ORDER IV. PKISMATIC BOKAX-SALT. 53 



(Pr + o>) 5 (r) = 88 9' ; (P) = 73 54' 



Pr + OD (Jl/) ; Pr + OD (T). 

 Char, of Comb. Hemi-prismatic. 



Combinations. 1. _. (Pr + ao) 5 . Pr + oo. 



. Pr+a>. 



3. . . Pr + oo. Pr + x. 



. . . 



Pr -|- oo. Fig. 51. 



Cleavage, f r -f- oo, perfect ; less distinct (Pr -J- oo) 3 ; 

 traces of Pr + oo. Fracture conchoidal. Sur- 



face of ?, ( j)l and (Pr + oo) 5 streaked pa- 



nl 2 



rallel to the edges of combination with -5. 



Jl 

 The rest of the faces smooth. 



Lustre resinous. Colour white, inclining to grey 

 and green. Streak white. Transparent . . . 

 translucent. 



Rather brittle. Hardness = 2-0... 2-5. Sp. Gr. 

 = 1'716. Taste sweetish alcaline, feeble. 



OBSERVATIONS. 



1. The natural borax consists, according to KLAPBOTH, of 

 Soda 14-5. 



Boracic-Acid 37-0. 

 Water 47-0. 



