Practically all of the unidentified strong lines of boron, carbon, nitrogen, oxygen, and fluorine occurring in the extreme ultra-violet spectra of the vacuum spark have been classified as due to jumps between levels in BI, CI, CII, NII, NIII, OII, OIII, OIV, FI, FII, FIII, and FIV. The levels thus found are correlated with those demanded by the Russell-Heisenberg-Pauli-Hund theory
