2 M. Thenard’s Observations on [Jan.. 
the receiver till the barometer gauge stands 10 or 12 centimetres: 
below the common barometer. By this means I obtained an 
acid sufficiently concentrated to give out 11 times its bulk of 
oxygen gas ; while in its first state it gave out only 1+ times its 
bulk of that gas. 
This ‘acid combines very well with barytes, potash, soda, 
ammonia, and neutralizes them; but I am afraid that it will 
scarcely be possible to crystallize the salts thus formed. When 
heated ever so little, the acid is decomposed, and gives out 
oxygen. They are decomposed likewise, at least this is the case 
with the oxygenized nitrate of barytes, when left to spontaneous 
evaporation. The decomposition takes place at the instant of 
crystallization. They are decomposed likewise when placed 
under an exhausted receiver. They have this last property in 
common with the solutions of the alkaline bicarbonates, which, 
when placed in an exhausted receiver, boil violently, and are: 
reduced to the state of carbonates. The oxygenized nitrate, 
when changed into nitrates, do not alter the state of their 
neutralization. 
Thus we see that oxygenized nitric acid, when united with 
bases, instead of becoming more stable, acquires, on thé eon- 
trary, the property of abandoning its oxygen with greater 
facility. This is so true, that if into a neutral and concentrated 
solution of oxygenized nitrate of potash we pour a concentrated 
solution of potash, a brisk effervescence takes place, and oxygen 
is disengaged. The potash acts doubtless upon the. nitrate, 
properly so called, Thus the bases act relatively to oxygenized: 
nitric acid as the ordinary acids relatively to certain peroxides ; 
sulphuric acid, for example, on the black oxide of manganese. 
I have not neglected to put oxygenized nitric acid in contact 
with the metals. 1 found that it did not act on gold; that it 
dissolved very well those metals which nitric acid is capable of 
dissolving ; and that this solution in general took place without 
the disengagement of gas, and with the production of heat. 
However, in some cases, there is alittle oxygen disengaged 
at first. This happens when the action is too violent, as is the 
case when oxygenized nitric acid concentrated so as to contain 
15 times its volume of oxygen is poured upon zinc. 
One of the most important questions was to know how much 
oxygen oxygenized nitrie acid contained. In order to ascertain 
the quantity, 1 began by analyzing the deutoxide of barium. [| 
heated a certain quantity of barytes with an excess of oxygen in 
a small curved tube standing over mercury. This base, to pass 
to the state of a peroxide, absorbed almost as much oxygen as it 
contained ; but having ascertained that barytes extracted from 
the nitrate always contains a little peroxide, I conclude thatin 
the peroxide, the quantity is double that which exists im the 
protoxide ; but in the neutral nitrates, the quantity of oxygen of 
the acid is to the quantity of oxygen of the oxide as five to 
