There is a risk for airmen when they carry a load of explosives. Should they make a bad landing, or fall to the ground and wreck their craft, there is the probability that their bombs would explode from the impact and blow them to pieces. This danger has been realized, and a form of safety bomb is now being used in tests. Each bomb is fitted with a safety catch, and unless this is released the bomb cannot explode, no matter how hard it strikes the ground. The manner in which the catch disengages itself is ingenious. Upon the rear of the bomb is a tiny propeller, which spins in the air as the bomb drops from the machine; and as it turns it uncoils a spring, which releases the safety catch and makes the bomb operative--but not until after it has fallen about 100 feet. Airships, like aeroplanes, are being armed with guns and bombs; and their power of raising weights enables them to carry heavy weapons. Large and highly destructive bombs have been tested in the German airships, being released over the sea and aimed at targets in the form of rafts. Latest-type airships also carry guns in their cars; and the Zeppelins have a platform upon the tops of their hulls, reached by a ladder through the middle of the ship, from which a machine-gun can be fired upward. This is a very necessary precaution, and is intended to frustrate the attack of an aeroplane. It would be the aim of the latter, whenever possible, to manœuvre above its big enemy--as suggested in Fig. 85--and drop a bomb upon its hull. Hence the construction of the top platform of the airship, from which her gunners can direct a vigorous fire aloft. [Illustration: FIG. 85.--Aeroplanes attacking an airship from above.] The ability of an airship to navigate at night, and steal unobserved above the land, gives it grim possibilities as a weapon of destruction. It motors quiet, and no lights showing, it can drift with the wind over a harbour or fortification, and drop bombs which will fall upon those below out of an empty sky. Searchlights would be used, of course, from the positions attacked, and artillery fired upward, but the airship would be a silent, elusive shape--difficult to see and more difficult to hit. Here, though, would be work for land or sea planes. It would be the aim of our Admiralty, upon the outbreak of war, to patrol the coast with a service of armed aircraft. A number of air-stations, at which machines are housed, are already in existence--mainly along the north-east coast. Between station and station the craft would fly in war, providing a continuous patrol, the aim being to shut out hostile craft, and attack a squadron of the enemy, should it approach land.