Before you are allowed to fly in a Nieuport and attend the School Aerial Acrobatics there is another requirement. This is a brief period of instruction at the Mitrailleuses School at Casso, where, on the shores of the long lake, the French army has established an ideal range for the training of its pointers. It is less than an hour by rail from Bordeaux and well within the reach of every military depot in the south-western part of France. Each branch of the service has its own course. For the Flying Corps the range consists of a number of captive balloons and of a series of moving targets on the lake. The pupil is taken up as a passenger in a double-seated aeroplane and operates the mitrailleuse. After two or three weeks of this practice he becomes quite used to shooting from an aeroplane and finds that he can score hits almost as easily as if he were on terra firma. In the beginning, however, one experiences great difficulty in adjusting himself to the changes of perspective found in the air. After this the pilot is sent back to Pau, where he has to perfect himself sufficiently in his art to master the various stunts essential in combat-work. Until then he may not go to the front for service in an "appareil de chasse." The first test is looping the loop. The machine is made to dive very fast for a short distance. Then the pilot gives a sharp pull on his controls, which makes it climb very abruptly, at the same time shutting off the motor. The little Nieuport climbs until it loses its speed, and then falls over backward. At the instant of reaching the line of diving the spark is then turned on again and the flight is resumed. The next requirement involves cork-screw looping, or, as they say in French, "le renversement sur l’aile." This requires still greater skill than the previous test. It is not an easy manoeuvre to explain and, besides, I have not yet attempted it myself. The theory, however, is as follows: If you tip your machine enough to fly in a vertical position, your controls become reversed; in other words, the control for climbing and diving becomes the rudder and the rudder becomes the climbing control. To do the "renversement" the machine is put in a vertical position and the spark is shut off. The machine then loses its momentum and starts to fall. At that moment you must give a pull on your control and push the rudder "hard a-port," as a sailor would say. This forces the machine to complete the turn and dive from the normal horizontal position.