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LONDON. Society of Public Analysts, Nov. 5.—G. M. Moir: The determination of the milk proteins. By mixing definite quantities of milk with a suitable acetic acid and sodium acetate buffer, maximum casein values are obtained between pH 4-5 and 4-7. Casein thus precipitated is identical with the substance precipitated by acetic acid alone at pH 4-2. For the combined determination of albumin and globulin the nitrate obtained from the iso-electric precipitation of the casein is treated with trichloroacetic acid to give a concentration of about 4 per cent, and the nitrogen in the resulting precipitate determined by Kjeldahl’s method. Casein and globulin are determined by precipitation with neutral saturated magnesium sulphate or sodium sulphate, and the individual proteins calculated by difference.—S. G. Clarke: The lead reduction method for the volumetric determination of tin, and the interference of copper and antimony. Tin is determined by Powell’s method of reduction from the stannic condition by means of lead, and direct titration with iodine, in an atmosphere of carbon dioxide. Copper causes the results for tin to be too low in direct proportion to the amount of copper present. Antimony also interferes, a considerable amount of tin being removed from the solution by the precipitation of the antimony; this reacts with the iodine during the titration.—W. J. Agnew: A new method for determining traces of chromium in steel. Chromium is oxidised with potassium permanganate, excess permanganate being reduced by hydrochloric acid. The iron is then precipitated with sodium carbonate, and the dichromate determined by Evans’s colorimetric method based on the purple coloration which it gives with diphenylcarbazide.