There is but one key to the victory. The two vessels were, as nearly as possible, equals in size, speed, armament and crew, and the contest was decided by the superiority of the 11-inch Dahlgren guns of the Kearsarge, over the Blakely rifle and the vaunted 68-pounder of the Alabama, in conjunction with the greater coolness and surer aim of the former's crew. The Kearsarge was not, as represented, specially armed and manned for destroying her foe; but is in every respect similar to all the vessels of her class (third-rate) in the United States Navy. Moreover, the large majority of her officers are from the merchant service. The French at Cherbourg were by no means dilatory in recognizing the value of these Dahlgren guns. Officers of all grades, naval and military alike, crowded the vessel during her stay at their port; and they were all eyes for the massive pivots and for nothing else. Guns, carriages, even rammers and sponges, were carefully measured; and, if the pieces can be made in France, many months will not elapse before their muzzles will be grinning through the port-holes of French ships-of-war. We have no such gun in Europe as this 11-inch Dahlgren, but it is considered behind the age in America. The 68-pounder is regarded by us as a heavy piece; in the United States it is the minimum for large vessels; whilst some ships, the "New Ironsides," "Niagara," "Vanderbilt," etc., carry the 11-inch _in broadside_. It is considered far too light, however, for the sea-going ironclads, although throwing a solid shot of 160 pounds; yet it has made a wonderful stir on both sides of the Channel. What, then, will be thought of the 15-inch gun, throwing a shot of 480 pounds, or of the 200-pound Parrot, with its range of five miles? We are arming our ironclads with 9-inch smooth-bores and 100-pounder rifles, whilst the Americans are constructing their armour-ships to resist the impact of 11 and 15-inch shot. By next June, the United States will have in commission the following ironclads: Dunderberg, 5,090 tons, 10 guns. Dictator, 3,033 " 2 " Kalamazoo, 3,200 " 4 " Passaconaway, 3,200 " 4 " Puritan, 3,265 " 4 " Quinsigamond, 3,200 " 4 " Roanoke, 3,435 " 6 " Shakamaxon, 3,200 " 4 " These, too, without counting six others of "second class," all alike armed with the tremendous 15-inch, and built to cross the Atlantic in any season. But it is not in ironclads alone that America is proving her energy; first, second and third-rates, wooden built, are issuing constantly from trans-Atlantic yards, and the Navy of the United States now numbers no less than six hundred vessels and upwards, seventy-three of which are ironclads.