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 (酒馆), and hospitals, and by some
forward-looking city dealers in fresh moat, 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 modem fridge, 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 (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 travel to travel to market at night in order to keep their produce
cool. Where was ice used after the Civil War