-PELOUZE ON CERTAIN COMBINATIONS OF A NEW ACID. 471 
this operation several times, the deutoxide of azote is completely ab- 
sorbed by the sulphite ; and these two bodies, upon disappearing, give 
birth to 2 very remarkable new salt. to which I shall revert presently. 
If, instead of causing the deutoxide of azote to act upon the sulphite 
at — 15°, we bring them in contact at zero, or rather at the ordinary 
temperature, the result is very different : the devioxide of azote is com- 
pletely destroyed, it is true, but it is replaced by hal? its volume of prot- 
.oxide of azote, and instead of a new salt we obtain the neutral sulphate 
of ammonia. 
Iam not aware that chemistry presents a single similar instance, 
namely, an example of actions so diderent at temperatures so nearly 
-equal, above all within the lower limits of the thermometrical scale. 
-It is probable that facts of this nature will eventually muliiply, and 
that by the aid o7 freezing mixtures we shall succeed in obtaining com- 
binations which, though little stable, may nevertheless offer a compo- 
sition and definite properties. 
Yo return to the experiment above described: If, when all the 
deuioxide of azote has been absorbed by the sulphite we leave the so- 
lution to itself, at the ordinary temperature, the new salt is gradually 
destroyed. pure protoxide of azote is disengaged, and the liquid retains 
only sulphate of ammonia. ‘The volume of the new gas collected is 
foand to be precisely equal to half the volume of deutoxide of azote 
employed. 
The instability of the new substance scarcely allowed me to examine 
it completely : at zero, it is converted into protoxide of azote and into 
sulphate of ammonia : at the ordinary temperature, its decomposition is 
rapid; at 40° and above, its aciion is violent, and appears like a brisk 
effervescence ; further than this, it is not easy, especially in summer, to 
operate on the gases in refrigerating mixtures. It was necessary then 
to conirive anovher mode of preparation, and the following was the rea- 
soning which led me to discover it. “ The salt cannot be what Davy 
has said, namely a combination of protoxide of azote and an alkali ; for, 
‘since it is possible to obtain it with a neutral sulphite, the sulphurous 
-acid eliminated from its base by the deutoxide of azote, and converted 
into sulphuric acid by the absorption of half the oxygen of the latter 
gas, would infallibly decompose it, and a disengagement of protoxide of 
azote would be the result ; but, on the other hand, Davy obtained these 
combinations, although impure, at the ordinary temperature ; he ob- 
tained them with sulphites mixed with free alkalies; the alkalies must 
therefore increase the stability of the salts in question, and it is proba- 
‘ble that by modifying more or less the process of Davy I shall obtain 
‘them pure.” 
This is in fact what takes place. The presence of a free alkali re- 
tards in a remarkable manner the decomposition of the precipitated 
