46 
MINUTES OF PBOCEEDINGS OF 
Further trial of my second casemate shield . March 3, 1863. 
The guns placed in position at 200 yds. in front of this shield for its 
further trial, consisted of four of the most formidable pieces of ordnance 
ever before brought together in a battery. 
They were as follows :— 
One 300-pr. Armstrong muzzle-loading 10 grooved shunt gun, veigliing Ilf tons, 
calibre, 10’48 in. 
One 7-in. 130-pr. Whitworth rifled gun, weighing 7 % tons. 
One 7-in. Lynall Thomas rifled gun, weighing 7^ tons. 
One 9-in. Armstrong muzzle-loading smooth-bore gun, weighing 6 tons. 
The first shot fired was from the Whitworth rifled gun. It was of Frith's 
steel, solid of course and flat-headed, weighing 148 lbs., length of shot, 
17*3 in.; charge of powder, 25 lbs.; velocity, at 12 yds. short of the shield, 
1240 ft. per second. 
TFJ 1 
The accumulated work in this shot on striking or - 1 -~ was 35,557 lbs., or, 
in other words, sufficient to raise about 1587 tons 1 ft. high. 
It struck on the joint of an 8-in. and 7-in. plank, and stuck there; two 
very small cracks appeared in the planks, and at the back of the shield a 
very slight bulge of less than i-in. might be detected, a little of the sheet 
lead was also squeezed out, but no injury of any consequence appeared. 
The shot which thus adhered to the face of the shield was subsequently 
got out by means of heavy sledges, and the indent made was found to be 
only from 2J-in. to 3|-in. deep; the impression made is a very remarkable 
one, and testifies to the superiority of the metal of the shield and the 
wonderful hardness as well as tenacity of the metal of the shot. The effects 
of this blow, and of a subsequent one soon to be described, are interesting, 
as they exhibit with an unusual distinctness the work done by the shot 
during its action upon the shield, and no doubt a very large part of the work 
accumulated in the shot on impact could be accounted for in the effects 
produced upon the shield. 
After this, the 9-in. smooth-bore Armstrong gun was fired. The shot 
was of wrought-iron, spherical, weighing 102 lbs., charge of powder 25 lbs., 
velocity, at 12 yds. short of the shield, 1461ft. per second. 
jfr 2 
The accumulated work on striking or =1537 tons raised 1 ft. high. 
It struck close to the edge of a 6-in. plank, and a bolt, with lead and iron 
washers, distant about 3 ft. from the point of impact, was broken ; also one 
of the horizontal backing pieces was cracked through in a vertical direction, 
and one of the vertical frame pieces slightly curved. 
The indent made by this shot was 2*4 in. deep, and in diameter from 10‘4 
to 11 -3 in. 
The next shot was from the 300-pr. shunt gun; it was of cast-iron, cylin¬ 
drical, with a hollow hemispherical head, and weighed 230 lbs.; length of 
projectile, 19 in.; charge of powder, 45 lbs.; velocity, at 12 yds. short of 
the shield, 1400 ft. per second. 
