LONDON Royal Society, April 24.—“On the Relation between the Electrical Qualities and the Chemical Composition of Glass and Allied Substances.” Parti. By Thomas Gray, B.Sc., F.R.S.E., and Andrew Gray, M.A., F. R. S.E., Assistant to the Professor of Natural Philosophy in the University of Glasgow, and J. J. Dobbie, M.A., D.Sc. (Edin.), Assistant to the Professor of Chemistry in the University of Glasgow. Communicated by Prof. Sir William Thomson, F.R.S.