e 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.

SECT. XXVI.--_Observations upon Tartarous Acid, and its Combinations._

Tartar, or the concretion which fixes to the inside of vesse