TRANSACTIONS OF SECTION G. 901 
The progress in armour-making referred to in my last public pamphlet (1894) 
has been continuous, and the United States (The Carnegie Steel Co., Ltd.) and 
Germany (Krupp) have produced armour fully 15% if not 20% better than 
the best plain steel Harveyed armour that Great Britain has placed upon her 
hattleships ; although one is handicapped in making thorough comparison so long 
as England continues to determine the value of her battleship armour by firing 
6-inch soft Holtzer shells against 6-inch plates at velocities below 2,000 ft. sec. 
In making a comparison of the tests I have cited, we must not lose sight of the 
fact that the German and French plates were eaperimental, and made to secure 
the greatest resistance possible, whereas those of the United States were service 
plates representing hundreds of tons of armour from which the inspectors had 
selected what they considered were the poorest of the lot. 
A summary of recent advances will include the cheapening and more extensive 
use of nickel; the substitution of the hydraulic forging-press for hammers and 
rolls ; better means of removing scale; simplification of the methods, and more 
uniform results of supercarburisation ; utilisation of the valuable sub-forging pro- 
cess (now required for all United States armour); improved facilities for harden- 
ing, and improvements in the machines and tools for shaping and finishing. 
While in the United States the increased resistance of armour has determined 
the authorities to retain the higher calibres of heavy ordnance, the Navy Depart- 
ment having ordered 13-inch B.L. rifles for battleships, and the War Department 
having commenced a type gun of 16-inch calibre (both adhering to the forged- 
hooped type), Great Britain still keeps the 12-inch as her limit, and continues the 
radical departure to wire construction made by Dr. Anderson when he became 
Director-General, and so successfully carried out by him. 
France adheres to types containing too many parts, and Germany is satisfied to 
possess a large number of comparatively low ballistic power. 
No matter which type, hooped or wire, is adhered to, improved armour and 
projectiles must be met by greater energies, which involve higher pressures, 
shorter guns (for utility), and stronger material. That this last is to be obtained 
in the United States is evident from the following requisites in a 38-inch test piece 
for nickel steel tubes for cannon of 8-inch calibre and over :— 
Tensile Strength *itesboterelas - 90,000 Ib. per sq. in. 
Elastic Limit . : c ; : ePID yeni, Vashi one! hy 
Elongation . : . . : c - 20 per cent. 
Contraction of Area . : : : sO enn 5 
Equally favourable progress has been made with projectiles, but as yet very 
few truly competitive results are at hand. The uncertainty of their relative 
value still causes a very large unknown quantity in the valuation of armour 
comparisons. f 
In conclusion we may count, at least in the United States, as commercial com- 
modities, armour having a resistance 10% better than the best of last year; heavy 
ordnance giving service velocities of 200 ft. sec. higher, and armour-piercing pro- 
jectiles, that to be accepted must perforate a thickness of nickel-steel carburised 
armour equal to their calibre. Truly an excellent record ! 
2. A new Spherical Balanced Valve for all Pressures. 
By James Casey, Consulting Marine Engineer. 
In this paper the author deals with the avoidable loss of life and damage to 
property caused through explosions of defective valves, whether from steam, water, 
or other fluid, where extreme pressures were used. Having described the valves 
generally in use, he points out that in many cases water that had passed into the 
valye-hox and steam-pipes from the boilers had caused danger and even fatal 
results, often attributed to defective steam-pipes, whereas both valve-box and 
