( 25S ) 



mann found the portion of filex to he 

 greateft, that of alumine, little, and that of 

 lime, leaf!:. 



Another, analyzed by Wiegleb, gave 



Silex - - - 65 



Alumine - - - i5 

 Iron - - « ^ 



The other 14. parts requifite to com- 

 plete the 100 were difperfed in the opera- 

 tion -. 



A third by Gmelin 



Silex - - - 90 



Alumine - - - 7 



Iron - - - 2 



The pitch-ftone lavas of the Euganean 

 mountains having never to my knowledge 

 been analyfcd, I undertook this operation 

 on the three fpecies mentioned above ; and 

 the following were the refults : 



* KIrwan's Mineralogy, 



Pitch- 



