Tesla’s latest invention is a device for producing almost incalculable electrical vibrations. By its use Mr. Tesla has been able to demonstrate the scientific possibility of producing brilliant illumination by means of vacuum tubes that were not in mechanical contract with the electric source. Under the influence of a current of electricity interrupted sixty million or eighty million times a second the tubes with which Mr. Tesla was experimenting burst into brilliant white light, which was demonstrated by photography to be much more powerful than the arc electric light, although the tubes were entirely disconnected and stood so far away from the exciting coils, that the inventor sat in a large armchair between the tubes and the coil while he was photographed by the light of the tubes.