Cobalt Ores from the Skutteruder 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*76 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. 
Fe° + 
On measuring the crystals the following angles were Ob'- 
tained. 
Fig, 
1 . 
Fig. 2. 
1. M :M' = 111° 40' 
2. M:M' = 111 49 
3. M:M'=112 2 
In arsenical iron it is M:M' = 111° 53', consequently 
but slightly deviating. 
2 K2 
