20 On a neiv fulminating Meteury. 



upper part of the barrel nearly from the touch-hole to iht 

 muzzle, and ftruck off the hand of the regifter, the furface 

 of which was evenly indented to the depth of o,i of an inch, 

 as if it had received the impreflion of a punch. 



The inftrument ufed in this experiment being familiarly 

 known, it is therefore fcarcely neceflTan.' to dcfcribe it; fuffice 

 it to fay, that it was of brafs, mounted with a ipring regifter, 

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

 and graduate the violence of the explofion. The barrel was 

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

 -where a fpring of the lock impaired half its thicknefs. 



Section V. 



A gun belonging to Mr. Keir, an ingenious artift of 

 Camden-town, was next charged with 17 grains of the 

 mercurial powder, and a ieaden 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 fufe. ISio recoil feemed 

 to have taken place; as the barrel was not moved from its 

 pofition, although it was in no ways confined. The report 

 was feeble : the bullet, Mr. Keir conceived, from the im- 

 preflion 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 bed gunpowder. We therefore recharged 

 the gun with 34 grains of the mercurial powder ; and, as the 

 great ftrength of the piece removed any apprehenfion of 

 danger, Mr. Keir fired it from his {houlder, aiming at the 

 fame block of wood. The report was like the firft in Sec- 

 tion IV, (harp, but not louder than might have been ex- 

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

 was not hurt, but the gun was burft in an extraordinary 

 manner. The breech was what is called a patent one, of 

 the beft forged iron, confifting 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 direftions, and the gold touch- 

 hole driven out. The barrel, into which the breech was 

 fcrewed, was 0,5 of an inch thick ; it was fplit by a finglc 

 crack three inches long, but this did not appear to me 10 be 

 the immediate effedl of the explofion, I think the fcrew of 

 7 ^>< 



