Of Chimney Fireplaces. 5 1 1 



which are formed by making the back as wide as the 

 opening of the fireplace in front, occasion eddies of wind 

 which frequently disturb the fire, and embarrass the 

 smoke in its ascent in such a manner as often to bring 

 it into the room. Both these defects may be entirely 

 remedied by diminishing the width of the back of the 

 fireplace. The width which, in most cases, it will be 

 best to give it is one third of the width of the opening 

 of the fireplace in front. But it is not absolutely neces- 

 sary to conform rigorously to this decision, nor will it 

 always be possible. It will frequently happen that the 

 back of a chimney must be made wider than, according 

 to the rule here given, it ought to be. This may be 

 either to accommodate the fireplace to a stove, which, 

 being already on hand, must, to avoid the expense of 

 purchasing a new one, be employed ; or for other 

 reasons ; and any small deviation from the general rule 

 will be attended with no considerable inconvenience. It 

 will always be best, however, to conform to it as far as 

 circumstances will allow. 



Where a chimney is designed for warming a room of 

 a middling size, and where the thickness of the wall of 

 the chimney in front, measured from the front of the 

 mantle to the breast of the chimney, is nine inches, I 

 should set off four inches more for the width of the 

 throat of the chimney, which, supposing the back of the 

 chimney to be built upright, as it always ought to be, 

 will give thirteen inches for the depth of the fireplace, 

 measured upon the hearth from the opening of the fire- 

 place in front to the back. In this case, thirteen inches 

 would be a good size for the width of the back; and 

 three times thirteen inches, or thirty-nine inches, for the 

 width of the opening of the fireplace in front ; and the 



