Mr. Barlow has so arranged a globe, as to identify the dip of the needle with electricity, a current of which appears to be always passing round the earth. At G, in the opposite diagram, is a globe having a wire covered with silk, coiled entirely over it, from one pole, round and round to the other. The ends of this wire dip into two cups, P and N, connected with the poles of a galvanic battery. When the current passes from this, the small and delicately balanced magnets, _m_, will show polarity, and dip, just the same as in the earth itself. [Illustration] Mr. Bain’s electric clock is a remarkable contrivance. Nothing can be more satisfactory or complete. Allowing for wear and tear of materials from friction, and the oxidating influence of the atmosphere, the perpetual motion appears to be realized. As long as the electricity of the earth continues, or, in other words, as long as the laws of nature last, so long will Mr. Bain’s clock continue its oscillations, and register the transit of time. The pendulum conducts, and is the treasury of that power, and two simple wheels and their attachments, with the dead escapement, complete the machine. By an ingenious provision, Mr. Bain’s electric clock at the manufactory extinguishes the gas-light which illuminates its dial, at half-past twelve precisely. Mr. Bain has invented and patented another kind of electric clock, the clock being in Glasgow, and the pendulum in Edinburgh. By means of the electric telegraph along the railway, constructed by Mr. Bain, he intimated his wish that the pendulum at the other end of the line should be put in motion. The clock was placed in the station-house in Glasgow, the pendulum belonging to it in the station-house at Edinburgh, the two being forty-six miles apart. They were joined by means of the wire of the telegraph, in such a manner as that, by a current of electricity, the machinery of the clock in Glasgow was made to move correctly, according to the vibrations of the electrical pendulum in Edinburgh. Thus, in like manner, were England and Scotland united in one great chronometrical alliance, a single electrical pendulum of this description, placed in the Observatory at Greenwich, would give the astronomical time correctly throughout the country. [Illustration]