Compare Abstr., this vol., ii, 81).-The ratio of silver iodide to silver bromide and silver chloride has been determined by converting a weighed quantity of pure silver iodide into silver bromide by heating it in a quartz crucible in a current of air and bromine vapour and afterwards this vol., ii, 382).-Most of the results of the work described in this paper have been published previously. When melted rhombic sulphur is heated, viscosity first appears a t 159.5". The absorption of heat

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... d with the transition occurs a t 162.5" and upwards, the liquid becoming viscous at the same moment. Distilled sulphur behaves somewhat differently from crystalline sulphur and appears to be much more liable to become superheated ; the viscosity is first apparent a t 161.5-162O and even then asserts itself rather gradually. These phenomena take place in the same way and at the same temperature whether the sulphur E. G. Formation of Ozone by Ultra-Violet Light.