Straight shooting, as in naval war, will be the vital need--that and a cool, quick skill in the manœuvring of a machine. The airship gunners, having a steady firing platform, will be at an advantage over aeroplane crews; but the latter in their turn will have quick manœuvring power and high speed. In the engagement between an airship and several planes, such as is certain to take place, the latter will be in the position of torpedo-boats when they attack a battleship. They will dash in, relying upon speed and the suddenness of their onslaught; and the saving of the craft attacked will rest upon the skill of her gunners. By a vicious, accurate fire they will seek to check the rush; and one or more of their assailants will crumple and fall headlong. The survivors, delivering their fire point-blank into the hull and cars of their opponent, will dive and swerve out of range; and while they are engaging the airship upon either side, one or more of their consorts will climb to a higher altitude, and endeavour to drop bombs upon the airship from above. To prevent them swooping near, as they circle above, marksman will be busy with machine-guns upon the top platform of the airship. Before and after the meeting of the main air-fleets, there will be duels and scattered fighting. Swift raids will be made by bomb-dropping craft, which will sweep above the supply stores of their enemy, attack his troops on the march, or seek to blow up the railway lines along which he is bringing his reinforcements. To drive off these raiders there will be the vigilant patrols; all vulnerable points being guarded by air as well as by land. This aerial fighting, which will wax and wane, dying down only to be renewed with a greater fierceness, must precede the battles of land or sea; and so, while the aerial armies are struggling for supremacy, those moving upon the land, or the fleets steaming upon the water, will be manœuvring for position and creeping stealthily nearer. A conquest in the air, if it be decisive, may spell also a victory upon land and sea. A nation which has its air-fleet destroyed or crippled will lie helpless before the attacks of hostile craft, and will lose also the aid of its aerial scouts and spies. It will fight, therefore, in the dark, assailed by a foe against which it cannot defend itself. All-important will be these aerial battles; granted a country wins supremacy in the air, its blows by land or sea can be delivered with a crushing force, unhampered either by attacks or spying from above. This fact is realised by every War Department of Europe. Aerial warfare is being studied closely; and the first armed craft, though they carry small guns, will pave the way for a powerful, armoured, multi-engined cruiser of the clouds.