Abstract
THE American Meteorological Journal for September contains the concluding part of an article on mountain meteorology, by A. L. Rotch. The subjects specially treated of are wind and temperature in connection with atmospheric pressure, as observed chiefly at the Blue Hill Observatory. The wind velocity is found to be two-thirds greater there than at Boston, about 500 feet lower, but the difference changes for various hours of the day. At low levels the wind force generally increases from the early morning until the afternoon, but the conditions are reversed at higher levels. This fact was pointed out by Prof. Hellmann in 1875, when studying the Mount Washington observations, and the same fact has since been observed at Ben Nevis and other Observatories. The wind has also a vertical as well as a horizontal motion, which has amounted to seven miles an hour in a storm. The normal temperature at the summit of Blue Hill is 2° lower than at the base, giving a decrease of 1° for each 220 feet of ascent, but inversions frequently occur, when the temperature of the base is lower than at the summit. Instances of this are given, together with records obtained during balloon ascents.—The aspiration psychrometer and its use in balloons, by Dr. R. Assmann. Such an instrument was first used by Welsh in 1853, but it was not fully adapted to use in balloons. The apparatus invented and described by Dr. Assmann, which is intended to register the changes, which ordinary thermometers do not show quickly enough, is made by Fuess, of Berlin. The aspirator may be driven by a small electric motor, instead of by clockwork.—The Bergen Point tornado, by W. A. Eddy. The track was about nine miles south-west of New York City, on June 16 last. The tornado was preceded and followed by showers of large hailstones, and extended only for about two miles.—The hot winds of California, by Lieutenant J. P. Finley. The period during which these winds occur is from May to September; the thermometer has been known to reach 118° in the shade, and the winds generally occur during entire absence clouds.—Altitude and hay fever, by Dr. W. J. Herdman. Special attention is drawn to the curative influence of mountain stations.
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Scientific Serials. Nature 44, 512 (1891). https://doi.org/10.1038/044512a0
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DOI: https://doi.org/10.1038/044512a0