458 On definite Proportions. 
in these salts as containing twice as much oxygen as the 
base, G.] Of the remaining 5°74 parts of nitrous acid, 
3°826 must therefore have been decomposed, and must have 
afforded +805 of oxygen to the lead. These, added to the 
17°59” parts of oxygen before mentioned, give ‘¢18°375,” 
which have been taken up by the lead dissolved ; but 18°375 
parts of oxygen combine with 238°8 of lead. If now 305-87 
parts of nitrate of the protoxide of lead dissolve 238°8 of 
Jead, 100 must dissolve 78; and we have seen that in these 
experiments the formation of the subsubsalt began exactly 
at this point. 
Perhaps none of the indirect proofs of the true composi- 
tion of the nitric acid, and at the same time of ammonia 
and nitrogen, is stronger than this. For the observations 
here adduced, even if they have no pretensions to the greatest 
accuracy, cannot possibly be so erroneous, as to render the 
formation of the subnitrite of the protoxide of lead compa- 
tible with any other idea of the composition and the capacity 
of saturation of these two acids, 
2. Neutral Nitrite of the Protoxide of Lead. 
I now wished also to be acquainted with the neutral ni- 
trite, and for this purpose [ adopted the following process : 
I mixed a saturated boiling solution of the subsalt with so 
much sulphuric acid as was required in order to saturate half 
of the protoxide contained in it: I found however that the 
experiment must be made in a long-necked flask, for other- 
wise a part of the nitrous acid will escape in the form of gas. 
I obtained a saturated solution of a golden yellow colour, 
which did not crystallize when cold; and, when I attempted 
to concentrate it by evaporation in a sand heat, was partly 
decomposed, and afforded subnitrate of the protoxide. I 
therefore left a part of it to evaporate spontaneously ; and 
by degrees a dark yellow salt was deposited from it, in octa- 
hedral crystals. The yellow salt thus obtained is consider- 
ably more soluble in water than the neutral nitrate. If it is. 
dissolved in water which has been boiled, and still remains 
hot, it leaves a smalj quantity of subnitrate, which has been 
formed during the evaporation of the water: in water which 
has not been boiled, this residuum is still more considerable. 
Since the salt cannot be obtained dry in a state of perfect 
purity, we cannot expect its analysis to be completely ac- 
curate. 
Ten grammes of this salt were exposed to heat in a small 
glass retort, It melted, and in this state resembled the 
muriate of the protoxide of lead or of silver; it had vey 
a dar 
OO OE EE 
