RECORD: Darwin, C. R. & Francis Darwin. [1878].10.31. Phalaris. CUL-DAR209.7.103-104. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 8.2022. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volumes CUL-DAR209.7-8 contain notes on heliotropism (phototropism) for Darwin's book Movement in plants (1880).


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Oct 31 Phalaris

Pots at 2 ft, 4 8 12 16 20 at 9 11-15 am

Pot 6 ft at 10.30

Pots 2 & 8 ft taken out 12. 15 to look at

All pots examined at 2.15 when it was found that lamp had gone out

This of no use

It is certain that 4 ft is bent more* than 2 ft & both more than 6 ft, 6 ft is more than 8, 8, 12 & 16 are almost indistinguishable, when I know which 8 is I can see it slightly more bent — I think the mica dodge is too rough & uncertain

*Pot. 2 ft was taken out for a minute & perhaps or probably was not put back quite true

At what rate does power of sight decrease in man with geotropical decrease of Light.—

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Phalaris

Radius of Curvature in CM

2 ft 2.15 pm cm 1, 1 1/4, (1 3/4 at far end) abt 35 with vertical 40

4 ft 1/2. 1. 1/2/ (1 1/2 far end) anyhow

6 ft 1 1/2, 1 1/4 1 1/2 about 35-40

8 ft 2, 3 1/2, the one most curved is 1 1/2 but clearly more than rest.

12 4, 2 /12 2, 3 difference between 4 & 3 almost impossible

16 2, 2 3 1/2 3

20 bent to door


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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

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