VARIETIES. 
77 
length of exposure. The ozonometer consists of a series of papers thus co- 
lored in different degrees, and bears some analogy to the cynometer long 
since proposed by Humboldt. 
Professor Faraday stated that, during the last autumn, when at Brighton, 
while walking close to the sea-shore, he exposed some strips of this prepared 
paper to the current of air coming over the sea, and, on subsequently wet- 
ting the paper, the presence of ozone was distinctly manifested by the blue 
color produced. On another occasion he received on the same paper the 
current of air blowing over the town, but no trace of ozone could be detected 
in it. When he went, however, on the windward side of Brighton, so as to 
catch the air blowing over the downs before it reached the town, ozone was 
strongly manifested by the result. It was thus established that in populous 
places there is a constant consumption of this principle. 
It had been shown that ozone was evolved with the ordinary electricity 
of the machine ; it was now proved that the current of the battery equally 
leads to its production. Water was decomposed by a Grove's battery, and 
the oxygen and hydrogen evolved were conducted through a tube in which 
cotton soaked in potash had been placed to arrest any traces of acid. The 
gases evolved at the end of the tube decomposed the iodide of potassium on 
starch-paper, and gave the usual indication of the presence of ozone. 
Ozone is evolved in numerous chemical processes. If pure ether, mixed 
with water, be introduced into a wide-mouthed capacious bottle, and the 
vapor allowed to become diffused, it will be found that litmus paper intro- 
duced is not reddened, and that starch-paper prepared with iodide of potas- 
sium is not rendered blue. If, however, a glass rod be made hot in the 
flame of a spirit-lamp, and then introduced into the vapor of the bottle, lit- 
mus paper held above the rod becomes strongly reddened, and the iodide 
of potassium paper intensely blue. In the oxidation of ether vapor at alow 
temperature, ozone is evolved. 
Ether, in its ordinary state, has no bleaching properties; but the ether 
thus treated had acquired the power of discharging the color from a large 
quantity of sulphate of indigo. 
Essential oils are thickened by long exposure to light and air; they be- 
come ozonized and their properties changed. This was illustrated by refer- 
ence to oil of turpentine. Freshly rectified and pure oil of turpentine was 
proved, by admixture with sulphate of indigo, to have no bleaching power. 
A small quantity of oil, which had been exposed to air and light (the air in 
a bottle half full,) destroyed the color in a few minutes like chlorine. 
We cannot doubt that ozone exerts an important influence on the atmos- 
phere, and, therefore, on the health of animals and vegetables. Schonbein, 
who is rather sanguine in his views, considers, from the irritant properties 
of ozone, that an undue proportion of it in air may give rise to epidemic 
influenza, bronchitis, and other affections of the air passages ; and in mak- 
ing experiments at Basle, he found that, concurrently with the prevalence of 
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