The salts of cadmium are decomposed by the alkalies. By the addition of potassa or soda to the solution of the nitrate, the sulphate, or muriate, a precipitate of a white colour is thrown down, which is not soluble in an excess of alkali. The precipitate is supposed to be the yellow oxide, in combination with water, which gives it the white colour. By the addition of ammonia to these salts, the same precipitate is formed, but is dissolved on adding an excess of the alkali.
Sulphuretted hydrogen, and the hydro-sulphurct of an alkuii, throw down a yellow precipitate, which, when dried, acquires an orange yellow colour, something simi lar to orpiment. The precipitate formed in this case is considered a hydro-sulphuret ; it is recommended as a yellow pigment, for which, from its durability, it seems well adapted.
Prussiate of potassa, when added to a solution of a salt of cadmium, throws down a white precipitate. Cadmium is precipitated in the metallic state, from a solution of any of its salts by zinc, the precipitate put ting on the dendritic form. On the contrary, when a piece of cadmium is put into a solution of a salt of gold, silver, copper, or lead, these metals are precipi tated.
Nitrate of cadmium crystallizes in prisms, and is de liquescent. It is composed of 110 acid, 117.50 oxide.
Carbonate of Cadmium is insoluble in water. Its component parts are 100 acid, 292.88 oxide.
Phosphate of Cadmium is also insoluble. When ex posed to a red heat it melts into a transparent glass. It is composed of 100 acid, 225.49 oxide.
Borate of Cadmium is little soluble. When dry it is composed of 27.88 acid, 72.12 oxide.
Sulphate of Cadmium is obtained in large rectangular transparent crystals, which are very soluble in water. It is efflorescent, and when exposed to a strong heat is decomposed, and forms a sub-sulphate. The sulphate is composed of 100 acid, 161.12 oxide.
Acetate of Cadmium is soluble and crystallizable. Tartrate and Citrate of Cadmium arc little soluble. Oxalate of Cadmium is insoluble.
Cadmium unites with other metals, and forms alloys, which are brittle.
The alloy with copper has a slight tinge of yellow. By the application of .1 strong heat to it the cadmium is vo latilized. It is composed of 100 copper, 84.2 cadmium.
When the cadmium does not exceed the one-hun dredth part of the copper, the latter is rendered very brittle. As however the cadmium is expelled by the application of heat to the alloy of these metals, there is no danger of brass made with the substances which con tain cadmium being injured by the presence of the latter met tl.
The alloy with mercury. Cadmium combines with mercury with vtat facility, and forms a hard brittle alloy, fusible at 167°. It is composed of 100 mercury, 27.78 cadmium.
The alloy with platinum is composed of 100 platinum, 111.3 cadmium.
The alloy with cobalt is brittle, and not easily fused.
Wodanium.
Lampadius, when examining a mineral supposed to contain cobalt, discovered in it a new metal, to which he has given the name of wodanium. The mineral in which this was found has a metallic lustre, and a greyish colour : its specific gravity was 5.192.
Wodanium has a bronze yellow colour ; it is mallea ble, and strongly attracted by the magnet. Its specific gravity is 11.47.
When exposed to the air it is not tarnished ; when subjected to heat in contact with the air it is oxi dated.
Nitric acid acts on wodanium ; and forms a solution which affords colourless needle-formed crystals, which are very soluble in water. By the addition of ammonia to the solution of a salt of wodanium, a blue precipitate is thrown down. The alkaline phosphates and the arseniates do not afford any precipitate.
Prussiate of potassa throws down a pear-grey preci pitate.
A piece of zinc, immersed in the solution of the mu riate, precipitates a black metallic powder.
The infusion of nut-galls does not cause any change when added to a solution ol a salt of wodanium.
Vestium, or Sirium.
According to Dr. Vest, there exists in the cobalt ore of Schladming, in Upper Steiermark, a peculiar metal, to which the name of Vestium has been given.
To procure this metal, the ore, after being freed from its impurities, was mixed with powdered glass, and fused ; what remained was digested in nitric acid, and the arsenic which was dissolved was separated by the addition of acetate of lead and sulphuretted hydrogen. Carbonate of potassa was then added, which threw down the oxide of iron. By evaporating the filtered fluid, a flaky substance was separated, which was a salt of vestium. By the addition of potassa to the fluid after filtration, a precipitate fell, which was dissolved in sulphuric acid. To the solution, sulphate of potassa was added, and another portion of the flaky matter was deposited, mixed with a salt of nickel. These were separated in a great measure by washing. To obtain the salt of vestium pure, the matter deposited was mixed with sulphate of potassa, dissolved in water, and crys tallized. What was obtained was boiled in a solution of carbonate of potassa, by which a precipitate was thro•.vn down. This was dissolved in nitric acid, the solution was evaporated to dryness, and the residue, after being exposed to a red heat, was washed with cold muriatic acid, and then dissolved in that acid at a boil ing temperature. By the addition of potassa to the so thc oxide of vestium was precipitated free, as Dr. Vest imagines, from the other substances contained in the ore. By mixing the oxide with arsenic, and ex posing it to heat, it was reduced, leaving a metallic button, which was brittle, and had a granular texture.