

1 88 Elements of Mineralogy. 



where, in the form of a white faline earth - 

 In this ore alum is formed by the action of 

 the phlogifticated vitriolic acid on argillaceous 

 lavas. -IOQ parts of it contain, according 

 to Mr. Bergmans analyfis, 88 of filiceous 

 earth, 4 of argillaceous, and 8 of alum; but 

 this proportion is variable. Before efflo- 

 refcence it is in a ftony form. 



5 th - Bituminous Alum Ore. Shale. 2 Wat- 

 fin, 314. This is a fhiftus impregnated with 

 fo much coaly matter or bitumen as to be in- 

 flammable ; it alfo contains fulphur. 120 

 parts of calcined fhale afford i of alum ; it 

 is found in Sweden^ and among the coal 

 mines at Whitehaijen^ and elfewhere. 8 Roz. 

 141. 



Alum might alfo be extracted from many 

 fpecies of pyrites, but fo contaminated with 

 iron as fcarce to quit coft > fo alfo from cala- 

 mineand pyritaceous wood. 



Native alum, mixed with vitriolic ammo- 

 niac, is found cryftalized on the borders of 

 the mineral lakes of Tufcany. 16 Roz. 363. 

 it is alfo found in a capillary form near the 

 lake of St. Agnano, in the grotto of St. 

 Germano. 37 Mem. Stock. 



SPECIES VIII. 



