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Darwin Correspondence Project

To Roland Trimen   24 May [1871]1

Down, | Beckenham, Kent.

May 24th

My dear Mr Trimen

I am much obliged for your long & interesting letter.2 You ask me whether I have any notion about the meaning of moths &c flying into candles, & birds against light-houses.— I have not.— I have looked at the case as one of curiosity, which is very strong with the higher animals, & I presume even with insects.3 A light is a very new object, & its distance cannot be judged, but how it comes that an insect is so stupid as to go on flying into the same candle I cannot conceive. It looks as if they were drawn towards it.— Sir C. Lyell, I remember, made years ago the difficulty greater by asking me, what stops all the moths in the world flying every moon-light night up to the moon, or as near as they could get.—4 Perhaps they have instinctively learnt that this cannot be done.—

With respect to humour, I think dogs do have it, but it is necessarily only of a practical kind. Everyone must have seen a dog with a piece of a stick or other object in his mouth, & if his master in play tries to take it away, the dog runs with prancing steps a few yards away, squats down, facing his master, & waits till he comes quite close & then jumps up & repeats the operation,—looking, as if he said, “you are sold”.—

I have many letters to write so pray excuse brevity.— My book has been very successful as far as sale has been concerned, & has hitherto been in most cases treated very liberally by the press.—.5 My notions on the moral sense have, however, been much reprobated by some & highly praised by others.— I have no news to tell, for I have seen hardly any one for months.—

I am extremely sorry to hear that you are no freer of official duties, for I feel sure if you had more leisure & especially if you lived in the country, you would make some grand new observations.—

With every good wish— Pray believe me | Yours sincerely | Ch. Darwin


The year is established by the relationship between this letter and the letter from Roland Trimen, 17 and 18 April 1871.
CD discussed curiosity in animals in Descent 1: 42–3.
Descent had been reprinted twice since its original publication on 24 February 1871 (Freeman 1977, p. 129–31) and widely reviewed (see Correspondence vol. 19, Appendix V).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

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

Freeman, Richard Broke. 1977. The works of Charles Darwin: an annotated bibliographical handlist. 2d edition. Folkestone, Kent: William Dawson & Sons. Hamden, Conn.: Archon Books, Shoe String Press.


Cannot explain why moths fly into candle flames and birds against lighthouses. Has felt it was just curiosity which attracted them.

CD does believe dogs have some sense of humour.

Letter details

Letter no.
Charles Robert Darwin
Roland Trimen
Sent from
Source of text
Royal Entomological Society (Trimen papers, box 21: 69)
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 7880,” accessed on 21 June 2024,

Also published in The Correspondence of Charles Darwin, vol. 19