224 Professor Forbes on the Leading Phenomena of Glaciers. 



the Montanvert, and it soon began to snow, and continued to do 

 so with little intermission during the day. The Mer de Glace 

 had been covered with snow for a week ; at the Montanvert, 

 to a depth of six inches, but in its higher parts of not less than 

 a foot and a half. I was not sorry, however, to have an op- 

 portunity of ascertaining the conditions of the ice, under cir- 

 cumstances so critical for the theory of dilatation, for now, if 

 at any time, the freezing and expansive effects of cold ought 

 to be visible, the ice having been completely saturated by the 

 preceding wet weather, and, it might be supposed, effectually 

 cooled by five days of frost. As the walk promised to be labo- 

 rious, if not difficult, owing to the thick coating of snow, I 

 took with me David Couttet of the Montanvert, and Augusta 

 Balmat, as usual, with the instruments and provisions. We 

 started in a lowering morning at half-past six, and in less than 

 an hour it began to snow, with a drifting wind, though for- 

 tunately without cold. To most persons, the journey would 

 have been an alarming one, but we were all three so intimate- 

 ly acquainted with the surface of the ice, and the direction of 

 the moraines, that we had no fear of losing ourselves. It re- 

 quired, however, all Auguste's intimate knowledge of the gla- 

 cier to keep us clear of dangerous crevasses and holes ; for 

 the snow was often knee-deep, and the glacier and moraines 

 alike filled with innumerable pit-falls. We crossed the mo- 

 raines, as usual, near the Moulins, and visited the stations B 1 

 and C. We then kept nearly under the ice-fall of the Glacier 

 du Talefre, and reached with precaution the higher glacier 

 of Lechaud, on our way to station E, where I anxiously wished 

 to make an observation of the progress of the glacier. But 

 now the bad weather increased so much, that we were glad to 

 get behind a great stone and eat our breakfast, waiting for a 

 favourable change. The wind blew in strong gusts from the 

 Grande Jorasse, tossing the snow about so as to render all ob- 

 jects at a distance undistinguishable, thus threatening to make 

 our expedition ineffectual, for the rock called the Capucin du 

 Tacul, which was my index for the bearings on the glacier, 

 from station E, was hopelessly invisible. After some delay, 

 the storm abated, and the Pierre de Beranger, whose azimuth 

 I had fortunately taken as a check, shewed itself. We there- 



