At the recent congress of German medical men and physicists, Dr. S.
Hoppe, of Hamburg, read a paper in which he sought to show that the
electricity of thunderstorms is generated by the friction of vapor
particles generated by the evaporation of water. This opinion was
strengthened by several experiments in which compressed cold air was
allowed to rush into a copper vessel containing warm moist air, thus
generating a large amount of electricity. He concludes that the rise of a
column of warm moist air into the colder atmosphere above will be
followed by a thunderstorm if it acquires sufficient velocity to prevent
neutralization of the electricity generated by the friction of the air.
Hence, in his opinion, open districts denuded of forests are more liable
to thunderstorms than wooded regions, where the trees forbid the rise of
humid air currents.
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