Rifled breech-loading guns were proposed by Major Cavalli, of the Sardinian artillery, and by Baron Warendorff, of Sweden, and experiments were made with the weapons in this and other countries. A great deal of difficulty was found in adopting rifling for heavy guns, owing to the much greater strain imposed upon the metal, and the difficulties were still further increased when it became necessary that ordnance should be produced of very large calibre and able to throw heavy projectiles with high velocities. One way in which it was sought to get over the difficulty was by reducing the charge of powder considerably, and as the form of the newer projectiles was different from that of the old spherical projectiles, and the windage was as far as possible eliminated, it was found that this plan gave the desired result. Wrought iron and steel replaced cast-iron and bronze, though a few cast-iron rifled guns were strengthened with steel hoops. Wrought iron was adopted for gun carriages, and steel or chilled iron for armour-piercing projectiles. Sir Henry Bessemer manufactured the first gun that was ever made of malleable iron without a weld or joint, and though he showed that guns could be made of steel, the Admiralty, with its then fondness for the things of the days that were, decided to continue making its guns of iron. But when the bore of the iron gun showed cracks, the Admiralty decided on the insertion of a steel tube, and tied it with a piece of iron. “Why not with a piece of steel?” Sir Henry Bessemer asked, in 1881, many years later. “Why not a cylinder made of steel in preference to that iron coil? For the making of steel cylinders was then an accomplished fact, but the making of those iron coils was not an accomplished fact. The iron coil system has been thoroughly shown up, but at an enormous expense to this country. The incident was the turning-point which made us have iron guns, while every other country in the world has got steel guns.” But the next year the Government decided that the Navy’s guns should be constructed entirely of steel. At the International Exhibition of 1862, a spherical steel cannon-ball was exhibited, and in January, 1864, some particulars were published of trials of projectiles of this class fired from a smooth-bore against armour-plate 5½ inches in thickness. This moved Sir Henry to remark that an expenditure of £50 three years earlier would have given as full a proof of the efficiency of these projectiles.