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Darwin Correspondence Project

To G. H. Darwin   29 October [1878]1

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

Oct. 29th

My dear old George

I have been quite delighted with your letter & read it all with eagerness.—2 You were very good to write it. All of us are delighted, for considering what a man Sir W. T. is it is really grand that you shd. have staggered him so quickly, & that he shd speak of your “discovery &c” & about the moon’s period.—3

I also chuckle greatly about the internal Heat. How this will please the geologists & Evolutionists.4 That does sound awkward about the heat being bottled up in the middle of the earth.—

What a lot of swells you have been visiting & it must have been very interesting.5

Hurrah for the bowels of the earth & their viscosity & for the moon & for all the Heavenly bodies & for my son George (F.R.S. very soon)6

Yours affecty | C. Darwin

P.S | Proctor has sent me a book just published by him with a wretched title “Pleasant ways of Science”, but several of the essays have proved to me extremely interesting, especially the astronomical ones, & one on Telegraphy.—7 He is a wonderful compiler.—


The year is established by the relationship between this letter and the letter from G. H. Darwin, 7 November 1878.
The letter has not been found.
William Thomson evidently referred to George’s work determining the orbital period of the moon over time. George had presented a paper with his preliminary results at the meeting of the British Association for the Advancement of Science (G. H. Darwin 1878c), and was preparing a more detailed paper on the topic (G. H. Darwin 1878d).
George proposed that internal tidal friction generated heat within the earth, so that calculations about secular cooling and the age of the earth would have to be revised, leading to an estimate of greater age (see G. H. Darwin 1878d, pp. 494–6). On disputes among geologists and physicists, most notably Thomson, regarding the age of the earth, and on CD’s early reaction to Thomson’s estimate, see Burchfield 1990, pp. 57–86.
The individuals alluded to have not been identified.
George was elected a fellow of the Royal Society of London on 12 June 1879 (Record of the Royal Society of London).
Richard Anthony Proctor’s book Pleasant ways in science, a compilation of articles from literary magazines, was published in October 1878 (Proctor [1878]; Publishers’ Circular, 2 November 1878, p. 841). The first six articles were on astronomy; CD also refers to ‘On some marvels of telegraphy’ (Proctor [1878], pp 232–73). CD’s annotated copy is in the Darwin Library–Down.


Burchfield, Joe D. 1990. Lord Kelvin and the age of the earth. With a new afterword. Chicago and London: University of Chicago Press.

Proctor, Richard A. [1878.] Pleasant ways in science. New edition. London: Chatto and Windus.

Record of the Royal Society of London: The record of the Royal Society of London for the promotion of natural knowledge. 4th edition. London: Royal Society. 1940.


Rejoices that he should have "staggered" William Thomson so quickly and that the latter should speak of GHD’s "discovery". The internal heat [of the earth] will please geologists and evolutionists.

Letter details

Letter no.
Charles Robert Darwin
George Howard Darwin
Sent from
Source of text
DAR 210.1: 74
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11729,” accessed on 4 December 2021,