The importance attached by England to mail-clad steamers may be inferred from the debates in the House of Lords on the 11th and 14th of June, 1861, in which it was officially stated that the Government had not authorized the construction of a single wooden three-decker since 1855, nor one wooden two-decker since 1859, although it had launched a few upon the stocks for the purpose of clearing the yards,—­and that it now contemplated culling down a number of the largest wooden steamships of the line for the purpose of plating them with iron, while it was constructing nothing but iron ships, except a few light despatch frigates, corvettes, and gun-boats.

In the same debate it was stated that bolts of steel had been forced by improved Armstrong cannon through an eight-inch mail composed of iron bars dovetailed together; but the quality of the iron and the mode of fastening were both questioned.  These experiments did not deter the Government from constructing mail-clad steamships.  Indeed, it must be obvious that the great cost of Armstrong cannon, fifteen hundred to two thousand dollars each, together with the cost of steel bolts, combined with the fact that this description of cannon is easily shattered, if struck by a ball from the adversary, must long prevent its introduction into use; and should it eventually succeed, it must prove far more destructive to wooden walls than to iron-clad vessels.

It has, however, been urged in England against iron ships of all descriptions, but more as a theory than as an ascertained fact, that a solid shot would make a large and irregular aperture, if it entered the side of a vessel, and a much larger orifice as it passed out on the opposite side.  To this theory, however, there are two answers:  first, that a solid ball can neither enter nor pass out of the sides of a mail-clad steamer; second, that, when it enters a common iron ship, there is evidence that it does less damage than would be suffered by a wooden vessel.  Captain Charlewood, of the Royal Navy, who recently commanded the iron frigate Guadaloupe in the service of Mexico, testified before a Committee of the British Parliament, that “his ship was under fire almost daily for four or five months,” that “the damage by shot was considerably less than that usually suffered by a wooden vessel, and that there was nothing like the number of splinters which are generally forced out by a shot sent through a wooden vessel’s side”; that “the vessel was hulled once in the midship part at about one thousand yards,” and the effect was “that the shot passed through the iron, making a round hole in the iron”; “that at two feet below water another shot passed through the vessel’s side and one or two casks of provisions, and that the hole was simply plugged by the engineer at the time.”  He testified also that none of the shot disturbed any rivets.  His evidence is the more valuable as it relates to an inferior vessel, whose plates were probably not more than half an inch thick.