THE FOWLING-PIECE. 16 i 



inches at a time, and hammering it upon an anvil 

 that has a number of* semicircular furrows in it, 

 adapted to the various sizes of barrels; and, by this 

 means, the whole of the barrel is rendered as per- 

 fectly continuous as if it had been bored out of a solid 

 piece. 



The barrel, when forged, is either finished in the 

 common way, or made to undergo the operation of 

 twisting ; which is a process employed on those bar- 

 rels which are intended to be of a superior quality and 

 price to others. This operation consists in heating 

 the barrel, in portions of a few inches at a time, to 

 a high degree of red heat; when one end of it is 

 screwed into a vice, and into the other is introduced 

 a square piece of iron, with a handle similar to that 

 of an augur; and by means of these, the fibres of the 

 heated portion are twisted in a spiral direction, which 

 has been found to resist the efforts of the powder 

 better than a longitudinal one. 



The next operation is that of giving the barrel its 

 proper calibre, which is called boring. The boring 

 bit is a rod of iron, somewhat longer than the barrel ; 

 one end being made to fit the socket of the crank, and 

 the other being furnished with a cylindrical plug of 

 tempered steel, about an inch and a half in length, 

 and having its surface cut in the manner of a perpe- 

 tual screw ; the threads being flat, about a quarter of 

 an inch in breadth, arid running with very little obli- 

 quity. The form gives the bit a very strong hold of 

 the metal; and the threads being sharp at the edges, 



