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MINUTES OF PROCEEDINGS OF 
A great many experiments appear to have been made on compound 
structures—such as india-rubber and iron plates in alternate layers, iron 
wire and wood, &c., &c.,—and with the same results as those obtained in 
this country, viz. to establish that these combinations are very inferior in 
their resisting powers to a simple iron plate of the same weight. 
Mr Holley gives the following general information about American 
guns:— 
15" cast-iron shot of 400 lbs. weight, and fired with 60 lbs. of powder 
at 50 yards range, will rupture and shatter, though will not completely 
penetrate laminated armour 13" thick, backed by 30" of oak. 
11", 169 lbs. shot at 100 yards range, fired with 30 lbs. charge, will not 
penetrate a 4|" solid plate of the best quality. 
The Parrott 8-inch rifle with 150 lbs. bolt, and 16 lbs. charge, breaks 
through but does not punch the best 4£" plates, and does not seriously injure 
the backing; and lastly, that the convex target representing the Monitor 
Turret offers very much greater resistance to both punching and racking than 
the flat target composed of the same materials. 
