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    American Meteorological Journal, February.—The cause of the cyclones of the temperate latitudes, by W. H. Dines. Two theories have found considerable support: (1) the convectional theory, commonly known as Ferrel's, because he so fully explained it, and showed that cyclones were caused by the convectional ascent of a current of warm air in the central parts, the heat necessary to sustain the current being supplied, at least in part, by the latent heat set free by the condensation of aqueous vapour; (2) the theory proposed by Dr. Hann, who considers that the storms are merely eddies formed in the general easterly drift of the atmosphere in temperate latitudes, just as small whirls are formed in a river. Dr. Hann found that the temperature at high mountain stations in the Alps is higher during anticyclonic conditions than during the passage of storms. Mr. Dines thinks that the evidence is in favour of Ferrel's theory, as mathematical laws show that it is a possible one, and that the latent heat set free by the condensation of moisture will, if it take the form of kinetic energy, be sufficient to produce a most violent storm.—Recent foreign studies of thunderstorms: Russia, by R. De C. Ward. The Imperial Geographical Society of Russia instituted a special study of thunderstorms in 1871, which has been continued until the present time. This service, and others subsequently established, such as that in south-west Russia by Prof. Klossovsky, have led to some valuable results. The district of greatest thunderstorm activity is the Caucasus, then the southern central region. The predominant direction of movement is north-east, and the storms occur most frequently in June and July, the maximum frequency being in the afternoon.—The journal also contains other articles of minor importance, including one on the moon and rainfall, by Prof. H. A. Hazen. The figures for Boston show a remarkable maximum at the day of new moon, and an equally remarkable minimum two days after full moon.

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