Ɛpsilon

To John Tyndall   4 December [1878]1

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

Dec. 4th

My dear Tyndall

I am going to beg a favour of you.— The day before yesterday & today I observed (but perhaps the observation will prove erroneous) that certain sensitive plants were excited into movement, by a prolonged note on the bassoon & apparently more by a high than a low note.2 I want much for several reasons to verify or disprove this.— On asking Litchfield whether he had ever seen a Siren, he said that he had at one of your Lectures, & that he thought it was only a small box.3 If this is the case, (but not otherwise) could you without much trouble bring it here on Saturday, that I & my son Francis might see & hear it, so as to judge whether it wd. do for our plants; for in this case I would buy one, if this is possible. I do not suppose we could test its powers during one day, on Sunday.—4

Please observe if Litchfield is mistaken, & the Siren is a large or delicate instrument, I am not so utterly unreasonable as to ask you to bring it.

My dear Tyndall | Yours very sincerely | Ch. Darwin

1
The year is established by the relationship between this letter and the letter from John Tyndall, 5 December 1878.
2
Francis Darwin played the bassoon (DNB). CD was evidently studying the sensitivity of plants to sound but no notes on his experiments have been found.
3
CD had stayed at the London home of Richard Buckley and Henrietta Emma Litchfield from 19 to 27 November 1878 (CD’s ‘Journal’ (Appendix II)). Tyndall had used a siren (or syren in Tyndall’s spelling) in one of a series of lectures on sound delivered at the Royal Institution of Great Britain (see Tyndall 1867, pp. 67–78; the apparatus is figured on p. 77).
4
According to Emma Darwin’s diary (DAR 242),Tyndall visited Down on Saturday 7 December 1878.

Manuscript Alterations and Comments

1.1 & today] interl
1.4 much] added
1.5 Siren, he] ‘he’ after del ‘&’
1.7 that] after del ‘so’
1.8 see] after del ‘&’
1.10 during one day,] interl
2.1 the Siren is] above del ‘it is’

Please cite as “DCP-LETT-11771,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11771