FIRE-ARMS a77 



and capable of being pressed onwards against the tapering bit of the borer, by the 

 bont lever c, worked by the left hand of the operative against fulcrum knobs at d, 

 which stand about two inches asunder. Whenever the barrel has been thereby ad- 

 vanced a certain space to the right, the bent end of the lover is shifted against another 

 knob or pin. The borer appears to a stranger to bo a very awkward and unsteady 

 meehauism, but its perpetual vibrations do not affect the accuracy of the bore. The 

 opening broach may bo of a square or pentagonal form ; and either gradually tapered 

 from its thickest part, or of uniform diameter till within two inches of the end, whence 

 it is suddenly tapered to a point. 



A series of bits may be used for boring a barrel, beginning with the smallest and 

 ending with the largest. But this multiplication of tools becomes unnecessary, by 

 laying against the cutting part of the bit, slips of wood, called spales, of gradually 

 increasing thickness, so that the edge is pressed by them progressively further from 

 the axis. The bore is next polished. This is done by a bit with a very smooth edge, 

 which is mounted as above, with a wedge of wood besmeared with a mixture of oil and 

 emery. The inside is finished by working a cylindrical steel file quickly backwards and 

 forwards within it, while it is revolving slowly. 



In boring, the bit must be well oiled or greased, and the barrel must be kept cool 

 by letting water trickle on it; fcr the bit, revolving at the rate of 120 or 140 times a 

 .minute, generates a great deal of heat. If a flaw be detected in the barrel during the 

 boring, that part is hammered in, and then the bit is employed to turn it out. . . 



Many sportsmen are of opinion that a barrel with a bore somewhat narrowed towards 

 the muzzle serves to keep shot better together ; and that roughening its inside with 

 pounded glass has a good effect, with the same view. For this purpose, also, fine 

 spiral lines have been made in their interior surface. The justness of the calibre of 

 . a fowling-piece or musket is tried by means of a truly-turned cylinder of steel, 3 

 or 4 inches long, which ought to movo without friction, but with uniform contact 

 from end to end of the barrel. Whatever irregularities appear must be immediately 

 removed. 



The outer surface of the barrel is commonly polished upon a dry grindstone, but it 

 is better finished at a turning lathe with a slide-rest. 



Rifle barrels have parallel grooves of a square or angular form cut within them, each 

 groove being drawn in succession. These grooves run spirally, and form each an 

 aliquot part of a revolution from the chamber to the muzzle. Rifles should not be too 

 deeply indented, only so much as to prevent the ball turning round within the barrel ; 

 and the spires should be truly parallel, that the ball may glide along with a regular 

 pace. 



The Parisian gun-makers, who are reckoned very expert, draw out the iron for the 

 barrels at hand forges, in fillets only one-ninth of an inch thick, one inch and a half 

 broad, and four feet long. Twenty-five of these ribands are laid upon each other, be- 

 tween two similar ones of double thickness, and the bundle, weighing 60 Ibs., bound 

 with wire at two places, serves to make two barrels. The thicker plates are intended 

 to protect the thinner from the violence of the fire in the numerous successive heats 

 necessary to complete the welding, and to form the bundle into a bar two-thirds of an 

 inch broad, by half an inch thick ; the direction of the individual plates relatively to 

 the breadth being preserved. This bar, folded flat upon itself, is again wrought at the 

 forge, till it is only half an inch broad, and a quarter of an inch thick, while the plates 

 of the primitive ribands are now set perpendicular to the breadth of the narrow fillet ; 

 the leugth of which must be 15 or 16 feet French (16 or 17 English), to form a fowl- 

 ing-piece from 28 to 30 inches long. This fillet, heated to a cherry red in successive 

 portions, is coiled into as close a spiral as possible, upon a. mandril about two-fifths of 

 an inch in diameter. The mandril has at one end a stout head for drawing it out, by 

 means of the hammer and grooves of the anvil, previous to every heating. The 

 welding is performed upon a mandril introduced after each heat ; the middle of the 

 barrel being first worked, while the fillets are forced back against each other, along the 

 surface of the mandril, to secure their perfect union. The original plates, having in the 

 formation of the ultimate long riband become very thin, appear upon the surface of 

 the barrel like threads of a fine screw, with blackish tints to mark the junctions. In 

 making a double-barrelled gun, the two are formed from the same bundle of slips, the 

 coils of the one finished fillet being turned to the right hand, and those of the other to 

 the left. 



The barrels forged, as above described, from a bundle of steel and iron plates laid 

 alternately together, are twisted at the forge several times, then coiled and welded as 

 usual. Fifteen workmen concur in one operation: six at the forge; two at the 

 boring mill ; seven at filing, turning, and adjusting ; yet altogether make only six 

 pairs of barrels per week. In the first instance, it will be understood, that, for the 

 construction of the superior barrels, a bundle of horse-shoe nails is welded into a flat 



