200 



tli8 deposits, however, have this feature in common, that they 

 both occur in the vicinity of cross-courses. The active mate- 

 rial is apparently of secondary origin. So far, only a few 

 pounds of ore showing any marked activity have been found. 



The Treuer's Shaft ore is of moderately high specific 

 gravity, is nearly black in colour, and as a general rule con- 

 siderably decomposed. The copper contents are high, as 

 will be seen from the analyses given subsequently, and most 

 specimens are characterized by the presence of small crystals 

 of smoky quartz. 



The active ore from Taylor's Shaft resembles brown coal 

 as much as anything else, it breaks readily with a lustrous 

 €onchoidal fracture ; some specimens are of very low specific 

 gravity (I'SS), and are remarkable for the large amount of 

 carbon they contain. 



Some considerable progress was made in the direction 

 of isolating the active material before any detailed chemical 

 analyses were made, and this preliminary work, done on a 

 few grammes of ore, is of interest in that it determined the 

 method for extracting and concentrating the activity from 

 larger quantities of material. 



On decomposing the finely-ground roasted ore with aqua 

 regia, the insoluble residue was found to be nearly inactive. 



The metals of the copper group were precipitated with 

 sulphuretted hydrogen. With regard to this precipitate, on 

 the only occasion when a measurement was made it showed 

 distinct activity when first separated, but this diminished 

 rapidly, and in twenty-four hours had practically disappeared. 



The bulk of the activity appeared to concentrate in the 

 hydrate precipitate, thrown down on the addition of ammo- 

 nia to the filtrate from the copper group, after the sulphur- 

 etted hydrogen had been expelled and the iron in the solu- 

 tion oxidized. The filtrate from this on being evaporated 

 down yielded a residue, which showed very little activity. 

 One lot of hydrate precipitate dissolved in nitric acid yielded 

 a small amount of precipitate of high activity on the addition 

 of ammonium oxalate, but this result requires confirmation. 



Further work having shown that the active constituent 

 was not readily soluble in sulphuric acid, ten grammes of 

 ore were treated as follows : — 



The ore was decomposed as before with aqua regia, the 

 insoluble residue filtered off, and the solution evaporated to 

 a small bulk ; a few c.c. of sulphuric acid were added, and the 

 evaporation continued on an air-bath until white fumes were 

 freely evolved. 



The mass after cooling was taken up with water and 

 heated for some time ; a small amount of white precipitate 



