406 DOMAIN XII. VOLCANIC. 



amid which they are found, on account of their 

 singular shape. 



cc They are collected on the cone of Etna, 

 lying among light drosses. 



"No. IX. Other pieces of the same form, 

 but more compact : the surface of these is more 

 smooth, and is sprinkled with white spots, which 

 seem produced by the vitrifaction of the felspar; 

 the internal part of these pieces assimilates with 

 obsidian. 



" These are found in the same place as the 

 last. 



" No. X. Oval pieces, nearly two inches in 

 length, composed of two parts of white felspar 

 transparent and glazed, some yellow chrysolites, 

 and some prismatic crystals of black schorl; the 

 surface of this specimen was changed by fire, 

 which had chiefly affected the schorl, occasion- 

 ing it to lose its angles. 



" Found near the crater. 



" No. XI. A compound stone, divisible in 

 parts, with a vitreous incrustation : one portion 

 exactly resembling lava, which elicits sparks 

 when struck with steel; the laminae are distin- 

 guished one from the other by their different 

 colours, the result of a calcination which has 

 acted differently on the various component mat- 

 ters; in it mica and felspar are found in an un- 



