Abstract
LONDON. Royal Society, Dec. 5.—F. A. B. Ward, C. E. Wynn-Williams, and H. M. Cave: The rate of emission of alpha-particles from radium. A new type of electrical counter was used in which the whole of the amplification is produced by triode valves. The amplification was linear, so that the counting of α-rays was undisturbed by the presence of β-rays. About 500 particles per minute could be counted. The rate of emission from radium determined by counting about 10 e-particles was 3.66 × 1010 α-particles per sec. per gm. of radium.—E. J. Williams and F. R. Terroux: Investigation of the passage of fast beta-particles through gases. The primary ionisation for beta-particles of 0.5-0.9 of the velocity of light, determined in the Wilson cloud chamber, appears to approach limits of 22 ions per cm. in oxygen, and 5 ions per cm. in hydrogen. Variation with velocity differs appreciably from that predicted on classical theory. From the frequency of branch-tracks, the magnetic moment of an electron seems considerably less than a Bohr magneton. Momentum appears to be con- served in branch collisions.—R. J. C. Howland: On the stresses in the neighbourhood of a circular hole in a strip under tension. The problem is solved by successive approximation for the case in which the stress-system is symmetrical both about axis of strip and about perpendicular diameter of hole. General formuke are given expressing each approximation in terms of the preceding. The coefficients of the transformation depend upon transcendental integrals which are estimated numerically and coefficients are then tabulated. When the ratio of diameer of hole to diameter of strip does not exceed 0.5, greatest stress at boundary of hole is nearly 4 times tension at infinity. On the edge, tension rises from a minimum of less than ¾ of applied tension at point nearest to hole, to maxima, not much less than twice applied tension, at about one-third of width of strip on either side of central section. On the axis, disturbance due to hole becomes inappreciable at a distance from centre of hole equal to about 1½ times width of strip.
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Societies and Academies. Nature 124, 932–934 (1929). https://doi.org/10.1038/124932b0
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DOI: https://doi.org/10.1038/124932b0