One of the spectra had dark lines and the other bright lines.
With 188 Illustrations and a table of Spectra in Chromo-lithography.
Their spectra show a complexity of helium and hydrogen bands.
The spectra of all the Algol variables are of the first or Sirian type.
In the same manner and under similar conditions the spectra of many other substances have been reversed.
Even the spectra of these elements seem to be identical so far as known.
The problem to solve is how to utilize these two spectra now we have got them.
Hydrogen is seen in the spectra of nearly all stars, and also in those of nebulæ.
The signals for colour we might get from the spectra direct.
In all, 15,729 spectra of bright and faint stars have been measured.