Thermal radiation of fused quartz.—The peculiarity of pure fused quartz in that it does not visibly radiate at all until its temperature nears the fusion point is explained by the displacement, with increasing temperature, of the ultraviolet absorption band toward the visible.

Selective thermal emission of neodymium oxide dissolved in quartz.—Quartz-neodymium rods, containing neodymium oxide were prepared. When heated they emit a radiation consisting of seven distinct bands. The wave-lengths of the centers of the bands are 8730, 8270, 7504, 6717, 5944, 5340, 4570A. Absorption measurements show bands in the same positions. A method for preparing the neodymium-quartz is described.

• Received 22 June 1931

DOI:https://doi.org/10.1103/PhysRev.38.487