As in the oxidizing flame. Behavior with Mic. Salt on Platinum wire in the oxidizing flame. As in borax. in the reducing flame. As in borax. * * * * * 23. Oxide of Gold, Au^{2}O^{3}. Behavior with Borax on Platinum wire in the oxidizing flame. Is reduced without being dissolved and can be collected into a bead on charcoal. in the reducing flame. As in the oxidizing flame. Behavior with Mic. Salt on Platinum wire in the oxidizing flame. As in borax. in the reducing flame. As in borax. * * * * * 24. Titanic Acid, TiO^{2} Behavior with Borax on Platinum wire in the oxidizing flame. Dissolves readily to a clear glass which, when but little acid is present, is colorless, but when in larger proportion, yellow, and, on cooling, colorless. When sufficiently saturated, it may be rendered opaque with an intermittent flame, and with a still larger addition of the acid becomes so spontaneously on cooling. in the reducing flame. In small proportion, it renders the glass yellow in larger quantity dark-yellow or brown. A saturated bead assumes a blue enamel-like appearance under an intermittent flame. Behavior with Mic. Salt on Platinum wire in the oxidizing flame. Dissolves readily to a clear glass, which, when sufficiently saturated, is yellow white hot, and becomes colorless on cooling. in the reducing flame. The glass obtained in the oxidizing glame becomes yellow in the hot state, but on cooling assumes a beautiful violet color. If too saturated, this color is so deep as to appear opaque, but is not enameline. If the titanic acid contains iron, the glass becomes on cooling of a brownish-yellow or red color. The addition of tin neutralizes the iron, and the glass then becomes violet. * * * * * 25. Tantalic Acid, TaO^{3}. Behavior with Borax on Platinum wire in the oxidizing flame. Dissolves readily to a clear colorless glass, which, when sufficiently saturated, may be rendered opaque with an intermittent flame, and with a larger addition of the acid becomes spontaneously enameline on cooling. in the reducing flame. As in the oxidizing flame. Behavior with Mic. Salt on Platinum wire in the oxidizing flame. Dissolves readily to a clear glass, which, when it contains a large proportion of the acid, is yellow while warm, but becomes colorless on cooling. in the reducing flame. The glass obtained in the oxidizing flame undergoes no change, nor does it, according to _H. Rose_, alter by the addition of sulphate of iron. * * * * * 26. Niobic Acid, Ni^{2}O{3} Behavior with Borax on Platinum wire