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Attraction and Repulsion Exhibited

In order to illustrate certain remarkable facts in this science of an amusing character, attention must be directed to the figure A B, which is a metal stand; c is a small piece of cork or pith, which is suspended from the hook by a dry silken thread. Having rubbed an electric, as a dry rod of glass, and presented it to c, the ball will be instantaneously attracted to the glass and will adhere to it. After they remain in contact for a few seconds, if the glass be withdrawn without being touched by the fingers, and again presented to the ball, the latter will be repelled instead of attracted, as in the first instance. By being touched with the finger, the ball can be deprived of its electricity, and if after this has been done we present a piece of sealing-wax in the place of the glass formerly employed, the very same phenomena will take place. On the first application the ball will be attracted and on the second repelled.(For a more complete account of this interesting science we would refer the young reader to "The Boy's Playbook on Science," or, if more advanced, to "Noad Manual of Electricity.") Before the young reader can perform any very important experiments with electricity, he must become possessed of an ELECTRICAL MACHINE, which is an instrument contrived for the purpose of rubbing together the surfaces of glass and leather. They generally consist of a cylinder, or plate of glass, and a piece of silk or leather for it to rub against, covered with an amalgam, the method of preparing which we shall hereafter describe.