The instruction in this way progresses rapidly. The "moniteur" first takes each pupil for a few rides to see how the latter takes to the air. The élève must follow every move of his pilot, until he appears perfectly at home in the machine, and then he is allowed to hold the controls alone. Each flight lasts only about five minutes, the French theory being that an aviator must take his instruction in small doses. In the interim, as in the preliminary courses, he remains on the field, observing and studying the mistakes of his comrades. If the progress of the instruction is too rapid, the pupil has not the time to grasp each step that has been passed and cannot, therefore, become an expert pilot. The double control works in this way: The controls and the pedals of the pupil are a duplicate set of those of the "moniteur," or instructor, and have the same connections with the engine and steering apparatus. Either set will steer the machine. The pupil takes hold of the controls and places his feet on the pedals. Every motion of the instructor is reproduced in the pupil’s control and pedals—their hands and feet move together. In this way the pupil develops a reflex action and instinct for doing the right thing. Each day, weather permitting, at least half a dozen flights are made by a pupil. Gradually the "moniteur" allows him to control the machine. Suddenly he finds himself running the biplane alone, with his instructor riding as a passenger behind him and merely giving him a word of advice or caution from time to time.