502 Mr. W. Fairbairn on the Properties of Iron. [May 9, 



the plates, notwithstanding the failure of the bolts in the first experi- 

 ment. It must, however, be admitted that plates on wood backing 

 have certain advantages in softening the blow, but this is done at the 

 expense of the plate, which is much more deflected and driven into the 

 wood, which, from its compressibility, presents a feeble support to the 

 force of impact. Again, with wood intervening between the ship and 

 the iron plates, it is impossible to unite them with long bolts so as to 

 impart additional strength to it ; on the contrary, they hang as a dead 

 weight on her sides with a constant tendency to tear her to pieces. 

 Now, with iron on iron we arrive at very different and superior results. 

 In the latter, the armour-plates, if properly applied, will constitute the 

 strength and safety of the structure ; and, notwithstanding the increased 

 vibration arising from the force of impact of heavy shot, we are more 

 secure in the invulnerability of the plates and the superior resistance 

 which they present to the attack of the enemy's guns. In these re- 

 marks I must not, however, attempt to defend iron constructions where 

 they are not defensible, and I am bound to state that in constructions 

 exclusively of iron there is a source of danger which it is only fair to 

 notice, and that is, that the result of two or more heavy shot, or a well 

 concentrated fire, might not only penetrate the plates but break the 

 ribs of the ship. This occurred in the last experiment on my own 

 target, where a salvo of six guns concentrated four on one spot, not 

 more than 14 inches diameter, went through the plates and carried 

 away a part of the frame behind. The same effect might have taken 

 place on the ' Warrior * target ; and certainly 9 inches of wood is of 

 little value when assailed by a powerful battery of heavy ordnance and 

 a well concentrated fire.* 



In closing these remarks, I have every confidence that the skill and 

 energy of this country will keep us in advance of all competitors, and 

 that a few more years will exhibit to the world the Iron Navy of Eng- 

 land, as of old with its Wooden Walls, unconquerable on every sea. 



[W. F.] 



* Since the above was written, another experiment has been made on the 

 * Warrior ' target with the 300-pounder smooth-bore gun. From this it appears 

 that the wood backing between the armour plates and the skin of the ship cannot 

 safely be dispensed with, and that some compressible or softer substance than iron 

 and iron is necessary to deaden the blow, and absorb the fragments of the shot and 

 the broken plates, which in this instance lodged in the wood, and did not perforate, 

 but only cracked, the skin of the target. From this fact it cannot be denied that 

 this experiment is more satisfactory than those on the iron on iron targets ; and 

 however desirous it may be to realize a more effective construction as regards the 

 strength of the ship, it cannot be doubted, in so far as the security of the ship 

 and the lives of those on board are concerned, that a vessel with wood backing is 

 safer in action than one composed entirely of iron. In the present state of our 

 knowledge the experiments are therefore against iron and iron, as regards security 

 from the effects of shot, but they are unfavourable as respects the strength of the 

 (ship. 



