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1、PASSAGE1Bythemid-nineteenthcentury,theterm"icebox"hadenteredtheAmericanlanguage,buticewasstillonlybeginningtoaffectthedietofordinarycitizensintheUnitedStates.Theicetradegrewwiththegrowthofcities.Icewasusedinhotels,taverns,andhospitals,andbysomeforward-l
2、ookingcitydealersinfreshmeat,freshfish,andbutter.AftertheCivilWar(1861-1865),asicewasusedtorefrigeratefreightcars,italsocameintohouseholduse.Evenbefore1880,halftheicesoldinNewYork,Philadelphia,andBaltimore,andone-thirdofthatsoldinBostonandChicago,wentto
3、familiesfortheirownuse.Thishadbecomepossiblebecauseanewhouseholdconvenience,theicebox,aprecursorofthemodernrefrigerator,hadbeeninvented.Makinganefficienticeboxwasnotaseasyaswemightnowsuppose.Intheearlynineteenthcentury,theknowledgeofthephysicsofheat,whi
4、chwasessentialtoascienceofrefrigeration,wasrudimentary.Thecommonsensenotionthatthebesticeboxwasonethatpreventedtheicefrommeltingwasofcoursemistaken,foritwasthemeltingoftheicethatperformedthecooling.Nevertheless,earlyeffortstoeconomizeiceincludedwrapping
5、theiceinblankets,whichkepttheicefromdoingitsjob.Notuntilneartheendofthenineteenthcenturydidinventorsachievethedelicatebalanceofinsulationandcirculationneededforanefficienticebox.Butasearlyas1803,aningeniousMarylandfarmer,ThomasMoore,hadbeenontherighttra
6、ck.HeownedafarmabouttwentymilesoutsidethecityofWashington,forwhichthevillageofGeorgetownwasthemarketcenter.Whenheusedaniceboxofhisowndesigntotransporthisbuttertomarket,hefoundthatcustomerswouldpassuptherapidlymeltingstuffinthetubsofhiscompetitorstopayap
7、remiumpriceforhisbutter,stillfreshandhardinneat,one-poundbricks.Oneadvantageofhisicebox,Mooreexplained,wasthatfarmerswouldnolongerhavetotraveltomarketatnightinordertokeeptheirproducecool.PASSAGE2ThegeologyoftheEarth'ssurfaceisdominatedbytheparticularpro
8、pertiesofwater.PresentonEarthinsolid,liquid,andgaseousstates,waterisexceptionallyreactive.Itdissolves,transports,andprecipitatesmanychemicalcompoundsandisconstantlymodifyingthefaceoftheEarth.Evaporatedfromtheoceans,watervaporform