Hot spark spectra of yttrium and zirconium.—Using aluminum electrodes, first with yttrium oxalate and borax fused into their cores, and second with zirconium hydroxide replacing the yttrium oxalate, the hot spark spectra of ${\mathrm{Y}}_{\mathrm{III}}$ and ${\mathrm{Zr}}_{\mathrm{IV}}$ have been identified and the series relationships and term values analyzed. The results are tabulated. In these stripped atoms the normal position of the electron is in a $4d$ orbit rather than in a $5s$.

• Received 28 July 1926

DOI:https://doi.org/10.1103/PhysRev.28.923