VOL. XLir.] PHILOSOPHICAL TRANSACTIONS. 601 



short piece of 5^ inch chace, the charge 12 dwts. and ball, as before, the touch- 

 hole being near the fore part of the powder ; the quantities of powder, seve- 

 rally collected, were 1 dwt. 74- grs. ; 1 dwt. 6 grs. ; and l dwt. 4 grs. And on 

 a discharge made with a little more powder, which filled the barrel exactly to 

 the edge of another touch-hole, the former being screwed up, the quantity 

 collected was 1 dwt. Q grs. 



The effect of firing with heavy slugs was also examined : the weight of the 

 slugs and quantities of powder collected, were as follow ; the charge in the 

 short barrel being 12 dwts. 



Discharge. Weight of Slugs. Powder collected. 



I .... 2 oz. 13 dwt. gr 1 dwt. 3 gr. 



II 2 11 14 O 17 



III 2 12 O O 8 



IV 5 5 6 .... O 13 



V 5 3 O O 8^ 



The powder used in all these experiments, made before the committee, was 

 presented to them by Mr. Walton, and is such as he makes for the king's ser- 

 vice. To ascertain as nearly as possible, that the powder had not undergone 

 any considerable alteration by damps or otherwise, a standard experiment was 

 previously made at every meeting, with the short barrel charged with 12 dwts. 

 of powder, and with a ball of 24 dwts. ; and the quantity of powder collected 

 was from 1 dwt. 8 grs. to 1 dwt. 12 grs. ; which is as great a regularity as can 

 well be expected. This powder of Mr, Walton being sifted, and divided into a 

 fine and a large sort, the following discharges were made with 12 dwts. of each, 

 and ball as usual : 



Discharges with Powder collected. Discharge with large Powder collected, j 



fine powder. powder. 



I 1 dwt. 4 gr. I 1 dwt. 1 1 gr. 



II O 21 II 1 l6 



III O 12 III 1 21 



In the third experiment the bullet, not being so exactly turned as the others, 

 was rammed down with great force. 



And the powder being bruised in a mortar, and sifted through a lawn sieve, 

 the charge and ball being as before, what was collected after 3 discharges, was 

 1 dwt. 10 grs. ; 1 dwt. 8 grs ; and 17 grs. 



Mr. Watson having had two parcels of powder delivered to him, the one 

 fresh, and the other collected after discharges with ball, gave an account of the 

 quantity of nitre he had separated from them, viz. 



VOL. VIII. 4 H 



