The advance which forty years have seen may be shown by the single statement that the Krupp 15.7-inch gun develops sufficient energy to penetrate at the muzzle 47 inches of wrought iron. The battleship is at best but a series of compromises, each factor of the structure yielding or growing as the skill or whim of her designer may indicate. In the present stage of this unceasing change, the gun would appear to be the victor, and the power of this mighty 132-ton rifle seems scarcely needed on the sea. The distinguished chief of ordnance of the United States navy, in his annual report for 1898, says:— “The development of the 12-inch gun has been so great and its power so much increased that the Bureau is of opinion that hereafter it will be the maximum calibre that it will be advisable to install on future battleships.” With armor, as with the torpedo, the talent of Europe reaped where the genius of America had sown. John Stevens of New Jersey was the first inventor of modern times to suggest the application of armor to a floating battery, his plans being submitted to the United States government during the war of 1812. They received, however, no serious consideration, and to France, forty-two years later, fell the honor of attaining the first practical results in the building of ironclads. Members of the Stevens family, however, continued the experiments of its founder, until by the year 1841 they had determined the thickness of iron necessary to stop spherical projectiles at point blank range, and the comparative resisting powers of iron and oak. These results led to an appropriation by Congress, in 1854, of $500,000 to begin work upon an ironclad,—the Stevens battery,—which vessel, however, never left the ways and was eventually broken up. [Illustration: PLATE VI. THE DISTRIBUTION OF ARMOR.] [Illustration: PLATE VII. THE DISTRIBUTION OF ARMOR.] General Paixhans, who revolutionized naval artillery by the invention of the modern shell, prophesied, in an official letter to the French government in 1824, that the new projectile would force the creation of armored ships. In 1841 he recommended officially the clothing of vessels with iron armor, as a protection against his own missiles; and in 1853 his words of warning met complete and terrible fulfillment in the annihilation by shell guns of the Turkish fleet at Sinope. This action was the immediate cause of the introduction of armor in modern navies.