STOVES. Several kinds of fire-places or stoves give out heat by conduction chiefly, others do so mainly by radiation. Open fire places are of the latter kind, and a consider able loss of heating-power results from the arrangement. The burning coals radiate heat into the room, and another portion of heat is reflected from the metallic portions of the grate ; but the heated air, which ought to contribute to the desired effect, is mainly allowed to escape up the chimney with the smoke and other results of combustion. Dr. Arnott, in his " Treatise on Warming and Ventilation," enumerates about a dozen evils which are more or less inseparable from open fires. Among these are waste of fuel, unequal heating, a stratum of cold air near the floor, the production of smoke and dust, loss of time in attendance, danger to person and property. Many contrivances have been brought forward to obviate one or other of these inconveniences. Count Rumford suggested the " register-stove," the peculiarity of which consists in narrowing the throat of the chimney by a plate which can be moved to vary the size of the aperture ; by this means, particularly if the opening be near the fire, the very hot air directly from the fire enters before it can mix with much colder air from the room, and thus the draught is increased so as to lessen the chance of smoking. But there is a great waste of heat in this as in all other open fire-places.
The common Dutch stove is one of the simplest examples of a close stove. It gene rally consists of a cylindrical case of sheet iron, within and near the bottom of which is a grating for containing the fuel. There is an ash-pit beneath the grating, and three open ings to the interior—one to the ash-pit, one for introducing the fuel above, and one lead ing to a flue or chimney. In this form of stove the heated iron case warms the air, which thus becomes much more nearly equalised in temperature than it is by a common fire. There is also great economy of fuel, and an absence of smoke and dust; but the air of the room acquires a dry, sulphureous, and un healthy condition. In Russian stoves, earthen ware and brickwork are largely used, instead of metal, as a means of making the heat less intense near the stove,-and of keeping up a reservoir of heat after the fire is extinguished. The stove is built in a massive style, and consists of a series of chambers, of which the lowest serves as the fire-place, and the upper ones as flues, and being composed almost entirely of brick and porcelain, the outer surface remains at a moderate temperature for a very long period.
Dr. Arnett has the merit of having devised means to prevent the too intense heating of the air near close metallic stoves, by the use of the stove which bears his name. [AR NOTT'S STOVE.] Numerous varieties of the close stove, bearing more or less on the above construction, have been brought forward since the publication of Dr. Arnott's book. Each professes to possess some peculiar merit ; but all present these features in common— that the air•hole by which the combustion is fed is very small, and capable of adjustment ; that there is a body of air to be warmed, external to the grate or fire-box itself, but confined within an outer case; that the con sumption of fuel is much smaller than in any variety of open fire-places; and that the flue for carrying off the smoke and gases is small in diameter, and capable of being carried in any direction. In the different forms of " kitchen-ranges " the open fire-place is com bined with what may be deemed a close stove; for the "oven" and " hot-closet " are repre • sentatives of the heated space within the outer case of a close stove. The " gas-stoves " and "steam-kitchens" of modern inventors may in like manner be included in the same category, for they are in effect close stoves heated by agents different from common coal.
In the arrangements above described, the stove is in the room which is to be warmed, and its heating effects are calculated with re spect to that room alone ; but in many factories and other large establishments the fire is in an outer or lower apartment, and the heated air is conveyed thence in a pipe to the apartment to be heated.
In Candy's patent stove, recently intro duced, the air is warmed by passing through channels made of artificial stone ; it is in tended for use in churches, schools, and other large rooms, and is charged for according to the number of cubic feet of air which it will warm in a given time.
One of the greatest improvements in stoves of recent manufacture is the adoption of such a form in the iron or steer work immediately contiguous to the fire as to reflect out into the room as much as possible of the heat, instead of allowing it to waste by ascending the chimney. In one of these forms, Jobson's patent stove-grate, the reflecting surface en tirely surrounds the fire, not only above and at the sides, but also beneath ; the ash-pit being so ingeniously arranged as not to inter fere with the lower part of the reflector.
Other details relating to heating by stoves, by gas, and by other means, will be found under COOKING APPARATUS, and WARMING and VENTILATION.