Of Chimney Fireplaces. 505 



current of air ever sets from any part of the opening of 

 a fireplace into the room, it is impossible to conceive 

 how the heat existing in the metal composing any part 

 of the apparatus of the fireplace, and situated within its 

 cavity, can come, or be brought, into the room. 



This difficulty may be in part removed, by supposing, 

 what indeed seems to be true in a certain degree, that 

 the heated metal sends off in rays the heat it acquires 

 from the fire, even when it is not heated red-hot ; but 

 still, as it never can be admitted that the heat absorbed 

 by the metal, and afterwards thrown off by it in rays, is 

 increased by this operation, nothing can be gained by it ; 

 and as much must necessarily be lost in consequence of 

 the great quantity of heat communicated by the hot 

 metal to the air in contact with it, which, as has already 

 been shown, always makes its way up the chimney, and 

 flies off into the atmosphere, the loss of heat attending 

 the use of it is too evident to require being further in- 

 sisted on. 



There is, however, in chimney fireplaces destined for 

 burning coals, one essential part, the grate, which cannot 

 well be made of anything else but iron ; but there is no 

 necessity whatever for that immense quantity of iron 

 which surrounds grates as they are now commonly con- 

 structed and fitted up, and which not only renders them 

 very expensive, but injures very essentially the fireplace. 

 If it should be necessary to diminish the opening of 

 a large chimney in order to prevent its smoking, it 

 is much more simple, economical, and better in all 

 respects, to do this with marble, fire-stone, or even with 

 bricks and mortar, than to make use of iron, which, as 

 has already been shown, is the very worst material that 

 can possibly be employed for that purpose ; and as 



