freuenhofer

Updated: May 2, 2025

Thus, for example, the ordinary Freuenhofer spectrum of the sun shows us no trace of the element helium, though through other observations at the time of eclipse Professor Lockyer had discovered that element there, as we have seen, some thirty years before anything was known of it on the earth.

Edward Huntington Williams - A History of Science, Volume 5 : Aspects Of Recent Science