冰箱的起源(The origin of Refrigerators)

师哈哈达人

　　by the mid-nineteenth century, the term "icebox" had entered the  american language, but ice was still only beginning to affect the diet  of ordinary citizens in the united states. the ice trade grew with the  growth of cities. ice was used in hotels, taverns, and hospitals, and  by some forward-looking city dealers in fresh meat, fresh fish, and  butter. after the civil war( 1861-1865),as ice was used to refrigerate  freight cars, it also came into household use.
　　even before 1880,half of  the ice sold in new york, philadelphia, and baltimore, and one-third of  that sold in boston and chicago, went to families for their own use.  this had become possible because a new household convenience, the  icebox, a precursor of the modern refrigerator, had been invented.
　　making  an efficient icebox was not as easy as we might now suppose. in the  early nineteenth century, the knowledge of the physics of heat, which  was essential to a science of refrigeration, was rudimentary. the  commonsense notion that the best icebox was one that prevented the ice  from melting was of course mistaken, for it was the melting of the ice  that performed the cooling. nevertheless, early efforts to economize  ice included wrapping up the ice in blankets, which kept the ice from  doing its job. not until near the end of the nineteenth century did  inventors achieve the delicate balance of insulation and circulation  needed for an efficient icebox.
　　but as early as 1803, and  ingenious maryland farmer, thomas moore, had been on the right track.  he owned a farm about twenty miles outside the city of washington, for  which the village of georgetown was the market center. when he used an  icebox of his own design to transport his butter to market, he found  that customers would pass up the rapidly melting stuff in the tubs of  his competitors to pay a premium price for his butter, still fresh and  hard in neat, one-pound bricks. one advantage of his icebox, moore  explained, was that farmers would no longer have to travel to market at  night in order to keep their produce cool.