On the presence of sulphur in some of the hotter stars

In connection with a particular study of the green region of stellar spectra, photographs of the spectra of several of the brighter stars have recently been obtained at Kensington, using the two 6-inch Henry prisms. An excellent photograph of the spectrum of Rigel is amongst those secured, and the increased dispersion available has afforded evidence which abundantly verified my previous conclusions as to the presence of sulphur in the hotter stars. With regard to the occurrence of sulphur, I stated in ‘Inorganic Evolution,' p. 169, “The evidence also suggests sulphur, and this is all the more probable because of the simplicity of its spectrum series." In the course of the reduction to wave-lengths of the lines in this recent Rigel photograph, an isolated clearly defined line was found at aboutλ 4815·7, which had not been observed in any previously studied stellar spectra. Reference to Watts’ ‘Index of Spectra’ showed that there was a strong line of sulphur close to that position recorded by Hasselberg. On referring to Eder and Yalenta’s record of the sulphur spectrum, a strong line was found of wave-length 4811·967. This was so large a discrepancy from Hasselberg’s wave-length that a Kensington photograph of the spark spectrum of sulphur was examined, and a very strong and isolated sulphur line was found atλ 4815·3 as nearly as could be estimated. It thus became fairly obvious that the wave-length 4811·967 given by Eder and Yalenta was, for some reason or other, in error. Dr. Eder was communicated with in reference to this line, with the result that he explained the discrepancy as being due to a clerical error in publishing the wave-lengths. It should have been 4814·967.