26S 
ON ANHYDROUS NITRIC ACID. 
ART. LX.— OBSERVATIONS ON ANHYDROUS NITRIC ACID 
By M. Deville. 
By treating nitrate of silver with absolutely dry chlorine 
M. Deville has succeeded in isolating anhydrous nitric acid, 
the existence of which is proved by numerous analyses. 
This beautiful substance forms perfectly transparent 
colorless crystals of great brilliancy, and capable of attain- 
ing a considerable size when slowly deposited in a current 
of gas strongly cooled. They are prisms of six faces, and 
are apparently derived from a right rhombic prism. They 
melt at a temperature a little above 85° F., and boil at 
about 113°. At 50° the tension of this substance is very 
considerable. In contact with water it -evolves much heat, 
and dissolves without any disengagement of gas or the pro- 
duction of any color, and then furnishes with baryta nitrate 
of baryta. Under the influence of heat its decomposition 
appears to begin very near its boiling point, which prevents 
the density of its vapor being determined by M. Dumas' 
process. 
The method by which M. Deville procured the anhy- 
drous acid is very simple ; but the ease with which it pene- 
trates caoutchouc tubes necessilates the uniting of all the 
parts of the apparatus before the blowpipe. The author 
employs a U-shaped tube, capable of containing 500 grms. 
of nitrate of silver dried in the apparatus at 356° in a cur- 
rent of dry carbonic acid. To this tube is joined another 
U-shaped tube of considerable size, and furnished at the 
bottom with a small spherical reservoir, in which a liquid, 
which is constantly developed during the operation, and 
which is excessively volatile, (nitrous acid ?) collects. The 
tube containing the nitrate of silver is immersed in water 
covered with a thin layer of oil, and heated by means of a 
spirit lamp communicating with a reservoir at a constant 
level. The chlorine is evolved from a glass gasometer, 
