( 101 ) 



But when, from the preceding obfervations, we refledl on the 

 time that Gunpowder, when fired, requires to drive the ball out of 

 a Gun, and how much of the charge of powder is confumed in that 

 time ; which confumed Gunpowder is injurious to the effetk of the 

 iiriiig, and alfo when we conlider how much of the charge may be 

 driven out of the Gun before it takes fire, the conclufion is, that 

 it is worthy of confideration to devife ways and means whereby the 

 whole charge of Powder in a Gun may, if poffible, be let on fire 

 all at once; and if this be accompliflicd, lb much powder will not 

 be required for a charge as is now in ufe. 



I will now explain the manner in which I make the foregoing ex- 

 periments on the exploilon of Gunpowder : I take a glafs tube of 

 the fliape and fize reprefented in Plate XV. Jig. 2(5, L M, at one 

 end of which I blow the glafs globe H 1 R M, then, after dropping 

 into it a grain of Gunpowder, I give the glafs the fliape repre- 

 fented at fig. 27, PO N Q, R, whereby the grain of powder fixes 

 itfelf in the tube at the place marked N. I then take a fmall pipe, 

 called by filverfmiths a blow-pipe, which they ufe to folder their 

 work, and, firll putting on my fpedlacles to defend my fight, I 

 bring the tube near my eye to fee the effedl of the firing; then 

 direcling the flame of a candle or lamp, by means of the blowpipe, 

 to the place where the grain of powder is lodged, it immediately 

 takes fire, producing the inconceivable number of particles in 

 violent agitation, refembling fmoke, as I have before defcribed ; 

 befides the multitudes of particles adhering to the glafs, and 

 indeed, the number of particles into which a grain of Gunpow- 

 der is divided, cannot be conceived, but by making the expe- 

 riment. 



I then blow a glafs of the fliape reprefented at fig. 28, S T V W, 

 taking care that it be fomewhat thicker at the part T, and filling 

 it with water, I hold it in the oblique pofition reprefented in the 

 figure. 



Vol. II. X 



