MR. NEEDHAM S NEEDLE GUN. 



269 



fore, it is desired to open the breech end of the barrel, it is 

 only necessary to shorten this plug, by turning up the lever 

 and then drawing it away from the barrel. It stands out at 

 a right angle, as represented in fig. 42, in which the under 

 side of the barrels is shown, with one lock and plug turned 

 out ready for loading, and the other in its place. On care- 

 fully examining these parts in the real gun, a needle is seen 

 projecting thro ugh the plug, and this is 

 the means by which the charge is ex- 

 ploded. The whole principle may there- 

 fore be now described as consisting of 

 the formation of a chamber behind 

 each barrel, of the same metal and con- 

 tinuous with it. In this is fixed, by 

 means of a bolt at the back, and a 

 strong cylinder, a plug so constructed 

 as to be capable of being lengthened 



FlG. 42. UNDER SURFACE OP BARRKI.S. THE LEFT Ol'ENED FOR INSERTION 

 OP CARTRIDGE | THE RIGHT CLOSED. (lIALF SIZE.) 



and shortened, and containing a needle which is projected 

 forward from the front of the plug into the breech end of 

 the barrel, where the cartridge is placed, with an explosive 

 cap iu its base. The details of these various parts it will 

 now be necessary to describe. 



The barrels are forged in the same way as usual, but they 

 must be selected of greater than the ordinary length by about 

 four inches, and as this extent of the breech end is occupied 

 by the chamber for the lock, the strength must be as great 



