We understand the possibility of determining their shapes, their distances, their sizes and
their movements; whereas we would never know how to study by any means their chemical composition,
or their mineralogical structure, and, even more so, the nature of any organized beings that might
live on their surface. In a word, our positive knowledge with respect to the stars is necessarily
limited solely to geometric and mechanical phenomena [...]
I persist in the opinion that every notion of the true mean temperatures of the stars will
necessarily always be concealed from us
—Auguste Comte, Cours de Philosophie Positive, 1835
One important object of this original spectroscopic investigation of the light of the stars and
other celestial bodies, namely to discover whether the same chemical elements as those of our earth
are present throughout the universe, was most satisfactorily settled in the affirmative [...]
a common chemistry, it was shown, exists throughout the universe.
—Publications of Sir William Huggins's Observatory (1909), Vol. 2, 49, in a footnote commenting on reprint of William Huggins and Dr. Miller, On the Spectra of Some of the Fixed Stars, Philosophical Transactions (1864)
