PEOFESSOE EOSCOE’S EESEAECHES ON VANADIUM. 
329 
acid, yielded 0-1515 of V 2 0 5 , or contained 11-75 per cent, of vanadium, the percentage 
required by the formula being 12-04. 
3. Lead Ortliovanadate arid Lead Chloride , artificial Vanadinite, 3(Pb 3 (V0 4 ) 2 )Pb Cl 2 , 
3VO"' 
or lead trivan ado-chlorby dine, Pb 5 
Cl 
If oxide of lead, vanadic acid, and chloride of lead be fused together for a few hours 
in the proportions in which they are contained in the above formula, the mass after 
slowly cooling is found to consist of a greyish-yellow crystalline substance, in the inter- 
stices of which groups of needle-shaped crystals occur. The fused mass on boiling in 
water is soon reduced to a powder entirely consisting of fine crystals. This crystalline 
powder is boiled with water until no further trace of chlorine can be detected in the 
washings when it is dried ready for analysis. The crystals obtained were too small for 
measurement ; they were, however, seen to consist of hexagonal prisms ; the faces of the 
hexagonal pyramid could not be identified. The crystals have a yellow colour, and pos- 
sess the waxy lustre characteristic of the natural mineral. 
(1) 0-738 substance fused with Na 2 CO :5 gave 0-0525 AgCl and 0-0122 Ag, or 2-33 
per cent, of chlorine. 
(2) 0-4135 substance dissolved in nitric acid and precipitated with silver nitrate, gave 
0-0347 AgCl and 0-0003 Ag, or 2-17 per cent, of chlorine. 
(3) 0-5582 substance dissolved in nitric acid and precipitated with sulphuric acid, gave 
0-5881 Pb S0 4 , or 71-96 per cent, of lead, and 0-1104 of V 2 0 5 , corresponding to 1T11 
per cent, of vanadium. 
(4) 0-5443 substance of another preparation, dissolved in nitric acid and precipitated 
with silver nitrate, gave 0-045 AgCl and 0-0035 Ag, corresponding to 2-17 per cent, 
chlorine, and 0-5705 Pb S0 4 , or 71-57 per cent, of lead. 
The following gives the composition of various specimens of natural vanadinites com- 
pared with that of the artificial mineral : — 
Natural vanadinites. 
c ^ ^ Artificial vanadinites. 
Calculated Zimapan 
Windischkappel 
Wieldow. 
Beresesowsk 
, 
h 
3(Pb 3 (V(J 4 ) 2 )Pb Cl 2 . (.Berzelius), (ltammelsberg). 
(Struve). 
(1) 
(2) 
Lead . . 73-08 70-40 
71-20 
68-72 
73-76 
71-96 
71-57 
Vanadium . 10-86 
9-77 
1315 
9-54 
11-11 
Phosphorus 
■ 
1-34 
Chlorine . 2 -56 2-54 
2-23 
2-44 
2-46 
2-33 
2-17 
Oxygen. . 13*55 
The specific gravity of the artificial vanadinite at 12° C. is 6-707, that of the natural 
mineral varies from 6-66 to 7-2*. 
* Pyromorphite and apatite were prepared artificially for the first time in 1852 by Makross (Ann. Ch. 
Pharm. lxxxii. p. 348), and afterwards by Deville and Caron, and Debray. Mimetesite has also been re- 
cently artificially prepared by Lechartier (Comptes Eendus, 1867, lxv. p. 172). 
