PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 611 



greater range, will be about doubled ; for instance, the 42-pounder 

 will be 80-pounder, and the other calibres in similar proportion. 

 *' This change will not, it is believed, injure the strength or 

 durability of the cannon ; for the Board, after careful and re- 

 peated examinations, before and during the firings, of both the 

 bronze and iron guns, could not detect the least abrasion, bruise 

 or other injury to the bores or other parts. 



" Indeed, the packing seems to prevent the possibility of any 

 injury or any leading, as no metal part of the projectile comes in 

 contact with the bore, the grooves and bands of which are 

 touched only by the greased canvas patch in the passage of the 

 ball through the bore. In making new rifled cannon for use with 

 James' projectiles, the wteght of the gun to throw the same 

 weight of metal, may be, it is believed, materially decreased; as 

 the guns used in our experiments have exhibited sufficient 

 strength to withstand the firing of these projectiles, of double the 

 weight of the spherical balls of their respective calibres. So far 

 as we can judge, without nice instruments for ascertaining the 

 facts, the strain on the gun appears to be lessened, in consequence, 

 probably, of the shape of the projectile, and its close fit to the 

 bore, with a lubricated surface interposed, causing it to glide 

 out smoothly without the shocks due to the windings and ballot- 

 ing of the round balls. 



" The board have no doubt of the fitness and utility of Gen. 

 James' plan of rifled cannon and projectile for the military ser- 

 vice, and they suggest and recommend that measures be taken at 

 once for rifling the whole, or at least fifty per cent, of the good 

 and serviceable cannon at our forts and arsenals, and for supply- 

 ing them as soon as it can be done, with a proper proportion, 

 of say one hundred rounds each, of the rifle projectiles." 



" We have the honor to be, very respectfully, your obedient 

 servants, 



" Wm. MAYNADIER, Capt. Ord. Pres. Board, 



" W. A. THORNTON, Capt. of Ord. and Bt. Major, 



" S. S. ANDERSON, Capt. 2d ArVy ajid Bt. Major U. S. A, 



"M. M. BLUNT, 1st Lt. 2d ArVy, 



" G. T. BALCH, 1^^ Lt. Ord. Corps, 



" JOHN POTTS, Recorder." 



Mr. Dunham said that some 18 or 20 years ago he made several 

 projectiles, under direction of Mr. Stevens, having the same 



