Stripped Oxygen,Ovi, the pp' Group inOv, and New Aluminum Lines in the Extreme Ultra-Violet

Lines of stripped oxygen ${\mathbf{O}}_{\mathrm{vi}}$ and of ${\mathbf{O}}_{\mathrm{v}}$.—The oxygen atom holds its last electrons so tenaciously that hitherto no lines assignable to stripped oxygen have been obtained. Using aluminum electrodes and high resolution, the "lithium doublet" of stripped oxygen has been definitely located at 1031.98, 1037.69A (see Plate I) the component of shorter wave-length being, as usual with this doublet, the more intense. The use of pure Al electrodes has also enabled the $p{p}^{\prime }$ group of ${\mathrm{O}}_{\mathrm{v}}$ to be obtained in the fourth order, definitely resolved as a sextuplet (see Plate II) the ratio $\frac{p_1{p}_2}{p_2{p}_3}$ coming out 2.27, reasonably close to the value 2 called for by Lande's interval rule.