86 
ARMOUR AND ITS ATTACK BY ORDNANCE. 
seen tliat the whole five Holtzer steel 6-inch projectiles broke up, and 
apparently did not gefc their points through the steel face. There was 
a weak spot at the centre from a blister discovered by hammering to 
exist between layers of the wrought-iron. To ascertain the exact 
extent of this, a small hole had been drilled in the back and water 
forced in. Eventually it was judged not sufficiently serious to detract 
practically from the strength of the plate, a screw plug was inserted in 
the hole thus drilled. This, however, constituted a slightly weak spot, 
but even here on the removal of the screw plug after the trial no trace 
could be found of the shot point. The success of the trial was, there¬ 
fore, most complete, and similar results were obtained soon afterwards 
both on board the Nettle and at Shoeburyness, the attack being made 
with Holtzer and Palliser projectiles. 
Comparison must naturally be raised between the Harvey and 
Tresidder plates thus tried, but such a comparison is useful rather to 
bring out the different powers exhibited than to say that one plate is 
absolutely superior to the other. Briefly, it may be said that Harvey’s 
Fig, 16. 
plate was much more severely tried, and in consequence that it suffered 
