22O ON THE WING. 



loss of full thirty-five per cent. And when welded 

 into barrels of the dimensions described, the relative 

 internal strength of each is 5,019^ Ibs., and 3,292 Ibs. 

 to the inch of tube. This constitutes a great difference. 

 But unfortunately that is not all. 



" In the preceding chapter I noted the fact that all 

 sorts of iron lose a portion of their strength by being 

 heated or softened ; but I found that Damascus suf- 

 fered more than any other sort of iron, excepting the 

 common kinds. For instance, the bar of wire-twist 

 would, in the state it came from the rolling-mill, bear 

 11,200 Ibs., but, after softening, it would only bear 

 10,180 Ibs., being a diminution of 10 percent. A 

 bar of Damascus suspending a weight of 8,940 Ibs., 

 the measure of its strength when annealed, was 

 7,840 Ibs., being a falling off of 12 J per cent. Thus, I 

 trust I have clearly shown, that whatever other 

 quality Damascus possesses, strength is not one of 

 its properties. It must not, however, be supposed 

 that the above weight indicates its greatest strength ; 

 on the contrary, its strength can be increased full 22 \ 

 per cent by cold hammering. Still, however, it will 

 only hold its relative position to other kinds of iron 

 with respect to strength, since they are all capable 

 of having their strength increased by the same pro- 

 cess. 



" Damascus barrels have fallen much into disuse, 

 being rarely seen except as pistol barrels, which, 

 together with a great quantity of counterfeits, are made 

 for the South and North American trades, in the shape 

 of double and single guns of a flashy appearance, 



