Page:Popular Science Monthly Volume 3.djvu/310

298 be closed by a close-fitting stopper or door. In fireplaces constructed for small stew-pans this opening may be omitted, and the fuel be introduced through the opening into which the stew-pan is fitted, by removing the stew-pan occasionally for the purpose.

4. All portable stew-pans should be circular, and suspended in their fireplace from the circular rim. The best form for large fixed boilers is an oblong square, broad and shallow rather than narrow, and deep, and it should be of thin metal.

5. All boilers and stew-pans should be fitted with covers to render them well adapted for confining the heat. The best arrangement is to make the covers of thin sheets of tinned iron, and double, that is, with an air space between the outer and inner cover.

We have, during the last twenty years, introduced, as a rule, close ranges. They are certainly cleaner and more convenient for cooking, and, if great care is exercised in the use of the dampers, they will be found more economical than open fires. But, as a rule, they are based on the principle of making one fire perform a variety of operations. Independently of the question of a combined fire, as compared with the separate fires advocated by Count Rumford, a consideration of the form of modern kitchen-ranges will show that most of the principles laid down by him have been entirely neglected. The doors of the fireplace and ash-pit seldom fit close; the boilers are rather deep and narrow than broad and shallow; the use of the hot-plate prevents the stew-pans from being suspended from the rims for the fire to play round them; the use of double covers for saucepans and boilers is rather a rarity than a usual arrangement.

To realize the question of economy of fuel, it is necessary to consider, in the first place, what a given quantity of fuel is capable of doing. As regards hot water, if water is kept at a temperature of 200°, or from that to 210°, the gases from the fire can, after communicating the heat to the boiler, pass off into the chimney at a temperature of little beyond that point; but, if the water be allowed to boil, in the first place a large amount of latent heat is absorbed by the steam, which is lost if the steam passes off into the air or the chimney, and, in the second place, it will be found that the gases, after they pass off from the boiler, will have a temperature of as much as 300°, 400°, and even 500°. Unless, therefore, water is required to be actually boiling for use, if the water is permitted to boil, a great quantity of heat is wasted up the chimney. For household purposes it is never necessary that the water in the boiler should exceed 200°. Tea, to be good, should be made (as clearly shown by Mr. Francis Galton in his "Art of Travel") with water of a temperature of from 180° to 200°. Very few culinary operations require the water really to boil, and, when boiling water is wanted, it is required in a saucepan standing on the fire. All operations of cleaning, etc. (except washing clothes), require water at a very much lower temperature than 212°. If, however,