60 Of the Management of Fire 



brilliant flame of a wax candle, which had just been 

 snuffed; and, by compressing the bladder, the flame 

 was projected against a small tube of glass, which was 

 very soon made red-hot, and even melted. 



Having repeated this experiment several times, and 

 having found how long it required to melt the tube 

 when the flame of the candle was forced against it by 

 a blast of fixed air, I now varied the experiment, by 

 making use of common atmospheric air instead of 

 fixed air; taking care to employ the same candle and 

 the same blowpipe used in the former experiments, 

 and even making use of the bladder, in order that, the 

 experiments being exactly similar and differing only in 

 the kinds of air made use of, the effect of that differ- 

 ence might be discovered and estimated. 



The results of these experiments were most perfectly 

 conclusive, and proved in a decisive manner that the 

 effect of a blowpipe, when applied to clear flame, arises 

 not from any real augmentation of heat, but merely 

 from the increased activity of the flame, in conse- 

 quence of its being impelled with force, and broken 

 in eddies on the surface of the body against which it 

 is made to act; the effect of the blowpipe on these 

 experiments being to all appearance quite as great 

 when fixed air was made use of (which could not 

 increase the quantity of heat), as when atmospheric 

 air was used. 



But, conceiving the determination of this question rel- 

 ative to the manner in which flame communicates heat 

 to be a matter of much importance, I did not rest my 

 inquiries here. I repeated the experiments very often, 

 and varied them in a great number of different ways, 

 sometimes making use of fixed air, sometimes of atmos- 



