PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 423 



The cast iron ring is cut open at a single point, the cut being made square 

 across the face of the ring, and of such shape as to receive a dovetailed 

 key which may be set up by a screw so as to expand the ring, and bear on 

 its outer face against the inner surface of the cjdindrical steam chest in 

 which the valve moves. The steam ports extend around the whole circum- 

 ference of the steam chest, and admit steam at their outer ends only. The 

 valves are necessarily balanced, and work with hardly any friction. From 

 their construction, the ring cannot be blown in, or reduced in diameter, by 

 the direct pressure of the steam, when the piston is opposite the steam 

 port; nor can it expand outward, except as it is forced open by direct 

 pressure in screwing up the dovetailed key, and the length of the pistons 

 in proportion to the width of the posts is such that no blow^ or shock occurs 

 as the pistons pass the ports. An objection to piston valves has been 

 urged in former times, that from unequal expansion of the valve they 

 would stick, but in Mr. Davis's plan the steam first surrounds the inner 

 case in w^iich the valve moves, and becoming heated before the valves, 

 renders it impossible for them to become fastened. 



The regular subject, "Improved Modes of Modern Warfare," was then 

 taken up. 



Mr. Geo. Bartlett exhibited and explained the Burnside rifle, invented by 

 Major-General Burnside. 



It was just brought out, and very highly approved, after trials before a 

 commission in the year 1851-8, but the manufacture did not succeed well. 

 Since the commencement of the present war it had been again renewed, 

 and a company in Providence are now making about 2,000 per month. The 

 arm was preferred, for cavalry use, to any other. 



Dr. Rich asked why this was superior to other breech loading arms. 

 It seems to have been so pronounced by the commissioner of army 

 officers. 



Mr. George Bartlett. — I believe it is mainly ascribed to the solidity with 

 which its parts were applied together. I do not know how fast it could be 

 fired, evidently not so fast as those which carry the percussion material in 

 the cartridge; this is used with separate caps. 



Mr. F. Dibben said rapidity of fire was not as important, for war pur- 

 poses, as accuracy, durability, strength, or force of its shooting. The Burn- 

 side rifle excelled in these, and especially in the provision for fitting the 

 plug tightly, at all times, in the barrel. 



Dr. Rich thought rapid loading was a very great desideratum. It was 

 certainly no disadvantage to load rapidly even if it was not desired to fire 

 rapidly. 



Mr. George Bartlett said this was a good target rifle, the only one, he 

 thought, of the breech loading class, which had worked well for such 

 purpose. 



The Secretary said the difference in time of loading, between the com- 

 mon muzzle loading and any breech loading arm, is much overrated. He 

 had, on a test trial, loaded and fired four times at a target in less time 

 than a friend had operated a breech loader at his side. He had found Mr. 

 Lewis, president of the National Rifle association, in favor of muzzle load- 

 ing pieces alone. 



