192 On Iodine. . [Supr. 
If we decompose nitrate of ammonia by heat, we obtain two pro- 
ducts—water, which is neutral; and protoxide of azote, which 
ought to be so too. I say which ought to be so, first, because it has 
no acid nor alkaline character ; secondly, because it is formed in a 
manner analogous to water, namely, two volumes of azote and one 
of oxygen. 
The chloruret, ioduret, and sulphuret of potassium, give neutral 
compounds when in solution in water. If this neutrality did not 
exist between their elements, there can be no doubt that it would 
not exist in the solution. If, for example, there were an excess of 
potassium, hydrogen would be disengaged. If the chlorine, iodine, 
or sulphur, were in excess, their properties would be easily recog- 
nised.. But the neutral hydro-chlorate of potash changing into 
neutral chloruret of potassium because water is formed, we see that 
when two of the four elements of this neutral salt form a neutral 
compound, that formed by the two other elements is neutral also, 
This is the fact which I wish to generalize, by saying that whenever 
a neutral compound is divided into two compounds of which the 
one is neutral, the other is so of necessity also; for example, in the 
neutral sulphate of ammonia all the oxygen of the acid, and all the 
hydrogen of the alkali, forming water which is neutral, the sulphur 
and azote which remain, and which are in the proportion of 20 to 
17°5, will form a sulphuret of azote which ought to be neutral also, 
and which will be composed of equal volumes of sulphur and azote. 
On decomposing neutral chlorate or iodate of potash by heat, we 
obtain neutral chloruret and ioduret of potassium ; consequently 
the potassium by losing its oxygen, which necessarily diminished its 
alkaline energy, has gained as much alkaline energy as the chlorine 
and iodine have gained of acid energy by losing five times as much 
oxygen. Here is a new proof that the acid properties of a body do 
not follow the ratio of the quantity of oxygen which combine 
with it. 
Another principle, which I think ought to be admitted, is that a 
neutral compound does not destroy the acid or alkaline energy of 
another compound with which it combines. This is proved by 
showing that when neutral compounds are mixed, the mixture re- 
mains neutral. According to this principle, water holding in solu- 
tion an acid or an alkali ought to remain always acid or alkaline, 
whatever be its proportion. This liquid, considered as a solvent, 
presents therefore this remarkable circumstance, that it overcomes 
the cohesion or elasticity of the bodies with which it unites without 
destroying their characteristic properties, which enables us often to 
observe these properties better than in the bodies themselves. 
In the neutral state, the acid or alkaline properties being in 
general saturated, it is evident that a neutral body ought to have 
less tendency to combine with acids or alkalies than those which are 
not so; and we may easily explain why, ceeéeris paribus, the affinity 
of an oxide for acids diminishes in proportion as it combines with a 
greater dose of oxygen. By that it approaches more and more to # 
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