Abstract
LONDON Physical Society, Dec. 16.—Allan Ferguson and J. T. Miller: A method for the determination of the specific heats of liquids, and a determination of the specific heats of aniline and benzene over the approximate range 20° to 50° C. The specific heats of aniline and benzene are determined by measuring the electrical power E2/R necessary to hold the temperature of a calorimeter and its contents steady at various temperature-excesses.—E. V. Appleton and G. Builder: The ionosphere as a doubly refracting medium. In a previous communication the occurrence of wireless echo doublets was described and was provisionally attributed to the influence of the earth's magnetic field on the dispersive properties of the ionosphere. A more extended study of the subject, which has included an experimental determination of the polarisations of the doublet components, has confirmed this hypothesis. In southeast England, for ionospheric reflection at vertical incidence, the echo component of lesser delay is in general of right-handed, and the component of greater delay of left-handed, circular polarisation, but this temporal sequence should be reversed in the southern hemisphere and in certain special circumstances in the northern hemisphere.—M Taylor: The Appleton-Hartree formula and dispersion curves for the propagation of electromagnetic waves through an ionised medium in the presence of an external magnetic field. (1) Curves for zero absorption. The curves are drawn to show the value of the squares of the indices of refraction and attenuation as functions of the electron density for a series of twelve frequencies, which are chosen to illustrate the various classes of curve and the boundary curves separating the classes and, in the case of frequencies of more than 1.321 megacycles per second, the various regions of short and ultra-short waves. The derivation and general properties of the Appleton-Hartree formula and the various possible modes of propagation are also discussed. The disperson curves are classified according to the infinities they contain and a diagram is given to show how the classes of curve holding for any angle of inclination of the direction of propagation to the magnetic field H depends on the ratio of the longitudinal component of H to H itself.—L. F. Bates: A new apparatus for the measurement of the earth's magnetic field. A small cylinder of mumetal is wound with fine wire, the ends of which are connected to wires forming a torsional suspension. This cylinder is placed with its centre at the mid-point of a Helmholtz coil system with its axis adjusted to coincide with the direction of the component of the earth's field which is to be measured, the suspension being perpendicular to the component. The current through the coil system can be adjusted so that there is no deflection of the suspended cylinder when the current in the solenoid wound upon it is reversed, in which case the calculated field produced by the coils is equal to the required component.—E G. Richardson and E. Tyler: The flow of liquid suspensions. Measurements of the velocity from point to point in a liquid rotating in the space between two concentric cylinders, of which the outer rotates while the inner is still, have been made by means of a hot-wire anemometer. In a suspension, the velocity gradients are abnormal but can be explained in terms of a variable viscosity, which is a function of the velocity gradient.—Lewis Simons and E. H. Smart: A model to illustrate the motion of a diatomic rotator with two degrees of freedom. An arm 5 in. long is pivoted at one end and carries at the other end a small electric lamp which is thus capable of moving on the surface of a sphere about the pivot as centre. The two angular velocities φ and θ can be independently controlled by two hand-regulated motors: φ is the azimuthal and θ the co-latitudinal angular co-ordinate of the arm. If φ and θ are commensurable, the resulting figure traced out by the lamp remains stationary in space. This path represents the motion of one of the atoms of the rotator, which has two degrees of freedom.
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Societies and Academies. Nature 130, 1010–1012 (1932). https://doi.org/10.1038/1301010a0
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DOI: https://doi.org/10.1038/1301010a0