with the stability of bodies pitching in the air and the internal movements of the wind, and I also revolutionized one leading part at least of the theory of explosive engines. These things are to be found in the Philosophical Transactions, the Mathematical Journal, and less frequently in one or two other such publications, and they needn't detain us here. Indeed, I doubt if I could write about them here. One acquires a sort of shorthand for one's notes and mind in relation to such special work. I have never taught nor lectured, that is to say I have never had to express my thoughts about mechanical things in ordinary everyday language, and I doubt very much if I could do so now without extreme tedium. . . .
My work was to begin with very largely theoretical. I was able to attack such early necessities of verification as arose with quite little models, using a turntable to get the motion through the air, and cane, whalebone and silk as building material. But a time came when incalculable factors crept in, factors of human capacity and factors of insufficient experimental knowledge, when one must needs guess and try. Then I had to enlarge the scale of my operations and soon I had enlarged them very greatly. I set to work almost concurrently on the balance and stability of gliders and upon the steering of inflated bags, the latter a particularly expensive branch of work. I was no doubt moved by something of the same spirit of lavish expenditure that was running away with my uncle in these developments. Presently my establishment above Lady Grove had grown to a painted wood châlet big enough to accommodate six men, and in which I would sometimes live for three weeks together; to a gasometer, to a motor-house,
