upon oxygenized and hyper oxygenized muriatic Acid , 153 
in water. The acid is thus separated into muriatic and hyperoxy- 
genized muriatic acid ; and, in these states, combines with the 
metallic oxide. The metallic hyperoxygenized muriates are differ- 
ent, in every respect, from the metallic muriates. Red oxide of 
iron is dissolved with difficulty. Oxide of copper more easily. 
Red oxide of lead exhibits the same appearances, during its com- 
bination with this acid, as with nitric acid. When nitric acid is 
poured, even in excess, upon red oxide of lead, only a part of the 
oxide is dissolved, unless heat be applied ; and what remains 
becomes a blackish brown powder. But, if metallic lead be 
added, in a just proportion, all the red oxide disappears, and none 
of the brown powder is formed; neither is there any disengage- 
ment of nitrous gas, when the metallic lead is dissolved. The 
precipitates caused in either case, by pouring an alkali into the 
nitric solution, are yellow. Hence it appears, that red oxide of 
lead contains too much oxygen to be dissolved by nitric acid. 
One part of the oxide takes up the excess of oxygen, and 
becomes brown; while the portion which loses oxygen, be- 
comes yellow, and is soluble in nitric acid. The presence of 
metallic lead promotes the total solution of the red oxide, by 
taking up the superabundant oxygen. I found that a current of 
oxygenized muriatic acid gas, like the nitric acid, dissolved a part 
of the red oxide, and caused the brown powder to be formed, 
upon which it could not act. Hyperoxygenized muriate of lead 
is much more soluble than muriate of lead; and the acid is 
very slightly attracted by the basis. 
But, of all the metallic salts formed by the combination of 
the muiiatic acid, in any of its different states, none so much 
deserve attention as those which have for their bases, the oxides 
of mercury. The nature of the salts which result from the 
md Cecil. x 
