| Bases. | Neutral Salts. | |
| Lime | Tungstat of | lime. |
| Barytes | barytes. | |
| Magnesia | magnesia. | |
| Potash | potash. | |
| Soda | soda. | |
| Ammoniac | ammoniac. | |
| Argill | argill. | |
| Oxyd of antimony(A), &c. | antimony(B), &c. | |
[Note A: The combinations with metallic oxyds were set down by Mr Lavoisier in alphabetical order; their order of affinity being unknown, I have omitted them, as serving no purpose.—E.]
[Note B: All these salts were unknown to the ancient chemists.—A.]
Sect. XXV.—Observations upon Tungstic Acid, and its Combinations.
Tungstein is a particular metal, the ore of which has frequently been confounded with that of tin. The specific gravity of this ore is to water as 6 to 1; in its form of cristallization it resembles the garnet, and varies in colour from a pearl-white to yellow and reddish; it is found in several parts of Saxony and Bohemia. The mineral called Wolfram, which is frequent in the mines of Cornwal, is likewise an ore of this metal. In all these ores the metal is oxydated; and, in some of them, it appears even to be oxygenated to the state of acid, being combined with lime into a true tungstat of lime.
To obtain the acid free, mix one part of ore of tungstein with four parts of carbonat of potash, and melt the mixture in a crucible, then powder and pour on twelve parts of boiling water, add nitric acid, and the tungstic acid precipitates in a concrete form. Afterwards, to insure the complete oxygenation of the metal, add more nitric acid, and evaporate to dryness, repeating this operation so long as red fumes of nitrous gas are produced. To procure tungstic acid perfectly pure, the fusion of the ore with carbonat of potash must be made in a crucible of platina, otherwise the earth of the common crucibles will mix with the products, and adulterate the acid.
Table of the Combinations of Tartarous Acid, with the Salifiable Bases, in the Order of Affinity.
| Bases. | Neutral Salts. | ||
| Lime | Tartarite of | lime. | |
| Barytes | barytes. | ||
| Magnesia | magnesia. | ||
| Potash | potash. | ||
| Soda | soda. | ||
| Ammoniac | ammoniac. | ||
| Argill | argill. | ||
| Oxyd of | |||
| zinc | zinc. | ||
| iron | iron. | ||
| manganese | manganese. | ||
| cobalt | cobalt. | ||
| nickel | nickel. | ||
| lead | lead. | ||
| tin | tin. | ||
| copper | copper. | ||
| bismuth | bismuth. | ||
| antimony | antimony. | ||
| arsenic | arsenic. | ||
| silver | silver. | ||
| mercury | mercury. | ||
| gold | gold. | ||
| platina | platina. | ||