By the desire of our first Patron, the late Lord Hardinge, Mr. Whitworth was induced to turn his mechanical genius to the Soldier’s Gun, which resulted in his adopting the polygonal form of bore. His barrel is hexagonal, and thus, instead of consisting of non-effective lands, and partly of grooves, consists entirely of effective rifling surfaces. The angular corners of the hexagon are always rounded. Supposing a bullet of a cylindrical shape to be fired, when it begins to expand it is driven into the recesses of the hexagon. It thus adapts itself to the curves of the spiral, and the inclined sides of the hexagon offering no direct resistance, expansion is easily effected. ~Westley Richards octagonal.~ Mr. Westley Richards has followed Mr. Whitworth, by using a polygonal bore, having applied his highly meritorious system of breech-loading to a barrel upon the Whitworth principle, of an octagonal form. ~Eliptic rifling.~ ~By Captain Berner, 1835.~ ~By Mr. Lancaster.~ The cardinal feature of this structure is, that the bore of the barrel is smooth, and instead of being circular, is cut into the form of an ellipse, i.e., it has a major and minor axis. Upon being expanded by the force of the powder, the bullet is forced into the greater axis of the ellipse, which performs the office of the grooves, rifling the projectile, and imparting to it the spiral or normal movement round its own axis. In 1835 a Captain Berner submitted his elliptical bore musket to the inspection and trial of the Royal Hanoverian Commission, appointed for that purpose, and which gave results so satisfactory, that it was considered admirably adapted for the Jäger and Light Infantry Battalions. This principle has been patented by Mr. Lancaster, and the advantages of this form have been previously adverted to. ~Odd number of grooves.~ It is supposed by some persons that if the number of grooves be even, so that they will be opposite to one another, the bullet would then require more force to enlarge it, so as to fill them properly. If the number be unequal, the lands will be opposite to the grooves, and the lead, in forcing, spreading on all sides, will encounter a land opposite to each groove, which will in some measure repel it, and render its introduction into the opposite groove more complete. This ingenious theory is set at nought by Whitworth, Jacobs, Lancaster, W. Richards, &c., &c., who all recommended an even number of grooves, while the Government arms have an odd number. ~Drift or cant.~