504 
ARMOUR-PIERCING PROJECTILES, 
On the 21st August, 1877, the trials were commenced with a long 
17 cra (6*698 ins.) Krupp hooped gun mounted on the gunnery ship 
Het-Loo; the projectiles used were Krupp shells of chilled-iron, with 
copper rings, weighted with sand to 59*8 kilos. (131*837 lbs.) ; the 
charge was 15*5 kilos (34*171 lbs.) of pebble-powder; the proportion 
of weight of charge to that of projectile was therefore about Jth, or 
exactly 
The initial velocity was 488 m (1601*079 f.s.); the range was 100 m 
(109*36 yds.); striking velocity was 478 m (1567*270 f.s.); the energy 
on striking was 696*4 tonnes-metres (2249*372 ft. tons.) 
Energy per centimetre of sheiks circumference was 13 tonnes-metres 
(106*6 ft. tons per inch of circumference). 
Energy per square centimetre of section 3*03 tonnes-metres 
(63*806 ft, tons per square inch of section). 
The motion on board the gunnery vessel occasioned by a violent 
wind rendered it difficult to lay the gun; the projectiles deflected 
sensibly to the left, but however struck the targets. (For results see 
Table I.) 
We must consider that the chilled projectiles of 17 cm (6*693ins.) 
gave excellent results, as they penetrated all the plates of very good 
quality, having a thickness of 1\ calibres. 
The wrought-iron plates are completely perforated, and the wood 
backing is more or less penetrated. Not a single crack is made in 
these plates. 
The steel plates are equally perforated, though the projectiles 
rebounded from them either whole or in pieces. The wood backing 
is uninjured, but the plates are cracked, and these cracks keep increas¬ 
ing in size for some time after the blow is given. 
The whole projectiles, as well as the fragments, were cold. 
On the 8th September, 1877, the experiments were continued with a 
9-in. (228*6 mm ) Armstrong M.L. gun, mounted on the “ Scorpion,” at 
a range of 113 metres (123*577 yds.) from the target. 
The charge was 22*7 kilos (50*045 lbs.) pebble powder; the projectile 
was a Palliser shell weighted up to 113*5 kilos. (250*224 lbs.); the pro¬ 
portion of weight of charge to that of projectile was therefore ^-th. 
The striking velocity was 408 metres (1338*607 f.s.) ; the energy 
on striking was 962*9 tonnes-metres (3110*167 ft. tons); energy per 
centimetre of circumference of projectile was 13*33 tonnes-metres 
(109*306 ft. tons per inch of circumference); energy per square cen¬ 
timetre of section was 2*32 tonnes metres (48*889 ft. tons per square 
inch of section). (Table II. gives the results of the practice.) 
To recapitulate, in spite of the difference of calibres, the effect pro¬ 
duced by the 9-in. shell is much less than that obtained with the long 
17 cm hooped gun, the only plate perforated (except when the projectile 
struck on a corner, or on a hole already made) was a horizontal Marrel 
plate, at the 7th round. 
The Palliser projectiles are inferior to the Krupp projectiles; they 
