To John Tyndall   4 February [1857]1

Down Bromley Kent

Feb. 4th

Dear Tyndall

I am very much obliged to you for your note. My only excuse for having troubled Huxley, was my very great curiosity to hear something more of your views.—2

I am as ignorant of mechanics as a pig as you will have perceived; but Glaciers for years & years have interested me greatly.3

I am so very glad to hear that you are continuing your experiments on ice; & I hope to hear that you will explain about the freezing together of ice under the freezing point.—

I can fancy a man so ignorant of nat. History as to advise Owen to compare a skull with a vertebra;4 on exactly same principle, I hope that you will squeeze together pieces of ice quite dry as far as water is concerned, but wetted with something which will not freeze. There is a valuable suggestion for you!!5

I wish you all sorts of good fortune in your most interesting investigations; & the Lord have mercy on you, when Forbes answers you is my prayer6

Most truly yours | C. Darwin

It is beautiful your having given cleavage to ice.7

1
Dated by the relationship to the letter to T. H. Huxley, 3 February [1857].
3
In Volcanic islands, pp. 70–1, CD compared the lamination he had observed in volcanic rocks to the zoned structure James David Forbes described in glaciers. See also Correspondence vol. 3, letters to J. D. Forbes, 11 October [1844] and [November? 1844].
4
Probably an allusion to Thomas Henry Huxley’s intention to attack Richard Owen’s theory of the vertebral origin of the skull as put forward in Owen 1846. Huxley attempted to demolish Owen’s vertebral theory in his Croonian lecture of 1858 (T. H. Huxley 1859), by which time the ‘jolly row’ mentioned in CD’s letter to T. H. Huxley, 3 February [1857], was well advanced (see A. Desmond 1982 and di Gregorio 1984).
5
This was presumably a suggestion as to how to investigate the question, posed in CD’s letter to T. H. Huxley, 17 January [1857], of how Tyndall knew ‘that the ice freezes together & not merely coheres, like two pieces of wet glass—’.
6
Forbes had previously engaged in a controversy with William Hopkins over the viscous theory of ice. Hopkins, like Tyndall, had challenged the physical principles upon which the viscous theory rested. See C. Smith 1989. For the ensuing controversy between Tyndall and Forbes, see Rowlinson 1971.
7
Tyndall had been drawn to the study of glaciers through his investigation of the role of pressure in producing slaty cleavage. Accepting the mechanical theory of cleavage put forth by Daniel Sharpe (Sharpe 1855), Tyndall held that the lamination observed in glaciers was, like the cleavage of slate, the result of pressure and that bedding and structure were different in nature and origin (Tyndall and Huxley 1857, pp. 339–46). CD, who had arrived at this conclusion through his consideration of cleavage and foliation in clay-slate, had been actively interested in the question for over a decade (Correspondence vols. 3, 4, and 5).

Please cite as “DCP-LETT-2046,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-2046