460 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



furnace, to a white-heat, — to a point just as near the meltinj^ as can be 

 attained without actually dropping apart, — and then passed between 

 three sets of rollers, each of which elongates the barrel, reduces its diame- 

 ter, and assists in forcing it to assume the proper size and taper. The 

 metal by this process is firmly compacted, becoming wholly homogeneous 

 through its entire length. 



There are forty men employed, day and night, running the rolling-mills, 

 but, instead of twelve cents, which was paid for welding, they now receive 

 but four cents for rolling u barrel, with the same contingency of a dollar 

 forfeiture for each one that bursts. Four persons are employed at each 

 mill, namelj'-, the foreman, who sees to the heating of the scalps and bar- 

 rels; the straightener, who straightens the barrel after it passes through 

 the roller; the catcher, who stands behind the roller to catch the barrel 

 when it has passed through, and the fireman. The rollers weigh two tons 

 apiece, and the five sets turn out one thousand barrels per day, one per 

 cent, of which bursts in the proving-house. 



The barrel when rolled is left much larger in the circumference, and 

 smaller in the bore, than it is intended to be when finished, in order to 

 allow for the loss of metal in the various finishing-operations. When it 

 passes into the roller, the scalp weighs ten pounds; when it comes from the 

 roller, the barrel weighs a little over seven; Avhen completed it Avcighs but 

 four and a half; so that more than one-half of the metal originally used is 

 lost in the forging, or cut away by the subsequent processes. 



The first of these latter is the boring-out of the interior by machines 

 called boring-banks, of which the water-shops contain a large number, in 

 constant operation day and night. These machines consist of square, solid 

 frames of iron, in wliich the barrel is fixed, and bored out by a succession 

 of operations performed by augers. These augers are square bars of steel, 

 highly polished, and ground very sharp at the edges, and terminating in 

 long, stout rods to enable them to pass through the barrel. The barrels 

 are fixed very firmly in the boring-banks, the shank of the auger inserted 

 into the centre of a wheel placed at one end of the bank, and a slow rotary 

 motion given to the auger, together with a still slower progressive motion 

 at the same time. By this means the auger gradually enters the hollow of 

 the barrel, and enlarges the cavity as it advances. After it has passed 

 through, another auger, a trifle larger, is substituted in its place, and thus 

 the calibre of the barrel is gradually enlarged to nearly the required size. 

 Formerly, six borings were given to each barrel, but at the present time 

 only four are permitted, aside from the rifling, which is a distinct operation, 

 performed at the works on the hill, and will be described hereafter. 



After the boring of the barrel, it is placed in a lathe, and the outside 

 turned down to the proper size. The piece is supported in the lathe by 

 means of mandrels inserted into the two ends, and there it slowly revolves, 

 brino-ing all parts of its surface successively under the action of a tool 

 fixed firmly in the right position for cutting the work to its proper form. 

 The barrel has a slow progressive as well as a rotary motion during this 

 process, and the tool advances or recedes very regularly and gradually, 

 forming the proper taper from the breach to the muzzle, but the main work 

 ia performed by the rotation of the barrel. In the boring, it is the tool 



