Calcareous Genus. 37 



SERIES II. 



Opake. 



i 



Thefe are diftinguifhed by the fame co- 

 lours ; their texture alfo is generally the 

 fame, but it is faid to be fometimes granular ; 

 their form is alfo regular, or amorphous, like 

 the foregoing. 



The phofphorefcent property of fluors 

 feems to arife not from the acid fingly, other- 

 wife all fluors would poflefs it, but from the 

 acid, in contadt with metallic particles, and 

 confequently from the acid and phlogifton, 



SPECIES IV, 

 Combined with the T'ungflen Arid* 



Tungftetii Lapis Ponderofus y Schiverere Zin- 

 graupen of the Germany. 



When pure it is of a grey colour and lamel- 

 lar texture, gives fire with fteel, and is very 

 weighty, its fpecific gravity being from 4,99 

 to 5,8. 



It is infoluble in acids, except by peculiar 



management; when powdered and digefted 



P 3 with 



