PROCEEDINGS OF THE POLYTECKXIC ASSOCIATION. 571 



shot five miles and over, which was never surpassed until Mr. 

 AVhit worth threw a shot five and a half miles. The last gun 

 made by Sir William Armstrong, and sent to be tried, was a 12 

 pounder. At seven degrees elevation in five rounds fired, the range 

 was from 2,465 to 2,495 yards, the difference in range being 65 

 yards, and the greatest difference in width three yards. With 

 these may be compared the practice with a Whitworth of the 

 same calibre (12 pounder,) fired at the same elevation (seven 

 degrees,) on February 1st. The range was from 3,078 yards to 

 3,107 yards, the difierence in range being 29 yards, the greatest 

 difference in width one and two-third yards. 



The range of the Whitworth at seven degrees, (2,495 yards,) 

 by 712 yards, it, in fact, exceeded the range obtained by the 

 latter gun at eight degrees, and even nine degrees, and was there- 

 fore not fixed at eight degrees or nine degrees. The shooting of 

 the Whitworth 80 pounder, at seven degrees, appears to have 

 been still more accurate ; the range attained was about two 

 miles, and three out of four shots fell in an area of 16 yards long, 

 by one foot wide. This comparison at seven degrees is sufficient 

 to show that in precision, as well as in range, the Whitworth has 

 proved itself the superior gun. I find by Robbins on gunnery, 

 that gunpowder has a speed of 7000 feet a second. 



Mr. Dibben thought Mr. Laman's estimate of the speed of gun- 

 powder very low, not one-tenth. 



Mr. Laman. — The range of a 10 inch columbiad, with an accel- 

 erator, on a barbette carriage, at an elevation of five degrees, is 

 1,814 yards; at an elevation of 10 degrees, 2,777 yards; at 20 

 degrees elevation, 4,020 yards. The quantity of powder used in 

 those discharges was 18 pounds, and the projectile weighed 128 

 pounds. I have not received any assistance from Secretary 

 Floyd for the purpose of testing the merits of my gun, but am 

 endeavoring to get it from the governments of France and England. 

 Mr. Babcock. — I think the reason that Mr. Laman has not re- 

 ceived the necessary assistance for making experiments with his 

 gun, is that Secretary Floyd has expended very large sums on 

 General James' gun. The shot used with Gen. James' gun are 7 

 inch shot, and cost $50 each. From all I have heard of this gun, 

 I believe it fires at an angle of 60 deg. from the muzzle of the 

 gun. About a fortnight, one shot fired from one of those guns, 

 went a quarter of a mile out of its range, and he offered a reward 

 for the recovery of the shot. 



