Many ingenious men have vainly attempted to apply what has been erroneously called "centrifugal force" as a motive power, conceiving that the effort made by bodies to fly off when whirled round in a circle was occasioned by a force generated by their rotation. The experiment of the "whirling table," which is commonly shown to illustrate centrifugal action, tends to confirm the notion that force is generated; for it is there seen that, when the velocity of rotation is doubled, the centrifugal force is quadrupled, and that it continues to increase in a geometrical ratio. It has, therefore, been conceived that a power might be generated of indefinite amount; for as a double velocity can be communicated by doubling the moving power, whilst the tendency to fly off at the circumference is quadrupled, there appeared to be a creation of power which, if properly applied, would realize perpetual motion. A working engineer known to the author was so fully possessed with the notion that power might thus be created, and that its application would be of the utmost benefit, that he imagined he had been specially appointed to reveal the principle to man, as a boon of inestimable value to the manufacturing arts. The plan he adopted was to employ what he called a generating engine, consisting of a centrifugal pump; and the force with which the water was projected from the ends of two rotating horizontal arms was directed against pistons working in cylinders, as the force of steam is in a steam engine. Having once set this machine in action, he expected to be able, by means of the self-creating centrifugal force, to generate the power that worked the generating engine, and thus to have a reservoir of force of any magnitude constantly at command. So completely satisfied was he of the practicability of the plan, founded, as he supposed, upon one of Newton's laws of motion, and he felt so happy in the thought of being charged with an important mission for the benefit of mankind, that it was almost cruel to attempt to correct his notions of the power of centrifugal force. He spent all his money in endeavouring to realize this impossible project, and even its failure did not convince him of his error. The simple kind of Centrifugal Pump applied in that chimerical scheme was known upwards of one hundred years ago. It consisted of a vertical hollow shaft, into which were inserted two horizontal arms. The shaft was supported on a pivot at the bottom, and was turned by a handle at the top, as represented in the accompanying drawing. The lower end of the vertical shaft was immersed in water, and when rotary motion was given to the machine, the centrifugal action propelled the water from the ends of the arms, and the water rose in the vertical shaft to supply its place. [Illustration]