A Note on the Spectra of Doubly and Trebly Ionized Lead

In the spectrum of Pb III three new singlet terms viz. 6s7s¹S₀, 6s7p¹P₁ and 6s7d¹D₂ have been found to give rise to seventeen new lines which are here reported.Certain discrepancies between the classification of terms by A. S. Rao and A. L. Narayan and the writer are discussed.In the spectrum of Pb IV the previously published classifications of lines by J. A. Carroll, A. S. Rao and A. L. Narayan are discussed, and certain anomalies are pointed out. Two schemes different in some respects from those already put forward are suggested.