428 LIFE OF HORACE BENEDICT DE SAUSSURE 



might, therefore, have been expected to treat glacial phenomena 

 with particular care and insight. Yet his contributions to the 

 better understanding of the movements and action of the ice- 

 stream are relatively incomplete and unsatisfactory. 



With regard to the advance of glaciers valleywards, he recog- 

 nised that the frozen mass was pushed down the mountain slope 

 by its weight, and by the pressure of the snows in the upper basins, 

 while he suggested that the natural heat of the earth, of which 

 he exaggerated the effect, assisted the process by melting the ice 

 where it touched the ground. 1 



He insisted on the main fact that the substance of glaciers, 

 neve or ice, moves continually downwards from the heights towards 

 the valleys. He was ready to hurl sarcasm at a foolish professor 

 of Tubingen, who had confidently asserted 'that any forward 

 movement of ice was a physical impossibility.' But here he 

 stopped ; he took no practical steps to ascertain the nature of 

 glacier movement , or to measure its rate . This is the more surprising 

 since the need of such measurements was already being insisted 

 on. In the chapter on ' Natural History ' in Laborde's monu- 

 mental work on Switzerland 2 published about 1780 the writer 

 says : ' We have proposed to plant stakes on the glaciers, and to 

 arrange them in a line with trees or other recognisable objects, 

 so that the rate of movement of the ice may be ascertained. . . . 

 We have urged this on priests and presbyters ; will it be done ? 

 We doubt it.' He goes on in a footnote to tell us that Monsieur 

 Hennin, while acting as the French Resident at Geneva, had seven 

 years before persuaded the Vicaire of Chamonix to have three 

 stakes set up on the Mer de Glace opposite the Pierre des Anglais, 

 and that in the first year they had advanced fourteen French 



1 It may be interesting to set beside de Saussure's statement the concluding 

 sentence of M. Vallot's Annales de VObservatoire du Mont Blanc, vol. iv., 1900 : 

 ' The conclusion of this work is that the advance of glaciers is caused by the 

 sliding of the mass caused by the slope of their beds, and aided by the thrust of 

 the upper portions. Weight appears to be the only agent, to the exclusion of any 

 action of heat.' 



2 Tableaux Topographiques, Pittoresques, Physiques, Historiques, Moraux, 

 Politiques, et Litt&raires de la Suisse, 4 vols., Paris, 1780. Owing probably to its 

 unwieldy dimensions, the amount of information, both topographic and scientific, 

 contained in this work has been generally overlooked. It was published only a 

 year after the first volume of the Voyages. The plates (in some copies coloured) 

 of the principal Swiss ice-streams are excellent, but there are none of the glaciers 

 of Savoy. 



