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From James Croll   15 February 1869

Edinburgh.

Feby 15th 1869.

Dear Sir,

I am much obliged to you for the copy of Scientific Opinion you sent me containing an abstract of Canon Moseley’s admirable paper on the motion of glaciers1

I have a curious incident to tell you, regarding the matter. The reading of the abstract thoroughly convinced me that the generally received theory of glacier motion, which I believe is that of Tyndall’s,2 must be given up and that some other explanation must be sought. Strange to say, this conviction had hardly got time to settle down, if I may so express myself, before, what I fully believe to be the true cause suggested itself. The cause is so simple, so beautiful, and obvious that I wonder that it should have escaped observation so long.

I have drawn up a short account of the matter and have sent it to the Phil. Mag   I have requested Dr Francis to send me two copies of proof and when they come to hand I shall send you one3

I am | Yours very truly | James Croll

Charles Darwin Esq MA FRS

2
For John Tyndall’s account of his own as well as earlier theories of glacier motion, see Tyndall 1860.
3
Croll’s paper ‘On the physical cause of the motion of glaciers’ (Croll 1869) appeared in the March 1869 issue of Philosophical Magazine. CD’s copy has not been found. William Francis was the editor of Philosophical Magazine.

Please cite as “DCP-LETT-6616,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-6616