and on the Tints of the Ocean. 325 



phere,,and it is distilled without the chance of those impuri- 

 ties which may exist in the vessels used in an artificial opera- 

 tion. We cannot well examine the water precipitated in the 

 atmosphere as rain, without collecting it in vessels, and all ar- 

 tificial contact gives more or less of contamination ; but in snow 

 melted by the sunbeams that has fallen on glaciers, them- 

 selves formed from frozen snow, water may be regarded as in 

 its state of greatest purity. Congelation expels both salts 

 and air from water, whether existing below, or formed in the 

 atmosphere ; and in the high and uninhabited regions of gla- 

 ciers, there can scarcely be any substances to contaminate, — re- 

 moved from animal and vegetable life, they are even above the 

 mineral kingdom ; and though there are instances in which 

 the rudest kind of vegetation (forms of the fungus or mucor 

 kind) is even found upon snows, yet this is a rare occurrence ; 

 and red snow, which is occasioned by it, is an extraordinary, 

 and not a common phenomenon towards the pole, and on the 

 highest mountains of the globe. 



Having examined the water formed from melted snows or 

 glaciers in different parts of the Alps, and having always found 

 it of the same quality, I shall consider it as pure water, and 

 describe its character. Its colour, when it has any depth, or 

 when a mass of it is seen through, is bright blue, and according 

 to its greater or less depth of substance, it has more or less of 

 this colour. As its insipidity and its other physical qualities 

 are not at this moment objects of your inquiry, I shall not 

 dwell upon them. In general, in examining lakes and masses 

 of water in high mountains, their colour is of the same bright 

 azure. And Captain Parry states that the water on the polar 

 ice has the same beautiful tint. When vegetables grow in 

 lakes, the colour becomes nearer sea-green, and as the quan- 

 tity of impregnation from the decay increases, greener, yellow- 

 ish green, andjit length when the vegetable extract is large in 

 quantity, as iri countries where peat is found, yellow, and even 

 brown. 



To mention instances, the Lake of Geneva, fed from sources 

 (particularly the higher Rhine), formed from melting snow, is 

 blue ; and the Rhone pours from it dyed of the deepest azure, 

 and retains partially this colour till it is joined by the Soane, 



