94 CHEMICAL ANALYSIS 



In ioo parts I found, 



Silex, ' - - - - 50.75 



Argil, - - i 7 . 5 o 



Oxyd of iron, - 14*25 



Lime, - - - 10 



Soda, about - 4 



Muriatic acid, about - _ - 1 



97-50 



In analyzing thefe two lavas, I examined the different folu- 

 tions, with particular attention, for magneua, and fulphuric 

 acid ; but could not detect any traces of either of thefe fub- 

 ftances. 



The refults of thefe analyfes fhow, that whins, and a certain 

 clafs of lavas, taken from remote quarters of the globe, confift 

 of the fame component elements, united in each, nearly in the 

 fame proportion. The only circumftance in which they mate- 

 rially differ, is the lofs of fome volatile matter in the fire, which 

 is peculiar to the whins alone. 



We need not be now furprifed at the facts mentioned by Do- 

 lomieu, and others, of foda being found about volcanos, or up- 

 on the furface of lavas j as it has thus been mown to exift in 

 thefe fubftances in combination with their earthy bafes. 



^■BV*- 



The facts and experiments I am next to mention will prove, 

 that whins and lavas are not the only ftones which contain fo- 

 da; 



