Of WHINSTONE and LAVA. . 93 

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

 maining undiffolved weighed 68 per cent. 

 There are in loo parts, 



5» 



19 



14.50 



Silex, - " 



¥^^' ' ' ' I .^o- 



Oxyd of iron, - " _ ^^ 



Lime, - " " 



Soda, about 

 Muriatic acid, about 



4 

 I 



99. 



ANALYSIS" V. 



Lava St" Venere, Piedimonte, Mtna *. 



This fpecies gives, hke the preceding, a greyifh powder 

 .hich becomes dark grey when wet, and xts colour .s fcarcely 

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

 traaed by the magnet, whether in fmall fragments or xn pow- 

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



'^Tx^'ftftens 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, undiffolved. Its fpecific gravity is 

 2.823. 



In. 



* DoLOMiEU, in defcribing this lava, fays, that its fraaure is conchoidal, l.ke that 

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

 blackifli-blue : in other refpefts, however, it anfwered to DoLOMiEC'^defcnpuon. 



