In that belief I remained for 50 years. Now, at the age of over 80 years, after long rest from business activities, in revising these reminiscences for publication, the idea has first occurred to me, and has grown into a conviction, that my advisers were wrong here as they had been in every other respect. They overlooked the fact that the angular velocity of the driving-joint increased equally with that of the balls, so that the ratio between them would remain constant. The law that the driving force required increases as the square of the speed imparted applies only to the original source of power, as, to the force of the steam exerted in the cylinder of an engine, the motion of the piston remaining the same, and to the transmitting belts or gears whose speed also remains the same. At all these points the force exerted must increase as the square of the speed imparted; but this does not apply to the pressure exerted in the governor joint. Its speed does not remain the same, but increases with that of the balls. So, while the centrifugal force of the balls, changes in which produce the vertical movements of the counterpoise, varies as the square of the speed, the force required to be exerted in this joint to drive the balls, and which produces the friction to retard these movements, does not increase at all, whatever the speed of revolution may be. This fact, unobserved by me or any one else so far as I ever heard, has all the time been the secret, a pretty open secret when once seen, of the surprising combination of sensitiveness and stability in the action of this governor which has led to its general use, and at which I myself have never ceased to wonder because I was ignorant of its cause. This, however, was not the only time that I builded better than I knew. I can imagine some persons, after having read the above explanation, to say, some of them perhaps flippantly, and some possibly sneeringly, “To a properly educated engineer this is obvious at a glance.” I think it will be so hereafter, but has it been so hitherto? If any one will produce the record of its observation I will cheerfully yield to him the priority and will congratulate him upon it.