74 Qualitative Tests. 
if the fluid remains long in contact with the copper, it 
turns bright red from separation of selenium. 
Confirm.—By blowpipe tests. 
SILICON, Si. 
WITH THE BLOWPIPE. 
On Coal, with Soda.—With its own volume of soda, 
disolves with effervescence to a clear bead. With more 
soda the bead is opaque. 
With Borax.—Clear and colorless. 
With S. Ph.—Insoluble. The test made upon a 
small fragment will usually show a translucent mass of 
undissolved matter of the shape of the original frag- 
ment. 
When not decomposed by S. Ph., dissolve in borax 
nearly to saturation, add 8S. Ph., and re-heat for a mo- 
ment. The bead will become milky or opaque-white. 
IN THE WET WAY. . 
Silicates are determined by the separation of SiO:. 
Fuse with Na:COstNaNOs, dissolve in HCl, and evap- 
orate to dryness. Upon evaporation gelatinous silica 
will separate out. Upon heating and dissolving with 
HCl insoluble SiO: remains behind. | 
Confirm.—By blowpipe test. 
SILVER, Ag. 
WITH THE BLOWPIPE. 
On Coal.—Reduction to malleable white metal. 
With Borax or S. Ph.—O. F. Opalescent. 
Cupellation—Fuse on coal with one volume of 
borax-glass and one to two volumes of test-lead in R. 
F. for about two minutes. Remove button and scorify 
it in R. F. with fresh borax, then place button on cupel 
and blow O. F. across it, using as strong blast and as 
little flame as are consistent with keeping button 
melted. 
