Page 650 - 89 history of astronomy_opt

are differentiated by the character of the ab-
sorbent vapours of their atmospheres.
It is very likely that, after the chemists
have taught us how to interpret all the va-
rieties of spectrum, it will be possible to as-
cribe the different spectrum-classes to dif-
ferent stages in the life-history of every star.
Already there are plenty of people ready to
lay down arbitrary assumptions about the
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