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pear brown like coffee, or of a greenish black. 

 These waters notwithstanding are the most beau- 

 tiful, the clearest, and the most agreeable to the 

 taste. I have observed above, that the croco- 

 diles, and, if not the zancudoes, at least the 

 moschettoes, generally shun the black waters. 

 The people assert too, that these waters do not 

 embrown the rocks ; and that the white rivers 

 have black borders, while the black rivers have 

 white. In fact the shores of the Guainia, 

 known to the Europeans by the name of the 

 Rio Negro, frequently exhibit masses of quartz 

 issuing from granite, and of a dazzling white- 

 ness. The waters of the Mataveni, when exa- 

 mined in a glass, are pretty white ; those of the 

 Atabapo retain a slight tinge of yellowish-brown- 

 When the least breath of wind agitates the sur- 

 face of these black rivers, they appear of a fine 

 grass green, like the lakes of Switzerland. In 

 the shade, the Zama, the Atabapo, and the 

 Guainia, are as dark as coffee grounds. These 

 phenomena are so striking, that the Indians 

 every where distinguish the waters by black 

 and white. The former have often served me 

 for an artificial horizon ; they reflect the image 

 of the stars with admirable clearness. 



The colour of the waters of springs, rivers, 

 and lakes, ranks among those physical pro- 

 blems, which it is difficult, if not impossible, to 

 solve by direct experiments. The tints of re- 



