444 LEWIS'S AMERICAN SPORTSMAN. 



to unite by a process termed "jumping," after the bar is entirely 

 twisted. The greater the number of spirals to an inch, the more 

 labored and perfect is the manufacture of the barrel, and the more 

 expensive is the getting of it up. The rods for wire-twist barrels 

 are extremely narrow, only three-eighths of an inch, or less, in 

 width ; and the quantity of spirals is consequently increased. 



After the hoops have been twisted round the rods, the spirals 

 are joined together by heating the unclosed cylinder to a welding- 

 heat and striking the end against the anvil, which springs them 

 together so forcibly that, with a little hammering, the whole 

 cylinder becomes welded as if formed of only one continuous piece. 

 After the spirals are joined, the barrel is hammered in the grooves 

 of the anvil to make it perfectly round. 



It requires two, three, or four spiral cylinders, according to the 

 length of the piece, to make one barrel; and great nicety and 

 dexterity are necessary to join them together so that the barrel 

 may appear to have been made out of one rod only. In common 

 barrels this union of the rods may be distinctly seen upon examina- 

 tion before they are stained, and indeed very often after they come 

 from the stainer's hands. 



The next process in the manufacture of barrels is what is termed 

 "hammer-hardening," which is accomplished by beating the metal for 

 a considerable time in the grooves of the anvil with light hammers, 

 for the purpose of closing the pores, increasing the density and 

 elasticity, and rendering the texture more firm, flexible, and solid. 

 This labor is not often bestowed upon ordinary barrels, got up 

 merely for the home or foreign trade, but on ordered or show-guns 

 only. 



BORING. 



The barrels are now submitted to the boring-mill for the pur- 

 pose of giving them their proper calibre. This end is accom- 

 plished with the assistance of steam. The barrel being properly 

 arranged on a frame, the boring-bit is introduced into the muzzle, 

 and, by the application of the necessary power, is made to traverse 



