344 On the Comlinations of the yellow Oxide of Lead 
which differs by 2:11 from the determination made by the calca- 
lation*. The solution of nitrite separated from the carbonate, 
and aiterwards concentrated, acted like that of the subnitrite; it 
gave out nitrous acid, and yielded crystals of nitrite. 
39. It follows from these facts: Ist, that the nitrite and the sub- 
nitrite are partly decomposed by the carbonic acid, because the 
affinity and the quantity of the nitrous acid are insufficient to 
overcome the whole of the tendency which the carbonic acid has 
to form an insoluble combination with the oxide of lead; but the 
instant there is a certain quantity of nitrous acid set free the 
decomposition stops, because this acid is much more soluble than 
the carbonic: 2dly, that the nitrous acid of a solution of nitrite, 
when passed to the carbonic acid, seems to he to the oxide which 
is not precipitated from it in a proportion corresponding to that 
of the elements of the acid nitrate of lead: Sdly, that the affi- 
nity of the nitrous acid set free for the nitrite is not great, siace 
by concentration and crystallization we obtain nitrite only: 
Athly, that, the nitrous acid set free being very capable of sepa- 
ration from the nitrite, it is possible to decompose a given quan- 
tity of nitrite by the carbonic acid. 
_ AQ. I shall conclude this memoir with an examination of the 
nitrite of lead prepared by M. Proust’s process. I have said a 
little higher, that when we wished to prepare this salt, and 
when we boiled too long the acid nitrate of lead over this metal, 
we obtained a nitrite which contained subnitrite, or more base 
than the nitrite¢. In order to avoid the production of the sub- 
nitrite, | made” several experiments with a view to ascertain if 
each of them would give me a homogeneous and identical pro- 
duct. I obtained two varieties of yellow crystals, one in com- 
pact leaves, the other in flexible scales, These crystais being of 
the same species, | confounded them together. 1 regarded them 
H 5 
in stars. I thought at first that they were acid, because they reddened 
turnsole paper; but, having pressed and dried them, they gave a solution 
which reddened at first turnsole paper slightly, but soon became blue again, 
Thad not enough of these crystals to ascertain by analysis their quantity 
of base. The solution yielded yellow needles. 
* In an experiment similar to the latter, T obtained 
Acid me sah tae 30:7 
Base Hans ti wordt ele 693 which is ostensibly 
the same with that of the calculation: but what prevents me from having 
as much confidence in it as in the foregoing, is, that the nitrite employed 
had been crystallized twice, and that it seemed to contain a little subnitrite, 
or more base than the nitrite. 
+ This salt is of a redder colour than the nitrite. When we dissolve it 
in boiling water, we obtain yellow and orange crystals, which contain much 
more base than the nitrite, and less than the subnitrite. 
100 parts of this nitrite contained 
Acid and water ., «- 16°56 
Base Je eee ee 
at 
