Hon. R. J. Strutt (Lord Rayleigh), devised a radium clock to run on this principle, consisting of a vacuum vessel in which was suspended a radio-active substance contained in a tube. At the lower end of the tube are two gold leaves as in an electroscope. Platinum wires extended through the glass and touched the gold leaves. The other end of the platinum wires are extended to connect with the earth. The radio-active substance electrifies the gold leaves and causes them to be extended, and upon being extended they come in contact with the platinum wires and their charge of electricity is lost, being conducted through the wires and dispersed in the earth, and the leaves losing their charge fall by the force of gravity from the wires back to their position near the tube containing the radio-active substance to be again charged, to again move to and touch the platinum wires, and again lose their charge; this process to go on indefinitely. Here, indeed, was Perpetual Motion, except for the fact that further and more refined experiments and investigations demonstrated that radio-active substances are not permanently radio-active, but gradually, though very slowly, lose their radio-activity just as a fire will finally burn out, no matter how slowly it burns, or just as an electric battery will finally lose its charge and become exhausted. This loss, however, of radio-active energy in radio-active substances is so slow that it is said the Strutt clock will run for over one thousand years. But the fact that it will not run permanently, and that the motion is the result of energy supplied by the radio-active substance, and is not supplied by the mechanism itself, deprives it of any right to be called a solution of the problem of self-motive power. It should be noted that Hon. R. J. Strutt (Lord Rayleigh) of England, who devised the radium clock, above mentioned, is not to be classed with the ordinary Perpetual Motion enthusiast. He was, and is, in fact, a man of very great scientific ability and attainments, and has to his credit many actual and splendid achievements demonstrating him to be a genius of the rarest and most exalted type. His radium clock is founded on correct principles, and surely a clock that will run one thousand years without having power supplied from an outside source is worth while. It should be here also mentioned that the force derived from radio-activity in the manner it is applied in the Strutt clock is very slight, and the instrument necessarily extremely delicate. CHAPTER IX Perpetual Motion Devices Attempting Its Attainment by a Misconception of the Relation of Momentum and Energy