512 Of Chimney Fireplaces. 



angle made by the back of the fireplace and the sides 

 of it, or covings, would be just 135 degrees, which is 

 the best position they can have for throwing heat into 

 the room. 



But I will suppose that in altering such a chimney it 

 is found necessary, in order to accommodate the fire- 

 place to a grate or stove already on hand, to make the 

 fireplace sixteen inches wide. In that case, I should 

 merely increase the width of the back to the dimensions 

 required, without altering the depth of the chimney or 

 increasing the width of the opening of the chimney in 

 front. The covings, it is true, would be somewhat 

 reduced in their width by this alteration ; and their 

 position with respect to the plane of the back of the 

 chimney would be a little changed ; but these alterations 

 would produce no bad effects of any considerable conse- 

 quence, and would be much less likely to injure the fire- 

 place, than an attempt to bring the proportions of its 

 parts nearer to the standard, by increasing the depth of 

 the chimney, and the width of its opening in front; or 

 than an attempt to preserve that particular obliquity of 

 the covings which is recommended as the best (135 

 degrees), by increasing the width of the opening of the 

 fireplace, without increasing its depth. 



In order to illustrate this subject more fully, we will 

 suppose one case more. We will suppose that in 

 the chimney which is to be altered, the width of the fire- 

 place in front is either wider or narrower than it ought 

 to be, in order that the different parts of the fireplace, 

 after it is altered, may be of the proper dimensions. In 

 this case, I should determine the depth of the fireplace, 

 and the width of the back of it, without any regard to the 

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



