Societies and Academies

Abstract

LONDON. Royal Society, June 27.—Lord Rayleigh: A photo-electric method of measuring the light of the night sky: with studies of the course of variation through the night.—J. C. McLennan, M. W Perrin, and H. J. C. Ireton: The action of high-speed cathode rays on acetylene.—Lord Rayleigh: Fluorescent and phosphorescent excitation of mercury vapour by the resonance frequency and lower frequencies.—T. E. Stern, B. S. Gosling, and R. H. Fowler: Further studies in the emission of electrons from cold metals. An extension of Nordheim and Fowler's work on electronic emission from clean cold metals. It explains a wide range of experimental results obtained with films of sodium (or tungsten). The normal stable sodium film formed is mono-molecular and reduces the work function from 4.5 volts to somewhat less than volts. The currents concerned are of high density; the space charge correction is negligible for the conditions of the experiments discussed.—A. E. H. Love: The stress produced in a semi-infinite solid by pressure part of the boundary. The method of potentials, invented by Boussinesq, is developed and applied to the case of uniform pressure over a circular area, among others. The solution is also discussed arithmetically with the object of throwing light on the technical question of the safety of foundations. Beneath a round pillar, there is a basin-shaped surface possessing a roughly similar property. The form of this surface is determined. In these cases failure arises through excessive stress-difference. Tensile stress is greatest near the base of a pillar, or a corner the base of a wall, and just outside it. It would not endanger a round pillar, but may be a cause of decided weakness if the boundary of the base of a wall or pillar presents a sharp corner.—A. N. Shaw and H. E. Reilley and R. J. Clark: The ageing of standard cells: increased accuracy in their use: and international comparisons.—H. Quinney: A comparison between behaviour at the Ac3 point of single crystal iron and polycrystal iron, both in the strained and unstrained states.—J. N. Pring and G. M. Westrip: An electrometric method for the determination of ozone high dilutions.—C. F. Jenkin and G. D. Lehmann: High-frequency fatigue.—J. S. Townsend and S. P. MacCallum: Ionisation by collision in monatomic gases. A discussion of some recent theories of conductivity.—?R. C. Johnson and R. K. Asundi: The structure of the high-pressure carbon bands and the Swan system. Both systems are due to a C2 molecule. Four new high-pressure bands have been found in the near ultra-violet, and two more in the near infra-red. These, with the known bands, form a single vibrational progression (n′ = 0), and both systems represent transitions to a common final state. The initial state of the high-pressure system is believed to be a normal 3P level and different in this respect from the two lower 2P levels, which are believed to be inverted.—D. M. Newitt: Gaseous combustion at high pressures (13). The experimental data from explosions of various 2CO +O2 4C0, 2H2 +O2 + xN2 and 2H2 + O2 + xA mixtures at high initial pressures have been analysed, and mean molecular heats of nitrogen and steam have been calculated for the temperature range 289°—2600° to 3000° K and for carbon dioxide for the range 289°—173° K. The results for nitrogen are in agreement with the generally accepted values, but those for steam and carbon dioxide are higher.—R. J. Clark: the direct determination of the electrostatic moments of molecules. Direct deflection in a rapidly varying field is used. Sodium and potassium atoms have either rio permanent electric moment, or one that is too small to measure. So far no polarisation by the field on these molecules has been found.—A. R. Low: On the criterion for stability of a layer of viscous fluid heated from below. Rayleigh gave a mathematical account of the modes of instability of a viscous fluid heated from below with the special assumption of zero tangential forces at the boundaries, and found unexpectedly that the top-heavy layer of fluid was stable until a certain temperature gradient, negative upwards, was exceeded. Jeffreys has reduced the problem to the solution of a linear differential equation of the sixth order with constant coefficients, the complete solution of which is now given.?R. B. Brode: The absorption coefficient for slow electrons in mercury vapour.—F. L. Usher: A mechanism of gelatinisation.—H. R. Hass and W. R. Cook: The determination of molecular forces from the viscosity of a gas.—J. C. McLennan, A. B. McLay, and M. F. Crawford: The spark spectrum of thallium (Tl III).—