J8 UN THE LOSS OF HEAT 



less capable of rapid union with the air, to produce the combus- 

 tion ; and as each successive portion of air in excess robs the 

 combustible of its heat, we see the fire languish for a short 

 period, and then expire 



Although atmospheric air is generally necessary to support 

 combustion, an excess of it, it is well known, will, in some 

 cases, extinguish a burning body, as expeditiously as water ; and 

 from this circumstance it may be inferred that, for ignition, 

 the air requires to be heated as well as the combustible body. 

 We may also infer, that the intensity of heat produced by the 

 union of the two bodies will be proportional to the excess with 

 which their united heats exceed their mean heat of ignition. 



Having had occasion, during the past winter, to warm two 

 warehouses, of different sizes, and it being necessary that the 

 temperature should be permanent during the night season, two 

 cylinder sheet iron stoves, of ordinary construction, lined with 

 fire brick, were procured, of different sizes, which were sup- 

 plied with Lehigh coal. 



The construction of the stoves being favourable to apply on 

 a large scale what I had found so advantageous in my experi- 

 ment stove, there being considerable space between the grate 

 and the bottom of the ash pan, this space was converted into a 

 reservoir for heating the air, by closing the apertures usually 

 made for its admission in the front of the ash pan. During 

 the igniting process, the ash pan was drawn out, but when this 

 was effected, it was closed as perfectly as its construction would 

 admit, leaving only the small crevices at its junction with the 

 body of the stove for the admission of air, and although the 

 largest stove usually contained more than half a bushel of coal, 

 this supply of air was found ample for producing intense com- 

 bustion, and the quantity of coal remaining on the grate un- 

 consumed, was found to be much less than when the stove was 

 supplied with a larger quantity of air, and a very important 

 saving was made in the heat by the diminished quantity and 

 velocity with which the current of heated air passed into the 

 chimney. Very important improvements may be made in the 

 construction of sheet iron stoves, for burning anthracite coal, 



