冰箱的起源(The origin of Refrigerators)

bythemid-nineteenthcentury,theterm"icebox"hadenteredtheamericanlanguage,buticewasstillonlybeginningtoaffectthedietofordinarycitizensintheunitedstates.theicetradegrewwiththegrowthofcities.icewasusedinhotels,taverns,andhospitals,andbysomeforward-lookingcitydealersinfreshmeat,freshfish,andbutter.afterthecivilwar(1861-1865),asicewasusedtorefrigeratefreightcars,italsocameintohouseholduse.

evenbefore1880,halfoftheicesoldinnewyork,philadelphia,andbaltimore,andone-thirdofthatsoldinbostonandchicago,wenttofamiliesfortheirownuse.thishadbecomepossiblebecauseanewhouseholdconvenience,theicebox,aprecursorofthemodernrefrigerator,hadbeeninvented.

makinganefficienticeboxwasnotaseasyaswemightnowsuppose.intheearlynineteenthcentury,theknowledgeofthephysicsofheat,whichwasessentialtoascienceofrefrigeration,wasrudimentary.thecommonsensenotionthatthebesticeboxwasonethatpreventedtheicefrommeltingwasofcoursemistaken,foritwasthemeltingoftheicethatperformedthecooling.nevertheless,earlyeffortstoeconomizeiceincludedwrappinguptheiceinblankets,whichkepttheicefromdoingitsjob.notuntilneartheendofthenineteenthcenturydidinventorsachievethedelicatebalanceofinsulationandcirculationneededforanefficienticebox.

butasearlyas1803,andingeniousmarylandfarmer,thomasmoore,hadbeenontherighttrack.heownedafarmabouttwentymilesoutsidethecityofwashington,forwhichthevillageofgeorgetownwasthemarketcenter.whenheusedaniceboxofhisowndesigntotransporthisbuttertomarket,hefoundthatcustomerswouldpassuptherapidlymeltingstuffinthetubsofhiscompetitorstopayapremiumpriceforhisbutter,stillfreshandhardinneat,one-poundbricks.oneadvantageofhisicebox,mooreexplained,wasthatfarmerswouldnolongerhavetotraveltomarketatnightinordertokeeptheirproducecool.