160 AIR AND LTFE. 



to be sought in the fact that cities contain a much larger quantity of 

 oxidizable organic material than is the case with tbe country and 

 small villages, and the result is that more ozone is absorbed from the 

 atmosphere over and around cities than from the atmosphere over tbe 

 country, over the fields, and especially over the oceans. Generally 

 speaking, ozone is more abundant near forests and the sea; the atmos- 

 phere in mid ocean is particularly rich in it. May we not attribute the 

 cause of the beneficial effects of life in the open air, of a residence in 

 the country, near the sea or in the mountains, and of long sea voyages 

 to the larger proportions of this gas found in those regions? Schoen- 

 bein thought so, and after him many have adopted the same view — 

 among them an English physician, Cook, according to whom a definite 

 relationship prevails in India between cholera and other zymotic dis- 

 eases and the proportion of ozone in the air, the diseases increasing 

 when ozone decreases, and decreasing when the latter becomes more 

 abundant. In consequence of the greater abundance of ozone in the 

 atmosphere over the country and in proximitj 7 to living plants, it might 

 seem advisable to advocate the presence of plants in apartments, 

 instead of excluding them as some feel inclined to do, arguing that 

 plants are living beings, that they breathe, and that, accordingly, they 

 increase the ratio of carbonic acid. Tbe view in favor of plants has 

 been strongly advocated by T. M. Anders (House Plants as Sanitary 

 Agents, 1887, Lippincott); but the most important point which should 

 be established in relation to this matter, the fact that plants do really 

 produce ozone, does not seem placed on a satisfactory basis. Proof is 

 still wanting. And this brings us to face the fact that very little is 

 known concerning the origin of ozone. We do not know whether any 

 agencies are at work now in nature evolving ozone to any important 

 extent. In the laboratory ozone may be produced by the electric spark, 

 and when so evolved causes the particular smell perceived in the vicinity 

 of electrical machineryj ozone is also evolved during the electrolysis 

 of water. Are we then to assume that in nature ozone is produced by 

 thunderstorms, those gigantic counterparts of our electrical discharge, 

 and under the influence of the electric currents so frequently in opera- 

 tion in the atmosphere? Many chemists think so, and if this is the 

 case it should be easily shown that the ratio of ozone to air is in fairly 

 exact relationship to the proportion of thunderstorms, or to their recent 

 occurrence. Ozone should be most abundant under the Tropics, should 

 decrease in high latitudes, where thunderstorms are least frequent, 

 and should be more abundant just after a thunderstorm than before. 

 But none of these points have been satisfactorily established. 



Without attempting to solve the riddle and to ascertain the origin 

 of ozone, a French chemist, M. Hautefeuille, who ascribes the blue 

 color of the heavens, or of the atmosphere, to ozone, asserts that this 

 gas is more abundant in the higher than in the lower strata of our 

 atmosphere. It may be so, at all events we are not much the wiser for 



