(Copy) Collingwood | March 17/57
Dear Sir
Allow me to thank you for your lecture on Glacial cleavage.1 There is one thing which a little puzzles me. How is it that regelation takes place when two masses of ice at 32° are placed in contact? 1st. are they really at 32°? is not the interior of every lump of ice some infinitesimal of a degree colder then the surface? Paradoxical as it may appear it is not impossible. On the occasion of one of the Arctic expeditions2 I suggested (and it was done) that boring rods should be taken to bore into the great Ice-blocks to try the internal temperature on this notion—viz: that any degree of cold might be conducted into ice, but no heat above 32°; since a higher heat applied at the surface would run off in water—Thus ice collected in winter below 32° might retain some little cold below 32° in its interior. In fact the Wenham Lake blocks packed for shipment to Calcutta3 are purposely shipped at a temperature very much below 32°—
2ndly. If this be not the cause, what is? Can it be possible that the crystalline forces should determine a movement of heat so as to thaw one part of the ice in order to freeze another? and if this were possible would it not at least require that the crystals should be juxta-posed with their axes parallel?
Have you examined the polarizing powers of your thawed and re-cemented ice—that for instance which exhibited a cleavage like gypsum?4
Excuse my troubling you with these crudities & believe meY[ou]rs very truly | (signed) J. F. W. Herschel
P.S. The failure of the ‘Ice Calorimeter’ as reported by Wedgewood5 in Phil. Trans.6—is in point of the regelation of Ice;—a’propos of Calorimeters I should very much like my modification of this instrument (Cape Obs[ns])7 to have a fair trial. Babinet8 wrote me word that he found it give perfectly satisfactory results but I have not seen them in print.
Profr. Tyndall
RS HS 17.386
Transcript Only
your lecture on Glacial cleavage: on 23 January 1857, Tyndall lectured at the RI on ‘Observations on Glaciers’; later published as J. Tyndall and T. H. Huxley, ‘On the Structure and Motion of Glaciers’, Phil. Trans., 147 (1857), pp. 327–46.
Arctic expeditions: not identified.
Wenham Lake blocks packed for shipment to Calcutta: a lake in Massachusetts (United States), where ice blocks were harvested for shipment to countries across the Atlantic from the 1840s and into the twentieth century.
gypsum: hydrous calcium sulphate, the mineral from which plaster of Paris is made (OED).
Wedgewood: Josiah Wedgwood (1730–95), founder of the highly successful Wedgwood pottery company, abolitionist, and maternal grandfather to naturalist Charles Darwin. Wedgwood was a noted experimental chemist (ODNB).
in Phil. Trans.: J. Wedgwood, ‘An Attempt to Compare and Connect the Thermometer for Strong Fire, Described in Vol. LXXII. Of the Philosophical Transactions, with the Common Mercurial Ones. By Mr. Josiah Wedgwood, F.R.S. Potter to Her Majesty’, Phil. Trans., 74 (1784), pp. 358–84.
Cape Obs[ns]: refers to ‘Suggestion of an improvement on the Ice Calorimeter’ in Appendix C of J. Herschel, Results of astronomical observations made during the years 1834, 5, 6, 7, 8, at the Cape of Good Hope (London: Smith, Elder and Co., 1847), pp. 446–7.
Babinet: Jacques Babinet (1794–1872), French physicist and mathematician who focused on the study of optics (CDSB).
Please cite as “Tyndall1356,” in Ɛpsilon: The John Tyndall Collection accessed on