346 On the Combinations of the yellow Oxide of Lead 
to the nitrate of lead*; for they did not colour water; they 
did not give out nitrous acid when boiled in nitric acid : 
they did not give nitrite or subnitrite when boiled in water with 
oxide of lead; they were reduced by the carbonic acid into car- 
bonate and into acid nitrate of lead. 
44, The yellowish white scales redissolved in boiling water 
gave yellow leaves, and a mother-water not highly coloured, 
which gave white needles of nitrate of lead mixed with a little 
nitrite. The yellow leaves still retained some nitrate. It was 
evident that these scales were a combination of nitrite and ni- 
trate of lead. 
45. The yellow crystals resembling in form the acid nitrate 
of lead, redissolved in boiling water, deposited small needles and 
small leaves of nitrate of lead; the mother-water which re- 
mained was acid and slightly coloured. The composition of 
these crystals is analogous therefore to that of the scales, but they 
differ in so far as they contain more nitrate: it is not impro- 
bable that they contain acid nitrate: the nitrate of lead which 
they yield when dissolved in boiling water does not contradict 
this idea; for, if it be true that the acid nitrate of lead when 
boiled with the nitrite decomposes it, and passes to the state of 
nitrate, this is not a sufficient reason for thinking that this de- 
composition takes place in a liquor left to itself, and which 
would contain oxide of lead with an excess of nitrous and nitric 
acid. 
46. The decomposition of the scales and of the yellowish 
erystals effected by the affinity of water, and the force of co- 
hesion, led me to examine the action of the water on the nitrite 
of lead prepared by M. Proust’s process. On dissolving this 
salt in boiling water, I obtained, Ist, yellow leafy crystals which 
were deposited upon cooling; 2dly, crystals slightly yellow : 
they were deposited by concentration and cooling from the 
mother-water of the former crystals; 3dly, a slightly coloured 
mother-water which yielded small yellow crystals, and small 
white grainy crystals. On passing a stream of carbonic acid 
into this mother-water, I obtained plenty of nitrate from it. 
47. 1 am of opinion that these facts ought to leave no doubt 
as to the compound nature of the nitrite of lead prepared after 
M. Proust’s method. It is on this account, in the experiments 
which I made upon this salt, that I employed the nitrite coming 
* In my comparative experiments with the pure nitrite, and that of 
M. Proust, I am convinced that the nitrate obtained from the latter was 
not formed in the course of the operation. It is nevertheless not impos- 
sible that it may be formed under certain circumstances ; for we can con- 
ceive that the nitrous acid, which is extricated when we evaporate the acid 
nitrate of lead, may, by combining with steam and oxygen, form nitric 
acid, a portion of which may be mixed with the nitrite, and oe it. 
rom 
