There cannot be any better place for recruiting strength than the lovely primitive valley of _Les Plans_, two hours up the course of the Avençon from hot and dusty Bex. Here I rejoined my sisters, intending to spend a month with them before returning to England; and the neighbouring glaciers afforded good opportunities for quietly investigating the structure of the ice which composes them, with a view to discovering, if possible, some trace of the prismatic formation so universal in the glacières. On one occasion, after carefully cutting steps and examining the faces of cleavage for an hour and a half, I detected a small patch of ice, under the overhanging rim of a crevasse, marked distinctly with the familiar network of lines on the surface; but I was unable to discover anything betokening a prismatic condition of the interior. This was the only case in which I saw the slightest approach to the phenomena presented in ice-caves. There remained one glacière on M. Thury's list, which I had so far not thought of visiting. It was described as lying three leagues to the north of Die in Dauphiné, department of the Drôme, at an altitude of more than 5,000 feet above the sea. M. Héricart de Thury discovered this cavern in 1805, and published an account of it in the _Annales des Mines_[82] to which M. Thury's list gave a reference. I have since found that this account has been translated into various scientific periodicals, among others the Philosophical Journal of Edinburgh.[83] It occurred to me that, by leaving Les Plans a few days earlier than I had intended, I could take advantage of the new line connecting Chambéry and Grenoble and Valence, and so visit this glacière without making the journey too long; and accordingly I bade farewell to Madame Chérix's comfortable room, leaving my sisters in their quarters in a neighbouring châlet, and started for Geneva.