ATMOSPHERIC AIR AS THE FOOD OF PLANTS. 67 
vegetable oils, as oil of turpentine, oil of lemon, oil of 
cinnamon, linseed oil, etc., possess the property of ozoniz- 
ing oxygen, or at least acquire oxidizing properties when 
exposed to the air. Hence the bleaching and corrosion 
of the cork of a partially filled turpentine bottle. 
It isa highly probable hypothesis that ozone may be 
formed in many or even all cases of slow oxidation, and 
that although the chief part of the ozone thus developed 
must unite at once with the oxidable substance, a portion 
of it may diffuse into the atmosphere and escape immediate 
combination. 
Ozone is likewise produced in a variety of chemical re- 
actions, whereby oxygen is liberated from combination at 
ordinary temperatures. When water is evolved by gual- 
vanic electricity into free oxygen and free hydrogen, the 
former is accompanied with a small proportion of ozone. 
The same is true in the electrolysis of carbonic acid. So, 
too, when permanganate of potash, binoxide of barium, 
or chromic acid, is mixed with strong sulphuric acid, ox- 
ygen gas is disengaged which contains an admixture of 
ozone.* 
Is Ozone Produced by Vegetation ?—It is an interesting 
question whether the oxygen so freely exhaled from the 
foliage of plants under the influence of sunlight is accom- 
panied by ozone. Various experimenters have occupied 
* It appears probable that ozone is developed in all cases of rapid oxidation at 
high temperatures. This has been long suspected, and Meissner obtained strong 
indirect evidence of the fact. Since the above was written, Pincus has announ- 
ced that ozone is produced when hydrogen burns in the air, or in pure oxygen 
gas. The quantity of ozone thus developed is sufficient to be recognized by the 
odor. To observe this fact, a jet of hydrogen should issue from a fine orifice and 
burn with a small flame, not exceeding %-inch in Jength. A clean, dry, and cold 
beaker glass is held over the flame for a few seconds, when its contents will smell 
as decidedly of ozone as the interior of a Leyden jar that has just been discharg- 
ed. (Ve. St., IX, p. 473.) Pincus has also noticed the ozone odor in similar ex- 
periments with alcohol and oil (Argand) lamps, and with stearine candles. 
Doubtless, therefore, we are justified in making the generalization that in all 
cases of oxidation ozone is formed, and in many instances a portion of it diffuses 
into the atmosphere and escapes immediate combination. 
