Page:Popular Science Monthly Volume 3.djvu/311

Rh water at a higher temperature is wanted, it can be supplied up to about 230° without the generation of steam, by heating it under pressure; this can be attained by having a close boiler fed from a cistern placed at the top of the house. For the preparation of preserves and some other cooking operations, such a system is most convenient.

One pound of coal should raise from fifty to sixty gallons of water from 45° to 212°, and, when raised, very little fuel is required to maintain it, in a properly-constructed boiler, at that temperature. The total amount of water, at such a temperature, used daily, in an ordinary middle-class house, does not exceed thirty or forty gallons, and, therefore, if the boiler were made so as to absorb as much heat as possible, the hot water used in an ordinary middle-class house, with a family of ten or twelve persons, ought not, with thorough economy, to consume more than one-sixth of a ton of coals in the year. Count Rumford shows in his treatise that 25 lbs. of bread ought to be baked with one pound of coal, and that 100 lbs. of meat should be cooked with 2¼ lbs. of coal. If, therefore, we fully utilized our fuel, it is clear that, in the preparation of our food and hot water for domestic purposes, ½ lb. of coal per head of the population ought to be a sufficient daily allowance, which would be equivalent to one-twelfth of a ton per annum, and in large households even less than that quantity ought to suffice. I do not suppose that we should ever attain to this minimum of consumption, but it is well to consider what the standard is, so that we may not rest satisfied till it has been much more nearly approached than hitherto.

Economy has, as I before observed, latterly been sought in combined apparatus. Where large numbers of persons have to be cooked for, and where, consequently, a carefully-constructed apparatus is always worked to its full extent, the results which have been obtained show a very moderate consumption of fuel; but the same apparatus, when used for smaller numbers of persons, gives results not favorable to economy.

The boilers in use in barracks, when I first took up the question, required from 16 ozs. to 20 ozs. of coal per head to supply water for breakfast and tea, and washing up, and to make soup for dinner for fifty or sixty men. The boilers I introduced would perform the same duty with from 3 to 4 ozs. of coal for each person cooked for, provided the number amounted to fifty or sixty persons. The ovens for roasting, which I introduced into barracks, would roast and bake with 1 oz. of coal for each person cooked for, when cooking for the full number for which the oven was designed, and for such numbers as 200 to 400 persons; smaller ovens would require 2 ozs. per head when cooking for 50 men. Of course, to produce these effects, great care was required.

Messrs. Benham introduced cooking apparatus which, when cooking for the full number of 300 soldiers, would perform the total daily