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purer azure than in high latitudes ; and this dif- 

 ference is remarked even in the Gulf-stream. 

 The ocean often remains blue, when, in fine wea- 

 ther, more than four-fifths of the sky are covered 

 with light and floating clouds. They who do 

 not admit Newton's theory of colors consider the 

 blue of the sky as the black of space seen through 

 a medium, the transparency of which is disturb- 

 ed by vapors * : this explanation they might ex- 

 tend to the blue tint of the Ocean. 



Whatever relates to the color of the water is 

 extremely problematic. The green tint of the 

 snow waters, that flow from the glaciers of the 

 Alps, and which contain very little air in solu- 

 tion, might induce us to believe, that this color 

 is appropriate to water in it's greatest purity. 

 We address ourselves in vain to chemistry to ex- 

 plain this phenomenon, or that of the blue color 

 of the Rhone near Geneva : there is hitherto no 

 proof, that waters exist which contain a greater 

 or less degree of hydrogen ; and the refrigera- 

 tion of the seas in tempests is much too weak, 

 to permit us to attribute the reflection of differ- 

 ent colored rays to the mere change of density. 

 It is no way probable, that the green color of the 

 water is owing to the mixture of yellow rays 

 from the bottom, and blue rays reflected by the 



* Antonio de Dominis, la Hire, and Mr. von Goethe 

 {M6m. de VAcad., t. ix, p. 615, Farbenlehre. t. i, p. 59.) 



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