Elihu Thomson, an engineer at Thomson-Houston (later General Electric), files a patent application in 1892 (US 500,630) for a circuit that applies a transverse magnetic field to a direct-current arc, rhythmically extinguishing it to generate alternating currents of up to 50 kHz. This is the first patented record of generating high-frequency oscillations by means of an electric arc, and the architecture William Duddell acknowledges as the basis of his own singing arc in 1900.