44 Sketch of the Mine of Pasco. 



years, established as a merchant at Lima, has availed hlfiiself of his 

 opportunities, to make various collections, interesting to the fine and 

 useful arts, particularly of numerous and valuable pictures, and abo 

 of noble native specimens of silver, which he has brought home. The 

 box containing them, being left in trust with me, during the absence of 

 its owner in Europe ; I have, with permission, examined its contents 

 with some attention, and a brief notice of them seems not an inap- 

 propriate introduction to the Memoir of Mr. Rivero. 



1 . Among the numerous pieces of native silver, there is one pure 

 and solid piece, widiout pores or intermixture. It is seven inches 

 long, five and a half broad, and from three to two and a quarter thick. 

 Its weight exceeds fourteen pounds avoirdupois, and its value, as 

 silver merely, is over two hundred and thirty dollars. It is fromj the 

 mines of Pasco, and appears to be a fine exhibition of the full dimen- 

 sions of a rich vein or cavity of virgin silver, as it has the natural 

 faces by which it was joined to the rock or vein stone, (a calcareous 

 one as appears by very small adhering portions.) On one side only, 

 does it bear marks of having been cut and forced by instruments 

 from the rest of the vein. It exhibits the appearance of having been 

 a knob or protuberance. 



2. There are other pieces of native silver, from the size of a hand 

 to that of a walnut, in many accidental and imitative forms ; protu- 

 berant, dendritic, cellular, pectinated, reticular, &;c. 



3. Two specimens are worthy of being mentioned, on account of 

 the beauty of their crystallization ; especially as good crystals are 

 much more frequent among the ores, properly so called, than among 

 the native metals. 



In these pieces, which are from two and a quarter to three and a 

 half inches in length, the silver is of the most perfect whiteness, 

 without tarnish, and with the lustre of the polished metal ; and the 

 numerous crystals, both adhering in rich groups of many hundreds, 

 and being also interspersed tlirough brilliant white calc spar, make a 

 very splendid appearance. The figures are between the cube and 

 octohedron, — usually the cubo octohedron. The forms of the crys- 

 tals are not readily distinguished, without a magnifier. 



4. An elliptical ovoidal mass, four and a half inches long by three 

 and a half wide, and two and a half deep, nearly flat on one side. 

 It is porous in every part, and has the appearance of having been 

 produced by amalgamation, and of having been moulded, while in a 



