After several trial journeys have been made, and the novice is no longer embarrassed by the strangeness of his position, he is allowed, by his instructor, to exercise temporary command over the aeroplane while it is in flight. This is accomplished by means of a dual control; a set of levers are before the pilot, and another in front of the pupil. The former, after warning his charge to be ready, relinquishes his hold upon the levers, and the pupil takes charge of the machine. The instructor, of course, keeps a keen eye upon the behaviour of the machine; should the pupil make an error, the pilot is able to rectify it before there is any chance of an accident. By this admirably practical system, a pupil can be led to a satisfactory state of proficiency without risk, either to himself or to his instructor. After he has controlled the machine, for a spell, during straight flights, he is given the opportunity of making a turn in the air. This operation requires the exercise of skill and judgment. Apart from moving the rudder, or rudders, which send the machine round, the pilot needs to operate his "ailerons," or wing-warping device, as the case may be, in order to "bank" the machine over, and so facilitate the turning movement. As soon as he shows sufficient skill in controlling an aeroplane, while with a pilot, the pupil is given an opportunity of flying by himself. As a rule, his previous tuition has been so valuable to him that he finds little difficulty in performing a solo flight, and so prepares himself for the obtaining of his certificate from the French Aero Club. This certificate of proficiency is obtained by making a series of flights before official observers, and in maintaining a certain altitude, while so doing. A descent has also to be made with the engine of the machine stopped, so as to demonstrate the pilot’s ability to effect a _vol plané_. In the case of a civilian airman, the passing of this test is considered sufficient evidence of his ability to control a machine; but, as regards French military airmen, a greater degree of proficiency is required. Therefore, when he has acquired his Aero Club certificate, the officer-airman has to prepare himself for another ordeal. The French military authorities demand that he should make a long flight across country, that he should remain in the air for a couple of hours without descending, and that he should demonstrate his capabilities by piloting his machine in a fairly-high wind. After this, he is regarded as a man well qualified to study the actual work to be undertaken by an airman in war-time. The next stage, as a matter of fact, is in learning to observe over a given tract of country. In this test of his skill, a superior officer indicates for him an aerial route, which covers a fairly-wide district in the vicinity of the air-station. The pupil flies over this, and, on his return, presents a report upon what he has seen while in the air.