PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 437 



tending or stretching the outside ductile metal; then, when the gun was 

 cooled, the inner metal was distended slightly beyond its elasticity, and it 

 was enlarged. This effect will always be more apparent in a bronze than 

 in a wrought iron or steel gun, and it destroys a bronze rifle gun after a few 

 rounds, and this effect is produced much sooner where the twist is very 

 quick, as in the Dahlgren navy bronze rifle howitzers, which have one turn 

 in five feet, or more than twice as much as is proper. After the " James' 

 gun," the next field rifle gun officially adopted was the three inch wrought 

 iron gun. In this model the caliber was still too large, as but forty rounds 

 can be carried in one ammunition chest, and the gun is much too long for 

 rapidity of working and accuracy of aim, and is too light for the weight 

 of projectile, it having only about eighty pounds of metal in the gun for 

 one pound- of shot. The best proportion is to have the gun about 100 times 

 as heavy as the powder and shot, and the gun and carriage about 300 times 

 that weight. The three inch gun was mounted on the same carriage as 

 the old six-pounder smooth bore gun, and its I'ecoil was found to be so 

 severe that the carriage was destroyed. Hon. P. H. Watson, the able 

 and intelligent Assistant Secretary of War, once informed me that he had 

 received a great many reports of broken carriages, and I saw about thirty 

 broken or bent axles after the second battle of Bull Run, all of them 3-inch 

 guns or 10-pounder Parrotts. I saw, also, at the Washington arsenal, 

 several axles injured by proving 12 and 24-pounder James' guns on their 

 carriages. These guns were afterward dismounted and fired while lying 

 on the ground, when they recoiled from twenty-three to thirty-four feet. 

 When it is considered that if the gun and shot were of the same weight, 

 the gun would be projected as far as the shot, it will be seen how impor- 

 tant a part "recoil" plays in the delivery of the shot, and of the accuracy 

 and range. A gun carriage wheel does not roll back as far as the gun re- 

 coils; it merely slips a part of the distance, and, as the wheels are the last 

 part of the carriage to recoil, the consequence is, many of the axles are 

 bent, broken, or twisted out and away from their fastening under the cheeks 

 and trail, where the fastening is insufficient, it being on the top of the axle 

 only, which is bent or broken by the resistance to recoil by the heavy 

 wheels. 



When the rebellion was first inaugurated, the authorities of the State of 

 New York caused all the gun carriages belonging to the State to be exam- 

 ined for the purpose of putting them in repair. These carriages had not 

 been in service, but had stood unused for years in the arsenals. I was 

 present when some of them were examined, and it was decided that all 

 would require repairs to the wheels; many of the spokes would have to be 

 taken out, wrapped with canvas and re-driven, and that all the tires would * 

 have to be cut, welded, and re-set. It was estimated this would cost $40 

 for each of the carriages belonging to the State. The wheel I have designed 

 and adopted for all my field artillery carriages, hereinafter shown, resulted 

 from the suggestions I received at that time. 



I have, however, found it necessary to make the following improvements 

 on my original carriages, viz: 



Improved sights and means of adjusting, a number of additional spare 

 articles for repairs, among which are two spare hubs and plates, and chains 



