376 THE CANADIAN NATURALIST. [June 



(which is a property it possesses of producing in bodies a state 

 opposite to its own) these particles of aqueous vapour once having 

 left the surface of the earth, by evaporation or any other cause, 

 become of an opposite or positive character, and are repelled in 

 accordance with another well-known electrical law ; this action of 

 repulsion repels the positive electricity towards the upper strata of 

 the atmosphere, carrying with it its positive character. During 

 the night the aqueous vapour becomes condensed into dew by 

 cold and radiation, and by the absence of the sun's rays, the 

 amount of positive electricity in the atmosphere is diminish- 

 ed, and the upper vapours possess a less amount of water ; 

 the effects of heat, furnished by the rising sun, cause the dew 

 and water to assume again its state of elastic vapour, to 

 be again subjected to the same laws of induction and repulsion, 

 and again placed between the negative earth and the positive 

 celestial space. The first particles, which change from dew to 

 the elastic state of vapour, come off the earth at a higher 

 negative tension, which is obtained by weakening or diminishing 

 the tension and repulsive power of the vapour they leave behind, and 

 which has become less negative than the earth itself, thus keeping 

 up an everchanging amount of electricity, differing both in 

 character and tension. 



It was in the year 1785, that Van Marum first called the 

 attention of scientific men to the existence of some anoma- 

 lous body, which further investigation proved to be Ozone ; for 

 he discovered, in passing the electrical spark through atmos- 

 pheric air, that there was generated a peculiar and strong odour 

 which, says he, is certainly the smell of electrical matter. For 

 more than fifty years this fact remained forgotten or unheeded, 

 until Schonbien, in 1839. while conducting some experiments by 

 passing the electric current through gases, became struck with 

 the same thought, and wrote to M. Arago, the French Astronomer 

 Royal, that for some years he had remarked the perfect 

 analogy that exists between the odour which is developed when 

 ordinary electricity passes the point of a conductor into the sur- 

 rounding atmosphere, and that which takes place when water is 

 decomposed by the galvanic current. 



To Schonbien, then, must be awarded the discovery of Ozone ; 

 it was he who gave it its present name, taken from a Greek verb 

 which signifies to give out an odour, but the name reveals nothing 

 of its real nature, 



