526 Of Chimney Fireplaces. 



to the width of the back and the opening of the chim- 

 ney in front. 



When the wall of the chimney in front, measured 

 from the upper part of the breast of the chimney to the 

 front of the mantle, is very thin, it may happen, and 

 especially in chimneys designed for burning wood upon 

 the hearth, or upon dogs, that the depth of the chim- 

 ney, determining according to the directions here given, 

 may be too small. 



Thus, for example, supposing the wall of the chimney 

 in front, from the upper part of the breast of the chim- 

 ney to the front of the mantle, to be only 4 inches 

 (which is sometimes the case, particularly in rooms situ- 

 ated near the top of a house), in this case, if we take 

 4 inches for the width of the throat, this will give 8 

 inches only for the depth of the fireplace, which would 

 be too little, even were coals to be burned instead of 

 wood. In this case I should increase the depth of the 

 fireplace at the hearth to 12 or 13 inches, and should 

 build the back perpendicular to the height of the top of 

 the burning fuel (whether it be wood burned upon the 

 hearth, or coals in a grate), and then, sloping the back 

 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 4 or 5 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 8 or 10 inches above the fire, otherwise it may 

 perhaps cause the chimney to smoke ; but when it is 

 very near the fire, the heat of the fire will enable the 

 current of rising smoke to overcome the obstacle which 

 this slope will oppose to its ascent, which it could not 



