Page:Popular Science Monthly Volume 3.djvu/314

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302

THE POPULAR SCIENCE MONTHLY.

fore, of great importance to remove any causes which tend to lower the inside temperature. Hence it is desirable to utilize some of the heat which passes off, at above 450°, into the flue, for the purpose of raising the temperature of the air to be admitted into the oven. As a general rule, however, and except in some apparatus, under present arrangements all this heat is wasted, and it certainly cannot be utilized properly so long as one fire is retained to perform so many separate operations.

The hot-plate is the third important part of the modern close cooking-range. Count Rumford proposed that the top of a hot-plate should be covered with sand, and the sand cleared away only under the saucepans. In its present shape, the hot-plate wastes an enormous amount of heat. It is wasteful, because it radiates the heat largely; because the application of heat to the saucepans is only through the bottom of the saucepan, and the bottom of the saucepan is not always in immediate contact with the flame, but is frequently allowed to receive the heat through the medium of the cast-iron hot-plate, which is a very moderate conductor of heat. Just consider what the difference of effect is. The heat of the flame, if directly acting on the bottom of the saucepan, would be 1,200° Fahr., but, unless the hot-plate is red-hot, probably not above 450° will pass through, but the heat in the flue which heats the hot-plate will be at 1,200°, and the spare heat from the flame will be wasted up the chimney. The hot-plate should be dispensed with, if economy is to be made paramount, and charcoal burners substituted for it. Where gas is available, the hot-plate can be dispensed with without extra trouble to the cook. The gas-burners should be properly protected in sunken holes, with side of fire-clay, and the saucepans should be dropped into the holes, so that the full effect of the heat shall be concentrated on them and round their sides, and the gas should be only kept lighted so long as the operation to be performed is going on. It may be assumed that one pound of coal is equivalent to from 28 to 30 cubic feet of gas; hence, as permanent fuel, gas would not be economical; but the simplicity of its application makes it a very convenient fuel in cooking, and economy is obtained from its use, because the full effect of the combustion can be utilized as soon as the gas is lighted, the flame can be regulated to any required extent, and the gas be extinguished as soon as the required operation is performed.

I have endeavored to enumerate, briefly, the economical conditions which should regulate the consumption of fuel for domestic purposes. By economy it is meant that, while all necessary operations of warming and cooking continue to be performed, the fuel employed should be utilized to the utmost. In the kitchen, the daily consumption of fuel, in small establishments, should not exceed half a pound of coal for each person cooked for, and in large establishments the proportion should be smaller. In the consumption of fuel for warming, so many