47 



and Frazier as superior to the best European 

 blacks. This clay is of a very fine grain, of a deep 

 black, a little bituminous, and very vitriolic ; it is 

 found in almost all the forests, and has the property 

 of communicating to pieces of wood that are buri- 

 ed in it for a short time, a sort of black varnish, very 

 shining and durable. The colour is obtained by 

 boiling the clay with the leaves of a plant called the 

 panke tinctoria^ hereafter described. 



The grey clay, which is the fifth species, possesses 

 all the properties requisite for pottery. It appears to 

 be of a kind suitable for retorts, crucibles, &c. as 

 the vessels that I have seen of it are very strong, and 

 capable of resisting the most violent fire. 



Among the calcareous earths is a kind of lime or 

 gravelly chalk, found in the Cordilleras, in quarries 

 of many miles in extent and of a depth hitherto un- 

 explored. I have given it the name of volcanic 

 lime (calx vulcanica) as I am convinced it was ori- 

 ginally marble reduced to this state by Volcanoes or 

 subterranean fires. Its surface appears to have 

 been burnt, and the surrounding mountains aíFord 

 unequivocal proofs of an extinguished volcano. 



This substance is distinguished from common 

 lime by several particulars : it is not so caustic even 

 when burnt; and, when mixed with acids, eíFervesces 

 but slightly, and deposits a neutral salt of a very 

 irregular crystallization. The only use to which 

 this lime is applied by the inhabitants is to white- 

 wash their houses. It is of two kinds, one perfectly- 

 white and easily reducible to an impalpable powder, 

 found in the mountains of Chalcagua and Maule \ 



