49 



(arena cyanea). Near Talca, the capital of the 

 province of Maule, is a little hill which furnishes a 

 species of cement sand, known by the name of Talca 

 sand (arena talcensis). This sand is finer than that 

 of Puzzoli in Italy, and appears, to be a volcanic 

 production, as its earthy and ferruginous parts are 

 half calcined. The inhabitants employ it in their 

 buildings for those walls which they intend to whiten, 

 as of itself it forms a very strong cement, to which 

 the lime adheres firmly. 



Sect. VII. Stones. — In Chili, a country whose 

 mineralogy is so imperfectly known, very few new 

 species of stones have been discovered, in either of 

 the four orders into which naturalists have divided 

 them. In the short excursions which my occupa- 

 tions allowed me to make among the mountains, I 

 have noticed, of the argillaceous kind, various sorts 

 of schistus, slate, talc, asbestos and mica. Of the 

 latter the membranaceous mica of Chili, otherwise 

 called Muscovy glass, is found there in its greatest 

 perfection, both as respects its transparency and the 

 size of its laminae ; of this substance the country 

 people manufacture artificial flowers, and, like the 

 Russians, make use of it for glazing their houses/ 

 The thin plates which are used for windows are by 

 many preferred to glass, from their being pliable 

 and less fragile, and possessing what appears to be 

 a peculiar property, of freely admitting the light' 

 and a vievv^ of external objects to those within, while 



persons without are prevented from seeing any thing 

 Vol. I. I 



