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1 argued thus with mylelf ; in a Gun eighteen feet long, half as 

 much time again is required for the Gunpowder to drive the ball to 

 the muzzle of the piece, than in a Gun which is twelve feet long ; 

 in which length of time, much of the Gunpowder in the long Gun 

 is conl'umed, before the ball gets into the open air ; this confumed 

 Gunpowder is not only wafted, but no fooner is the Gunpowder ex- 

 ploded, than immediately nearly one-fourth part of the expanfion 

 efcapes out of the Gun, which fpace muft be filled up by fome 

 other fubftance, and this is fnpplied from that part of the Gunpow- 

 der which firft takes fire, and thus the force of the powder is dimi- 

 nifhed before the ball has quitted the Gun, in like manner as I have 

 before faid, refpecling the firing of Gunpowder in a glafs, namely, 

 that fo foon as it is fired and the flame is fpent, the air within the 

 glafs is rendered fo thin and fubtile, that about a fourth part of the 

 expanfion produced by the firing of the Gunpowder muft be replaced 

 in order to fill the glafs again. 



In converfation with a certain gentleman of high authority 

 in military matters, who came to vifit me in company with fome 

 foreigners of rank, I mentioned my opinion of the inutility of too 

 long great Guns, (for our difcourfe turned upon that fubje6l), and 

 he informed me, from his own experience, that upon firing two 

 guns, one of eighteen feet long, and the other of fourteen feet long, 

 in order to prove their greateft power, he had feen the gun of four- 

 teen feet long, carry its ball much farther than the other, which 

 was eighteen feet long, and hereby I was confirmed in my before 

 mentioned opinion 



It was formerly my firm belief, that there could be no other rea- 

 fon of the great explofion produced by the firing of Gunpowder, 

 than firft, from the faltpetre particles being put into a violent agita- 

 tion and divided into fmaller parts; and fecondly, from the fire, 

 and that when thofe particles fubfided to a ftate of reft and the fire 

 efcaped, the remaining fubftances left no greater fpace than they 

 had occupied before the faltpetre was by the lire divided into many 



