Since the advent of aviation, many inventors have directed their energies to aërial bombs and bomb-dropping appliances. There have been, from time to time, fearful forecasts of the destruction of warships, coast fortifications, and large cities; for it was claimed that air-craft would be able to drop explosive bombs capable of wrecking the heaviest battleship and of blowing up coast fortifications and utterly laying waste cities and towns. It was predicted that the aëroplane would be able, with its bombs, to scatter armies like chaff before the whirlwind. The hopes of those who have believed in such dire destructiveness of bomb-dropping from air-craft have been dashed to the ground, with the bombs they have dropped. Of course, aviators may drop any form of infernal machine which, on exploding, will mangle by-standers with fragments of scrap iron, but the effect must necessarily be very local. The most effective use aviators can make of bombs and infernal machines is to destroy one another in the sky and to attack magazines and storehouses, wireless stations, hangars, and balloon-sheds within the enemy's lines, and beyond the reach of other means of attack. Also, in connection with the attack of advancing troops, aërial bombs dropped from aëroplanes may be used with effect, especially in disentrenching an enemy. At sea, too, with the latest types of aëroplane, bombs of sufficient size and weight and power of penetration may be used destructively against unarmored or light-armored war-vessels. A more efficient means, however, than has yet been adopted is needed to secure the required accuracy. Naturally, such bombs are admirably adapted to the destruction of dirigible balloons. The swift-winged aviator is able to manoeuvre at will around and above a huge dirigible and to attack it from any quarter. There is probably no one subject about which there is more popular error than concerning the use and destructive effects of high explosives. An anarchist once attempted to blow up London Bridge with two small sticks of dynamite, and succeeded merely in getting himself into trouble. At another time, a dynamiter entered the Houses of Parliament and exploded ten pounds of dynamite in one of the large corridors, with the result that it only made a hole in the floor and smashed a few windows. As a matter of fact, airships are capable of working comparatively small damage by dropping bombs, unless the bombs can be made to hit and penetrate the object struck before exploding, for the reason that, unless confined, explosives have but little effect.