68 JOURNAL OF THE 



3a=Rhombic system 



3b=Monoclinic system 



3c has no system 



3d=Triclinic system. 



By this conception we excinde from the possibilities of crystal 

 form lb. lc. Id. because equality of length among the three 

 axes is always connected with rectangularity of intersection. 

 We exclude also 2c. and 2d. because with axes of two different 

 values no other conceptions are crystallographically possible than 

 that of rectangularity of intersection, as in the Tetragonal sys- 

 tem, and obliquity of intersection as in the Hexagonal system. 

 Lastly we exclude 3c. because with axes of three different values, 

 we do not have, in crystals, one of the axes oblique to the rect- 

 angular intersection of the other two. 



(Compare V. v. Lang, Lehrb. der Krystallog. S. 99; Sohncke, 

 Entw. einer Theorie der Krystallstructur, Leipzig, 1879, and an 

 article by Sohncke, Ann. d. Phys. u. Chem. Bd. 132). 



CHLORINATION OF AURIFEROUS SULPHIDES. 



E. A. THIES. 



Chlorination is the name applied to the treatment of oxidized 

 gold ores with free chlorine, and the success of the process de- 

 pends upon thoroughness of the previous oxidation. 



The material employed is auriferous pyrite containing also 

 from one to two per cent, copper in the shape of sulphide. 



At the Phoenix Mine, in Cabarrus county, the gangue is 

 quartz with varying amount of heavy spar (Barite). 



The ore from the mine is passed through a Blake crusher and 

 stamped in ordinary ten stamp mill for the purpose of pulver- 

 izing it to 40 mesh and saving most of the free gold, which is 

 always present. The shines are passed over True Vanuer con- 



