In such an arrangement as this, the reconnoitring machine would probably be a slow-flying, reliable biplane, equipped exclusively for its work of observation. The fighting machines, on the other hand, would be built for speed. Fast-flying, strongly-built monoplanes would most likely be used; and one prominent constructer suggests that such fighting units should be fitted with a gun firing a small explosive shell, something like a "pom-pom." Such a form of armament would certainly be effective; and such an aerial cruiser is likely to prove a formidable opponent. In connection with the carrying of guns upon an aeroplane, it may be mentioned that a light machine-gun has already been fitted to a biplane; but little has been said about such tests, and nothing definite, in the way of experiments, has, as yet, been recorded. In connection with the aerial battles that are certain to precede the land actions of the future, it is difficult to foresee, exactly, what method will be pursued by the Commanders of two rival Air Battalions. It is fairly clear, however, that each will seek to prevent a hostile aeroplane from coming within observation distance of his forces; and, at the same time, by such strategy as wide detours, each will endeavour to slip reconnoitring craft through the enemy’s lines. In the elaboration of any such plans of campaign, it is obvious that the fighting units of the air-fleet—the fast "cruisers" which will carry machine-guns—will come into speedy conflict. Combat, probably, will resolve itself into a question of manoeuvring for position; then the opponents will open fire. Marksmanship and skill in handling a machine will spell all the difference between victory and defeat. After a preliminary exchange of shots, two machines will sweep into closer range, and then one of them, "winged" by well-directed fire, will be put out of action, and will flutter away earthwards. It is obvious that an exceptionally fast, high-powered aeroplane, capable of rising at a maximum speed, will be most suitable for hostile work against other machines. The question has been discussed as to protecting, with some form of armour, the vital parts of aircraft for offensive work. It seems likely that some such plan will be adopted. II. An encounter in the air—Importance to an army of an aerial victory. It was the late Captain Ferber—one of the first military enthusiasts in France upon the subject of the aeroplane—who was asked the question: "How will a fight take place between aeroplanes?" In reply, this famous pioneer said:—