From:
Sir John Herschel
To:
William Selwyn
Date:
[23 October 1869]
Source of text:
RS:HS 24.288
Summary:
Is working on a compilation of the measures of double stars. If [Rudolf] Wolf's period of 11.11 years is correct, why should 1810-11, a minimum, mark the first observations of solar spots?
Contributor:
John Herschel Project