Of WHINSTONE and LAVA, 93 



When boiled like the whins in muriatic acid, the part re- 

 maining undiflolved weighed 68 per cent. 

 There are in 100 parts, 



Silex, - - - - 5 1 



Argil, - - - - 19 



Oxydofiron, - l A-5° 



Lime, - - 9-5° 



Soda, about 4 



Muriatic acid, about - 1 



99. 



ANALYSIS V. 



Lava St<* Venere y Piedimonte, JEtna *. 



This fpecies gives, like the preceding, a greyifh powder, 

 which becomes dark grey when wet, and its colour is fcarcely 

 affected by being expofed to a low red heat. It is but feebly at- 

 tracted by the magnet, whether in fmall fragments or in pow- 

 der ; and its qualities in this refpect are not changed by low 

 ignition. 



It foftens at 32 of Wedgwood, and does not lofe any weight 

 in fires between 150 and 160. After being boiled in muriatic 

 acid, it left 68 parts per cent, undiflolved. Its fpecific gravity is 

 2.823. 



In. 



* Dolomieu, in defcribing this lava, fays, that its fra&ure is conchoidal, like that 

 of filex. The fpecimen which I analyzed had an uneven fracture ; and its colour was 

 blackifh-blue : in other refpefts, however, it anfwered to Dolomieu's defcription, 



