44 
MINUTES OE PKOCEEDINGS OE 
Some were tried with flat ends, some with flat ends in steps, some with 
conical ends, and others slightly concave in front. 
On the whole the conical end answered best, and the steel manufactured 
by Messrs Makin, of the Attercliffe Works, Sheffield, gave highly satisfactory 
results. 
Armour plates suddenly cooled . Dec. 1862. 
This experiment was made to set at rest a question which had been much 
disputed, and upon which there had been some contradictory results in former 
trials. The plates used were 4J-in., made by Messrs Beale, of Kotherham, 
and had been rapidly cooled down from a high temperature by sudden 
immersion in cold water; they were tried by 68-prs. and 110-prs., in 
comparison with plates manufactured by the same firm in the ordinary 
manner. 
The indents made on the cooled plate were about twice as deep as those 
on the ordinary plate, and altogether no advantage seemed to be gained by 
the cooling process. 
Second casemate shield of my own construction. Dec. 29, 1862. 
In the Paper in Yol. XI., before referred to,* a short account is given of 
the trial of the first shield proposed by myself, and the Committee on Iron 
having formed a favourable opinion of the results then gained, recommended 
further trial of the principle. 
Accordingly, a new shield was made of which the following is a 
description:— 
It measured lift, in length, by 8ft. 2in. in height, and contained an 
embrasure 3 ft. 6 in. high and 2 ft. 4 in. wide. 
It was composed of vertical face planks of hammered iron of various 
sections, namely, 23 in. by 8 in., 23 in. by 7 in., 19 Jin. by 8 in., 19jin. by 
7 in., and 19J in. by 6 in.; these were backed by horizontal planks of rolled 
iron 14 in. by 5 in., and secured by 3-in. screw bolts and rivets to a 
framework in the rear. This framework consisted of four vertical pieces 
14 in. by 4 in., and two horizontal pieces 14 in. by 5 in., and the whole was 
supported at either end by a boiler plate diagonal strut having a base of 
3 ft., and made up of a web of 1-in. plate, and angle iron stiffening pieces 
8 in. by 5 in. by 1 in., and 5 in. by 5 in. by 1 in. 
These struts w r ere secured to sill pieces 14 in. by 4 in., running front and 
rear, and these again secured to a cross beam 18 ft. long, 11 in. wide, and 
3 in. deep, placed 6 ft. in rear of the shield. 
This beam was heavily weighted, and secured at each end in a mass of 
masonry in precisely the same manner as it would be in the real piers of a 
fort, and formed the sole means of holding the shield in its place. 
One half of the target was made to represent half of a shield 12 ft. wide, 
and the other half, one 10 ft. wide. 
* Vide p. 37. 
