ATMOSPHERIC ELECTRICITY AND OZONE. 461 



ent seasons and in different hours of the day, and is considerably de- 

 pendent on various meteorological conditions. 



It varies with the Locality. — It is more abundant in the country than 

 in the city ; by the sea-side than inland ; among mountains than in val- 

 leys; in well-drained neighborhoods than in those where such sanitary 

 provisions are disregarded. The opposite results of different observa- 

 tions in different localities are accounted for in part by the fact that the 

 amount of ozone is not everywhere constant. Ozone is not often found 

 in closed rooms or chambers. Those who stay in-doors are deprived 

 both of atmospheric electricity and ozone. Like electricity, it increases 

 with the altitude ; hence we may in part explain the beneficial effects of 

 mountain-air. The air of the sea is richer in ozone than the air of the 

 land, because evaporation is attended with the simultaneous develop- 

 ment of oxygen and ozone. Hence it is that tests applied over the sur- 

 face of the sea or of lakes, ponds or rivers, show a deeper tint than tests 

 applied over the land. An excess of sea-air will blight vegetation in 

 the vicinity of the ocean ; delicate fruits, as the peach and the plum, 

 are cultivated only with difficulty. It has been observed that a pro- 

 longed storm coming from the sea will blight vegetation. Possibly 

 the excess of ozone may be a factor in this destruction. 



It varies with the Season. — Ozone, like electricity, is more abundant 

 in the winter than in the summer. Atmospheric ozone is not measured 

 with the same accuracy as atmospheric electricity, and therefore the 

 regular gradations during the spring and autumn have not been estab- 

 lished as in the case of the latter agent. For the same reason there 

 is much discrepancy among different observers. It is believed that 

 the relatively small amount of ozone in the summer and early fall is due 

 partly to the fact that it is consumed in oxidizing the impurities of 

 the air, and partly to the fact that there is less atmospheric electricity 

 at that time. 



It varies with the Sour of the Day. — There is considerable difference 

 in the conclusion of different observations, but the average results 

 seem to show rather more ozone in the atmosphere during the night 

 than during the day. Like atmospheric electricity, ozone rises and 

 falls in pretty regular tides twice during the twenty-four hours. The 

 maximum periods are between 4 and 9 A. M. and 7 to 9 p. m. 

 The minimum periods are between 10 a. m. and 1 p. m. and be- 

 tween 10 p. m. and midnight. It will be seen that ozone is at its 

 minimum when the sun is at the zenith, and its maximum about sun- 

 rise and sunset. It varies with atmospheric conditions, as electricity, 

 rain, fog, thunder-storms, snow, wind, clouds, halos, and auroras, 

 eclipses, etc. There is a certain correspondence between the tides 

 of electricity and of ozone ; they seem to rise and fall together. 

 This will be apparent on comparing the statements made above. A 

 comparison between atmospheric ozone and electricity has been made 

 by Quetelet, who has given the subject special attention. His obser- 



