Band Spectrum of Chlorine or Hydrogen Chloride

IN the Zeitschrift fur Physik for August, Kondratjew and Leipunsky describe the emission spectrum of chlorine heated in a silica tube to about 1000° C. I compared their photograph with one taken by W. West and myself in 1924 of the flame of chlorine burning in hydrogen, which shows a continuous spectrum with a maximum at 480 μμ. I could find no record of the brand of plate used, so asked two honours students, Messrs. Reid and Soutar, to obtain a new photograph and compare it with the one obtained by simply heating chlorine. To my surprise a beautifully clear band spectrum was obtained.