Clarke and Catlett — Nickel Ore from Canada. 373 



some chalcopyrite, possibly some pyrite, and a very little 

 quartz. Two samples were examined in mass ; one gave 3141 

 per cent of nickel with a little copper, the other gave 35*39 

 per cent of nickel and 5 -20 of copper. The nickel mineral 

 itself proved to be a sulphide of nickel and iron, and as ores 

 of that composition are not common, it was thought desirable 

 to examine the substance further. 



As above stated, the nickel mineral is the predominating 

 constituent of the masses submitted for examination. It is 

 steel- gray, massive, and exceedingly alterable in the air, and its 

 specific gravity, determined by pycnometer, is 4-54:1. An 

 analysis of carefully selected material gave the following re- 

 sults : 



Ni 41-96 



Fe 15-57 



Si0 2 1-02 



Cu -62 



S 40-80 



99-97 



Neither cobalt nor arsenic could be detected. 



The foregoing figures work out sharply into the ratio 

 R : S : : 4 : 5 ; and approximately into the formula Ni 3 FeS 6 . If 

 we deduct silica, together with the copper reckoned as admixed 

 chalcopyrite, and recalculate the remainder of the analysis to 

 one hundred per cent we have the following figures : 



As found. Calc. as Ni 3 FeS 5 . 



Ni 43-18 44-6 



Fe 15-47 14-4 



S 41-35 41-0 



100-00 100-0 



In short, the mineral has the composition Ni 4 S 5 , with about 

 •one-fourth of the nickel replaced by iron. The only known 

 species with which this agrees is Laspeyres's polyclymite, of 

 which the Sudbury mineral is evidently a ferriferous variety. 

 "What relations it may bear toward beyrichite, pyrrhotite, etc., 

 is as yet a matter of considerable uncertainty. Probably in 

 most cases the niccoliferous constituent of pyrrhotite is mill- 

 erite, but other sulphides, like the polydymite, may perhaps 

 occur also. 



The polydymite which was selected for the above analysis 

 came from the mass in which, in average, 35'39 Ni and 5*20 

 Cu had previously been found. The mass weighed several kil- 

 ograms, and was remarkably free from quartz. The same 

 mass, with two smaller pieces resembling it, were also examined 



