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of amphibolic slates were shown to me near An- 

 gostura, without any mixture of heterogeneous 

 substances, which had been worked under the 

 whimsical name of black ore of gold, oro negro. 

 This is the place to make known, in order to 

 complete the description of the Oroonoko, the 

 principal results of my researches on el Dorado, 

 the White Sea, or Laguna Pari me, and the 

 sources of the Oroonoko, as they are marked in 

 the most recent maps. The idea of an aurife- 

 rous earth, eminently rich, has been connected, 

 ever since the end of the 16th century, with that 

 of a great inland lake, which furnishes at the 

 same time waters to the Oroonoko, the Rio 

 Branco, and the Rio Essequebo. I believe, 

 from a more accurate knowledge of the country, 

 a long and laborious study of the Spanish authors 

 who treat of el Dorado, and above all from 

 comparing a great number of ancient maps ar- 

 ranged. in chronological order, I have succeeded 

 in discovering the source of these errors. All 

 fables have some real foundation ; that of Dorado 

 resembles those mythoi of antiquity, which, tra- 

 velling from country to country, have been suc- 

 cessively adapted to different localities. In the 

 sciences, in order to distinguish truth from error, 

 it often suffices to retrace the history of opinions, 

 and to follow their successive developments. 

 The discussion to which I shall devote the end 

 of this chapter is important, not only because it 



