Meteorologische Zeitschrift, May.—Rainfall probability and cloud in the United States, by W. Köppen. The author has submitted the rainfall charts published by the United States Government to a thorough investigation. The following are the generalised results as regards the distribution of rainfall:—(1) There is a district of continental summer rains, enclosed on both sides by littoral winter rains, which, corresponding to the contrast of the yearly oscillation of temperature, are much more marked in the west than in the east. (2) A district of isobaric summer rains, in the south-east, with equatorial sea-winds in summer, and with anticyclonic weather in winter. (3) Transition districts, in which both rainfall maxima occur near each other, while the minima occur in spring and autumn. Maxima after the equinoxes are nowhere very well marked, but the April and May rains of Colorado and Kansas and the autumn rains on Lake Superior are indications of them. With regard to the seasonal distribution in the tropical zone, the differences of temperature play only a small part compared to that of extra-tropical regions; this result naturally follows from the small variation of temperature in the tropics.—On the dynamics of the atmosphere, by M. Möller. This first part deals chiefly with the causes of the inversion of temperature with height, and with the cold experienced in the centres of areas of high barometric pressure. He deals especially with three causes of inversion:—The cooling of the lower strata by radiation, the effects on the higher strata by dynamic heating or cooling analogous to those caused by the action of Föhn winds, and the transference of warm air to the higher regions by horizontal winds coming from warmer parts. Various cases are separately considered from data afforded by mountain stations, such as Ben Nevis, and from discussions by Dr. Hann and others. Particular attention is also given to the formation and motions of clouds, as furnishing visible evidence of the processes in action in the higher strata of the atmosphere.