LONDON. Royal Society, December 11.—Sir William Crookes, O.M., president, in the chair.—A. Mallock: Intermittent vision. When a wheel turns so rapidly that the separate spokes cannot be seen or easily followed by the eye, and if at the same time the observer receives a small mechanical shock of almost any kind, the spokes appear almost stationary for a fraction of a second. The appearances depend on the speed of rotation, on the brightness of the illumination, and, to a lesser degree, on the nature of the shock. Suitable shocks are given by the contact of the feet with the ground, as in walking, by tapping the head or body, and in many other ways. Experiments are described bearing on the relation between the appearances and the speed of rotation, and an explanation is suggested depending on an assumed variation of sensibility produced by a slight shock. This variation, which it appears is rapidly extinguished, has a periodic time of about 1/18 second, but this differs slightly for different individuals.—Prof. R. J. Strutt: Attempts to observe the production of neon or helium by electric discharge. The present experiments were begun in the hope of confirming the work of Collie and Patterson (Trans. Chem. Soc, 1913, vol. ciii., p. 419, and Proc. Chem. Soc, 1913, vol. xxix., p. 217). The results have been negative, whether from a failure to appreciate the proper conditions for the production of neon by electric discharge through hydrogen or from some other. cause;—Walter Wahl: The relations between the crystal-symmetry of the simpler organic compounds and their molecular constitution. Part iii. —Prof. G. G. Henderson and I. M. Heilbron: The selective absorption of ketones. The authors have found that the selective absorption of a large number of simple ketones is of the same type, since the absorption bands of all are practically identical. They suggest that the absorption of these compounds may be due to electronic disturbances accompanying oscillations which arise from the alternate formation and breaking down of unstable ring systems within the molecule.—F. E. Smith: Absolute measurements of a resistance, by a method based on that of Lorenz. The instrument employed differs from all other forms of apparatus based on the method of Lorenz, inasmuch as two discs are employed instead of one. The disturbing effect of the earth's magnetic field is thus practically eliminated. The result of the experiments is that a resistance of one international ohm is equal to 1.00052 0.00004 ohms (109cm./sec).—A. N. Shaw: A determination of the electromotive force of the Weston normal cell in semi-absolute volts. With a preface by Prof. H. L. Callendar. This paper represents the completion of work commenced by Prof. H. L. Callendar and Mr. R. O. King in the years 1894 to 1898. The final result for the E.M.F. of the Weston cell in semi-absolute volts comes out 1-01827 at 200 C, which agrees closely with the mean of the best recent determinations, namely 1.01824.—F. E. Howett: Elastic hysteresis in steel. A thin-walled steel tube was coupled to a coaxial tube of greater section and length. The compound tube was twisted, and the twist in each component measured by spirit levels. The twist of the large tube, in which the stress and therefore also the hysteresis was small, measured the torque applied to the small tube. The elastic hysteresis in hard-drawn tubes was about one-eighth of that in the same tube after annealing.—F. W. Aston: A simple form of micro-balance for determining the densities of small quantities of gases. (1) A simple micro-balance is described, by which the densities of gases may be determined relative to some standard gas, using a null method; (2) about half a cubic centimetre only of the gas is required; (3) the determination can be performed in a few minutes, with an accuracy of 01 per cent; (4) possibilities of its use in other fields of research are indicated.—T. R. Merton: A second spectrum of neon. The spectrum of neon has been investigated under different conditions of electrical excitation. It has been found that with a condensed discharge a second spectrum is developed, as in the case of argon, krypton, and xenon. The strongest lines of the ordinary spectrum are also feebly visible when a condensed discharge is used.