, 1910 In 1890, he began research at the
Kenwood Astrophysical Observatory, which Hale's father had built for him; he was professor of
astrophysics at
Beloit College (1891–93); associate professor at the
University of Chicago until 1897, and full professor (1897–1905). He was coeditor of
Astronomy and Astrophysics, 1892–95, and after 1895 editor of the
Astrophysical Journal. He also served on the board of trustees for Science Service, now known as
Society for Science & the Public, from 1921 to 1923. In 1908, he used the
Zeeman effect with a modified spectroheliograph to establish that
sunspots were magnetic. This systematic property of sunspot magnetic fields is now commonly referred to as the "
Hale–Nicholson law," or in many cases simply "Hale's law." Hale spent a large portion of his career trying to find a way to image the solar corona without the benefit of a total solar eclipse, but this was not achieved until the work of
Bernard Lyot. In October 1913, Hale received a letter from
Albert Einstein, asking whether certain astronomical observations could be done that would test Einstein's hypothesis concerning the effects of gravity on light. Hale replied in November, saying that such observations could be done only during a
total eclipse of the Sun. == Founding and organizing of institutions ==