10 M. Thenard’s Fifth Series of Observations [JAN 
7. I have already spoken of the action of -oxide of silver on 
oxygenized muriatic acid, and I stated that these bodies by their 
mutual action produced water, the disengagement of oxygen 
gas, and the chloride of silver. But this chloride is violet.. Now 
violet chloride, in what manner soever it is produced, leaves 
always a metallic residue when treated with ammonia—a pheno- 
menon, which Gay-Lussac observed respecting the white chlo- 
ride rendered violet by the action of light. It follows from this, 
that when oxygenized muriatic acid is treated with oxide of 
silver, a small part of the oxygen disengaged comes from the 
oxide itself. Consequently to determine, by the process, which 
I pointed out in the last paper, the quantity of oxygen in oxyge- 
nized muriatic acid by means of oxide of silver, we must take 
an account of the oxygen proceeding from that portion of oxide. 
To do this we must make a second experiment, in which we 
collect the chloride of silver, produced and mixed with oxide of 
silver. This mixture is treated with ammonia, and we obtain as a 
residue the portion of the metal that had been reduced. The 
quantity of this residue makes us immediately acquainted with 
the quantity of oxygen wanted. 
I shall remark, with respect to the violet chloride of silver, that 
it probably corresponds with the protoxide of silver. 
8. As soon as we plunge a tube containing oxide of silver 
into a solution of oxygenized nitrate of potash, a violent effer- 
vescence takes place, the oxide is reduced, the silver precipitates, 
the whole oxygen of the oxygenized nitrate is disengaged at the 
same time with that of the oxide; and the solution, which con- 
tains merely common nitrate of potash, remains neutral, if it was 
so at first. 7 
9. Oxide of silver produces the same effects upon oxygenized: 
muriate of potash as upon the oxygenized nitrate. 
10. If silver ina state of extreme division be put into the 
oxygenized nitrate, or murate of potash, the whole oxygen of 
the salt is immediately disengaged. ‘The silver is not attacked, 
and the salt remains neutral as before. The action is less lively 
(indeed much less lively) if the metal be in*a less divided state. 
Tn all cases the action is less violent in the munate than the 
nitrate. 
11. Silver is not the only metal capable of separating the 
oxygen of the oxygenized nitrate and muriate of potash. Iron, 
zinc, copper, bismuth, lead, platmum, possess likewise this pro- 
perty. lron and zinc are oxydized, and, at the same time, 
occasion the evolution of oxygen. The others are not sensibly 
oxydized. They were all employed in the state of filings. 
I tried hkewise the action of gold and of tin. These metals 
do not act sensibly on the neutral solutions, or, at most, only a, 
few bubbles are disengaged at intervals. 
12. Several oxides, besides those of silver and mercury, are 
capable of decomposing the oxygenized nitrate and muriate of 
