55 



(Iocs not effervesce with acids, and instead of 

 losing in the the anj portion of its shining 

 wJiitenesSj it a'-finires a slight degree of trans- 

 })arency. From its external appearance, when I 

 fust saw tills clay, I supposed it a kind of 

 fuller's earth very common in the country ; but 

 I af:erwards discovered that it was not lamellous, 

 was easily wrought, and retained the form 

 tliat was given it, and, although saponaceous to 

 the touch, did not foam with water. These cir- 

 cumstances induce me to believe that this clay 

 is very analogous to the kaolin of the Chinese, 

 and that combined with fusible spar, of which 

 there are great quantities in the same province, 

 it would furnish an excellent porcelain. 



The third species is the subdola (argilla 

 subdola) so called from the places where it is 

 found, which are usually marshes, containing 

 pits very dangerous for animals, especially horses, 

 \s\w, if they fall in them, are sure to perish 

 unless immediate assistance is obtained. This 

 clay is black, viscous, and composed of carse 

 particles of various sizes ; the ])its are from 

 hfteen to tv^enty feet in circumference, and of an 

 immense depth. Walleruis and Linnaeus de- 

 MTii)e a clav, found in Sweden, that has resem- 

 blance to this, to which they have given the 

 name \.^^ aV2,illa tumcscciu, but on investigation it 

 appears to be very diirer(Mit botli in its colour 

 a ;d properties. The Chilian clay is a little 



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