A high-temperature vacuum furnace using tungsten for container, and heating elements as well, has been designed to study the furnace spectra of high melting point substances. The furnace spectrum of beryllium in both absorption and emission has been observed from $\lambda 2150\mathrm{A}-7000\mathrm{}\mathrm{A}$ and over a range of temperature up to 2500°K. The prediction that the beryllium line 2348.62A is the first line of the principal series of singlets for the neutral atom has been successfully confirmed and the diffuse and the sharp series of singlets of this element discovered and tabulated.

• Received 15 August 1928

DOI:https://doi.org/10.1103/PhysRev.33.16