Perhaps few of our readers are aware of the extraordinary wastefulness of our usual processes for obtaining artificial heat; at the most moderate computation, seven-eighths of the warmth produced by an open fire, pass up the chimney, and are entirely useless; and according to other estimates, which we regard as being nearer the truth, fourteen parts out of every fifteen are uselessly wasted. It may be asked what are the defects of a common fireplace that render it so wasteful, and in what way is the heat carried off? In reply it may be stated, that one half the heat produced passes away with the smoke and heated air arising from the fire, a quarter is carried up by the draught of cold air from the room, which, flowing around the fire and between it and the mantel-piece, rises with the smoke. Again, the soot which passes away is unburned fuel, and is therefore useless; and a large portion of heat is thrown downwards upon the ashes and is wasted; while the iron of which the ranges are generally made, conveys away a considerable quantity. On the continent of Europe \he production of heat is more economically managed - stoves of very admirable construction being constantly had recourse to, both for the purpose of producing warmth and for cookery. It is to the latter application of heat that we must mainly confine ourselves, having been at some considerable pains in examining the various stoves and ranges now to be obtained.

The cooking-stove common in Europe, consists of an enclosed fire-pan, with a grating below and a lid at the top for the supply of fuel; this is enclosed in an oven, supported on the floor of the room by feet, and which is heated by the warmth thrown out by the sides of the fire-pan, and also by a flue spreading over the top, which is thus heated; while the upper surface of the flue forms a hot plate, on which many saucepans, etc, can be kept boiling, and any vessel can also be placed over the fire by the removal of the lid. As the draught is under perfect control, the fuel is slowly consumed, and the stove affords means of baking, boiling, frying, and stewing, at a very small expense,

Those of our readers who visited Prince Albert's Model Cottages opposite the Exhibition in London, may have noticed a stove looking very much like a long oblong box, standing on four legs, having two doors in the front, one opening into a large sized oven, the other disclosing the fire-grate, which was fed by the removal of a lid at the top; - the draught from the fire passed over the oven, heating it, and the hot plate above. This stove combines all the advantages of the continental cooking-stove, with the cheerful appearance of an open fire; at the same time, by closing up the fire-place door, it is converted into a close stoves with an excessively small consumption of fuel. It bakes admirably, either large joints, or bread, at the same time it boils a saucepan and steamer over the fire-hole, and also four large, or six smaller saucepans on the top of the hot plate. It fries well, and broils before the fire, and this with less than one half the fuel that was employed to do a portion of the work in the range. The Bain Marie, which is so excellent a means of keeping soups, gravies, sauces, etc, hot without burning or drying them up, is readily used with it; and the saute pan. or deep frying-pan, which is employed as a preliminary operation in most French made dishes, is conveniently used; this contrivance derives its name from the verb sauter, to jump - the meat being rapidly turned over and browned previous to stewing.

An apparatus may bo connected with this or any other stove by which many of the articles for the table or sick-room may be kept fresh and warm. The following cut represents a Patent Adjustable Shelf for this purpose, manufactured by Gorton Brothers, New London, Conn.

Stove Pipe Shelf.

Those who object to a stove, preferring a range, even at a greater sacrifice of economy, should still be somewhat guided by correct principles in their selection; a range surrounded by iron is an absurdity, as the metal conducts away the heat rapidly; it should be backed and lined with fire-brick, or Welsh lumps, which throw out the heat with great power. In an open fire-place, the active combustion is wanted in front for roasting, and there only should air enter the fire; in most ranges the air enters below, causing the greatest heat to be thrown upon the ashes. It may be thought that closing up the bottom would produce the same effect as allowing it to be choked up with ashes in a common grate, deadening the fire; this is not the case with a properly constructed range. Backed with a slanting back of fire clay, the ashes can be readily removed at the bottom, and all the draught being in front, there is a bright fire at the place where it is required.

In situations where gas is to be obtained, it forms a ready, and for some purposes, very economical means of obtaining heat; its economy does not arise from its cheapness compared with other means, but from the fact that it need not be lighted till the instant it is required, and can be as quickly extinguished when it has done its required duty; for heating any vessels containing liquids, especially if the heat is required to be only of short continuance, gas will be found extremely advantageous. A ring burner, constructed as shown in Fig. 2, less than three inches in diameter, will quickly boil a gallon of water in a metallic vessel; burners of this description are usually used in the laboratory, surrounded by a case made of sheet iron or tinned plate, as in Fig. 3; this serves to support the vessel to be heated, to steady the jets of flame, and to conduct every portion of hot air against the bottom; the door also gives a ready access to the burner for the purposes of Lighting the gas.