402 On the Connexion which exists between 
If we precipitare the muriate of antimony by zine, we 
obtain a compound efiect. This salt being with a very 
great excess of acid, and the mufiate of zinc being perhaps 
almost in. the acl state, it happens at the same time 
that the zine takes up the oxygen from the antimony, it 
decomposes the ‘water, and consequently produces hy- 
drogen gas. It may also happen that the salt to be preci- 
pitated is neutral, and that which we ought to obtain does 
not enjoy this property: in this case, the metal precipitated 
is mixed with more or less oxide. Finally, the preeipi- 
tating metal may exercise a very powerful action on the 
acid of the solution, may decompose it, and give a com- 
plex product. This Rappene when we precipiiate by zine 
the nitrate of copper*: a part of this metal decomposes a 
part of the acid, and the oxide which results from it preci- 
pitates oxide of copper which is mixed with the metallic 
copper. But these particular facts are not opposed to the 
priuciple which I have esiabhi ished, and we could give a 
very satisfactory explanation of it. 
The oxides which I have hitherto considered are'in ge- 
neral those which M. Proust has called oxzdes at the mini- 
mums and we may ask if those which ase at the maximum 
enjoy the same properties : : 7.4, if their capacity of satura- 
tion for the acids is proportional to the quanuty of oxygen 
which they contain. 
It would seem that we ought not to have any doubt on 
this head ; for nothing indicates @ priori, if the oxides which 
we regard as being ai the minimum are effectually so; and 
even when they should be at the minimum or at the eae i- 
mum, relatively to the chemical means which we employ 
to produce them, tt does not follow that they would repre- 
sent corresponding degrees of oxidation. But without en- 
tering upon discussions which would perhaps be foreign 
to my object, [may quote some facts which give consider- 
able generali ty to the principle which I have established. 
These facts, however, will not be very numerous; for al- 
most all the metals, when <ihcy are very much oxidized, 
form salts with a greater or less excess of acid which i$ 
foreign to the saturation, and which has no other effect 
than to overcome the cohesion of the oxide and to hinder 
its precipitation. 
We may in the first Blane proye that the highly oxidated 
metal: take more acid than those which are Tess Su. M.” 
* Vauquelin, Aan. deChinie, tome xxviii. p. 45. 
Proust 
