powder.

([chi].) _Deutoxide of Molybdenum_ (MoO^{2}).--This oxide is a dark
copper-colored crystalline powder.

_Reactions before the Blowpipe._--Metallic molybdenum, its protoxide
and binoxide, are converted in the oxidation flame into molybdic acid.
This acid fuses in the flame of oxidation to a brown liquid, which
spreads, volatilizes, and sublimes upon the charcoal as a yellow
powder, which appears crystalline in the vicinity of the assay. This
sublimate becomes white after cooling. Beyond this sublimate there is
visible a thin and not volatile ore of binoxide, after cooling; this
is of a dark copper-red color, and presenting a metallic lustre.

Heated in a glass tube, closed at one end, it melts to a brown mass,
vaporizes and sublimates to a white powder upon a cool portion of the
tube. Immediately above the assay, yellow crystals are visible; these
crystals are colorless after cooling, and the fused mass becomes light
yellow-colored and crystalline.

Upon platinum foil, in the flame of oxidation, it melts and vaporizes,
and becomes light yellow and crystalline after cooling. In the
reduction flame it becomes blue, and brown-colored if the heat is
increased.

Upon charcoal, in the reduction flame, it is absorbed by the charcoal;
and, with an increase of the temperature, it is reduced to the metal,
which remains as a grey powder after washing off the particles of
charcoal.

_Borax_ dissolves it, in the oxidation flame, upon platinum wire
easily, and in great quantity, to a clear yellow, which becomes
colorless while cooling. By the addition of more of the molybdenic
acid the bead is dark yellow, or red while hot, and opalescent when
cold. In the reduction flame, the color of the bead is changed to
brown and transparent. By the addition of more of the acid, it becomes
opaque.

_Microcosmic Salt_ dissolves it in the oxidation flame, upon platinum
wire, to a clear, yellowish-green bead, which becomes colorless after
cooling. In the reduction flame the bead is very dark and opaque, but
becomes of a bright green after cooling. This is the case likewise
upon charcoal.

_Carbonate of Soda_ dissolves it upon platinum wire in the oxidation
flame with intumescence, to a clear bead, which appears milk-white
after cooling. Upon charcoal the soda and the molybdic acid are
absorbed, the latter is reduced to the metallic state, the metal
remaining as a grey powder after washing off the particles of
charcoal. When mo