LONDON. Faraday Society, April 14.—Sir Robert Robertson, president, in the chair.—T. A. Heppenstall and W. J. Shutt: Conditions of the appearance of anode effect in the electrolysis of fused chlorides. Anode effect is an irreversible condition at the positive electrode which manifests itself during the electrolysis of fused salts by a sudden drop of the current passing through the cell; simultaneously gas evolution at the anode ceases, and the latter has the appearance of being “unwet “by the electrolyte. The effect is reproducible at constant current density at a given temperature. When an alternating current was superimposed upon the direct current used for electrolysis, the effect was produced at a lower direct current density.—R. Ashton Hill: The photochemical decomposition of gaseous sulphur dioxide. The decomposition of sulphur dioxide gas under the action of light radiated from a uviol mercury vapour lamp has been investigated, and the resulting photostationary state, characteristic of a given set of conditions, determined, using a number of different light filters. The wavelength chiefly responsible for such decomposition is 313 up, which lies within the first absorption band of sulphur dioxide (at a pressure of 600 mm.), but does not correspond with the head of the band (296-1 MM). The actual wave-length producing maximum decomposition depends on the nature of the source of radiation, i.e. upon the intensity distribution of the emission spectrum. Of the radiation emitted from the uviol lamp the longest wave-length capable of decomposing sulphur dioxide is the 313 MM line itself. Probably any wave-length within the absorption band of the substance is capable of bringing about decomposition, provided the intensity is sufficiently great. The bearing of the photochemical decomposition of sulphur dioxide upon the critical increment of the thermal union of oxygen aud sulphur vapour is discussed. The molecule Sz as distinct from the atom seems to be involved in this process.—F. C. Thompson and W. H. Dearden: Note on an experiment in solid diffusion, and its possible bearing on the structure of solid solutions. The experimental work consisted in the determination of the relative rates of diffusion of copper into gold, silver, and an alloy of those metals in equal proportions. These particular materials were chosen since their atomic volumes are almost identical. It was found that diffusion takes place much more readily into a pure metal than into a solid solution. This is more easily understood on the assumption that the added atoms in the solution are accommodated in spaces in the lattice than if they replace atoms in the lattice itself.—J. P. McLare: The repair of worn components by electro-deposition. This method of repair was first adopted on a considerable scale during the War. Success depends primarily on the condition of the cathode surface. Electrolytic methods of cleaning are indispensable.