In a previous paper read before the Society on April 8, 1897, I suggested that the special lines present in spectra of the first division of helium stars (Type I, Divison la) might possibly be clue to oxygen. These stars are associated by their position and distribution with the gaseous nebulae, and some of the lines in their spectra correspond with bright lines observed by Campbell in nebulae. The suggestion from this was that these stars are in the first stage of tellar development from gaseous nebulæ.
A search for variability in intermediate helium stars