Apologies for this error--I've gone back and verified that you are correct, Eddington was indeed talking about variable stars generally, not pulsars specificall

Apologies for this error--I've gone back and verified that you are correct, Eddington was indeed talking about variable stars generally, not pulsars specifically. Eddington brings up this issue in "The Internal Constitution of the Stars" (1920), and discusses at length why the eclipse theory doesn't hold up: "There are certain stars, known as Cepheid variables, which undergo a regular fluctuation of light of a characteristic kind, generally with a period of a few days. This light change is not due to eclipse. Moreover, the color quality of the light changes between maximum and minimum, evidently pointing to a periodic change in the physical condition of the star. Although these objects were formerly thought to be double stars, it now seems clear that this was a misinterpretation of the spectroscopic evidence. There is in fact no room for the hypothetical companion star; the orbit is so small that we should have to place it inside the principal star. Everything points to the period of the light pulsation being something intrinsic in the star; and the hypothesis advocated by Shapley, that it represents a mechanical pulsation of the star, seems to be the most plausible. I have already mentioned that the observed period does in fact agree with the calculated period of mechanical pulsation, so that the pulsation explanation survives one fairly stringent test. But whatever the cause of the variability, whether pulsation or rotation, provided only that it is intrinsic in the star, and not forced from outside, the density must be the leading factor in determining the period. If the star is contracting so that its density changes appreciably, the period can not remain constant. Now, on the contraction hypothesis the change of density must amount to at least 1 percent. in 40 years. (I give the figures for 8 Cephei, the best-known variable of this class.) The corresponding change of period should be very easily detectable. For 8 Cephei the period ought to decrease 40 seconds annually." You can find the article at: https://www.jstor.org/stable/6491 https://www.jstor.org/stable/6491