SHORT NOTES ON PROFESSIONAL SUBJECTS. 
7 
10. Chalmers* * * § target.^ An experiment was made at Shoeburyness on 8th 
March, 1867, to test the power of resistance of this target to Palliser projectiles. 
For this purpose a 7 // M.L. rifled gun of 7 tons was placed at 70 yds. from the target 
and at an angle of 60°. Five rounds were fired, viz. three shot of 114 lbs. weight 
each, and two shell of 115 lbs., charge 22 lbs. The result of the experiment 
was that the target, when struck on an undamaged portion, was not penetrated, 
thus confirming previous experiments which had shewn that the " Chalmers ” target 
has greater power of resistance to projectiles than the “Warriorthe latter having 
been penetrated by Palliser shot fired under precisely similar conditions. The 
striking velocity of the projectiles was about 1460', and the energy about 78 foot 
tons per inchf of shot’s circumference. 
11. Experimental armour plate. A very interesting experiment was 
made at Portsmouth on 12th March 1867, to ascertain whether the addition of a 
proportion of steel would add to the resisting power of wrought-iron plates, to the 
impact of projectiles. 
A plate 12' x 4' x 7" was manufactured by Messrs Cammell of Sheffield, of 
alternate thin layers of wrought-iron and steel, and was secured by through bolts 
to 42" of timber. It was fired at on board H.M.S. “ Thunderer ” by a 68-pr. S.B, 
gun of 95 cwt. using a charge of 13 lbs.|| and service cast-iron shot of 66-|lbs. 
weight, at 10 yards range, six rounds were fired, striking on a space of 20 square 
inches, and the result of these rounds was almost to detach this portion of plate 
and drive it into the backing to a depth of 4’5". 
Two rounds were then fired at the same range, but at an angle of 79°, from a 
7" M.L. rifled gun of 6£ tons, one round with 14 lbs.J and one with 22 lbs. charge, § 
and Palliser shot of 114 lbs., the former buried itself in the plate and broke up, 
the latter penetrated the plate, drove the pieces into the backing, and broke off 
a large piece of the corner of plate (!' x 6" x T) and threw it to the rear. || The 
welding of the plate seemed excellent, but cracks were developed after each round, 
as has ever been the case in firing at plates wholly or partially of steel, and its 
power of resistance was considered very inferior to that of an Al wrought-iron 
plate, thus confirming previous experiments which have shewn that " no material 
for armour plates yet tested has been found to be equal to wrought-iron of the 
softest quality.’’^]* 
12. Trial of 7-ton guns designed as broadside guns for the 
nayy. This experiment took place on board H.M.S. “ Thunderer ” at Portsmouth, 
in July and December 1866. The following guns and shot were used :— 
No. I. 8" M.L. shunt rifled gun 7 tons, firing hemispherical headed shot of 
Firth’s steel, 150 lbs. with a charge of 30 lbs. 
* For description of this target, see Yol. III. p. 316, “Proceedings,” R.A. Institution, 
f This expression enables an easier comparison to be made of the effects of projectiles striking 
an object with different amounts of “ work h than the more usual one of recording the result in 
foot lbs. It is thus obtained, 
jfr v i 
- — ^rj -—-— *= foot tons per inch of shot’s circumference, 
2g x 2240 x 2 itr r ’ 
in which W = weight of shot in lbs. $ v, its velocity on impact j g, gravity ; 2240 for conversion td 
tons | w, ratio of circumference. 
J Service charge. 
§ Battering charge, 
|| Equivalent to service charge at 200 yards. 
^ “ Proceedings,” R.A. Institution, Yob IY. p. 435* 
