Rifle, a kind of firearm whose peculiarity consists in the barrel being grooved instead of smooth-bored, the grooving having more or less of a twist, thus insuring greater accuracy of flight for the bullet, since it bores, as it were, its way through the air, and presents every side of the projectile in turn to the lateral resistance. The invention is not new, and was known on the Continent in the 15th century, but was not introduced into the British army till the first American War, the Americans being the first demonstrators of its superiority. The weapon was not used gener. ally in the British army till about the time of the Crimean War. The first improvement in it was the introduction of the elongated bullet, which underwent various modifications tending to improvement in range and accuracy. The Enfield rifle, which on the introduction of breech-loading was converted into the Snider, gave place to the Henry-Martini, which, although a most serviceable weapon, has been superseded by the Lee-Metford magazine rifle. The tendency of modern improvements has been in the direction of increasing the twist of grooving to a degree once thought inadvisable, and of diminishing the calibre, the net result being a greater degree of penetration, a longer range, and a lower trajectory. In 1858 the principle was applied to cannon, both Armstrong and Whitworth having been very successful in then' manufacture.