THE ROYAL ARTILLERY INSTITUTION. 
67 
projectile of 336 lbs., an initial velocity of 1140 ft. per second was obtained. 
The English maximum charge was 43 lbs. of B.L.G. powder, and this 
charge was never increased or varied during the trials. 
Three shields, the plates for which had been obtained from Sir J. Brown, 
of Sheffield, had been erected for the purpose of the experiment, representing 
ships' broadsides covered with 5, 6, 7, 8, and 9-inch plates. No. 1 shield, 
which represented the broadside of the Prussian “ Eriedrich Karl," consisted 
of 6-inch plates upon a backing similar in general features to the well- 
known composite, Chalmers' backing. Over the upper part of the target 
a 5-inch plate was substituted for the 6-inch. No. 3 target, which repre¬ 
sented the broadside of the “Konig Wilhelm," was similar to No. 1, but 
stronger, the lower plate being 9 ins. and the two top plates 8 ins. thick* 
Both shields had a stout iron skin at back. No. 2 target consisted of 
7-inch armour upon 30 inches of wood backing, without any iron struts or 
strengthening. 
The practice against the shields was commenced on March 31, 1868, by 
the Krupp gun firing 46*30 lb. charges, and both Gruson's and Krupp's 
steel projectiles. Out of 7 rounds, only 4 struck the target without 
ricochetting p a result which, at ranges of 1028 and 782 yds*, is hardly 
compatible with Captain von Doppelmair's statement, that the Krupp gun 
had “ a very satisfactory accuracy." 3 The result of this trial, as far as 
penetration went, was very unsatisfactory. Even the 6-inch shield was not 
completely penetrated—a failure which is attributed to the shot having 
" struck on a particularly strong place." 8 However this may be. Captain 
von Doppelmair frankly admits that the Prussian gun “ would have proved 
too weak against ships with 7, 8, and 9-inch plating, not only at great but 
also at smaller distances. The result of the trial consequently was, that the 
gun was not sufficiently powerful to fulfil the conditions under which the 
trial was held, and therefore could not satisfy the requirements of coast and 
marine artillery." 4 This result occasioned, as may easily be understood, the 
keenest mortification in Prussia. The established power of the English guns 
was already well known to be largely in excess of that which the representative 
Prussian gun had exhibited. 
Something must be done—and three expedients were proposed. The 
charge might be increased; some of the lead coating might be removed, so 
as to facilitate the passage of the shot through the bore; or a quicker 
powder might be employed. So we find the Prussians increasing their 
charge from 46 lbs. to 49J lbs., then to 53 lbs., and again to 55 lbs. of 
Prussian powder; the velocities being thus increased to 1151*6, 1170*9, 
and 1184*7 ft. per second. But with heavier charges than 49J lbs. the 
accuracy, fortunately perhaps for the endurance of the guns, began to 
diminish, and it was therefore decided to continue the trials with this charge 
as a maximum. 6 The proposed reduction in the lead coating was not 
attended with advantage, either as regards velocity or accuracy, and it was 
not adopted. 6 Then came an experiment which is worthy of particular 
attention. An attempt was made to improve the velocity by employing 
1 Doppelmair, pp. 7, 8. 
4 Ibid. p. 9. 
2 Ibid. p. 6. 
5 Ibid. p. 11. 
3 Ibid. p. 8. 
6 Ibid. p. 12 
