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Darwin Correspondence Project

To G. H. Darwin   12 October [1873]1

Down, | Beckenham, Kent.

Oct 12th

My dear George

Can you tell me on what inclination a polished or waxy leaf ought to hold to the horizon, in order to let vertical rain rebound off as completely as possible.2 I can see that if it depended at 70o or 80o the rain wd. be apt to trickle down; if at only 10o or 20o the rain wd rebound & fall on leaf again.— Is it known at what angle a surface shd. be inclined, in order that a marble dropped from vertically above shd rebound to the greatest distance. This, I imagine, wd be a guide for rain-drops; & I fancy that 45o wd. be the best inclination for the surface.—

We shall be glad to hear how you are.— In yesterday’s Spectator there is a rather unfavourable review of you; but the writer does the next best thing to agreeing & lauding you, viz he discusses your paper.3

Your affect | C. Darwin

I will ask Mamma to send you the Spectator.

Footnotes

The year is established by the reference to an article in the Spectator (see n. 3, below).
CD was interested in whether some plants moved their leaves to throw off water more easily (see letter to J. D. Hooker, 12 September [1873], and letter to Fritz Müller, 14 May 1877 (Calendar no. 10960; also printed in ML 2: 361–2). There are a few references to movements brought about by water in Movement in plants (pp. 126, 128, 363), but evidently CD came to no firm conclusions.
An anonymous article headed ‘The graver magazines’ in the Spectator, 11 October 1873, pp. 1283–4, included comments on George’s article in the October Contemporary Review, ‘Commodities versus labour’ (G. Darwin 1873c). The author said George’s paper could have been more graphic and lucid, and disagreed in detail with some points of his argument.

Summary

Asks GHD whether he can tell him what inclination a polished or waxy leaf ought to hold to the horizon in order to let vertical rain rebound off as much as possible.

Letter details

Letter no.
DCP-LETT-9096
From
Charles Robert Darwin
To
George Howard Darwin
Sent from
Down
Source of text
DAR 210.1: 13
Physical description
3pp

Please cite as

Darwin Correspondence Project, “Letter no. 9096,” accessed on 15 December 2017, http://www.darwinproject.ac.uk/DCP-LETT-9096

Also published in The Correspondence of Charles Darwin, vol. 21

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