RESEARCHES IN ELECTRO-CHEMISTRY. 217 
both cases, the negative polarity results from the presence of 
ozone. Indeed water charged with that principle is negative to 
pure water, whilst the same fluid holding oxygen dissolved is, 
in a voltaic point of view, inactive to pure water. Water 
mixed with some peroxide of hydrogen bears to common water 
the same voltaic relation as zinc does to copper. Without 
having recourse to actual electrolysation, we may indeed pro- 
duce, by means of insulated ozone, all the phenomena of nega- 
tive voltaic polarization, a fact which seems to prove the 
correctness of the explanation offered of the phenomena in 
question. 
I also suspect that the peculiar condition of iron, or its in- 
active state, has something to do with ozone ; but for the pre- 
sent I cannot enter into that subject. 
It is now time to speak of the phenomena of polarization 
produced by the agency of the electrical brush. On comparing 
them with those called forth by ozone, we cannot but perceive 
a strong analogy between both series of phenomena. The very 
same metals which become negatively polarized by ozone, are 
brought into a similar state by the action of the electrical 
brush. The same conditions to be fulfilled, in order to polarize 
gold and platina by ozone, are likewise requisite to render 
these metals negative by the agency of common electricity. 
The negative polarity developed by ozone is destroyed by the 
same means by which we annihilate the negative poiar state 
called forth by the brush. These facts are sufficient to coun- 
tenance the conjecture, that the cause of the negative polarity 
is in both cases the same, z.e. that it is a film of ozone sur- 
rounding the metals. I have stated (§ 16) that the brush can 
easily be deprived of its peculiar smell, and that by so doing 
the former loses its polarizing power. ‘This fact clearly 
proves that it is not the electrical brush or discharge itself 
_ that excites in the metals exposed to its action the negative 
polar state, but the odoriferous principle accompanying the 
brush. This principle affecting our olfactory nerves precisely 
in the same manner, and also producing the same voltaic effects 
as ozone does, are we not entitled to infer that the smelling 
matter in the electrical brush and the odoriferous principle 
evolved at the positive electrode, are identical bodies? It ap- 
pears to me that they are, and I do not, therefore, hesitate to 
ascribe the familiar electrical odour to ozone. 
_ But how does it happen that ozone makes its appearance, 
whilst common electricity is passing from the points of a 
charged conductor into the atmosphere? To account for such 
a remarkable fact, we certainly must suppose that there is an 
