THE ROYAL ARTILLERY INSTITUTION. 
47 
jy v 2 
Accumulated work on striking or- 7 - =3145 tons raised 1 ft. high. 
*9 
This shot struck on an 8 -in. plank, and made an indent of 1*45 in. deep, 
and 9*5 to 10 inch in diameter. The plank was cracked through the indent, 
and at another place distant from the point of impact, two bolts were broken 
and two or three others more or less injured. Some other minor injuries were 
inflicted but nothing of a serious character. 
The Lynall Thomas gun was next fired ; the projectile was of wrought-iron, 
cylindrical, with a round head, weighing 151 lbs. Its length was 16 J in. 
The charge of powder was 25 lbs., and the velocity at 12 yds. in front of the 
shield was 1215 ft. per second. 
TV' ^ 
The accumulated work on striking or =1547 tons raised 1 ft. high. 
It struck a 7 -in. plank within 5 in. of its edge, making an indent 1*8 in. 
deep, and 7 J in. to 8 inches in diameter; the plank was cracked through a 
bolt hole rather more than a foot from the point of impact, and at another 
bolt hole about 18 in. below the point of impact. 
The shield seemed to be generally shaken, though not materially so, and 
little or no further injury appeared at the back. 
The next round was from the 7-in. Whitworth, with the same shot and 
charge as the first round. 
This shot struck an 8 -in. plank, and broke up, but a large portion of it 
remained imbedded in the face of the plank. When subsequently removed, 
this indent was found to be from 2 J to 3 in. deep, or rather less than on the 
other occasion before described; two bolts were broken, and some minor 
injuries received elsewhere, but nothing worth speaking of. 
After this the 300-pr. shunt gun was again fired, the shot this time 
weighing 307 lbs.: it was of cast-iron, cylindrical, with a round end, 18 \ in. 
long. It was fired with a charge of 45 lbs. of powder, and at 12 yds. in 
front of the shield had a velocity of 1225 ft. per second. 
TV v 2 
The accumulated work on striking or = 3186 tons raised 1 ft. high. 
This shot struck at the joint of an 8 -in. and 7-in. plank, and of course 
broke up. It made an indent varying from 1*3 in. to 2 inches in depth, 
broke a bolt, and enlarged some cracks previously made. The shield showed 
general symptoms of having been shaken by this terrific blow, but on the 
whole bore it remarkably well. 
The Lynall Thomas gun was next fired with a solid steel shot weighing 
138 lbs., and a charge of 27 Jibs, of powder, but the gun burst, and the 
shot did not hit the shield. 
After the success of this day it was deemed proper to reserve the shield 
for further experiments proposed in connection with a masonry casemate 
about to be erected at Shoeburyness, by which arrangement the Armstrong 
600-pr. lately mounted there, will probably be brought against it. 
The chief lesson to be learnt from this experiment is that,—given a big 
gun, a shield of wrought-iron can be made that shall resist it, and that being 
decided, the problem narrows itself into a simple enquiry as to how the 
necessary resistance can be obtained at the least cost. 
It would be too much of course to say that the principle here tried fulfils 
these conditions better than any other that can be invented, but that it fulfils 
