The story of the contest can be briefly told. In 1858 the armament of the newest ships was principally a broadside battery of 32-pounders; in this were included a few 56-pound shell-guns and one or two eight-inch 68-pounders, though of the whole number not one had an energy, that is, a force of blow when striking, sufficient to penetrate four and a half inches of wrought-iron at short range. In the earliest iron-clads—the French _La Gloire_ and the English _Warrior_—batteries mainly of nine-inch calibre were carried, the latter mounting forty guns of all kinds. The _Minotaur_, the first representative of the next English type, had fifty guns, but after this class was launched there appeared that distinctively modern tendency to decrease the number of pieces while increasing the intensity of their fire. The succeeding vessels carried from fourteen to twelve pieces, until, in 1874, the principle of concentration reached its maximum in giving the _Inflexible_ only four guns. These, like the _Warrior’s_, were muzzle-loaders, and their relative dimensions and power may be compared as follows: +--------------------------------+----------------+------------------+ | | _Warrior._ | _Inflexible._ | +--------------------------------+----------------+------------------+ | Weight of gun | 4¾ tons. | 80 tons. | | Length | 10 feet. | 26 feet 9 inches.| | Calibre | 8 inches. | 16 inches. | | Powder charge | 16 pounds. | 450 pounds. | | Weight of projectile | 68 ” | 1700 ” | | Energy at 1000 yards | 452 foot-tons. | 26,370 foot-tons.| | Penetration of 4½ inches of | | | | wrought-iron at short range | None. | ... | | Penetration of wrought-iron at | | | | 1000 yards | ... | 23 inches. | +--------------------------------+----------------+------------------+ The term energy, when employed to indicate the work that a gun can perform, is expressed in foot-tons, and signifies that the amount developed is sufficient to raise the given weight in tons to the height of one foot. The piercing power of the _Inflexible’s_ projectile was, under the same conditions of charge and range, sufficient to penetrate twenty-five feet of granite and concrete masonry, or thirty-two feet of the best Portland cement.