Hamilton, California: "I congratulate you on the appearance of this very important book; it is indispensable to all astronomers and students of spectroscopy."
"An Introduction to Chemical Science"
R.P. Williams
spectroscopy showed that the atmosphere was well supplied with oxygen, and so the inhabitants were evidently oxygen-breathing men, unlike those of the Negrian people who live in an atmosphere of hydrogen.
"Invaders from the Infinite"
John Wood Campbell
In the earliest days of spectroscopy the spectra of the stars were classified according to their visual spectra.
"Lectures on Stellar Statistics"
Carl Vilhelm Ludvig Charlier