64 Lampic Acid. 
drochloric acids do not act readily on cadmium, but they in- 
stantly dissolve its oxide. The evaporated hydrochlorate attracts 
moisture; and at a heat below redness is volatilized. 
A neutral solution of the nitrate gives, with prussiate of potash, 
a white precipitate; with hydrosulphuret of ammonia, a fine 
bright yellow precipitate; with a solution of sulphuretted hy- 
drogen, a precipitate of the same colour, which passes to a crim- 
son when heated, but becomes yellow again on cooling; with 
oxalate of ammonia, a white precipitate insoluble in oxalic acid. 
Potash, ammonia, and their carbonates, give a white precipitate ; 
chromate of potash, succinate and benzoate of ammonia, in- 
fusion of galls and sulphate of soda cause no precipitation. 
Cadmium is readily precipitated by zinc from its solution in 
hydrochloric acid, in the metallic state ; but not so readily from 
nitric acid. 
When ammonia is employed to precipitate the oxide of ead- 
mium from its solution in an acid, the precipitate is redissolved 
by excess of the alkali: potash does not dissolve the oxide, but 
throws it down from its solution in ammonia—furnishing a ready 
method of separating it from zinc, and of ascertaining its pre- 
sence when accompanied by a large portion of that metal, as in 
blende. 
‘¢ Dissolve the mineral supposed to contain cadmium, in ni- 
tric acid; to the filtered solution add ammonia in excess, to 
throw down the oxides of iron,, and redissolve those of zinc and 
cadmium: pure hydrate of potash will then separate the latter, 
which, when redissolved in diluted hydrochloric acid, will afford 
the characteristic bright yellow precipitate on the addition of sul- 
phuretted hydrogen.’’— By this process Mr. Children separated 
the metal from a brown lameliar blende from Freyberg, furnished 
to him by Mr. Heuland. 
LAMPIC ACID. 
{n the course of his experiments on the nature and properties 
of flame, Sir Humpbry Davy made known the curious fact, that 
certain combustible bodies may be made to combine with oxy- 
gen at comparatively low temperatures. Sir Humphry’s disco- 
very was applied to the keeping a platinum wire in a state of 
ignition by means of a lamp with spirit of wine—the result by 
this slow combustion is a peculiar acid. To obtain this in larger 
quantities, J. F. Daniel, esq. employed the head of an alembic 
properly supported, to the beak of which he applied a receiver, 
and under its larger opening placed a small lamp, with a coil of 
platinum wire. In the account which he has published in the 
Journal of Science (No. XII.) he states that a little nicety is re- 
quisite in trimming the lamp, and in placing it so as to obtain ona 
est 
