Rifled cannon must be elevated by raising the muzzle; no depression of the breech must occur as by the usual elevating screw; and the recoil must be received and borne by fastenings and axle in rear of the breech only. Trunnions and all impinging influences are incompatible with correctness of fire. The muzzle must be raised in a similar manner to the raising of a hand rifle, the recoil being thrown backwards, in as direct a line as possible with that of the shot. It is only on account of the difficulty of experimenting with rifled cannon that they are at all behind rifled muskets in point of perfection. The ardent lover of science is appalled when an experiment costs hundreds of pounds. We have not a General Jacob everywhere who can afford to spend a thousand or two in experiments; but, nevertheless, the lover of science, could he experiment, might attain such extraordinary accuracy of range, as to blow up a smaller magazine than that of Kurrachee at four times the distance; and that, too, with a more certain effect, though with a projectile heavier than several of Jacob’s rifles tied together. Correct direction is certain in proportion to the increase of weight; deflection being in the minimum with the heavier weight, from the well known law of momentum. That astute and energetic sovereign, the Emperor Napoleon, is pursuing experiments with rifled cannon; with what result there can be little doubt. It must be by the use of rifled cannon that our artillery will regain the place it has lost. A short time will suffice to make the disparity between our artillery and small arms as great as when we were content with the six-pounder field gun and old “Brown Bess.” Ranges will only be ruled by sight, and objects will be hit eventually with as much ease at 5,000 yards as they now are at 1,000. Steel, rifled cannon, and projectiles of gun-metal will assuredly bring about as complete a revolution in artillery as the Greenerian rifle and bullet have effected in small arms. The form of gun best suited for all purposes has yet to be determined; and we have pointed out these defects in our artillery with the hope that some of the great practical philosophers of the present age may devote themselves to the study of this question. It is nearly allied to the science of bell-making, and a few more fractures of Big Ben will extend our knowledge of the subject, and produce a remedy which lies not very deep below the surface. The laws which should guide us in the construction of cast steel guns, so as to insure their durability, are very analogous to those which determine the durability of bells; for the laws which regulate disintegration of crystalline structures are very similar. Hitherto the rule of thumb has, unfortunately, been the only rule observed in measuring out the quantity of metal which shall surround that portion of a cannon which has to sustain the most violent concussion.