43 2 2"* Ar Can. [Book V. 



ments a quantity of air is condenfed by various con- 

 trivances, in fuch a manner that the condcnfmg force 

 being removed, a bullet will be fent to a confiderable 

 dillance with little or no noife, but with great force. 

 ' The common air-gun is made of brafs, and has two 

 barrels. The middle barrel K A (fee Plate XXX. 

 Fig. 3.) from which the bullets are {hot, and the larger 

 outfide barrel, clofed up at the end C D, and in this 

 the air is driven and kept condenfed, by means of a 

 iyringe M, which drives the air in, but fuffers none to 

 go back. This fyringe having been worked for fome 

 time, the air is accumulated in great quantities in the 

 external barrel, and this air may be made to ftrike 

 upon the ball K by means of the trigger O, which 

 pulls back the fpiral R, and this ipiral opens a valve 

 behind the ball. When the valve is open, the air 

 condenfed in the outward barrel rufhes in behind the 

 ball, and drives it out with great violence, fo great, 

 that at twenty-fix yards diilance it would drive through 

 an oak board half an inch thick. If the valve behind 

 K is iliut fuddenly,-one charge of condenfed air may 

 make feveral difcharges of bullets. The little pellet 

 guns, in the hands of children, Ihew alfo the force 

 and fpring of the air; for one pellet ftopping the 

 mouth of the gun at one end, and another being driven 

 in at the oppofire end, the air contained in the bore 

 of the gun between each pellet is continually condenf- 

 i:ig, as the hinder pellet is driven towards the foremofl, 

 till at lad the fpring becomes fo great as to drive the 

 foremoft pellet forward with fome noife and violence. 

 In the large air-gun, however, the noife is by no 

 means fo great : upon its difcharge nothing is heard 

 but a fort of a rulhing wind ; and it is very poflible, 

 that what we are vulgarly told of fome men killing 

 others, by loading their piftols with dumb powder, 



might 



