When a mass of high explosive is detonated upon a firm, resisting body, like the earth, or the deck of a battleship, or armor-plate, the effect is to rebound from the resisting body with small result. For example, when a mass of high explosive is set off on the earth's surface, the ball of incandescent gases bounds upward, spreading out in the form of an inverted cone. While it will blow a hole of considerable size into the ground, still the effect in a horizontal plane is practically nil. The windows of buildings standing in the vicinity of an explosion of this character are not blown inward, but are blown outward in the direction of the explosion by atmospheric reaction. At Sandy Hook, several years ago, an experiment was tried with two hundred pounds of guncotton exploded against a twelve-inch plate, immediately back of which were placed a cage containing a rooster and a hen, and another cage containing a dog. The guncotton was hung against the plate and detonated. The effect upon the plate was nil. On examination, it was found that the dog and the two fowl had been made rather hard of hearing. That was the only noticeable effect upon the animals. We all remember the test of the big, eighteen-inch Gathmann gun at Sandy Hook about twelve years ago, which threw a bomb containing six hundred pounds of compressed guncotton that was exploded against the face of a twelve-inch Kruppized plate. The first shot produced no visible effect except a yellow smudge on the face of the plate. It took three shots even to crack the plate and to shift it in its setting. In competition with the Gathmann gun, a twelve-inch army rifle was fired against another plate of the same size and thickness and mounted in the same manner. The projectile contained only twenty-three pounds of Maximite. Yet, as the projectile penetrated the plate before the Maximite was exploded, a hole was blown through it a yard wide, and it was broken into several pieces. These tests proved the effectiveness of even a small quantity of high explosive when properly confined, as by explosion after penetration, and the utter ineffectiveness of a large mass of high explosive when not confined or when exploded on the outside of a body. Bombs carried by an airship and dropped upon the deck of a battleship may damage the superstructure a little, but they can have no material effect upon the ship itself, unless they are made heavy enough and strong enough, with the proper armor-piercing shape, and are dropped from a sufficient height to pierce the deck. Not unless the bomb can be made to penetrate an object before exploding can it effect much destruction. At Santiago, the _Vesuvius_, with its pneumatic guns, threw several six-hundred-pound bombs, and exploded them on the Spanish fortifications, but the effect was wholly insignificant.