Of Chimney Fireplaces. 499 



The whole of the combined heat escapes by the chim- 

 ney, and is totally lost ; and, indeed, no part of it could 

 ever be brought into a room from an open fireplace, 

 without bringing along with it the smoke with which it 

 is combined ; which, of course, would render it impos- 

 sible for the room to be inhabited.' There is, however, 

 one method by which combined heat, and even that 

 which arises from an open fireplace, may be made to 

 assist in warming a room ; and that is by making it pass 

 through something analogous to a German stove, placed 

 in the chimney above the fire. But of this contrivance 

 I shall take occasion to treat more fully hereafter; in 

 the mean time I shall continue to investigate the prop- 

 erties of open chimney fireplaces, constructed upon the 

 most simple principles, such as are now in common 

 use ; and shall endeavour to point out and explain all 

 those improvements of which they appear to me to be 

 capable. When fuel is burned in fireplaces upon this 

 simple construction, where the smoke escapes immedi- 

 ately by the open canal of the chimney, it is quite evi- 

 dent that all the combined heat must of necessity be 

 lost ; and as it is the radiant heat alone which can be 

 employed in heating a room, it becomes an object of 

 much importance to determine how the greatest quantity 

 of it may be generated in the combustion of the fuel, 

 and how the greatest proportion possible of that gene- 

 rated may be brought into the room. 



Now, the quantity of radiant heat generated in the 

 combustion of a given quantity of any kind of fuel 

 depends very much upon the management of the fire, 

 or upon the manner in which the fuel is consumed. 

 When the fire burns bright, much radiant heat will be 

 sent off from it ; but when it is smothered up, very little 



