ON OZONE. 95 
stance having a tendency to unite with oxygen or ozone, and that besides 
the temperature of the liquid to be electrolyzed be as low as possible. When 
the conditions indicated are fulfilled, the disengagement of ozone taking place 
at the positive electrode will last as long as the current continues to pass 
through the said liquid. Hence it follows that no production of ozone will 
take place if the electrodes consist of other metals than gold or platinum, or 
if the liquid to be electrolyzed contains small quantities of sulphuretted 
hydrogen, sulphurous acid, proto-sulphate of iron, zther, alcohol, &c. An 
aqueous solution of potash does not yield a trace of ozone, because free ozone 
is taken up by that solution. 
21. The electrical brush developes, as is well known to philosophers, a 
peculiar odour which cannot, as I have already mentioned, be distinguished 
from that of diluted ozone, be that ozone produced by the agency of phos- 
phorus or by the electrolysis of water. But the chemical and voltaic reac- 
tions exhibited by the electrical brush are also quite the same as those pro- 
duced either by chemical or voltaic ozone. Platinum foil being exposed 
to the action of that brush assumes the state of negative polarity, a piece of 
litmus paper is bleached, iodide of potassium or hydro-iodic acid decomposed, 
iodine being eliminated, the ferro-cyanide of potassium transformed into the 
sesqui-cyanide, the hydrate of protoxide of lead changed into the brown 
peroxide, provided the substances mentioned be sufficiently long acted upon 
by the electrical brush. If only small quantities of sulphurous acid, nitrous 
acid, sulphuretted hydrogen, olefiant gas, or vapour of zther or alcohol are 
present in the air into which the electrical brush is passing, the latter does 
not develope the peculiar electrical smell, neither does it produce any of the 
chemical or voltaic reactions before mentioned. A point of electrical emis- 
sion being heated not quite red-hot, yields a brush which has no smell what- 
soever, has no polarizing or bleaching power, does not decompose iodide of 
potassium, &c.; but as soon as the point in question is suffered to cool down 
again below a certain degree of temperature, the peculiar smell reappears, and 
along with it we obtain again all the reactions peculiar to ozone. From these 
facts we are allowed I think to draw the inference, that the odoriferous prin- 
_ ciple disengaged by the electrical brush is identical with the odoriferous sub- 
stance which is developed at the positive electrode during the electrolysis 
of water, and identical also with the electro-uegative principle resulting from 
a peculiar action exerted by phosphorus upon the moist atmospheric air. 
In order to ascertain the nature of that remarkable principle, I have tried 
a variety of methods with the view of procuring it in an isolated state, but all 
my endeavours made to that effect have hitherto failed, and I am not yet 
able to give quite a decisive answer to the question, What is ozone? 
That principle being developed by phosphorus within a mixture of oxygen 
and nitrogen, but not in pure oxygen; having in many experiments obtained 
no ozone from electrolyzing water which had been boiled and deprived of its 
atmospheric air; producing the same principle within the atmosphere by the 
agency of common electricity; and considering the striking analogy which 
exists between ozone and chlorine; I was for a time induced to think the 
former to be an elementary substance forming a constituent part of azote, and 
_to give up my first idea, according to which I considered ozone as a peculiar 
compound consisting of oxygen and hydrogen. ‘ 
_ The impossibility of isolating the principle, and the fact that nothing but 
oxidizing effects could be obtained from making ozone to act upon a great 
‘number of substances, induced me to resume the first view I took of the 
subject in question, and to institute a series of experiments with the intention 
of ascertaining more accurately the conditions required for the formation of 
4 
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