In the course of an investigation on the spectra of certain light elements in the region 2000 Å to 900 Å, some bands due to hydrogen were observed. The bands have, as far as I know, not been described before, although some of the stronger lines have been measured by Lyman and given as lines probably belonging to hydrogen. On the reproduction in a later paper by Lyman, the stronger lines of the bands can be seen. The discharge tube was of a special type, being constructed for the investigation of the spectra of easily evaporating metals and other substances. The discharge usually took place inside a molybdenum box, along the axis of which is suspended a heated tungsten wire. Currents up to 2 amps, can pass through the gas from the tungsten wire to the sides of the molybdenum box under varying potentials, from a few volts up to about 400 volts. The pressure of the gas (or vapour) inside the discharge box was of the order of 0.1 mm.