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By the mind-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(酒
馆), 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 fridge, had been invented. Making an efficient icebox as 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(未发展的). 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.
47. What is the topic of the passage? 48. Where was ice used after the
Civil War?
49. What was essential to a science of refrigeration according to the
passage?
50. It can be inferred from the passage that the theoretical foundation of
ice box should be that ________.
51. Without an ice box, farmers had to go to the market at night because
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发表于 2017-8-12 12:10:27