374 



REPORT UNITED STATES GEOLOGICAL SURVEY. 



This blue color is not confined to springs, for many lakes, notably the 

 Swiss lakes and Lake Tahoe of California, have it in j)erfection, and in 

 the glaciers of the Alps* and in those of Norway it is seen. It is also 

 noted in many rivers, the Ehone being one. The Ehine, at Geneva, is 

 also blue. 



It is to be regretted that we could not bring in some specimens of the 

 water from the springs of the National Park in w-hich the blue color was 

 most noticeable, but the bottles did not reach us soon enough. Those 

 that were procured were, however, examined by Dr. Henry LefFmann 

 and myself, and compared with other waters. These experiments I pre- 

 sent here in tabular form. 



Glass tubes, 5 feet long and a half inch in diameter, blackened on 

 the outside and wrapped with heavy brown paper, were used. Over 

 the ends the glass was corrected for greenness, and they were held against 

 a surface of snow first and afterwards against white porcelain: 



* Forbes (Travels tliroug]ithe Alpsof Savoy, Edinburgli, 1843, page 71), speaks of blue 

 caverns in the glaciers, and considers the color to be that of pure water. 



Fig. 18. 

 Ornamented Basins at Mammoth 

 Hot Springs of Gaidiner'a Kiver 



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