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Darwin Correspondence Project

To G. H. Darwin   [before 25 October 1881]1

[66 Hills Road, Cambridge.]


Ask Lord R. whether gas-men in testing light, exclude the diffused light; for I suppose that they cannot always make the trials in the same room, & therefore with exactly the same amount of diffused light—2


The date is established by the relationship between this note and the letter to Julius Wiesner, 25 October 1881.
John William Strutt was the third Baron Rayleigh. In recent experiments on the response of plants to light, Julius Wiesner had claimed that the intensity of light was not proportional to the distance of the plant from the source (see Wiesner 1881, p. 78); George suggested that the presence of diffused light might account for Wiesner’s results (see letter to Julius Wiesner, 25 October 1881).


Wiesner, Julius. 1881. Das Bewegungsvermögen der Pflanzen. Eine kritische Studie über das gleichnamige Werk von Charles Darwin nebst neuen Untersuchungen. Vienna: Alfred Hölder.


Will GHD ask Lord R[ayleigh] whether "gas-men in testing light, exclude the diffused light".

Letter details

Letter no.
Charles Robert Darwin
George Howard Darwin
Sent from
Source of text
DAR 210.1: 115
Physical description
AL 1p

Please cite as

Darwin Correspondence Project, “Letter no. 12961,” accessed on 31 March 2023,