Qualitative Tests. 63 
COPPER, Cu. 
WITH THE BLOWPIPE. 
On Coal, R. F.—Formation of red metallic metal. 
Flame.—Emerald-green or azure-blue, according 
to compound. The azure-blue flame may be obtained 
(sulphur, selenium, and arsenic should be removed by 
roasting; lead necessitates a gentle heat)— 
(a) By moistening with HCl or aqua regia, drying 
gently in O. F., and heating strongly in R. F.; 
(b) By saturating S. Ph. bead with substance, add- 
ing common salt, and treating with blue flame. 
With Borax or S. Ph—O. F. Green hot, blue or 
greenish blue cold. (By repeated slow oxidation and 
reduction, a borax bead becomes ruby-red. ) 
R. F. Greenish or colorless hot, opaque and brown- 
ish red cold. With tin on coal this reaction is more 
delicate. ' 
Interfering Elements. 
General Method.—Roast thoroughly, treat with bo- 
rax on coal in strong R. F. (oxides, sulphides, sulphates, 
are best reduced by a mixture of soda and borax), and— 
If Button Forms.—Separate the button from the 
slag, remove any lead from it by O. F., and make either 
S. Ph. or flame test upon residual button. 
If No Visible Button Forms.—Add test lead to the 
borax fusion, continue the reduction, separate the but- 
ton, and treat as in next test (lead alloy). 
Lead or Bismuth Alloys——Treat with frequently 
changed boracic acid in strong R. F., noting the ap- 
pearance of slag and residual button. 
Trace.—A red spot in the slag. 
Over One Per Cent.—The residual button will be 
bluish green; when melted will dissolve in the slag and 
color it red upon application of the O. F., or may be re- 
