60 
PROFESSOR GRAHAM ON THE CONSTITUTION OF 
This view seems likewise to be necessary to account for the great force with which 
the single atom of water is retained by the subnitrate of copper. The water cannot 
be expelled without decomposing the salt, notwithstanding the great excess of oxide 
of copper present. 
4. Nitrate and Subnitrate of Bismuth. 
BiN H s 
H N Bi 3 
The neutral nitrate is admitted to contain three atoms of water, like the nitrate of 
copper, and its constitution appears to be similar. 
No portion of the constitutional water of this salt can be expelled without decom- 
posing the salt. Indeed this salt loses acid by exposure to dry air at a temperature 
not exceeding 80° Fahr. The crystals of the salt are resolved by a heat of 212° into 
a solid and fluid portion, the first of which is probably the subnitrate, while the last 
is hydrated nitric acid containing much nitrate of bismuth in solution, and not a 
supernitrate of bismuth. But the fluid portion fixes so readily upon cooling that 
the solid product cannot be obtained in a definite state. 
Experiment. 28*63 grains of nitrate of bismuth in good crystals, being exposed to 
a gradual ignition, left 14T6 grains of fused oxide of bismuth. This result accords 
with the view which is taken above of the composition of this salt : 
Experiment. Theory, 
Oxide of bismuth ..... 14T6 100* 100* 
Nitric acid and water . . . 14*45 102*04 102*72 
28*61 202*04 202*72 
It appears likewise that three atoms of the hydrated nitrate of bismuth are re- 
solved, when dried at a high temperature, into two atoms hydrated nitrate of water 
and one atom subnitrate of bismuth, which last is of the same constitution as the 
subnitrate of copper. 
Experiment 1 . Dried on the sand bath at a temperature above the melting point of 
tin, 28*61 grains of nitrate of bismuth lost 9*29 grains, and retained 5*16 grains of 
volatile matter, or consisted of 
Experiment. Subnitrate by theory. 
Oxide of bismuth. .... 14*16 100* 100* 
Volatile matter ..... 5*16 36*44 34*24 
19*32 136*44 134*24 
Experiment 2. A portion of nitrate dried in a stove at a temperature not exceeding 
180° Fahr., till it ceased to lose weight, was thereafter found to consist of 
Oxide of bismuth 21*24 100* 
Volatile matter „ 7'57 35*64 
28*81 
135*64 
