RECORD: Darwin, C. R. 1877.09.28-29. Tropaeolum minus / Draft of Descent vol. 1, folio 29. CUL-DAR209.14.157-158. Edited by John van Wyhe (Darwin Online,

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 7.2023. 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-DAR209.14 contains material for Darwin's book Movement in plants (1880). Draft is in the hand of Ebenezer Norman with corrections by Darwin. The text of the draft corresponds to Descent 1: 274 -5.


Sept 28' 1877. Tropæolum minus, moderately young leaf, standing at ∟ angle to light— N.E. window— traced on vertical glass— At Tracing copied by eye roughly — Went for a long time down so as to become almost vertical & cd not be traced & then rose & at after 1° 25, went rather zig-zag— At 3°. 55' I had accident with leaf & ceased tracing.— The great movement to the left in diagram to the light. [sketch]


31 29

Chap. 8

acquired through natural selection from by the more & more eager males continually leaving a larger number of offspring.

The great eagerness of the male has thus indirectly led to the much more frequent development in him of secondary sexual characters in the male than in the female sex. But the acquirement of such characters will have been much aided, if the conclusion 14*(10) at which I arrived after studying domesticated animals can be trusted, namely that the male is more liable to vary than the female. I am aware how difficult it is to verify such a conclusion. Some slight evidence, however, can be gained by comparing the two sexes in man mankind, as man they has been more carefully observed than with any other animal. During the Novara Expedition 15*(11) a vast


Sept 29th 77

Tropæolum minus

Same leaf observed as yesterday, but bristle fixed transversely across leaf so as not to point so low down, leaf being much inclined downwards—

As plant had stood in same position as yesterday, not nearly so much movement to light, as yesterday. First rose & at 9° 50' began to fall; continued falling till 11° 20', after which began to rise & continued at 11° 55° began to zig-zag in rise & sky became brighter with some clouds. till 1° 24', when it fell in curious zig-zag line till 5° 53' after which rose greatly & receded from source of light, after which fell slightly & then abruptly: during night & before next morning 6° 45 a.m Sept. 30 had risen to cross.

A second leaf, at ∟ to light, had bristle fixed transversely & was observed from 8° 23 to 2° 40' when the bristle became detached: course shown on the vertical glass in Fig 2.

[slip of paper pasted on, see CUL-DAR209.14.161.]

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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (

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