experiment, at first with models, and then with full-scale machines. The dangerous work of trying conclusions with the air fell to the young men of the factory. A brilliant young Cambridge man, Mr. E. T. Busk, of King's College, who had been trained in the laboratory of Professor Bertram Hopkinson, joined the staff of the factory in the summer of 1912, having previously spent a month at the National Physical Laboratory, to acquaint himself with the work there. He understood the theoretical basis of aeroplane design, and he was a daring and skilful pilot. The R.E. machine was designed by the staff of the factory; Mr. Busk, in collaboration with Mr. Bairstow, worked at the problem of giving it stability. He cheerfully took all risks in trying the full-sized machines in the air. When the R.E. 1 had been theoretically warranted, by experiments with models, to right herself after a nose-dive, he tested the theory by flying the machine to a great height, turning her nose down and letting go the controls. As he expected, she righted. To test the machine he flew her in all weathers, hurling her against the wind storms. For the purposes of these practical tests he invented an instrument of his own called the Ripograph, which recorded on a single strip all the pilot's movements in warping and steering, as well as the speed, inclination, and roll of the machine. This machine, when the rudder was turned right or left, automatically banked itself; and when the engine was cut off, took the angle of gliding flight. It was a later variant of the same machine, an R.E. 8 belonging to the Australian Flying Corps, of which it is told that, when the pilot and observer had both been shot dead, in December 1917, the machine continued to fly in wide left-hand circles, and ultimately, when the fuel was exhausted and the engine stopped, fell near St.-Pol, some thirty miles from the scene of combat, without completely wrecking itself. When the war broke out Mr. Busk was more than ever needed at the factory. On the 5th of November 1914 he mounted in an experimental B.E. 2c machine to a height of about eight hundred feet. Exactly what happened will never be known; the petrol vapour must have been ignited by a spark; the machine burst into flames, and after drifting aimlessly for a time, fell on Laffan's Plain. The death of such men as Charles Rolls and Edward Busk was a part of the heavy price that had to be paid for victory; before victory was in sight. There was no other way; the work that they did could not be spared, and could never have been even attempted except by the quiet of absolute courage.