xxxiv Historical Sketch of the Physical Sciences, 1818. 
in sulphuric and muriatic acids with the evolution of hydrogen 
gas ; but the solutions in these last two acids go on very slowly. 
‘All the acid solutions of cadmium are colourless; and the salts 
which it forms with acids are white. 
The sulphate, nitrate, muriate, and acetate of cadmium, crys- 
tallize readily, and are very soluble. The phosphate, carbonate, 
and oxalate of cadmium are insoluble. ‘ 
The oxide is thrown down white by the fixed alkalies, probably 
in the state ofa hydrate. Ammonia, and likewise its carbonate, 
redissolves the precipitated oxide. Hence it is easy, by means of 
carhonate of ammonia, to separate cadmium from zinc or copper 
when they happen to be mixed. 
Prussiate of potash throws it down white; sulphuretted hydro- 
gen, or a hydrosulphuret, throws it down yellow. 
Zinc precipitates cadmium from its acid solutions in the metallic 
state ; but cadmium throws down copper, lead, silver, and gold, 
in the metallic state. It belongs, therefore, to my fourth family 
of alkalifiable combustibles, and must be placed immediately 
after zinc.—(See Annals of Philosophy, xii. 108.) 
2. Vestium.—The characters of this metal have been so 
imperfectly ascertained, and Mr. West’s paper on the subject 
has appeared so lately in the Annals of Philosophy that it will 
be sufficient, I conceive, to refer those readers who are curious 
on the subject to the paper itself. 
3. Wodanium.—The few characters of this metal which have 
been communicated to the public by Lampadius (see Annals of 
Philosophy, xiii. 232) are sufficient to satisfy us that it is entitled 
to be considered as a peculiar metal. 
Its colour is bronze yellow; it is malleable; has a hackly 
fracture ; the hardness of fluor spar; and is strongly attracted 
by the magnet. Its specific gravity 1s 11-470. 
Its oxide is black, and is easily formed by heating itin contact . 
with the air. 
It dissolves im acids, and the solutions have a light wine- 
yellow tinge. The alkaline carbonates throw it down white ; 
caustic ammonia precipitates it blue. 
Nitric acid dissolves both the metal and the oxide with faci- 
lity, and the solution yields white needle-form crystals, which 
dissolve readily in water. 
A plate of zine throws it down black. Prussiate of potash 
throws it down pearl grey. 
4. Cyadide of Potasstum.—When potash is calcined with an 
animal substance, the compound formed is not a cyadide of 
potash, but a cyadide of potassium; for if cyanogen be united 
directly with potassium and the compound be dissolved in water, 
it is converted into hydrocyanate of potash. Acids decompose 
it, hydrocyanic acid is disengaged, and no ammonia is formed ; 
but if cyanogen be absorbed by a solution of potash, and an acid 
be added to the solution, there are disengaged carbonic acid, 
