Edison, in common with others, turned his attention to the subject, and took up the neglected incandescent lamp. He improved it by reducing the rod of carbon to a mere filament of charcoal, having a comparatively high resistance and resembling a wire in its elasticity, without being so liable to fuse under the intense heat of the current. This he moulded into a loop, and mounted inside a pear-shaped bulb of glass. The bulb was then exhausted of its air to prevent the oxidation of the carbon, and the whole hermetically sealed. When a sufficient current was passed through the filament, it glowed with a dazzling lustre. It was not too bright or powerful for a room; it produced little heat, and absolutely no fumes. Moreover, it could be connected not in but across the main circuit of the current, and hence, if one should break, the others would continue glowing. Edison, in short, had 'subdivided' the electric light. In October, 1878, he telegraphed the news to London and Paris, where, owing to his great reputation, it caused an immediate panic in the gas market. As time passed, and the new illuminant was backward in appearing, the shares recovered their old value. Edison was severely blamed for causing the disturbance; but, nevertheless, his announcement had been verified in all but the question of cost. The introduction of a practical system of electric lighting employed his resources for several years. Dynamos, types of lamps and conductors, electric meters, safety fuses, and other appliances had to be invented. In 1882 he returned to New York, to superintend the installation of his system in that city. His researches on the dynamo caused him to devise what he calls an 'harmonic engine.' It consists of a tuning-fork, kept in vibration by two small electro-magnets, excited with three or four battery cells. It is capable of working a small pump, but is little more than a scientific curiosity. With the object of transforming heat direct from the furnace into electricity, he also devised a 'pyro-electric generator,' but it never passed beyond the experimental stage. The same may be said for his pyro-electric motor. His dynamo-electric motors and system of electric railways are, however, a more promising invention. His method of telegraphing to and from a railway train in motion, by induction through the air to a telegraph wire running along the line, is very ingenious, and has been tried with a fair amount of success. At present he is working at the 'Kinetograph,' a combination of the phonograph and the instantaneous photograph as exhibited in the zoetrope, by which he expects to produce an animated picture or simulacrum of a scene in real life or the drama, with its appropriate words and sounds.