Mr. Aaron Rose, of Worcester, Eng land, has just enrolled his description of a new method of manufacturing twisted gun barrels, which is thus described:— An iron or steel rod, or a mixture of both, of sufficient length and thickness to form a gun or pistol barrel, is wound into a compact coil, and then placed in an anvil having a semi-circular groove, where it is submitted to the action of the tilt hammer. The coil is then submitted to a welding heat in an air furnace, then hammered and rolled, a stream of water being used in both cases to wash away the scale.
The tilt hammer has a groove on its face corresponding with the anvil to act upon the coil, before the welding.
1N1r. Vandenberg, a Flemish gentleman, has invented a new gun which can make six and eight charges per minute, carry ing the distance of 2000 feet ; the ball weighs about one ounce and a quarter, and the powder is one-twelfth the weight of the ball. An ordinary gun requires three times more powder, the ball does not weigh half an ounce. The new gun is loaded from the breech. The shape of the ball is round. At Utica, N. Y., the new rifle of Mr. Milo M. Cass dis charged 24 balls in two minutes and 30 seconds ; then loading with 26 cartridges in 4 minutes, and discharged 24 in 2 mi nutes and 30 seconds, thusloading once and firing 48 shots in 9 The shooting was very accurate, considering the rapidity, and the performance of the gun gave great satisfaction to those pre sent. The barrel of the gun was so little heated after the first 24 discharges, that it was immediately loaded and again fired the same number of times.
The Air-Gun is a machine in which highly-compressed air is substituted for gunpowder to expel the ball, which will be projected forward with greater or less velocity, according to the state of conden sation and the weight body pro jected. The effect will, therefore, be similar to that of a gun charged with gunpowder, for inflamed gunpowder is nothing more than air very greatly con densed, so that the two forces are exactly similar, There is this important con sideration to be attended to, namely, that the velocities with which balls are im pelled arc directly proportional to the square root of the forces ; so that if the air in an air-gun be condensed only ten times, the velocity will be equal to one tenth of that arising from gunpowder ; if condensed twenty times, the velocity would be one-seventh that of gunpow der, and so on. Air-guns, however, pro
ject their balls with a much greater 'Ve locity than that assigned above ; and for this reason, as the reservoir or magazine of condensed air is commonly very large in proportion to the tube which contains the ball, its density is 1;cry little altered by passing through that narrow tube, and the ball is urged all the way by nearly the same force as at the first instant ; whereas the elastic fluid arising from inflamed gunpowder is but very small indeed in proportion to the tube or barrel of the gun, and therefore, by dilating into a comparatively large space, as it urges the ball along the bar rel, its force is proportionally weakened, and it always acts less and less on the ball in the tube.
An air-gun recently invented by Mr. Shaw, of Glossop, England, is one of much simplicity of construct m. It has not the effective force of gunpowder, but it will enable a sportsman to amuse him self at but little expense, and will do execution, too, at considerable distance from time mark. The air that projects the bullet is condensed by a piston, which draws out a strong India rubber spring, which, when it is set free, suddenly draws up the piston, condensing the air in the air chamber, and impelling it against the bullet to discharge it with considerable velocity and power.