58 Of the Management of Fire 



a manner that its current may be broken, and that 

 whirlpools may be formed in it ; for the rapid motion 

 of the flame causes a quick succession of hot particles ; 

 and, admitting our assumed principles to be true, it is 

 quite evident that every kind of internal motion among 

 the particles of the flame by which it can be agitated 

 must tend very powerfully to accelerate the communi- 

 cation of the heat. 



The effect of a blowpipe is well known, but I do 

 not think that the manner in which it increases the 

 action of flame has ever been satisfactorily explained. 

 It has generally been imagined, I believe, that the cur- 

 rent of fresh air which is forced through the flame by 

 a blowpipe actually increases the quantity of heat ; I 

 rather suppose it does little more than direct the heat 

 actually existing in the flame to a given point. A cur- 

 rent of air cannot generate heat without at the same 

 time being decomposed; and, in order to its being 

 decomposed in a fire, it must be brought into actual 

 contact with the burning fuel, or at least with the unin- 

 flamed inflammable vapour which rises from it. But 

 can it be supposed that there can be any thing inflam- 

 mable, and not actually inflamed, in the clear, bright, 

 and perfectly transparent flame of a wax candle ? A 

 blowpipe has however as sensible an effect, when 

 directed against the clear flame of a wax candle, as 

 when it is employed to increase the action of a common 

 glass-worker's lamp. 



Conceiving that the discovery of the manner in 

 which the current of air from a blowpipe serves to 

 increase the intensity of the action of the flame could 

 not fail to throw much light upon the subject under 

 consideration, namely, the investigation of the man- 



