165 
RECENT DEVELOPMENT OF ARMOUR AND ITS 
ATTACK BY ORDNANCE. 
BY 
CAPTAIN C. ORDE BROWNE, late R.A. 
A 6-incli gun at Elswick was lengthened for experimental purposes Elswick 
to 100 calibres, by screwing an additional piece on the muzzle. A ^ityTrla?. 0 ' 
trial took place on January 23rd, 1893. Fired with a projectile weigh¬ 
ing 100 lbs., a velocity of 3231 f.s. w r as obtained, and with a 70-lb. 
projectile the enormous velocity of 3711 f.s. The highest record that 
has hitherto been recorded was that of the Canet 10 cm (3'9-in.) gun of 
80 calibres length, which with a 13 kilos. (28*7 lb.) projectile achieved 
3366 f.s. muzzle velocity. The Elswick result is a great advance, both 
in velocity and in being carried out on a much larger scale. The gun 
is intended for experimental purposes only; and there are questions 
which might be solved by it, which at the present time are important. 
As before pointed out, the foreign and British formulae for perforation 
are widely divergent when a shot strikes with a velocity sensibly over 
2000 f.s. With velocities approaching 3000 f.s. the differences in the 
perforations calculated by the different systems are, indeed, wild. In 
the case before us, the muzzle energy of the 70-lb. projectile with 
3711 f.s. velocity is 6685 foot-tons, that of the 100-lb. shot with 3231 
f.s. is 7238 foot-tons. It is really doing violence to the English systems 
of calculation to apply them to such a case, for reasons which need 
not here be discussed. Nevertheless, they are all we have in this 
country, and applied to this case, the perforation through wrought-iron is 
19-7 inches. Krupp^s formula gives 27T inches, and that of De Marre, 
used in France, 29*1 inches. Even a round or two with this gun at 
thick wrought-iron might teach much, and it must not be supposed 
that this is merely a theoretical question. Wrought-iron remains a 
fixed quality, while steel varies continually, so that our basis of cal¬ 
culation must be wrought-iron, to which we may apply an equation 
suited to any harder shield which may be in question. 
The Portsmouth trial of a Vickers-Harvey 6-inch plate, to be noted 
presently, suggests the re-introduction of thin armour on a very large 
scale, seeing that comparatively thin plating will defeat the best 6-inch 
projectiles under service conditions. It may be that high velocity is of 
special importance in the attack of such armour, so as to enable a 
breaking shot to work mischief before it yields. This, however, is 
speculation. 
A competitive trial of armour plates took place at Ochta, near St. 
3, YOB. XX, 
