406 CHARACTEHISTIC. GLASS I. 



2. TETARTO-PRISMATIC. Tetarto-prismatic. 



Cleavage, two faces, one of them more apparent ; both 



indistinct. Inclination = 124 2'. 

 Colour blue. 

 H. = 2-5. 

 G. = 2-2 ... 2-3. 



Blue Vitriol. J. ii. 44. 



3. PRISMATIC. Prismatic. P + 03 =90 42'. 



Cleavage, Pr + co, perfect. 

 Colour white. 

 H. = 2-0 ... 2-5. 

 G. = 2-0 ... 2-1. 



White Vitriol. J. ii. 46. 



VII. EPSOM-SALT. Prismatic. 



Taste saline, bitter. 

 H. = 2-0 ... 2-5. 

 G. = 1-7 ... 1-8. 



1. PRISMATIC. Prismatic. P + co = 90 38'. 

 Cleavage, Pr + co, perfect. 



Prismatic Epsom Salt. J. ii. 48. 



VIII. ALUM-SALT. Tessular. 

 Taste sweetish, astringent. 

 H. = 2-0 ... 2-5. 



G. = 1-7 ... 1-8. 



1. OCTAHEDRAL. Tessular.. 

 Cleavage, octahedron. 



ii. 5Q. 



IX. BORAX-SALT. Prismatic. 



Taste sweetish, feebly alcaline. 

 H, = 2-0 ... 2-5. 

 G. = 1-7 ... 1-8. 



