Abstract
LONDON. Physical Society, Nov. 9.—J. B. Seth, Chetan Anand, and Gian Chand: The effect of moist air on the resistance of pencil lines. The resistance of a pencil line increases when it is kept in a moist atmosphere. This change may, in certain circumstances, be utilised to measure humidity.—L. F. Richardson, V. Stanyon, and other students of Westminster Training College. An absolute current-balance having a simple approximate theory. A simple form of current-balance has been constructed which measures currents with a probable error of about 1 part in 1000. The coils are single layers, so that they can in the future be made as precise helices. The authors had to aim at cheapness rather than at perfection, and so irregularities of shape leave the current uncertain by 5 parts in 1000. A second approximation, depending on a simple deduction from Laplace's equation, corrects the elementary theory by 1.4 parts in 1000 of current. —E. V. Appleton: Notes on wireless methods of investigating the electrical structure of the upper atmosphere (I.). Various direct wireless methods of measuring the ‘effective’ height of the atmospheric ionised layer are discussed and compared. For a layer of horizontal stratification, and under conditions for which the influence of the earth's magnetic field may be neglected, the effective height is greater than the maximum height reached by the atmospheric ray.
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Societies and Academies. Nature 122, 982–984 (1928). https://doi.org/10.1038/122982a0
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DOI: https://doi.org/10.1038/122982a0