1862.] and its Resistance to Projectiles at High Velocities. 495 



Now, it is evident that our future ships of war of the first class 

 must be long and shallow ; moreover, they must contain elements of 

 strength and powers of resistance that do not enter into the construc- 

 tion of vessels that are shorter and nearly double the depth. If we 

 take a first-rate ship of the present construction, such as the ' Duke of 

 Wellington,' and compare it with one of the new or forthcoming con- 

 struction, carrying the same weight of ordnance, we should require a 

 vessel nearly twice the length and little more than half her depth. 

 Let us, for example, suppose the ' Duke of Wellington ' to be 340 feet 

 long and 60 feet deep, and the new construction 500 feet long and 

 46 feet deep ; we should then have for the resistance of the * Duke of 

 Wellington ' to a transverse strain tending to break her back, 



a d c 



W = 



/ 



Taking 60 as the constant, and the area of the bottom and upper deck 

 as 1060 square inches, we have 



Wrr 



1060 X 60 X 60 

 340 



= 11,223 tons, 



as the weight that would break her in the middle. Let us now take 

 the new ship, and give her the same area top and bottom, and again 

 we have 



W = 



1060 X 46 X 60 

 500 



= 5851 tons. 



which is little more than half the strength. From this it is obvious — if 

 we are correct in our calculations — that the utmost care and atten- 

 tion is requisite in design and construction to ensure stability and 

 perfect security in the build of ships. 



Mechanical Properties of Iron. — It is unnecessary to give more 

 examples in regard to strength, and the proportions that should be ob- 

 served in the construction of our future navy. I have simply directed 

 attention to it as a subject of great importance, and one that I am 

 satisfied will receive careful consideration on the part of the Admiralty 

 and the Comptroller of the Navy. 



The next question for consideration is, the properties of iron best 

 calculated to resist the penetration of shot at high velocities, and in this 

 I am fortunate in having before me the experiments of the Committee 

 on Iron Plates, which may be enumerated as under : — 



