Yesterday my observer and I had an extraordinary experience when chasing an Albatross biplane. While behind his own lines the Boche was some 12,000 feet up, and when we first saw him our machine was some 2000 feet lower. The German tried to get away and dive home. There was no chance of catching him at the time, so we turned away and went and hid in a big cloud, in the hope that the German would come back to continue his work in our absence. This of course is quite an ordinary manœuvre and usually works. Once inside the cloud, however, trouble began, as it rapidly developed into the worst type of thunderstorm cloud, in which the air currents are very rapid and revolve in a most disconcerting manner. It was also very wet and cold, and quite dark. This made flying extraordinarily difficult, and after a short time we had not the faintest idea where we were or whither we were going. Things started falling about inside the nacelle, and it was soon quite obvious that the machine was flying or falling on anything but a level keel. Finding my automatic pistol trickling between my legs, I turned my eyes inside the machine and anxiously watched the instruments, which I was horrified to see were behaving very oddly; for instance, the compass was gyrating madly, like a puppy chasing its own tail; the aneroid-needle, which was supposed to show our height above ground, was quivering with the rapid variations of atmospheric pressure, but yet enabled me to grasp the alarming fact that the earth was approaching at an extremely rapid rate. The speed indicator, which in this particular aeroplane consisted of a column of red liquid actuated by pipes, connected with a special type of nozzle fixed on one of the struts of the machine, amused itself by gurgling up and down between thirty and a hundred miles an hour; and the red liquid added injury to insult by spilling itself over my new breeches. Besides this, the rudder, the elevators and the balancing ailerons sometimes took effect and sometimes did not; all of which added to the terror of the approaching flashes of lightning, the horrible feeling of being utterly unable to control the machine, which was by this time careering about in the noise and darkness like a frightened horse. The German aeroplane, too, was known to be about, and there might well have been an awful collision, without a second’s warning, in the middle of a thunderstorm cloud. Suddenly the observer looked round with a grin and pointed to a light patch in the darkness; this rapidly cleared, and, as the visibility increased, I recognised one of the canals. It was not underneath me, as one might expect; it was right out, beyond one wing-tip. The machine, therefore, was obviously falling in a quick spiral towards the canal.