112 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 



APPARATUS FOR TESTING THE ELECTRIC CONDITION OF THE ATMOSPHERE, 



153. Ozone*. During the action of a powerful electric machine, and in 

 the decomposition of water by the voltaic battery, a peculiar odour is perceptible, 

 which is considered to arise from the generation of a substance to which the 

 term Ozone has been given, on account of its having been first detected by smell, 

 which for a, long time after its discovery was its only known characteristic. A 

 similar odour is evolved by the influence of phosphorous on moist air, and in 

 other cases of slow combustion. It is also traceable, by the smell, in air, 

 where a. flash of lightning has passed immediately before. 



Ozone according to Faraday is oxygen is an allotropic condition, and from 

 the observations of Mr. Glaisher is to be found almost always present in the 

 atmosphere ; the quantity depending on the elevation above the surface of the 

 earth, and the prevalence of particular winds, being more abundant during 

 southerly than during northerly winds, and at a high elevation than at the 

 surface of the earth. It is more abundant at the sea-side than inland, and is 

 almost absent in thickly-populated towns. This may seem, remarks Admiral 

 FitzRoy, in The Weather Book, to point to some connection between Ozone and 

 Chlorine gas, which is present in and over sea water, and is no doubt brought 

 inland by any wind blowing from the. sea. 



Ozone plays an important part in the purification of the atmosphere, and 

 its continued presence in a locality indicates a pure and healthy climate. More 

 and careful observations are however required before its true functions can be 

 determined. 



M. Howzeau states : That the amount of Ozone in the air is variable, the 

 maximum being about one volume of Ozone in 700,000 of air. Ozone possesses 

 the property of bleaching blue litmus paper without previously reddening it, 

 and it is found present most in Spring, less in Summer, diminishing in quantity 

 in Autumn, and very little in Winter. Generally it may be detected during 

 Wet and Stormy weather, and largely augmented in quantity after heavy Snow 

 Storms. 



Dr. B. W. Richardson, F.R.S., in a Lecture on Yital Air, delivered at 

 the Society of Arts, states, as an undoubted fact, that he found that oxygen 

 which had been rendered prejudicial to animal life from repeated breathing was 

 restored by means of an electric discharge to its original exhilarating state, 

 and was again capable of supporting animal life. So that there is, possibly, a 

 very close relation between the electrical condition of the atmosphere and the 

 amount of ozone present, as indicated by the Ozonometer. The ozone is usually 



* Discovered by Schonbein in 1848. 



