Page:Popular Science Monthly Volume 4.djvu/478

462, which were made with Peltier's electrometer in August, 1842, are represented in the following table:

Ozone, like electricity, seems to depend in a measure on the humidity of the air. The relation of fog to atmospheric ozone is not yet determined, but it seems to be agreed that during snow-storms it is increased. Thus, Wolf gives the following comparison:

Amount of atmospheric ozone in fine days, 4.186. Amount of atmospheric ozone in rainy days, 11.40. Amount of atmospheric ozone in snowy days, 14.15.

It will be remarked that snow-storms also favor atmospheric electricity. The direction of the wind has a certain influence, as is well recognized, on ozone. According to Lowe, ozone is most abundant during a southwest or south-southwest wind, and least abundant when the wind is north or northeast. There is a maximum when the barometer is low, and a minimum when it is high. Other inland observers agree with Mr. Lowe. At the sea-side, winds blowing from the sea bring with them abundant ozone.

When the sky is darkened with clouds, there is more ozone than when it is clear. Before thunder-storms, or while they are at a distance, ozone, like electricity, increases, and various changes and fluctuations may occur during the progress of the storm.

Summing up in a few words, we may say that atmospheric ozone is more abundant during the winter and spring, because in those seasons there is much rain, snow, hail, and wind, a low temperature, and a maximum of electricity. During these seasons, also, there is little decomposition going on in the vegetable world. In the summer and autumn, atmospheric ozone is least abundant, because, during these seasons, there is no snow, or hail, less wind, rain, high temperature, a minimum of electricity, and a great amount of decomposition of animal and vegetable matter, by which the air becomes polluted, and is neutralizing and purifying while the ozone is consumed.