MECHANICS AND USEFUL ARTS. 101 



the lips of every jagged metal wound there is a kind of red ulcer, the 

 oxidization produced by the instantaneous and awftfl (lame of the im- 

 pact ; while when; the bolt or ball has torn its way through the tough 

 iron, the sides of the cut are actually "blued 17 like gunsmith's furni- 

 ture, by the same momentary and fiery heat of percussion. 



Experiments on Tiii'i/c.ls of compressed Wool. Some experiments 

 have been made in England during the past year on the resisting prop- 

 erties of compressed wool to shot : Mr. Nasmyth and other authori- 

 ties entertaining a confident opinion that a good thickness of wool, 

 w'i;".i pressed tight, would offer an amount of resistance to shot which, 

 if no} ssrli-ient to keep it out altogether, was, at least, certain to be 

 enough to justify the Government in making experimental inquiries on 

 tile subject. We do not know, says the London Times, even if the 

 discovery had been successful, how it was proposed to utilize it, how, 

 for instance, to recoat our ironsides with 10 or 12 feet of pressed wool, 

 or how to apply so bulky and cumbrous an appliance in any way. For- 

 tunately there is no necessity for considering such embarrassing spec- 

 ulations now, inasmuch as the experiment proved the. wool rather 

 more permeable to shot than almost any other novelty that has yet 

 been fired at. A very few words is sufficient to tell the result. The 

 target, if we may so call it, was a wrought-iron tube, like a boiler or 

 iron funnel, open at both ends, 10 feet in diameter and about 11 feet 

 long. The wool part of the target was constructed by tilting this on 

 end and filling it with wool as tightly as men could trample it down 

 till the cylinder was full. It was then laid on its side fronting the gun, 

 so as to present the appearance of a large white circular target or 

 drum, 10 feet in diameter, and 1 1 feet thick of solid wood. 



The first shot was fired from the Armstrong 100-pounder, with a 

 10-lb. charge, and this not only passed through the target from end 

 to end, but buried itself in the earth behind. A second shot was fired 

 from the 68-pounder, with the usual service charge, and this also went 

 through, burying itself in the bank, and as a means of resistance the 

 target was such a palpable and utter failure that even Mr. Nasmyth was 

 satisfied with these two shots, and concurred in the'uselessness of 

 firing any more. 



Firing C> mnon under Water. Some experiments on the firing of 

 cannon under water, recently made at Portsmouth, England, are thus 

 described : 



" A stage was erected in the harbor within the tide mark; on this 

 an Armstrong 110-pounder was mounted, loaded, and aimed, at low 

 water, at a target placed also within the rise of the tide. When botli 

 gun and target were covered by the water to the depth of six feet the 

 gun was fired by means of a tube. The targets were placed at from 

 _! ; ) to 25 feet from the muzzle of the gun. One was composed 

 of piles and oak planking of a thickness of 21 inches ; another 

 consisted of the hull of an old vessel, the Griper, laid on a mnd- 

 b.iik; a third was made up of three inches in thickness of iron 

 boiler-plates, bolted together and backed with timber. On all these 

 the effect of shot and shell from, the submerged gun was very startling. 

 The wooden target was pierced through and through, the iron target 

 was broken in pieces and driven into the backing, the solid shot passed 

 right through both sides of the vessel, malting a huge hole through 

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