with the Nitric and Nitrous Acids. 269 
18. The sulphuric acid precipitates sulphate from it, it li- 
berates a nitrous smell, but the red vapour is not very perceptible. 
It would seem that the latter remains in solution. 
19. The nitric acid and the acetic acid, which form with the 
oxide of lead salts very soluble, emit the nitrous vapour when 
we project into these boiling acids the nitrite reduced into 
powder. 
20. The carbonic acid gas when passed into the solution of 
nitrite of lead precipitates from it a part of the oxide in the state 
of carbonate. There remain in the liquor oxide of lead, ni- 
trous acid in excess, aud carbonic acid. The carbonic gas which 
is not absorbed carries with it an atom of nitrous acid. I shall 
return to this decomposition of the nitrite by the carbonic acid. 
21. The carbonate of potash decomposes it: there is a for- 
mation of nitrite of potash and carbonate of lead. 
22. When we heat it gently it becomes clammy, and its co- 
lour is deeper. At a red heat it is reduced to pure oxide. The 
first portions of acid are extricated from it at the heat of boiling 
water. — 
23. The solution of nitrite, when boiled with yellow oxide of 
lead, is converted into subnitrite, but it requires a long time. 
When ebullition commences, the oxide, no matter how pulveru- 
lent it is, becomes flaky and white, and seems to pass to the state 
of hydrate. I am ignorant if it absorbs a little nitrous acid. 
Examination of the Subnitrite. 
24. It is of a pale red, inclining to yellow. It crystallizes in 
small silky needles which unite in stars. 
25. 100 grammes of boiling water dissolved three grammes of 
subnitrite. 100 grammes of water at 23° of the centigrade 
thermometer dissolved about seven decigrammes of it after being 
24 hours in contact with it. 100 grammes of boiling water, sa- 
turated with subnitrite and cooled to 23°, retain nearly 1:09 gr. 
of salt. 
26. The carbonate of potash and the sulphuric, nitric, and 
acetic acids decompose it like the foregoing. 
27. The carbonic acid when passed into its solution forms an 
abundant precipitate of carbonate of lead. The liquor becomes 
yellow by losing the oxide, and it contains oxide of nitrous acid 
in excess and carbonic acid. 
28. The solution of subnitrite when poured into the nitrate of 
copper precipitates from it a powder of a greenish blue, which is 
a combination of the hydrates of copper and lead. I am ig- 
norant if the acid, which I obtained from it by distillation, was 
essential to it, or if it was occasioned by my not having well 
: washed 
