32 Of the Management of Fire 



pure air a great quantity of heat is known to be set 

 loose, or to become redundant, it has been supposed 

 by many (and with much appearance of probability) 

 that by far the greater part, if not all the heat produced 

 in the combustion of inflammable bodies, is derived 

 from this source. 



But whether it be the air or the fuel which furnishes 

 the heat, it seems to be quite certain that the quantity 

 furnished depends much upon the management of the 

 fire, and that the quantity is greater as the combustion 

 or decomposition of the fuel is more complete. In all 

 probability, the decomposition of the air keeps pace 

 with the decomposition of the fuel. 



It is well known that the consumption of fuel is 

 much accelerated, and the intensity of the heat aug- 

 mented, by causing the air by which the combustion 

 is excited to flow into the fire-place in a continued 

 stream, and with a certain degree of velocity. Hence, 

 blowing a fire, when the current of air is properly 

 directed and when it is not too strong, serves to accel- 

 erate the combustion and to increase the heat; but 

 when the blast is improperly directed, it will rather 

 serve to derange and to impede the combustion than 

 to forward it ; and when it is too strong, it will blow 

 the fire quite out, or totally extinguish it. There is no 

 fire, however intense, but may be blown out by a blast 

 of air, provided it be sufficiently strong, and that as 

 infallibly as by a stream of cold water. Even gun- 

 powder, the most inflammable perhaps of known sub- 

 stances, may be actually on fire at its surface, and yet 

 the fire may be blown out and extinguished before 

 the grain of powder has had time to be entirely con- 

 sumed. 



