66 M. Oh. Martins on the Colour of the Ice of Glaciers. 



without them. M. Dollfus, again, has shewn that the specific weight 

 of white ice is 871 ; that of blue ice 909 ; that of water being 1000 ; 

 a result which confirms the preceding. 



M. Durocher then affirms, " that the waters which flow from fields 

 of snow and glaciers have a very decided sky-blue tint. When," ho 

 adds, " the detritus mingled with water are grey, they produce no other 

 effect than to make the blue tint paler, and make it pass into dull 

 blue." This assertion appears to me to be very rash, particularly 

 when it is applied equally to the waters furnished by melted snow 

 and those which come from the melting of glaciers. The former are 

 more or less pure, but the colour varied, without, however, presenting 

 the limpidity of that of springs. Thus, the little lake of Lioson, in 

 the Canton do Vaud, fed by the snows of Tete~de-Moine, is of the 

 most beautiful azure. The Bachalp-See, situate 2-275 metres above 

 the sea, which receives the waters flowinor from the snows of the 

 Faulhorn, is of a yellowish-green. 



Let us bestow a few words on the consideration of the waters which 

 issue from glaciers. They are always charged with a considerable 

 portion of mud, produced by the pulverisation of the fragments of rock 

 which the glacier grinds down in its ceaseless progress. Thus, water 

 taken from the surface of the Aar, at some metres from the glacier 

 of the same name, contains, according to the experiments of M. Doll- 

 fus, 142 grammes of impalpable powder in a cubic metre of water. 

 It is the same with the torrents which issue from glaciers. All of 

 them roll along in a turbid, grey, milky, or dark stream, according 

 to the nature of the pulverised rock. Hence the vulgar denomina- 

 tions of torrents, derived from the colour of their waters. The black 

 water, which throws itself into the Rhone, near Martigny, in the 

 Valais, comes from the glaciers of Trient and Buet. The wJiite 

 Lutschine derives its origin from the numerous glaciers which occupy 

 the bottom of the valley of Lauterbrunn ; and the black Lutschine 

 comes from those of the valley of Grindelwald. Can it be true, as 

 M. Durocher states (p. 445), that " the mud of glaciers has no other 

 effect than to make the blue tint become paler, and pass into a muddy 

 blue ?" The Swiss geologist Ebel expressed the same idea thirty 

 years ago : " the water of glaciers," he says,* " is of a whitish-blue, 

 and the torrents which issue from them preserve this colour for many 

 leagues, when other rivulets do not alter them by mixing with them." 

 This, we perceive is the same opinion which M. Durocher has repro- 

 duced before the Academy. Nevertheless, I believe it to be incor- 

 rect. The waters which flow from glaciers have never appeared to 

 me blue ; this is also M. Agassiz's opinion, when he says (page 574 

 of his work on existing glaciers, which will be published speedily), 

 " It is the mud which gives the water of glaciers the milky tint which 

 characterises themy 



* Manuel au Voyageur en Swisse. 3d Ed., French Trans., tome ii., p. 521, 

 Article Glaciers. 



