TheLSeries Spectra of the Elements from Calcium to Zinc

Using the first inside order of a plane grating (600 lines per millimeter) $L$ lines of the elements Zn, Cu, Ni, Co, Fe, Mn, Cr, V, Ti and Ca have been measured. Separation of the $L_{\alpha }$ and $L_{\beta }$ lines as well as the $L_l$ and $L_{\eta }$ is attained by adjusting the grating so that the angle between the inside order and the plane of the grating is small. Under this condition the angular dispersion is given by $\left(\frac{d\alpha }{d\lambda }\right)=\left(\frac{1}{D\beta }\right)$, where $D$ is the grating space and $\beta$ the small angle between the plane of the grating and the first inside order. The results obtained are somewhat higher than those obtained by crystal measurements but are entirely consistent with the work of other experimenters. The failure of the $L_{\alpha }$ and the $L_{\beta }$ lines to appear in the case of calcium is in accord with Foote's extension of Stoner's arrangement of the electrons. All measurements are absolute.