AN important series of discussions arranged by the Faraday Society took place in the Biochemical Theatre of the University of Oxford on September 15-17 on the subject of “Luminescence”. A more appropriate time for the discussion of work in this field could scarcely have been chosen, and in spite of recent events, a surprisingly large number of visitors from overseas was present. The discussions were formally divided into three parts: luminescence of vapours, liquids, and solutions ; luminescence of solids ; chemiluminescence. The subject of luminescence is of particular interest at the present time for two reasons. First, it forms an excellent testing ground for some of the more recent theories, particularly with respect to the physical properties of solids, and the nature of chemical reactions. Secondly, a good deal of stimulation has been given by the technical interest in the subject. The use of fluorescent solids in discharge tubes as a means of modifying the colour of the light or increasing the efficiency of such devices is undoubtedly leading up to new work of interest, and contributions to the meeting were made by more than half a dozen industrial laboratories.