so8 Mr. E. Howard on a new fulminating Mercury. 



the moveable hand of which closed up the muzzle, to receive 

 and graduate the violence of the explosion. The barrel was 

 half an inch in caliber, and nearly half an inch thick, except 

 where a spring of the lock impaired half its thickness. 



section v. 



A gun belonging to Mr. Keir, an ingenious artist of Camden- 

 town, was next charged with 17 grains of the mercurial powder, 

 and a leaden bullet. A block of wood was placed at about eight 

 yards from the muzzle, to receive the ball, and the gun was 

 fired by a fuse. No recoil seemed to have taken place ; as the 

 barrel was not moved from its position, although it was in no 

 ways confined. The report was feeble : the bullet, Mr. Keir 

 conceived, from the impression made upon the wood, had been 

 projected with about half the force it would have been by an 

 ordinary charge, or 68 grains, of the best gunpowder. We 

 therefore recharged the gun with 34 grains of the mercurial 

 powder ; and, as the great strength of the piece removed any 

 apprehension of danger, Mr. Keir fired it from his shoulder, 

 aiming at the same block of wood. The report was like the 

 first in section iv. sharp, but not louder than might have been 

 expected from a charge of gunpowder. Fortunately, Mr. Keir 

 was not hurt, but the gun was burst in an extraordinary manner. 

 The breech was what is called a patent one, of the best forged 

 iron, consisting of a chamber 0,4 of an inch thick all round, 

 and 0,4 of an inch in caliber ; it was torn open and flawed in 

 many directions, and the gold touch-hole driven out. The 

 barrel, into which the breech was screwed, was 0,5 of an inch 

 thick ; it was split by a single crack three inches long, but this 



