1889. 

 ABOUT COMMON WATER* 



WE have already spent what I trust has proved to 

 you an agreeable and instructive half-hour over 

 water in its solid form. We have conversed about the 

 behaviour of those vast collections of ice which go by 

 the name of glaciers, tracing them to their origin in 

 mountain snow. Closely compacted, but still retain- 

 ing a certain power of motion, the snow passes from 

 the mountain-slopes and reservoirs where it was first 

 collected into the valleys, through which, becoming 

 more and more compacted, it moves as a river of ice. 

 From the end of this solid river always rushes a liquid 

 one, rendered turbid by the fine matter ground from 

 the rocks during the descent of the glacier. An effect 

 which I thought remarkable when I first saw it may 

 be worth mentioning here. Thirty-two years ago I 

 followed the river Khone to the place where it enters 

 the Lake of Geneva. The water of the lake is known 

 to be beautifully blue, and I fancied beforehand that 

 the admixture of the water of the Rhone must infal- 

 libly render the lake turbid. To my surprise, there 

 was no turbidity observable. A moment's reflection 

 rendered the reason of this obvious. The Rhone water, 

 rushing from its parent glaciers, was colder, and there- 

 fore heavier, than the water of the lake. Instead of 

 mixing with the latter, it sank beneath it, disposing 

 of itself along the bottom of the lake, and leaving the 

 surface-water with its delicate azure unimpaired. 



I propose now to talk to you for half an hour about 



1 Written for The Youth" s Companion. 





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