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 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 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, an 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, more explained, was that farmers would no longer have to travel to market at night in order to keep their produce cool. 

    直到19世紀(jì)中期，"冰箱"這個(gè)名詞才進(jìn)入了美國(guó)語(yǔ)言，但冰僅僅只是開(kāi)始影響美國(guó)普通市民的飲食。 冰的買賣隨著城市的發(fā)展而發(fā)展。 冰被用在旅館、酒館、醫(yī)院以及被一些有眼光的城市商人用于肉、魚(yú)和黃油的保鮮。 內(nèi)戰(zhàn)(1861-1865)之后，冰被用于冷藏貨車，同時(shí)也進(jìn)入了民用。 甚至在1880年前，半數(shù)在紐約、費(fèi)城和巴爾的摩銷售的冰，三分之一在波士頓和芝加哥銷售的冰進(jìn)入家庭使用，因?yàn)橐环N新的家庭設(shè)備，冰箱，即現(xiàn)代冰箱的前身，被發(fā)明了。 制造一臺(tái)有效率的冰箱不像我們想象的那么簡(jiǎn)單。 19世紀(jì)早期，關(guān)于對(duì)冷藏科學(xué)至關(guān)重要的熱物理知識(shí)是很淺陋的。 認(rèn)為最好的冰箱應(yīng)該防止冰的融化這樣一個(gè)普遍的觀點(diǎn)顯然是錯(cuò)誤的，因?yàn)檎�是冰的融化起了制冷作用�?早期為節(jié)省冰的努力，包括用毯子把冰包起來(lái)，使得冰不能發(fā)揮它的作用。 直到近19世紀(jì)末，發(fā)明家們才成功地找到有效率的冰箱所需要的精確的隔熱和循環(huán)的精確平衡。 但早在1803年，一位有發(fā)明天才的馬里蘭農(nóng)場(chǎng)主，托馬斯·莫爾，找到了正確方法。 他擁有一個(gè)農(nóng)場(chǎng)，離華盛頓約20英里，那里的喬治鎮(zhèn)村莊是集市中心。 當(dāng)他用自己設(shè)計(jì)的冰箱運(yùn)送黃油去市場(chǎng)時(shí)，他發(fā)現(xiàn)顧客們會(huì)走過(guò)裝在競(jìng)爭(zhēng)者桶里那些迅速融化的黃油而給他比市價(jià)更高的價(jià)格買他仍然新鮮堅(jiān)硬，整齊地切成一磅一塊的黃油。 莫爾說(shuō)他的冰箱的一個(gè)好處是使得農(nóng)民們不必在夜里上路去市場(chǎng)以保持他們產(chǎn)品的低溫。