From:
Sir John Herschel
To:
Photographic News
Date:
[7 February 1864]
Source of text:
TxU:H/L-0303; Reel 1054
Summary:
Asserts that a process for obtaining 'Turnbull's blue' recently published in PN was discovered and published in 1842 by JH. Adds a second case in which JH anticipated another author's result.
Contributor:
John Herschel Project