Mr. Whitworth’s rifled gun, with which experiments were lately made near Liverpool, is also a breech-loading piece, and of the following construction. The form of the bore is that of a hexagonal spiral, the corners of which are rounded off. The inclination of the spiral varies with the diameter of the bore, but is in all these guns very great, the projectiles being comparatively long. ~French rifled ordnance.~ Rifled ordnance were introduced into the French service just previous to the commencement of the late Italian war of 1859, and aiming at the greatest practical simplicity, the French government adopted only one nature of gun for field service, and one for siege purposes, both made of bronze. The French rifled cannon are muzzle loading, and those first introduced had two or three grooves, but the field pieces used in Italy had six grooves, their inclination being about one turn in 59 inches. A number of heavy cast-iron guns are rifled with two grooves, and have been placed on board French ships of war; and these, unless strengthened, could be used but with very small charges. ~Advantages of rifled guns.~ The advantages obtained by the successful employment of rifled guns-- Great accuracy of fire, Long range, Penetration, Small charge, Simplicity of equipment and ammunition, Lightness of gun. ~Classification of artillery.~ Artillery may be classed under the several heads of field artillery (including artillery of position), siege artillery and artillery for the armament of garrisons, fortresses, and coast defences; its equipment is a combination of men, materiel, and horses necessary for these services. ~Three kinds of guns.~ All ordnance employed in the service, may be divided into three classes, viz., Guns, Mortars, and Howitzers. ~Carronades discontinued.~ Carronades may be considered obsolete, although a certain number are still supplied to the navy, and a few will be found mounted in some garrisons and coast batteries. ~Classification of guns and their uses.~ Guns are used for projecting shot and shell, horizontally or at very low angles, and as they are fired with large charges of powder, which are fixed for each nature of gun, very great strength and considerable weight are required in their construction. Guns are of two kinds, viz., (solid) shot guns, and shell guns. Some guns are also classed as heavy, medium, and light. Those generally employed for field service, are made of bronze or gun-metal; all guns of higher calibre, of cast-iron. ~Mortars.~ Mortars are short pieces of ordnance, used to throw shells at high angles (vertical fire), generally 45°, the charge varying with the range required; they are distinguished by the diameters of their bores. Mortars are made of cast-iron or bronze; the former being principally intended for garrisons, battering trains, the navy, &c., and the latter, which are of small calibre, and very light, are chiefly employed in sieges. ~Howitzers.~