WE have received the Proceedings of the Chemical Engineering Group, Society of Chemical Industry, vols. 11 and 12, 1929 and 1930 (in one volume). This contains a number of valuable papers, dealing with such subjects as surface energy, flotation, water treatment, alloy steels, gas and electric heating furnaces, and welding. The standard of the papers is high, and they are usually followed by interesting discussions. The Transactions of the Institution of Chemical Engineers, vol. 8, 1930, has also been received, and contains important papers on various subjects related to chemical engineering, such as cellulose products, crystallisation, high pressure reactions, tannery waste, wood pulp, pulverised fuel, and the recovery of metals from waste materials. Both these volumes are very well printed and illustrated, and form valuable contributions to the literature of applied chemistry and engineering.