Series spectra of potassium and calcium

Several of the strongest extreme ultra-violet lines in the Kiii, Kiv, Caiv, and Cav spectra are given their series designtion. In Kii several lines are identified in addition to those found by DeBruin. The absolute value of the terms of Kii are determined thus fixing the ionization potential at 31.7 volts. 137 lines are classified in Caiii and the term values of the levels involved are calculated. These correspond to an ionization potential of 51.0 volts.