ADVANCED BY LIEBIG AND OTHERS. 
5 
arising in them, is not like that which they induce. Hence, 
obviously, they operate differently either from the platina 
sponge or platina black, or from silver in the alloy formed 
by it with platina. 
Liebig conceives that this increased solubility of platina 
by union with silver, is at war with electro-chemical prin- 
ciples;agreeably to which, any metal in contact with another 
metal, relatively electro-positive, becomes less susceptible 
of attack. But agreeably to the principles thus cited, this 
insusceptibility does not arise in one of two heterogeneous 
metals in chemical combination with each other, but in one 
of two such metals either in contact merely, or only com- 
municating through a metallic conductor. 
I am surprised that Liebig should find the mystery of 
catalysis lessened by the solubility of the alloy of platina 
with silver, when it must be evident that if the oxidation 
of an atom of a comparatively electro-positive metal, were 
a sufficient reason why an electro-negative metal, combined 
with it, should be oxidized, an alloy of gold with silver ought 
to be soluble; whereas it is known that the common process 
of parting, is founded on the utter insolubility of gold when 
so alloyed. 
Liebig alleges that there can be no doubt that the aceti- 
fication of alcohol is of the same order, as the reaction by 
which the bioxide of nitrogen provokes the formation of sul- 
phuric acid in the leaden chamber; in which process the 
oxygen of the air is transferred to sulphurous acid by the 
intervention of that bioxide ; since, in like manner, organic 
substances, associated with spirit of wine, absorb oxygen, 
and bring it into a particular state which enables two atoms 
of this element, to replace two atoms of hydrogen, simul- 
taneously oxidized and removed. 
But in the case thus cited, for every equivalent of acid 
formed, an equivalent of the bioxide combines first with an 
equivalent of oxygen, (perhaps with two,) and in the next 
place with an equivalent of the sulphurous acid, forming a 
1* 
