From:
John Henry Dallmeyer
To:
Sir John Herschel
Date:
[14 February 1867]
Source of text:
RS:HS 6.3
Summary:
Has not had time until now to carry out experiments on 'the central spot' as seen in photographs as related in JH's last letter. His recent trials with various lenses have verified JH's theories.
Contributor:
John Herschel Project