460 
PRINCIPLES OE GUNNERY. 
l'he effect 
of common 
shell on 
ax-mour- 
plates. 
The effect 
of Palliser 
shells with 
wrought- 
iron points. 
Wood. 
Earth. 
attack by steel projectiles; at tlie same time, it is a useful fact to 
remember in case of attack with chilled projectiles.* 
The penetration of common shell is considerable, although not 
to be compared with that of Palliser shell under similar conditions. 
The large bursting charge in the common shell renders it particularly 
destructive in cases where the armour-plate can be pierced. It may 
be fired with or without a percussion fuze. With the general service 
percussion fuze the burst takes place quicker than when no fuze is used. 
The 10-in. M.L. gun, with battering charge and common shell, is 
capable of perforating a 6-in. iron unbacked armour-plate at 70 yds. 
It has been ascertained by experiment that if a thin wrought-iron 
plate is placed in front of a steel plate, the whole structure may be 
perforated; while if the steel plate is placed in front of the wrought- 
iron plate, the projectile is broken up on impact and fails to perforate 
the target. In the latter case, the hard steel breaks up the projectile, 
and a part of the energy of the projectile is expended in breaking up 
before it can be impressed on the target; while in the former case, 
although the projectile may be broken up eventually, yet time is 
allowed, through the support afforded by the wrought-iron, for the 
projectile to impress nearly all its energy on the target. 
On the same principle it was proposed by Captain English, B.E., to 
try the effect of a wrought-iron cap placed on the point of a Palliser 
shell, when firing against steel armour-plates. The wrought-iron cap 
was wrapped round the head of the shell, and secured by two steel 
pins fitting into the extractor-holes. The shell so capped was found 
to penetrate the steel armour, where the uncapped shell, under similar 
conditions, had broken up into small pieces and failed to penetrate. 
The effect of a projectile fired against wood depends on the nature of 
the wood, the direction of the blow with regard to the fibre of the wood, 
and the diameter of the projectile. Oak is the best wood to resist artil¬ 
lery fire, but its efficiency depends on the way in which the fibre of the 
wood is disposed. If the fibre is arranged perpendicularly to the general 
direction of fire (which is the best), there is a tendency in the wood to 
close up the hole completely when the projectile is of small calibre. With 
projectiles fired front siege and garrison guns the hole does not close up 
entirely, and large splinters are torn away from the back of the target. 
If the wood is arranged so that the projectile strikes it along the 
fibre, it is seen to split and splinter even under the fire of field guns. 
At about 900 yds. the 16-pr. gun may be expected to perforate 
3 ft. 3 ins. of wood, and the 9-pr. gun at the same distance may be 
expected to perforate 1 ft. 10 ins. of wood. 
The effect of a projectile on earth can be more easily repaired than 
in the case of any other material. In general, the earth closes up the 
hole made; and if the earthwork is thick enough to resist complete 
penetration, the projectile buries itself in the earth with its point more 
or less turned round towards the direction from which it was fired. 
* For information on this subject, and on armour-plated targets generally, vide “Targets for 
the Trial of recent Heavy Ordnance,” by Colonel T. Inglis, R.E., in the “ Occasional Papers of 
,thc Royal Engineer Institute.” 
