What, however, above everything else, specially distinguishes the _Dreadnought_ from all other warships afloat, is her terrific battery. Hitherto four 12-inch guns have formed the standard main armament for all battleships. The _Dreadnought_ carries ten 12-inch guns of a new and more powerful type than any heretofore in existence. They are mounted in pairs in “redoubts,” armoured with Krupp steel eleven inches thick, and are so grouped on board that when fighting broadside-on with an enemy, eight of the ten guns will bear on the enemy and be in action throughout. In chase, or fighting end-on, six of the guns are available at all times. The firing charge per gun of “modified” cordite weighs by itself 2 cwt.—the weight of a sack of coals on a street coal-cart. In the hour of battle each discharge from the _Dreadnought’s_ broadside will hurl into the enemy three tons of “metal”—bursting shells—each shell being from three to four feet long, and weighing singly 7½ cwt. With each shot also, bang goes £80, the cost of the cartridge and its projectile. Twelve thousand yards will be the _Dreadnought’s_ chosen range for engaging—six miles—about as far as clear vision is possible above the horizon. [Illustration: [Curve of flight, or trajectory, of 850 lb. projectile from a _Dreadnought_ 12-in. turret-gun fired with full service charge.]] [Illustration: [The 12-in. gun is about the same weight as an ordinary railway passenger train engine.]] “Mark X” is the official style for the _Dreadnought_ class of 12-inch gun. It is the most powerful piece of ordnance in the world. It weighs upwards of fifty-eight tons, about the weight of a larger “tank” railway engine of the kind that brings the suburban bread-winner up to London every morning. Its muzzle velocity—the speed at which the shot flashes forth from the gun—is 2900 feet (966⅔ yards, or well over half a mile) in a second. The force with which the shot starts off is enough to send it through a solid slab of wrought iron set close up in front of the muzzle of the gun 4¼ feet thick. When fired with full charges, each gun develops a force able to lift the _Dreadnought_ herself bodily nearly a yard up, exerting a force equivalent to 47,697 “foot-tons,” in gunnery language. The entire broadside of eight 12-inch guns, fired simultaneously, as at the gun trial off the Isle of Wight, develops a force sufficient to heave the huge vessel herself, 21 feet up—nearly out of the water, in fact. [Illustration: [Extreme range of the _Dreadnought’s_ turret-guns:—Fired from in front of St. Paul’s Cathedral.]]