238 THE POPULAR SCIENCE MONTHLY. 



by a gentle inclination forward, bring it to its proper place, that is to 

 sa y> 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 man- 

 Der 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 un- 

 expected ; 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 pos- 

 sible 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 spar- 

 ingly 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 perfec- 

 tion ; but observation shows that the " tall " flame extends far beyond 



