Page:Popular Science Monthly Volume 29.djvu/250

238 by a gentle inclination forward, bring it to its proper place, that is to say, perpendicularly under the back part of the throat of the chimney. This slope (which will bring the back forward four or five inches, or just as much as the depth of the fireplace is increased), though it ought not to be too abrupt, yet it ought to be quite finished at the height of eight or ten inches above the fire, otherwise it may perhaps cause the chimney to smoke.

"Having been obliged to carry backward the fireplace in the manner here described, in order to accommodate it to a chimney whose walls in front were remarkably thin, I was surprised to find, upon lighting the fire, that it appeared to give out more heat into the room than any fireplace I had ever constructed. This effect was quite unexpected; but the cause of it was too obvious not to be immediately discovered. The flame rising from the fire broke against the part of the back which sloped forward over the fire, and this part of the back being soon very much heated, and in consequence of its being very hot (and when the fire burned bright it was frequently quite red-hot), it threw off into the room a great deal of radiant heat. It is not possible that this oblique surface (the slope of the back of the fireplace) could have been heated red-hot merely by the radiant heat projected by the burning fuel; for other parts of the fireplace nearer the fire, and better situated for receiving radiant heat, were never found to be so much heated; and hence it appears that the combined heat in the current of smoke and hot vapor which rises from an open fire may be, at least in part, stopped in its passage up the chimney, changed into radiant heat, and afterward thrown into the room.

"This opens a new and very interesting field for experiment, and bids fair to lead to important improvements in the construction of fireplaces. . . . But, as I mean soon to publish a particular account of these fireplaces, with drawings and ample directions for constructing them, I will not enlarge further on the subject in this place. It may, however, not be amiss just to mention here that these new invented fireplaces not being fixed to the walls of the chimney, but merely set down upon the hearth, may be used in any open chimney; and the chimneys altered or constructed on the principles here recommended are particularly well adapted for receiving them."

Of recent years "lean-over" backs have been reinvented and sparingly used. The "Milner" back is excellent. It burns fuel well, and gives out a great heat. But it is extravagant in consumption, unless controlled by the "Economizer."

Captain Douglas Galton saw the virtue of the "lean-over," and adopted it in the grate which goes by his name. The "Bee-hive" back was the same in principle and very good, and, having a very small grid, was economical.

The "Rifle" back gives an admirable fire, little short of perfection; but observation shows that the "tall" flame extends far beyond