skip to content

Darwin Correspondence Project

To G. H. Darwin   22 October [1874]1

Down, | Beckenham, Kent.

Oct 22d.

My dear G.

I send index.— You need not look over the pages of Ch. XX. There will be no occasion for Revise & do not correct anything except actual errors— I send 2d. vol. of Descent for Printers have not sent old Proofs. If at all intelligible, it is useless to make any expression in Index better. Make any corrections very clear. Return proofs as soon as you can to Clowes address—ie “Stamford St. Blackfriars, London.”—2

Please return 2d. vol. of Descent by Post.—

And now can you answer me 2 queries in physics. I am nearly sure that some crystals & I think fibrous iron conduct heat more easily or quickly in certain directions than in others.— Is not this so?

Secondly, I believe a very hot body radiates heat quicker than a less hot body; but how is this in conduction. Is heat conducted away more quickly or easily from a very hot than from a less hot body? It is too long a story to explain why I want this information; it is to illustrate, as mere analogy, the transmission of the motor impulse through the leaves of Drosera.3

Yours affect | C. Darwin


The year is established by the relationship between this letter and the letter from G. H. Darwin, 24 October 1874.
George was assisting with the second edition of Descent, published in a single volume in November 1874 (letter from R. F. Cooke, 12 November 1874). William Clowes & Sons were the printers used by CD’s publisher, John Murray. From 1827, their printworks were in Duke Street (now Duchy Street), off Stamford Street, between Blackfriars and Waterloo Bridge in London (Clowes [1953], pp. 25–6).
In Insectivorous plants, pp. 234–43, CD discussed his experiments on the transmission of the motor impulse in Drosera rotundifolia (the round-leaved or common sundew).


Clowes, William Beaufoy. [1953.] Family business 1803–1953. London: William Clowes and Sons.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Insectivorous plants. By Charles Darwin. London: John Murray. 1875.


Sends index [of Descent, 2d ed.] with instructions for proof-reading.

Asks GHD questions about heat transmission; he wants to use it as an analogy to illustrate transmission of motor impulses through leaves of Dionaea.

Letter details

Letter no.
Charles Robert Darwin
George Howard Darwin
Sent from
Source of text
DAR 210.1: 34
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9693,” accessed on 30 November 2020,

Also published in The Correspondence of Charles Darwin, vol. 22