On the modern battleships the function of the great guns is the penetration of the enemy's armor, either at the waterline belt or on the turrets and gun positions, while that of the rapid-firers is the destruction of the unarmored parts or the disabling of the guns not armor protected. The six, three, and one-pounders direct their rain of shots at the turret portholes, gun shields, or unprotected parts of the ship, having also an eye to torpedo-boats, while from the fighting tops, the Gatlings rain a thousand shots a minute on any of the crew in exposed positions. With such a storm of large and small projectiles it would seem to be rather a question of who would be left alive rather than who would be killed. The guns in use in the United States navy are the 13-inch, 12-inch, 10-inch, 8-inch, 6-inch, 5-inch, 4-inch, 6-pounders, 3-pounders, 1-pounder, Hotchkiss 37 mm. revolver cannon, and the machine guns. In the following table is given the length and weight of these guns, as well as of the shell they carry: Length Powder weight of gun, charge, of shell, GUNS. feet. pounds. pounds. One-pounder 5.1 .3 1 Three-pounder 7.3 1.7 3 Six-pounder 8.9 3.0 6 Fourteen-pounder 11.6 8.0 14 Four-inch 13.7 14.0 33 Five-inch 17.4 30.0 50 Six-inch 21.3 50.0 100 Eight-inch 28.7 115.0 250 Ten-inch 31.2 240.0 500 Twelve-inch 36.8 425.0 850 Thirteen-inch 40.0 550.0 1,100 HOW THE BIG GUNS ARE USED. The 14-pounder, although not included in the navy armament, is given for the purpose of comparison, since it is with guns of this caliber that some of the Spanish torpedo-boat destroyers are armed. The largest gun as yet mounted on our largest torpedo-boats is the 6-pounder, while a single 1-pounder is the gun armament of the ordinary torpedo-boat. The Hotchkiss revolver cannon is not given in the table because its caliber, etc., is the same as that of the 1-pounder, and, in fact, the latter has superseded it in the latest armaments, so that it is now found only on the older ships of the modern fleet. The machine guns are not given because their effective work is practically the same. The Gatling is of 45-caliber, and uses the government ammunition for the Springfield rifle. A look over the table shows some general principles in the matter of powder and shell used. The powder charge is about half the weight of the shell, while the length of the shell is a little over three times its diameter.