

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30TheoriginofRefrigeratorsBythemid-nineteenthcenturytheterm“icebox”hadenteredtheAmericanlanguagebuticewasstillonlybeginningtoaffectthedietofordinarycitizensintheUnitedStates.Theicetradegrewwiththegrowthofcities.Icewasusedinhotelstavernsandhospitalsandbysomeforward-lookingcitydealersinfreshmeatfreshfishandbutter.AftertheCivilWar(1861-1865)asicewasusedtorefrigeratefreightcarsitalsocameintohouseholduse.Evenbefore1880halfoftheicesoldinNewYorkPhiladelphiaandBaltimoreandone-thirdofthatsoldinBostonandChicagowenttofamiliesfortheirownuse.Thishadbecomepossiblebecauseanewhouseholdconveniencetheiceboxaprecursorofthemodernrefrigeratorhadbeeninvented.Makinganefficienticeboxwasnotaseasyaswemightnowsuppose.Intheearlynineteenthcenturytheknowledgeofthephysicsofheatwhichwasessentialtoascienceofrefrigerationwasrudimentary.Thecommonsensenotionthatthebesticeboxwasonethatpreventedtheicefrommeltingwasofcoursemistakenforitwasthemeltingoftheicethatperformedthecooling.Neverthelessearlyeffortstoeconomizeiceincludedwrappinguptheiceinblanketswhichkepttheicefromdoingitsjob.Notuntilneartheendofthenineteenthcenturydidinventorsachievethedelicatebalanceofinsulationandcirculationneededforanefficienticebox.Butasearlyas1803andingeniousMarylandfarmerThomasMoorehadbeenontherighttrack.HeownedafarmabouttwentymilesoutsidethecityofWashingtonforwhichthevillageofGeorgetownwasthemarketcenter.Whenheusedaniceboxofhisowndesigntotransporthisbuttertomarkethefoundthatcustomerswouldpassuptherapidlymeltingstuffinthetubsofhiscompetitorstopayapremiumpriceforhisbutterstillfreshandhardinneatone-poundbricks.OneadvantageofhisiceboxMooreexplainedwasthatfarmerswouldnolongerhavetotravelto