tg2 PHILOSOPHICAL TRANSACTIONS. [aNN0 1668. 



Observations in a Voyage from Spain to Mexico, particularly of the 

 Minerals in that Country. By an English Gentleman. N" 41 , p. 817- 



Nature has so prodigally enriched this country of Mexico with all sorts of 

 minerals, both perfect, imperfect, and mixed, that she almost overwhelms the 

 observation of the most diligent and curious naturalists. I have conversed with 

 the most skilful miners in those parts, but I found them to know of and care 

 for little about minerals, except gold and silver. I was once desired to visit a 

 famous cave there, some leagues from Mexico, on the north-west side of the 

 city, beyond the lake : this was said to be gilded all over with a kind of leaf- 

 gold, which had deluded many Spaniards with its promising colour, for they 

 never could reduce it into a body, either by quicksilver or fusion ; though the 

 fame ran, that the ancient Indians knew how to make use of it, and that the 

 great Montezuma had borrowed thence a considerable part of his treasure. I 

 rode thither one morniog, taking one Indian only for my guide. I found it 

 situated somewhat high, in a place very convenient for the generation of metals. 

 I went in with my candle lighted, but could not make the Indian follow me, 

 being afraid of spirits and hobgoblins. The light of the candle soon discovered 

 to me on all sides, but especially above my head, a glittering canopy of these 

 mineral leaves ; at which I greedily stretching forth my hand to reach some 

 parcels of it, there fell down so great a lump of sand on my head and shoulders, 

 that not only it put out my candle, but almost my eyes also. And calling out 

 with a loud voice to my Indian, who remained at the mouth of the entry, there 

 rebounded within those hollow caverns such thundering and redoubled echoes, 

 that I admired it, and the Indian imagining by those tumultuous voices that I 

 was wrestling with some infernal ghosts, soon quitted his station, and thereby 

 left a free passage for some rays of light to enter, and to serve me for a better 

 guide ; my sight mean while being not a little endangered by the corrosive acri- 

 mony of the mineral dust. Having got my candle lighted again, I proceeded 

 in the cave, and heaped together a quantity of the mineral mixed with sand, 

 and scraped also from the surface of the earth a quantity of the same kind of 

 glittering leaves, none of which exceed the breadth of a man's nail ; with the 

 least handling they divide themselves into many lesser spangles, and with a 

 little rubbing they leave the hand all gilded over like gold. I began first to 

 make experiment on the sand, which had been the matrix of the mineral ; and 

 there I tried first the ordinary way used in the Indies on such occasions, which 

 was, to observe the colour of the fumes yielded from the spangled sand in a 

 strong reverberating fire ; but here little could be observed, by reason of the 



