THE DEVELOPMENT OF ARMOUR. 
519 
The effects of the rounds may be fairly seen by the photographs— 
Figs. 24 and 25. The first round near the centre caused a dish in the 
face round the point of impact about yq in* deep ; the shot spread to 
a diameter of about 12 in. A bulge 15 in. long was formed at the 
back, but no cracks were effected, nor was any injury done to bolts or 
structure. The projectile, which was hardened to 3 in. below the 
bourrelet, was not broken up small, one fragment containing a large 
portion of it. 
The second shot struck near the right-hand bottom corner. The 
projectile, which was hardened to about 2*5 in. below the bourrelet, 
broke up, a great part remaining welded in the plate. A bulge 4*5 in. 
high was formed on the back of the plate. The front was dished about 
I in. round the point of impact. The face flaked off to the extent 
hown in Fig. 24. There was no injury done to the structure and 
bolts, and the plate was not cracked. 
The third round was fired with a charge of 25 lb. of California S.P. 
perforated cylinder powder. It was the hardest blow delivered in the 
trial. The shot was hardened to 2| in. below the bourrelet. It 
struck near the left-hand bottom corner—see Fig. 24—and perforated 
the plate and broke up, carrying all its fragments into the backing 
where they remained, being stopped by the skin. The hole in the 
plate was oval, its greatest diameter being 8*5 in. The effect was a 
punching one, the projectile driving the disc of plate in front of it. 
The flaking of the face is shown in Fig. 24. The plate was not cracked, 
nor were bolts or structure injured. The fourth round was fired with 
a Carpenter projectile capped, thus weighing 104 lb. The projectile 
was hardened to 4 in. below the bourrelet. It struck low down to the 
right of the centre line—see Fig. 24. It perforated the plate, backing, 
and skin, and broke up, barely entering the sand butt in rear. The 
hole was oblong to a less extent than in the previous round, the 
greatest diameter being 6*75 in. There was no dish in front, and but 
little flaking. The plate was not cracked, and bolts and structure 
were not injured. 
The plate was naturally held to have shown remarkable powers of 
resistance. Its appearance was good both in face and back. 
Certain features in this trial are of special interest compared with 
our own trials. First, the plate was tested up to complete perforation. 
Round three, in which the shot stopped in the backing, is probably 
nearly the exact measure of the plate’s powers of resistance, seeing 
that the plate kept out the previous round with only 113 foot-seconds 
less velocity. Probably, however, a shot with even considerable 
increase of velocity might effect no more practically, seeing that the 
shot broke up and perforated by punching, for it may readily be 
admitted that a great amount of energy would be necessary to drive 
fragments and disc through the skin. 
That perforation should eventually be only achieved by punching is 
extremely interesting, showing the behaviour of the face in defeating 
the entrance of the sharp point. The dishing of the face round the 
point of impact in this and the previous rounds seems to show how 
