In my opinion the separation of the c- and ac-stars is the most important advancement in stellar classification since the trials by Vogel and Secchi ... To neglect the c-properties in classifying stellar spectra, I think, is nearly the same thing as if a zoologist, who has detected the deciding differences between a whale and a fish, would continue classifying them together.

In my opinion the separation of the c- and ac-stars is the most important advancement in stellar classification since the trials by Vogel and Secchi ... To neglect the c-properties in classifying stellar spectra, I think, is nearly the same thing as if a zoologist, who has detected the deciding differences between a whale and a fish, would continue classifying them together.