On definite Proportions. 267 
of salts, as sulphur, phosphorus, carbon, arsenic ; or if 
they doin some cases afford bases, for instance, in the sul- 
phureted or phosphureted murijatic acid, they have infinitely 
jess the character of a base than water has. The bodies 
most decidedly [positive] have this character in such a de- 
gree, that even when they have compined with so much 
oxygen as no longer to constitute bases, for instance, the 
oxides which I call peroxides, they still are not [negative], 
and do not exhibit any characters of an acid. ‘This is the 
case with lead, manganese, cerium, and some other sub- 
stances ; their peroxides contain oxygen so little saturated, 
that it is [negative] in comparison with almost every com- 
bustible body, although the whole peroxide can never 
be [negative] with respect to any other oxidated body, 
[Our author’s language has here been translated into one 
which has been more generally adopted, and which bad on 
a former occasion heen substituted for it by Professor Gil- 
bert, in pursuance of Sir H. Davy’s theory, without any 
objection from Professor Berzelius; he is indeed still dis- 
pesed to call those substances positive which are collected 
at the positive wire, but does not insist on the absolute ne- 
cessity of employing this language. ] 
Now neither hydrogen nor nitrogen is so highly [positive] 
in its electrical power as ammonia itself ; it is therefore in- 
conceivable whence this property should be derived, unless, 
like the fixed alkalis, ammonia is an oxidated meiallic body. 
Sulphureted hydrogen derives its acid properties from the 
[negative] nature of sulphur, the attraction of which for 
most bases it overpowers, because the oxygen in the base, 
which is still in some degree [negative], enters”into a sort 
of neutral state with the hydrogen of the sulphureted hy- 
drogen, which we may compare with that of the cake of 
resiv and the metallic disc or cover of the electrophorus. 
We see therefore in the constituent parts of sulphureted 
hydrogen a cause why it possesses the character of an acid, 
that is, of a [negative] body. 
Since ammonia contains, according to the analysis of 
Gay-Lussac, 18:475 per cent, of hydrogen, it might be 
resumed that in the salts of ammonia as much acid should 
found, as contained either exactly oxygen enough to 
form water with this quantity of hydrogen, or some simple 
multiple of that quantity. ‘This however is not universally 
the case; for we shall find that ammonia is combined in 
this proportion with thgse acids only which contain three 
times as much oxygen as the base that saturates them, Of 
those acids which contain twice or four times as much 
oxygen 
