From James Croll   17 August 1871

Edinburgh

August 17th 1871

Dear Sir,

I am much obliged to you for your letter of 19th ult. which I received through Mr. Youmans.1

This gentleman wished me to write a small treatise on Geol. Time. But I explained to him, that in the present state of the question nothing satisfactory could be written on it, which would be of any service to general readers2   I believe he left satisfied that the better plan was to let this subject lie over, for some time to come.

I have been doing little for some time back, owing to pain in the head;3 but I expect to have a long paper in the Oct number of the Phil. Mag. on Dr Carpenter theory of Ocean Currents.4

I am | yours most sincerely | James Croll

Charles Darwin Esqre Ma. FRS.—

1
CD’s letter to Croll of 19 July [1871] was a letter of introduction for Edward Livingston Youmans, who was commissioning books for the International Scientific Series published by the Appleton publishing company of New York. CD’s son George had suggested Croll to Youmans as a possible author for a small monograph (see letter from G. H. Darwin, [17 July 1871]).
2
The question of the age of the earth had since the late 1860s been one of the most hotly debated topics in British science, involving not only Croll but such senior figures as William Thomson (later Lord Kelvin) and Charles Lyell. For an overview of Croll’s contributions to the debate, see Burchfield 1990, especially chapter 3. See letter from G. H. Darwin, [17 July 1871], n. 2.
3
Croll had suffered head pains since childhood. Their intensity increased sharply in 1871, requiring him to take intermittent leave from his work at the Geological Survey of Scotland (Irons 1896).
4
Croll refers to the second instalment of the third part of his paper on the physical causes of ocean currents (Croll 1870–4, pp. 241–80); it was published in the Philosophical Magazine in October 1871 as a response to William Benjamin Carpenter’s paper, ‘On the Gibraltar current, the Gulf Stream, and general oceanic circulation’ (Carpenter 1871).

Please cite as “DCP-LETT-7908,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-7908