To Roland Trimen   24 May [1871]¹

My dear M^r 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