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Darwin Correspondence Project

From Charles Lyell   5 March 1866

– March 5th, 1866 … In the beginning of Hooker’s letter to you he speaks hypothetically of a change in the earth’s axis as having possibly co-operated with redistribution of land and sea in causing the cold of the Glacial period.1 Now, when we consider how extremely modern, zoologically and botanically, the Glacial period is proved to be, I am shocked at any one introducing, with what I may call so much levity, so organic a change as a deviation in the axis of the planet …2


Lyell refers to Joseph Dalton Hooker. See letter from J. D. Hooker, 21 February 1866. CD had forwarded part of that letter to Lyell at Hooker’s request (see letter from J. D. Hooker, [26 or 27 February 1866], and letter to J. D. Hooker, [28 February 1866] and n. 2).
James Croll had newly calculated that the glacial epoch ended 80,000 years before 1800, having begun 240,000 years earlier; he estimated that the coldest period occurred between 200,000 and 210,000 years before 1800 (Croll 1866a). In his letter of 21 February 1866, Hooker expressed the view that the evidence on which belief in the glacial period was founded could have been produced by various earlier global circumstances, including a slight shift in the earth’s axis. Hooker may have misinterpreted Croll 1865a as implying a change in the axis of the earth (see Correspondence vol. 13, letter from F. H. Hooker, 6 September [1865] and n. 6); however, Croll 1865a concerned the effect of icecaps on the centre of gravity, rather than the axis, of the earth (see also Fleming 1998, p. 166). Lyell did not believe that the earth’s centre of gravity had altered much either (see Reader, 13 January 1866, p. 44).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Fleming, James Rodger. 1998. Charles Lyell and climatic change: speculation and certainty. In Lyell: the past is the key to the present, edited by Derek J. Blundell and Andrew C. Scott. London: Geological Society.


Surprised at Hooker’s introducing "so organic a change as a deviation in the axis of the planet" to explain the cold of the Glacial Period.

Letter details

Letter no.
Charles Lyell, 1st baronet
Charles Robert Darwin
Sent from
Source of text
ML 2: 158

Please cite as

Darwin Correspondence Project, “Letter no. 5027,” accessed on 19 January 2021,

Also published in The Correspondence of Charles Darwin, vol. 14