12 BARRELS. 



to publish, the secret. But as the little knowledge I 

 possess has been acquired by my own discovery, and 

 proved by experiments to be correct, it becomes my 

 own property ; and as such therefore I have no further 

 hesitation in presenting it to my readers. 



A SINGLE SWIVEL-GUN. 



Barrel made by Fullerd : average of bore, an inch 

 and \ : weight of barrel 621bs. 



Feet. Inches. 



Cylinder . .28 



Relief . . .41 



Opened behind . . 6| 



Total (exclusive of plug) 7 3J 



DEPTH OF CUT. Relieved to the 20th of an inch : 

 opened behind to the 24th of an inch. 



MY NEW DOUBLE SWIVEL-GUN (weight 193 Ibs.). 



Barrels by Fullerd. 



Feet Inches. 



Cylinder . .29 



Relief . '- .' .42 



Opened behind . .13 



Total (exclusive of plugs) 8 2 



DEPTH OF CUT. The bore, in cylinder, an inch 

 and -J all but a S2d : relief forward an inch and \ and 

 a 32d (a 16th difference), and cut rather less deep be- 

 hind than at the muzzle. 



