My next climb to six thousand feet was better. In fact, I felt a certain degree of confidence. It took me somewhat longer to mount to the required height, because some clouds came up and I had to search for a hole through which to pass. Everywhere below me, as far as my eyes could reach, was a sea of clouds. The sun was shining on their snowy-white crests. It looked for all the world as though I was looking down upon an enormous bowl of froth. The following morning was the day fixed for my ten-thousand-foot ascension. The atmosphere was remarkably clear, and I felt an extraordinary sense of freedom and power as I rose from the ground. The earth below me was bright with color. As I climbed higher the shades became less brilliant. At ten thousand feet all color had vanished. The only hue visible was a varying degree of shading, gray and black. Below me I could make out the city of Chartres. Forty miles away lay Orléans. To one side, the Loire wound its course in a gray, ribbon-like band. On all sides the straight, white roads were merely blurred streaks in the murky mass. A few days later I started on my endurance test, the triangle, in company with five other machines. In this flight of two hundred and fifty kilometres I had to make landings at two towns where there were aviation-fields, and the third my own field. At each place I had to report to the aviation officer in charge and have my papers signed. In case of a breakdown on this flight I had forty-eight hours in which to make the necessary repairs and complete the test. [Illustration: A Farman artillery-machine.] The day of my triangle was a poor one for flying. It was the first warm morning of early spring and the sun was just soaking the moisture out of the ground. The air was, in consequence, spotty and there were many "remous," or whirlpools. These whirlpools often cause a sudden "perte de vitesse" and are therefore very dangerous. The machine is sailing along quietly and smoothly, when suddenly the controls become lifeless. You glance at your speed-indicator and at your engine-speed. Both show that the machine is travelling well above the minimum safety speed. This is apt to puzzle the beginner, for without warning there follows a sudden jolt. Your machine trembles like a frightened horse and unexpectedly leaps forward again. On a day like this you have to fight the machine all the time to maintain its equilibrium.