In like manner glance cobalt is
1 atom disulphide of arsenic
1 atom disulphide of nickel.
Zinkenite is composed of
3 atoms sulphide of antimony
1 atom sulphide of lead;
and jamesonite of
2½ atoms sulphide of antimony
1 atom sulphide of lead.
Feather ore of antimony, hitherto confounded with sulphuret of antimony, is a compound of
5 atoms sulphide of antimony
3 atoms sulphide of lead.
Gray copper ore, which has hitherto appeared so difficult to be reduced to any thing like regularity, is composed of
1 atom sulphide of antimony or arsenic
2 atoms sulphide of copper or silver.