Of Chimney Fireplaces. 503 



to it at an angle of about 135 degrees; and in conse- 

 quence of this position, instead of being parallel to each 

 other, each of them presents an oblique front towards 

 the opening of the chimney, by means of which the 

 rays which they reflect are thrown into the room. A 

 bare inspection of the annexed drawings (Plate VIII., 

 Fig. i, and Plate IX., Fig. 3) will render this matter 

 perfectly clear and intelligible. 



In regard to the materials which it will be most ad- 

 vantageous to employ in the construction of fireplaces, 

 so much light has, I flatter myself, already been thrown 

 on the subject we are investigating, and the principles 

 adopted have been established on such clear and obvious 

 facts, that no great difficulty will attend the determina- 

 tion of that point. As the object in view is to bring 

 radiant heat into the room, it is clear that that material 

 is best for the construction of a fireplace, which reflects 

 the most, or which absorbs the least of it ; for that heat 

 which is absorbed cannot be reflected. Now, as bodies 

 which absorb radiant heat are necessarily heated in con- 

 sequence of that absorption, to discover which of the 

 various materials that can be employed for constructing 

 fireplaces are best adapted for that purpose, we have 

 only to find out by an experiment, very easy to be 

 made, what bodies acquire least heat when exposed to 

 the direct rays of a clear fire ; for those which are least 

 heated evidently absorb the least, and consequently 

 reflect the most radiant heat. And hence it appears 

 that iron, and, in general, metals of all kinds, which are 

 well known to grow 'very hot when exposed to the rays 

 projected by burning fuel, are to be reckoned among the 

 very worst materials that it is possible to employ in the 

 construction of fireplaces. 



