([gamma].) Peroxide of Lead (PbO^{2}).—­It is a dark-brown powder.  It yields with hydrochloric acid the chloride of lead and chlorine gas.  When heated it liberates oxygen, and is reduced to the protoxide.

Lead combinations give the following reactions before the blowpipe:  Metallic lead tarnishes when heated in the oxidation flame, and is instantly covered with a grey matter, consisting of the protoxide and the metal.  It fuses quickly, and is then covered with a yellowish-brown protoxide until all the lead is converted into the protoxide, which melts to a yellow liquid.  In the reduction flame and upon charcoal, it is volatilized, while the charcoal becomes covered with a yellow sublimate of oxide.  A little distance from the assay, this sublimate appears white (carbonate of lead).  Protoxide of lead melts in the flame of oxidation to a beautiful dark yellow bead.  In the flame of reduction, and upon charcoal, it is reduced with intumescence to metallic lead, which is volatilized by a continued blast, and sublimates on charcoal, as mentioned above.

Red oxide of lead turns black when heated in the glass tube closed at one end, and liberates oxygen, which is easily detected by the introduction of an ignited splinter, when a more lively combustion of the wood proves the presence of uncombined oxygen.  The red oxide in this case is reduced to the protoxide.  Heated upon platinum foil, it first turns black, is reduced to the protoxide, and melts into a dark yellow liquid.  In the reduction flame, upon charcoal, it is reduced to the metal with intumescence.  After a continued blast, a yellow sublimate of protoxide is produced upon the charcoal, and at a little distance off, around this sublimate, a white one of carbonate of lead is produced.  This sublimate disappears when touched by the flame of reduction, while it communicates an azure blue-tinge to the external flame.  This is likewise the case with the peroxide of lead.

The different oxides of lead produce with the blowpipe reagents the same reactions.

Borax dissolves lead compounds with the greatest readiness upon platinum wire in the oxidation flame to a transparent bead, which is yellow when hot, but colorless after being cooled.  With the addition of more of the lead oxide, it becomes opalescent.  When heated by the intermittent flame, and with still more of the oxide, it acquires a yellow enamel after cooling.  Heated upon charcoal, in the flame of reduction, the bead spreads and becomes opaque.  After a continued blast, all the oxide is reduced with effervescence to metallic lead, which melts and runs towards the edges of the bead, while the bead again becomes transparent.

Microcosmic Salt dissolves oxides of lead upon platinum wire in the flame of oxidation easily to a clear, colorless bead, which appears, when highly saturated, yellow while hot.  A saturated bead becomes enamel-like after cooling.  The bead appears in the flame of reduction, and upon charcoal, of a greyish color and dull.  By the addition of more oxide, a yellow sublimate of protoxide is produced upon the charcoal.  By the addition of tin, the bead appears of a darker grey, but it is never quite opaque.