30 Experiments upon Gunpowder. 



when it is cold. Great numbers of sparks, or red-hot 

 particles from the flint and steel are frequently seen to 

 light upon the priming of a musket, without setting fire 

 to the powder, and grains of powder may be made to 

 pass through the flame of a candle without taking fire ; 

 and what is still more extraordinary, if large grains of 

 powder are let fall from the height of two or three feet 

 upon a red-hot plate of iron, laid at an angle of about 

 45 with the plane of the horizon, they will rebound 

 intire, without being burnt, or in the least altered by 

 the experiment. In all these cases the fire is too feeble, 

 or the duration of its action is not sufficiently long to 

 heat the powder to that degree which is necessary in 

 order to its being rendered inflammable. 



Now as gunpowder, as well as all other bodies, ac- 

 quires heat by degrees, and as some space of time is 

 taken up in this, as well as in all other operations, it 

 follows that powder which has been warmed by being 

 put into a piece made hot by repeated firing is much 

 nearer that state in which it will burn, or, I may say, is 

 more inflammable, than powder which is cold ; conse- 

 quently, more of it will take fire in a given short space 

 of time, and its action upon the bullet and upon the 

 gun will, of course, be greater. 



The heat of the piece will also serve to dry the air in 

 the bore, and to clear the inside of the gun of the 

 moisture that collects there when it has not been fired 

 for some time ; and these circumstances doubtless con- 

 tribute something to the quickness of the inflammation 

 of the powder, and consequently to its force. 



As it takes a longer time to heat a large body than a 

 small one, it follows that meal-powder is more inflam- 

 mable than that which is grained ; and the smaller the 



