152 ELEMENTS OF APPLIED MICROSCOPY. 
group, unaffected by acetic acid but volatilized by sul- 
phuric acid, includes nitrates, acetates, chlorates, ‘chlo- 
rides, bromides, iodides, cyanoferrates, cyaniferrates, and 
borates. The third group of non-volatile acids com- 
prises the sulphates, phosphates, arsenates, and arsenites 
(colorless solutions), the permanganates, bichromates, 
and chromates (colored solutions), and the silicates, 
molybdates, and tungstates (precipitates). 
In each case specific confirmatory tests are made 
for each of the acids indicated. In the two first groups 
the volatilization is repeated twice, once with silver 
nitrate and once with lead acetate on the upper watch- 
glass. Nitrates yield negative results with the first and 
octahedral crystals of lead nitrate with the second. Ace- 
tates show the long white prisms with rhombic ends 
characteristic of silver acetate, and no reaction with 
the second reagent. Chlorides are characterized by 
thick rhombic prisms of lead chloride and minute cubical 
crystals of silver chloride. In each case comparison 
with known substances makes it possible to identify the 
compound present without serious difficulty. 
REFERENCES. 
BreHrens, H. A Manual of Microchemical Analysis. Trans. 
by J. W. Jupp. London, 1894. _ 
Coun, A. O. Tests and Reagents, Chemical and Microscopical. 
New York, 1903. 
Hanavusek, T. F. Lehrbuch der technischen Mikroskopie. 
Stuttgart, rgor. 
Hinricus, C. G. Microchemical Analysis. St. Louis, 1904. 
LEHMANN, O. Die Krystallanalyse. Leipsic, 1891. 
Wormtey, T. G. The Microchemistry of Poisons. Phila- 
delphia, 1885. : 
