Abstract
LONDON Royal Society, November 23.—Sir Charles Sherrington, president, in the chair.—T. E. Stanton: On the characteristics of cylindrical journal lubrication at high values of the eccentricity. The arc of contact of the film was limited in extent in the experiments and the intensity of pressure was considerably higher than in normal practice; the arcs of contact varied from 14 to 35 degrees and the maximum intensities of pressure from 14 to 35 tons per sq. inch. In all the cases observed, the pressure distribution in the film has been in accordance with the hydrodynamical theory of Osborne Reynolds. By means of a careful determination of the pressure distribution in the film, and a measurement of the radius difference of bearing and journal, sufficient data have been obtained to calculate the viscosity of the lubricant and the attitude and eccentricity of the bearing. The values of the viscosity of the lubricant so calculated were in good agreement with those determined in a viscometer, and it was concluded that the calculated values of the eccentricity were trustworthy. In the case of a journal 2.5 cm. diameter, the least distance apart of the surfaces was found to vary from 0.0024 to 0-0024 mm.—J. H. Jeans: The propagation of earthquake waves. Earthquake waves are regarded as being compounded of a number of free vibrations of a non-homogeneous gravitating earth. In 1885, Lord Rayleigh discussed a certain type of surface waves which would travel over the earth's surface with a velocity of about 0.92√(μ/p). It is now shown that there are additional, and far more numerous, surface waves which travel with velocities √(μ/p) and √(λ+2μ)/p). If such waves are generated by an earthquake at any point close to the earth's surface, they will refocus themselves upon this point after intervals which are integral multiples of 2π√(φ/(λ+2μ)) and 2√(φ/(λ + 2μ)), the numerical values of these quantities being about 223 and 126 minutes respectively. In 1917, two series of earthquakes, each originating from the same centre, had their times given approximately by formulæ of the type
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Societies and Academies. Nature 110, 794–796 (1922). https://doi.org/10.1038/110794a0
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DOI: https://doi.org/10.1038/110794a0