OF PALLADIUM AND PLATINUM. 
293 
solution so obtained, it becomes more reddish, and if set aside when of a sirupy 
consistence, and allowed to cool slowly, the nitrate of palladium crystallizes in long 
rhombic needles, which are, however, so deliquescent that I found it impossible to 
determine with accuracy the quantity of water of crystallization which they contain. 
In general, the solution of this salt dries down to a mass with scarcely any trace of 
crystalline structure. 
If a solution of nitrate of palladium be diluted with much water, a dark brown 
powder falls, which is a basic nitrate. It may be generated also by adding solution 
of potash, or water of ammonia in small quantity, to a solution of the metallic salt. 
This basic nitrate, when heated, evolves water, and then red fumes of nitrous acid ; 
leaving oxide or suboxide of palladium, according to the temperature to which the 
material may have been finally exposed. 
The following analyses will show that the basic nitrate, as prepared by different 
methods, is really of uniform constitution. 
A. Basic nitrate prepared by water of ammonia. 
60*808 grains of this specimen were placed in a tube of Bohemian glass, about 
twelve inches long, and in front of this, but completely separated by some rolled 
pieces of platinum foil, the tube was filled for a space of about four inches, with clean 
finely-divided metallic copper, as reduced from the oxide by hydrogen gas. To each 
end of the tube was attached a bulb-tube, containing recently fused chloride of cal- 
cium, and that next the metallic copper was placed, by a caoutchouc connecter, in 
communication with a vessel of water, by the flowing out of which a current of air 
might be established through the apparatus, precisely as is effected in the process 
proposed by Liebig for drying organic substances previous to analysis. The long 
tube containing the palladium salt and the metallic copper being placed in a charcoal 
furnace, that portion containing the copper was heated to redness, and then, whilst 
by the flowing out of the water a stream of air was brought through the tube, a gentle 
heat was applied to the basic nitrate of palladium. Water and red fumes were given 
off, which latter were reduced to the state of nitrogen or nitrous oxide by contact with 
the ignited metallic copper. The current of air, which had been accurately dried by 
passing through the first chloride of calcium tube, carried these products forwards. 
The water was collected by the chloride of calcium tube into which it passed, whilst 
the gases mixing with the general current of the air passed into the vessel from 
which the water flowed. 
As soon as the palladium salt had been feebly ignited, the process was interrupted, 
and the tube allowed to cool. It was then so cut by a file, as that the residual oxide 
of palladium could be removed without any sensible loss. It weighed 44*620 grains, 
or 73T5 per cent. The chloride of calcium tube in which the water had been col- 
lected, was weighed before and after the operation. The increase of weight was 
7*208 grains, indicating 11*85 per cent, of water. 
In order to verify the degree of oxidation and determine the quantity of metal in 
