PROPERTIES OF TANTALITE.

185

into a colourless glass. Exposed to a high temperature with char-coal, it agglutinates and acquires a metallic aspect. Its fractureis brilliant, and its colour greyish black.

These properties together with its great specific weight haveinduced Mr. Ekeberg to consider it as a new metal.

The substances with which it might be confounded are theoxids of tin, tungsten, and titanium, all of which are more or lesssoluble in alcalies, and under certain circumstances resist theaction of acids. But it is well known that the oxid of tin iseasily reducible, whereas the oxid of tantalite requires an in-tense heat to reduce it even imperfectly. The oxid of tungstenis soluble in ammonia, but that of tantalite is not. The colourcommunicated to phosphate of soda and ammonia by fusion withthe oxid of titanium is yellow or hyacinth colour, and that of theoxid of tungsten is blue ; but oxid of tantalite fuses with thesesalts into a colourless glass.

Whether this substance will retain its place among the metals,ipust be left to future investigation, at present we have only theauthority of Mr. Ekeberg* for inserting it.

* Journal de Mines, No. 20, An. z, p. 248, and Annalea de Chimie, An: x,p. 276.