THE NIPPLE. 235 



kinson's, on the other hand, there is an oval chamber, one 

 end connected with the nipple, and the other being con- 

 tracted so as to retard the ignition. 



Great stress is laid upon tlie form, of tJie breech by all the 

 advocates of the muzzle-loader ; and they assert that if the 

 powder is burnt in a chamber of the same size and form as 

 the barrel itself, with a mere closure at right angles, the 

 effect is greatly deteriorated. I have tried the experiment 

 myself, firing the same barrel with different breeches, but I 

 confess I have not been able to obtain any very reliable con- 

 clusions. As far as my experience goes, the barrel is all in 

 all; and so long as the breech is sound, and the ignition 

 perfect, it matters comparatively little what shape the 

 chamber may bear. It is very commonly supposed that the 

 recoil is materially increased when the powder is fired any- 

 where but at its posterior part; but this is now proved to 

 be a myth, and, according to the experiments made by the 

 Board of Ordnance, the recoil is least when the centre of 

 the charge is fired. The Prussian needle-gun, also, in which 

 the ignition is in front, is remarkable for the absence of 

 recoil ; so that, I think it may fairly be assumed that the 

 point of ignition has no reference to recoil. There is also 

 another point which requires consideration namely, whether 

 it is desirable to allow of a vent for the explosive gases at 

 the end of the cross-hole ? The proposed object is to lessen 

 recoil, and until very recently most of the better classes of 

 guns were made with a " vent hole," lined with platina to 

 prevent corrosion ; but the plan is now almost entirely 

 abandoned, being found to be quite inoperative. The grains 

 of the powder enter the fine hole, and fill it up even prior 

 to the first discharge ; but subsequently it is quite closed by 

 the residuum left after the explosion. 



THE NIPPLE. 



I)i the ordinary percussion gun, which is that now being 

 described, the powder in the chamber is ignited by exploding 

 a cap upon n nipple, whose canal communicates with the 

 cross-hole of the breech, or, in some cases, with the chamber 

 itself. The nipple in either case is of a conical form ex- 



