Text Online
From:
Darwin, Emma
To:
Litchfield, H. E.
Date:
[10 October 1878]
Source of text:
DAR 219.9: 183
Summary:
No summary available.
Contributor:
Darwin Family Letters
From:
George Howard Darwin
To:
Charles Robert Darwin
Date:
10 Oct 1878
Source of text:
DAR 210.2: 70
Summary:
Recounts the experiments on Fechner’s law he has found in Helmholz; they are on the smallest perceptible differences of illumination. Describes how to test whether plants’ responses to lights are in accordance with it.
Contributor:
Darwin Correspondence Project
