The spectrum of neutral chlorine excited by means of a Raytheon Microtherm unit in electrodeless tubes filled with the pure gas has been observed in the region between 10 000 and 25 000 A. A description has been prepared giving wavelengths, wave numbers, and relative intensities of 283 radiometrically observed lines. Newly classified lines selected from a recent set of photographic observations by Corliss in the interval between 7000 and 10 000 A are included. Extensions to the established classification include identification of all 22 of the previously unobserved levels of the family associated with the <sup>3</sup><i>P</i> ion limit, comprising the levels from the 3<i>s</i><sup>2</sup>3<i>p</i><sup>4</sup>5<i>s</i> and 3<i>s</i><sup>2</sup>3<i>p</i><sup>4</sup>3<i>d</i> configuration. From a study of this material, along with his list of wave numbers, Corliss has found fourteen new odd levels. Further systematic combing of the data by useof an automatic computing program has revealed four additional odd levels. The new odd levels originate probably in the 3<i>s</i><sup>2</sup>3<i>p</i><sup>4</sup>4<i>f</i> configuration.
CURTIS J. HUMPHREYS and EDWARD PAUL, JR., "First Spectrum of Chlorine; an Extension Based on Observations in the 7000 to 25 000 A Region," J. Opt. Soc. Am. 49, 1180-1183 (1959)