LONDON. Chemical Society, March 1.—Mr. A. G. Vernon Harcourt, F.R.S., past president, in the chair.—Studies of dynamic isomerism, part iv., stereoisomeric halogen derivatives of camphor: T. M. Lowry. Measurements were given of the solubility in alcohol of α-chloro- and α-bromocamphors, αβ- and απ-dibromocamphors, and αβ- and απ-chlorobromocamphors, both alone and in presence of a small proportion of sodium ethoxide. The increase of solubility on addition of the alkali is ascribed to the formation in the solution of a small proportion of the stereoisomenic α′-compound.—The coagulating action of colloids, part i.: W. P. Dreaper and A. Wilson. The results obtained by the authors throw some light on dyeing and tanning processes. The influence of gallic acid in the manufacture of leather seems to be of a more direct nature than was previously supposed.—Studies on optically active carbimides, iii., the resolution of α-phenyl-α′ -4-hydroxy- phenylethane by means of l-menthylcarbimide: R. H. Pickard and W. 0. Littlebury. The l-menthylcarbamates formed by combination with l-menthylcarbimide can be separated by fractional crystallisation, and are then hydrolysed by alcoholic sodium hydroxide-Experiments on the synthesis of the terpenes, part viii., synthesis of the optically active modrfications of δ3-p-menthenol(8) and δ3:8(9)-p-menthadiene: F. W. Kay and W. H. Perkin, jun. δ′-Tetrahydro-p-toluic acid, l-δ3-pmenthenol(8), δ3:8(9)-pmenthadiene, and d-δ3:8(9)-p-menthadiene have all been synthesised. By fractional crystallisation of the brucine and strychnine salts of the first-named compound it was resolved into optical isomenides, and from these the two other compounds were prepared in an optically active condition—Studies in the acnidine series, iii., the methylation of chrysaniline: A. E. Dunstan and J. T. Hewitt. —Note on the application of the electrolytic method to the estimation of arsenic in wall-papers, fabrics, &c.: T. E. Thorpe.—Nitrogen halides from camphoryl-ψ-carbamide: M. O. Forster and H. Grossmann. The action of potassium hypobromite and hypochlonite on camphoryl-ψ- carbamide has been found to give rise to dihalogen derivatives which have all the properties of compounds contaming halogen attached to nitrogen.—The relation of position isomerism to optical activity, vi., the rotation of the menthyl esters of the isomeric chloronitrobenzoic acids J. B. Cohen and H. P. Armes. In the present investigation the combined effect of the halogen and nitro-group on the activity 9f the menthyl group has been examined.