190 TRAVELS IN BRAZIL. 



some years before, and lately prosecuted by hira, 

 where we became acquainted with a formation of 

 gold which we had not previously seen, namely, 

 the carvoeira. * This is a friable, rough-feeling, 

 greasy mass of greyish green colour, which con- 

 sists of a very fine-grained quartz, and a smoky 

 grey mica, with earthy grey manganese ore, and 

 probably forms a layer several feet thick, between 

 the planes of separation of the quartzy mica-slate, 

 and the clay-slate lying under it. It generally 

 contains a considerable quantity of gold, and had 

 therefore been washed with particular care by the 

 Mineifos, who had dug the adit into the morro» 

 Yet they had left so much metal in the earth which 

 they had washed, that Mr. Von Eschwege found 

 it worth his M'hile to wash it again with that which 

 he dug up afresh. For this purpose, he had con- 

 structed a vessel moved horizontally by a water 

 wheel, in which the gold was to be separated from 

 the finest particles mixed with it, but he subse- 

 quently found this machine not quite answerable 

 to his expectation, from the difficulty of separating 

 the gold dust from the specular iron-ore (esmeril), 

 brown stone, antimony, and arsenic. A perfect 

 separation can probably never be obtained without 

 amalgamation ; but this method is at present al- 

 most wholly unknown in Brazil, where the general 

 deficiency in the proper management of the metal, 

 fully corresponds with the defective manner of 

 * See Note 6. page 204. 



