Great changes had taken place at Pau since my first visit six months before. The school had been improved and enlarged. Permanent sheds had replaced the canvas hangars, and the German prisoners had built a narrow-gauge railway from the town out to the field. The trains ran out to the aviation school every morning and afternoon, and returned before luncheon and again in the evening. This was a great convenience for many of us and in bad weather saved us many a long, weary walk. When the days were clear, however, we often made the journey on foot, as in this way we had sufficient exercise to keep us in good physical condition. Only men who had already qualified as pilots or who had had previous experience at the front were allowed at the Ecole de Combat. We enjoyed practically the same liberties as at the front. We were free to go where we pleased, except during the working hours, when strict attendance and discipline were enforced. I thought that my previous experience with the heavier machines would enable me to omit some of the more elementary courses, but this was not the case. I had to start at the very bottom. The management of a monoplane or of a small Nieuport is more delicate than anything I had ever tried, and the pilots have, therefore, to acquire a new "sense of touch" which is not required when flying in the larger biplanes. [Illustration: A Penguin.] My first assignment was to a Penguin, so called because it is nothing more than a Blériot monoplane with its wings cut down so that it cannot fly. The Penguins, however, are just as difficult to manage as a full-fledged flying-machine, for on the ground your movements have to be more rough than when flying in the air. There are so many irregularities and air currents to affect your course that you have to be very quick with the controls. The Penguin, besides, does not answer the rudder as easily as the other types. I found that it was very difficult to keep a straight course when tearing across a field at the rate of about forty miles an hour. It was comical to see how the clumsy contraption behaved, turning circles, making "chevaux de bois," rolling over on its wing, and behaving in every way like a drunken sailor trying to walk on a chalk line. You have to keep your head all the time, because the slightest misjudgment may result in an accident. When engaging a "chevaux de bois," you must turn off your motor instantly, for neglect to do so will probably cause your machine to fall over sideways on its wing. When moving you must constantly keep the tail of the Penguin in the air in an imaginary line of flight, and if the tail is lifted too high you run the risk of sticking the nose of the machine into the ground and turning an unpleasant somersault. It was really interesting to discover how much skill it takes to manage a Penguin. It was several days before I could make the six straight lines required before you are allowed to pass into the next higher class.