Qualitative Tests. 81 
8. An acidified solution of vanadates upon being 
shaken with hydrogen dioxide acquires a red tint; if 
ether is then added, and the solution shaken, its retains 
its color, the ether remaining colorless. 
ZINC, Zn. 
WITH THE BLOWPIPE. 
On Coal.—O. F. The oxide becomes yellow and 
luminous. 
R. F. Yellow coat, white when cold, assisted by 
soda and a little borax. 
With Cobalt Solution.—Moisten the coal in front 
of the assay, with the solution, and blow a strong R. F. 
upon the assay. The coat will be bright yellow-green 
when cold. 
Interfering Elements. 
Antimony.—Remove by strong O. F., or by heating 
with sulphur in closed tube. 
Cadmium, Lead, or Bismuth.—The combined coats 
will not prevent the cobalt-solution test. 
Tin.—The coats heated in an open tube, with char- 
coal dust by the O. F., may yield white sublimate of 
zine. 
IN THE WET WAY. 
1. Alkali hydroxides precipitate white Zn(OH):, 
soluble in excess of precipitant. 
. 2. HS precipitates (from neutral or acetic acid 
solution) white ZnS. 
3. K«FeCsNe percipitates white Zn:FeCsNe, insolu- 
ble in very dilute solutions of HCl. 
4. (NH:):S precipitates white ZnS, insoluble in 
KOH and HC:H:0:. 
Confirm.—By blowpipe test. 
Fureman’s “Manual of Practical Assaying.”’ Prof. Moses on “Useful 
Tests,’’ School of Mines Quarterly, vol. xi, no. 1. 
