There is force and weight in these contentions, yet they are not conclusive. If the navy were itself a new invention, a very similar kind of argument might be used to subordinate it to the army. The main business of the navy, it might be said, is to supply the army with transport facilities and mobile gun-platforms. But this is absurd; the sea will not submit to so cavalier a treatment. Those who believe in a single air force base their opinion on certain very simple considerations. As the prime business of a navy is the navigation of the sea, so, they hold, the prime business of an air force is the navigation of the air; all its other activities depend on this. The science of aeronautics is yet in its childhood; its development must not be cramped by tying it too closely to a service which works under narrower conditions. If there should be another great war (and though no one desires it, no one dares to think it impossible), the fittest man to hold the command of united land and sea forces might well be a Marshal of the Air. But the strongest argument for a single air force is not so much an argument as an instinct. Every kind of warfare develops in men its own type of character. The virtues of the soldier and the virtues of the sailor are not the same; or, if they are the same (for courage and duty can never be superseded), they are the same with surprising differences. The soldier is drilled to fight men when the occasion arises; the sailor is at war all his life with the sea. The character of the sailor--his resourcefulness and vigilance, his patience and stoicism, his dislike of formality--is put upon him by his age-long conflict with his old enemy. In seafaring men there is a temper of the sea, admired by all who have ever made acquaintance with it. Those who were privileged to watch the performance of our flying men in the war know that there is developed in them a temper not less remarkable and not less worthy of cultivation--the temper of the air. War in the air demands a quickness of thought and nerve greater than is exacted by any other kind of war. It is a deadly and gallant tournament. The airman goes out to seek his enemy: he must be full of initiative. His ordeal may come upon him suddenly, at any time, with less than a minute's notice: he must be able to concentrate all his powers instantaneously to meet it. He fights alone. During a great part of his time in the air he is within easy reach of safety; a swift glide will take him far away from the enemy, but he must choose danger, and carry on. One service cannot be judged by the standards of another service. A soldier who knows nothing of the sea might easily mistake naval discipline for lack of discipline. A like mistake has often been made by those who are brought into casual relations with the air force. But the temper of the air force is a new and wonderful thing, born of the duties and dangers which war in the air has brought with it. To preserve that temper as a