COLLECTIONS IN ECONOMIC GEOLOCxY AND METALLURGY. (')9 



Tlicse two samples on analysis by the writer sbovvwd: 



Insoluble residue (810^) 



Suli.liuie of Lead (PbS) 



Suli>liide of zinc (ZnS) 



Sulphate of lead (PbSOj,) 



Oxide of lead (PbO) 



Oxide of ziuc (ZnO) 



Sesquioxide of iron (FejOs) 



Alumina (AI2O3) 



Liuie (CaO) 



Magnesia (MgO) 



Carbonic acid (CO2) 



On combustion they yielded 



Carbonic acid (COj) , 



Water(H50) 



(3) From first hopper, first row, blue room. (5510(1.) 



(4) From sixth hopper, second row, blue room. (55167.) 



(5) From first hopper, fourth row, blue room. (55168.) 



(6) From tenth hopper, fourth row, blue room. (.55169.) 

 Composition of the blue powders analyzed by the writer : 



Sulphide of lead (PbS) , 



Sulphate of lead (PbSOi) 



Oxide of lead (PbO) , 



Zinc (Zn) , 



Sestjuioxide of iron and alumina ((FeAl)203) 



Limo (CaO) 



Silica (SiOj) 



Carbonic acid (CO-^) 



Sulphurous acid (SO.j) 



Ou combustion yielded: 



Carbonic acid (CO-^) 



Water (HjO) 



55169. 



Percent. 

 8.61 

 43.57 

 44.18 

 0.61 

 0.07 

 0.02 

 0.14 

 0.08 

 0.44 



2.92 

 1.71 



(1) The roasted blue powder consists of oxidized compounds of lead, formed by- 

 roasting the blue powder. (55170). 

 An analysis by the writer yielded : 



Per cent. 



Sulphate of lead (PbS04) 4j^_ 7^ 



Oxide of lead (PbO) 46 8'^ 



Oxide of zinc (ZuO) ^j q~ 



Sesquioxide of iron (FcjOa) q .j.-) 



Alumina (Al.jOn) q q- 



Lime (CaO) q ^^ 



Silica (SiOj) q' jq 



Carbonic acid (COj) q yQ 



Snl.phurou8 acid (SO.) j (55 



Water (H.O) ............].... 37 



