450 On definite Proportions. 
to 100 of nitric acid, we have already seen in the examina= 
tion of this salt. I therefore repeated once more the ana- 
lysis of the neutral nitrate. 
For this purpose I dried the finely powdered neutral ni- 
trate of the protoxide of Jead in the sunshine, and, after 
some hours, I exposed ten grammes of it in a small glass 
retort to a higher temperature, until the protoxide, deprived 
of its acid, was half vitrified, and the retort began to melt. 
Neither in the neck of the retort, nor in the receivers, had 
a single drop of acid been condensed ; a proof that this 
nitrate contains no water. The weight of the retort was 
now oply increased 6729 gr. by that of the residuum 5 
and it lost nothing more by further exposure to heat, al- 
though it was now completely flattened by partial fusion. 
I have repeated this experiment several times with the 
most careful attention, both in retorts and in a platina 
crucible, and it always afforded results which only varied 
from 67°3 to 67°31 of the protoxide of lead for 100 of the 
salt. This-is somewhat more than the 67°222, which I 
had found in my former experiments; [and hence the neutral 
nitrate contains 205°87 parts of the protoxide to 100 of 
nitric acid, G.] The neutral nitrate of the protoxide of lead, 
which was employed for these experiments, produced not 
the least turbidness with the nitrate of the pratoxide of 
silver, and the remaining protoxide of lead emitted, when 
dissolved in nitric acid, no yas, as would have been to be 
expected from the analogy of the alkaline and earthy nitrates 
which have been exposed to heat. No more gas was evolved 
from 6:73 gr. of half vitrified protoxide of lead than oc- 
cupied the bulk of a pea; I therefore consider this as at- 
mospherical air, which had been mechanically absorbed by 
the oxide in cooling. 
Hence it is most clearly established: first, that if we 
choose to consider the nitric acid as composed of nitrogen 
and oxygen, the acid contained in the neutral nitrate cannot 
possibly contain oxygea in any quantity which is an in- 
tegral multiple of the oxygen in the base; and secondly, 
that in the subnitrate here described, the base can be no 
integral multiple of that quantity of the same base with 
which the same quantity of acid is combined in the neutral 
nitrate. Consequently the want of agreement between the 
results cannot depend on errorsin the analyses, but the 
last described subsalt is either a double combination with 
the base, or there are some causes for which the nitric acid, 
when united with the greatest possible quantity of the base, 
retains the oxygen in the nitrogen so strongly, that it has 
ne 
