RECORD: Darwin, Francis. [ny].12.03. Cress. CUL-DAR209.7.40. 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).
[40]
Dec 3 Cress
10 AM exposed to yellow light {all slightly converging to centre
12 about C.D. looked & certainly no effect
2.30 no bending to be seen— I did not make a note at time but am fairly sure I think it is right
2.30 pure water instead of chromate.
3.45 slightly bending evident towards light.
5.15 distinct & well marked bending
Temperature of water in screen 24 C°
yellow light produced by sending the light from a big duplex paraffine lamp through a layer thick of bichromate of potassium solution. Distance from edge surface of lamp chimney to surface of vessel full of chromate is about inches. Pot is inside box against the opening of which vessel of chromate fits pretty well.
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 25 September, 2022