Page:Popular Science Monthly Volume 23.djvu/612

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antly until the oxidation of the great air-chamber proved that the engine burned iron as well as coal at a ruinous cost.

Although no mention is made by Rumford of such destruction of the blow-pipes, he was evidently conscious of the costliness of his original roaster, as he describes another which may be economically substituted for it. This has an air-chamber formed by bringing the body of the oven-door so as to inclose the space occupied by the blowpipes shown in Fig. 1, and placing the dripping-pan on a false bottom joined to the front face of the roaster just below the door, but not extending quite to the back. An adjustable register door opens at the front into this air-chamber, and when this is opened the air passes along from front to back under the false bottom, and rises behind to an outlet pipe like that shown at v, Fig. 1. In thus passing along the hot bottom of the oven the air is heated, but not so greatly as by the blow-pipes, which, being surrounded by the flame on all sides, are heated above as well as below, and the air in passing through them is much more exposed to heat than in passing through the air-chamber.

To increase the heat transmitted in the latter, Rumford proposes that "a certain quantity of iron wire, in loose curls, or of iron turnings, be put into the air-chamber."

This modification he called a "roasting-oven," to distinguish it from the first described, the "roaster." He states that the roasting oven is not quite so effective as the roaster, but from its greater cheapness may be largely used. This anticipation has been realized. The modern "kitchener," which in so many forms is gradually and steadily supplanting the ancient open range, is an apparatus in which roasting in the open air before a fire is superseded by roasting in a closed chamber or roasting oven. Having made three removals within the last twelve years, each preceded by a tedious amount of house-hunting, I have seen a great many kitchens of newly-built houses, and find that about ninety per cent of these have closed kitcheners, and only about ten per cent are fitted with open ranges of the old pattern. Bottle-jacks, like smoke-jacks and spits, are gradually falling into disuse.

When these kitcheners were first introduced, a great point was made by the manufacturer of the distinction between the roasting and the baking oven; the first being provided with a special apparatus for effecting ventilation by devices more or less resembling that in Rumford's roasting-oven. Gradually these degenerated into mere shams, and now in the best kitcheners even a pretense to ventilation is abandoned. Having reasoned out my own theory of the conditions demanded for perfect roasting some time ago (about 1860, when I lectured on "Household Philosophy" to a class of ladies at the Birmingham and Midland Institute), I have watched the gradual disappearance of these concessions to popular prejudice with some interest, as they show how practical experience has confirmed this theory, which, as already expounded, is that the meat should be cooked by the