ATMOSPUEllIC AIU AS THE FOOD OF PLANTS. 67 



Tegetal)le 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 is a highly probable liypothesis that ozone may b i 

 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 oxi<lable substance, a portion 

 of it may diffuse into the atmosphere and escape immediate 

 combination. 



Ozone is likewise produced m a variety of chemical re- 

 actions, whereby oxygen is liberated from combination at 

 ordinary temperatures. When water is evolved by gal- 

 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 ccmtains an admixture of 

 ozone.* 



Is Ozone Produced by Vej^etation ? — It is an interesting 

 question whether the oxygen so freely exhaled from the 

 foliage of }tlants 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 Meissiier 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 

 pas. 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 pg-inch in length. 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. (Vs. St., IX, p. 47.3.) Pincus has also noticed the ozone odor in similar '.i- 

 periments with alcohol and oil (Ararand) lamps, and with stearine candles. 



Doubtless, therefore, we are justified in making the generalization that I, mI 

 casus of oxidation ozone is formed, and in many instances a portion of it dififuse* 

 into the atmosphere and escapes immediato combiuation. 



