59 



Sect. VII. Stones. In Chili, a country 

 whose mineralogy is so imperfectly known, very 

 few new species of stones Iiavc been discovered;, 

 in either of the four orders into which naturalists 

 have divided them. In the short excursions 

 which my occupations allowed me to make among 

 the mountains, I have noticed, of the argilla- 

 ceous kind^ various sorts of schistus, sla(e, talc, 

 asbestos, and mica. Of the latter the membra- 

 naceous mica of Chili, oth( rwise called Mus- 

 covy glass, is found there in its greatest perfec- 

 tion, both as respects its transparency and the 

 size of its laminas ; of this substance the country 

 people manufacture artiticial flowers, and, like 

 the Russians, make use of it for glazing their 

 houses. The thin plates which are us^ed for 

 windows are by many preferred to g^ass^ from 

 their being pliable and \es fragile, and possess- 

 ing what appears a pc culiar property, of fi'cely 

 admitting the light and a view of external ob- 

 jects to those within, while persons without are 

 prevented from seeing any thing in tlie house. 

 It is as white and transparent as tlie best :lass, 

 and is frequently found in plates of a foK)t l;>n-; 

 and I am convinced, if a little care was used in 

 digging it, they might he procured of double 

 that size. There is a second kind, foi:nd in very 

 large plates, which i have called /,v/Vyz rarkgata.. 

 It is spotted with yellow, red, and blue; but as it 



