Cobalt Ores from the SJcutteruder Mine. 483 



however, that it contains a considerable quantity of cobalt; 

 three analyses gave the following composition: — 



1. 2. 3. 



17'57 sulphur 17*34; sulphur 18*06 sulphur. 



47*55 arsenic 46*7G arsenic 46'01 arsenic. 



26*54 iron 26*36 iron 26*97 iron. 



8*31 cobalt 9*01 cobalt 8*38 cobalt. 



99*97 99*47 99*42 



In a fourth analysis merely the quantities of iron and cobalt 

 were determined, and were found to be 28*77 iron, 6*50 co- 

 balt. In a fifth the cobalt was 10*8. 



All these analyses were performed with quantities of dif- 

 ferent crystals. 



From the difference in the relative quantities of iron and 

 cobalt it follows, that these two metals can remplace one 

 another, which is still more evident if the quantities of both 

 be added together, when each time the same sum is obtained. 



1. 2. 3. 4. 



Iron 26-54 26*36 26*97 28*77 



Cobalt 8*31 9*01 8*38 6*50 



34*85 35*37 35*35 35*27 



The formula for this mineral would therefore be the same 

 as that for arsenical iron, only that iron and cobalt are 

 united in the combination, viz. 



}«'-^:} 



As^ 



Co 



Fe /^ "^Fe 



On measuring the crystals the following angles were ob- 

 tained. 



Fig. 1. Fig. 2. 



In arseiAoal iron it 

 but slightly deviaiiug. 



M' = 111° 40- 



49 



2 



1. M 



2. M:M' = 111 



3. M:M'= 112 

 is M:M' = 111 



53', consequently 



2 K2 



