404 DOMAIN XII. VOLCANIC. 



" No. IV. Light drosses in separate pieces; 

 the largest are ten inches long, one in width, 

 and two in breadth ; from this size they dimi- 

 nish to that of a pigeon' s-egg ; their pores are 

 rounded, glossy* vitrified, and of a pitch black ; 

 some of them seem to be damp as soot; seen 

 through a magnifying-glass, they appear a real 

 vitrifaction, porous, and of a greenish colour. 



" These drosses are found at a greater distance 

 from the crater than the former; some even as 

 far from it as six miles. 



Sand. " No. V. A very fine and shining sand, which, 



seen through a microscope, is found to be com- 

 posed of grains of volcanic chrysolites, trans- 

 parent, and of a golden green, and greenish 

 colour. Among the sand also are fragments oi 

 transparent quartz, and laminated felspar. 



" Sand of this description fell at Catania, on 

 the 18th of July. 



" No. VI. Light sand, formed of small grains 

 and filaments of a glossy vitrifaction, analogous 

 to the drosses No. IV. 



" This sand fell in every part of the second 

 region ; and on the confines of the first, from the 

 eastward to the south and south east, on the 

 18th of July ; it is mingled with fragments ol 

 the drosses before noticed. 



" No. VII. Puzzolana composed half of crys* 



