114 ANNUAL OF SCIENTIFIC DISCOVERY. 



Common rifle with 



Diameter , Elevation. 



of bare. 2. 5. 10. 



Inches. Yards. Yards. Yards. 



James' shot, 30-pounder, 4.2 1,000 2,200 3,500 



Sawyer's, 30-pounder, 4.2 1,000 2,200 3,500 



Hotehkiss shot, 30-pounder, 4.2 1,000 3,500 



Armstrong's rifle, 12-pounder, . . . 1,200 



Whitworth's, 12-pounder, 3.25 1,254 2,330 .... 



Accelerator, 12-pounder, 2.55 1,590 3,584 .... 



In an accelerator we must use a small quantity, and very 

 slow powder, at the breech for the initial charge, because we uso 

 a long, heavy shot. Then, when the curve has run down consid- 

 erably and the shot is well under way, it passes over the lirst accel- 

 erator, containing perhaps 10 times as much as the initial charge. 

 The fire sets back, down into, and lights this, and raises the pres- 

 sure or curve nearly as high as the perpendicular made by the 

 initial charge. 



It was said by the officer in charge of the navy yard in Washing- 

 ton that the most powerful gun they ever had there for penetration 

 was the Whitworth muzzle-loader, 5 inches diameter of bore, 

 a gun made by shrinking bands of steel upon a core of steel. 



They had tested this gun upon the same plate upon which they 

 tested the 2i-mch bore accelerator. The shot of this Whitworth 

 gun was cast steel, about 12 inches, or 2| diameters long ; the 

 propelling power was 14 pounds of powder (No. 7), which, with, 

 the cartridge bag, filled the gun about 20 inches deep. The target 



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plate. Next they 

 18 pounds of powder (No. 7), which filled the gun over 2 feet deep. 

 As the Whitworth gun uses a cake of beeswax and tallow for a 

 wad, there was very' little windage, but perhaps nearly the whole 

 of that long column of strong powder was converted into an elas- 

 tic fluid, as heavy as water and hotter than melted iron, before tiie 

 inertia of the shot was overcome. Or it may be, as believed by 

 some, that only a foot or so of the column was burned, while 

 another foot next to the shot was rammed into a cake as hard as 

 dry pressed brick, and not burned until it left the gun. This 

 would make a very obstinate sabot, particularly if the bore was 

 rough. 



The shot penetrated but 3 inches, and that splendid Whitworth 

 gun was ruined. It was cracked along its top several feet. There, 

 were no other shot marks on this plate except the two Whitworth, 

 which were still sticking in it, and though it was a very perfect 

 plate, it was supposed the solid oak backing only prevented their 

 passing through. 



The accelerator had but 4 inches depth, three-fourths of a pound, 

 .of mammoth powder in the breech, but it had enough of the strong- 

 est cannon powder in the chambers to have filled the bore 30 inches 

 deep. The shot was 17 inches or about 7 diameters long. The twist 

 of bore, being 1 revolution in 3 feet, keeps this long shot point on. 

 The gun stood at the same port-hole that had been occupied by 



