456 DOMAIN XII. VOLCANIC. 



contrast, and render the glass irregularly spot- 

 ted. I have large pieces of the fifth sort cut and 

 polished: their colour, which is that of pitch, 

 gives them a peculiar beauty. The blackest 

 and choicest marbles of Varena and Verona are 

 far inferior to them in fineness of grain and 

 lustre ; yet, from their uniformity of colour, they 

 are less beautiful than this spotted glass, when it 

 has received a delicate polish from the hands of 

 the artist. On the shore, where the torrent fell 

 into the sea, we find pieces of all sizes, rounded 

 and smoothed by the continual agitation of the 

 sea: I have met with more than one of half a 

 foot and a foot in diameter. Notwithstanding 

 the powerful action of the waves, which have 

 beaten on them for so long a time, their internal 

 parts are not injured ; and, when cut and po- 

 lished, they present surfaces very beautiful to 

 the eye. Tablets of this kind of glass (and 

 there is no want of pieces of a proper size to 

 form them) would add much to the grandeur 

 and splendour of any sumptuous gallery. 

 Origin. But disregarding the beauty which delights 

 the eye, let us proceed to objects that attract 

 and interest the curiosity of the philosophical 

 inquirer. We shall find that the cinereous bo- 

 dies included in this glass are only points of lava 

 with a felspar base ; and on examining in va- 



