Calcareous Genus. 



II. VARIETY. 



Tungften intimately mixed with Iron. 

 Red or Flefh-coloured Tungften. 



It does not effervefce with acids, fcaroely 

 gives fire with fteel ; is of a coarfe texture, 

 eaiily pulverized: its fpecific gravity from. 

 4,9 to 5,8 j becomes magnetic after calcina- 

 tion ; eafily melted with its own weight of 

 fluor ; with great difficulty affords about 30 

 per cent, of iron. Cronfted. Mem. Stock. 

 1751. Hence it is never ufed as an iron ore. 



Compound Species^ in 'which the Calcareous 

 Genus predominates. 



SPECIES I. 



Compounds of the different Jimple Species of 

 the Calcareous Genus; 



Here I place all the different compounds 

 of mild calcareous Earth and gypfum, or 

 fluor, or tungften, &c, which may occur; 

 alfo thofe of gypfum and fluor, gypfum and 

 tUiigften, or fluor and tungften, &c. which 

 may be placed as varieties of ^his compound 

 fpecies. 



SPECIES II. 



