11th Dec. 1859
My dear Wills,
I was just preparing for bed when accident drew my eyes to the following passage in your article in the National Review:2—
“The theory commonly called De Saussure’s3—now more than a century old—was based upon the supposed immobility of glaciers during winter. De Charpentier4 and Agassiz in our own day have supported the Dilatation theory5 by an appeal to the equally erroneous notion that glaciers move faster at the sides than at the centre.”6
I would take it as a great favour if you would refer me to the passage in De Saussure’s works in which he bases his theory upon the supposed immobility of glaciers during the winter, and also to the passage in Charpentier’s works in which he appeals to the quicker motion of the sides in support of the theory of Dilatation.
Believe me | very sincerely yours | John Tyndall.
Wellcome Library, MS. 7777/02
Alfred Wills (1828–1912), judge and mountaineer. Wills was very involved in the Alpine Club, and was its third President between 1863 and 1865 (ODNB).
your article in the National Review: Alfred Wills, ‘Glaciers and Glacier Theories’, the National Review, 17 (July 1859), pp. 1–30.
De Saussure’s: Horace-Bénédict de Saussure proposed what was called the sliding theory of glacier movement, which assumed that glaciers were rigid bodies that moved by sliding in its entirety. He published his ideas in his four volume Voyage dans les Alpes (Lyon: Fauche-Borel, 1779–96).
De Charpentier: Jean de Charpentier.
the Dilatation theory: The ‘dilatation theory of glacier motion’ is associated with De Charpentier; see his book Essai sur les glaciers et sur le terrain erratique du bassin du Rhône, (Lausanne: 1841). The theory was further developed by Agassiz. Dilatation means expanding, or widening out (OED); in relation to glaciers it means the flow of water permeating the ice thereby expanding and moving the glacier.
“The theory commonly called De Saussure’s … than at the centre”: passage appears on p. 3 of Wills’s article, see n. 2.
Please cite as “Tyndall1666,” in Ɛpsilon: The John Tyndall Collection accessed on