RECORD: Darwin, C. R. & Francis Darwin. [ny].10.19-20. Nankin cotton. CUL-DAR209.4.276-278. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 9.2022. 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 volume CUL-DAR209.4 contains materials for Darwin's book Movement in plants (1880).
Oct 19 Nankin cotton
Movement of cotyledons observed by fixing glass filament to one cotyledon the stem of this seedling being free. Dots made on a vertical glass by foreshortening the glass fibre The whole pot was covered a with a double cylinder of brown paper with paper lids. The cylinder was removed to make observations. The cotyledon under observation pointed from the light.
[annotated sketch and diagram] glass AD = 180mm AB = 17 AC =. 34
The amount of magnifying power will f vary with different positions, but it can never by less than 180/17 (say 10)
Oct 20 [Figure]
X As the bit of stalk above the collar was growing & bending slightly I thought it would put out the measurement of the angle, so I made a rough sketch of another seedling at night & in morning & it was clear that the cotyledons sunk at night so as to be almost horizontal & rose in the morning.
Nankin Cotton Oct 20
The seedling whose cotyledon was traced Oct 19 has now a collar of paper gummed round the stem below the cotyledons & this is f fastened to a peg. The angle of which the glass filament makes with horizon was then read. X
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 30 September, 2022