MESSRS. J. STONE AND Co., LTD., of Deptford, have introduced a new light alloy to which they have given the name of “Ceralumin C”. This alloy contains copper 2-5, nickel 1-5, magnesium 0-8, iron 1-2, silicon 1-2 and cerium 0-15 per cent. It thus belongs to a well-known class of light alloys, but contains cerium in addition to the more usual elements. It is claimed that cerium refines the microstructure, and also suppresses the formation of the brittle iron-aluminium constituent. The alloy is used in the heat-treated condition, being heated to 515°-535° C. for four to six hours in order to bring the constituents into solid solution, and then quenched. Ageing is effected in 16 hours at 175°, after which the alloy is again quenched. Chill castings after heat treatment have a tensile strength of 23-27 tons/in.2, a proof stress of 21-24 tons/in.2, an elongation of 1 per cent, and a Brinell hardness of 130-140. A fatigue range at 20 million reversals of ±8-25 tons/in.2 has been obtained, which is high for alloys of this class. When the ageing at 175° is replaced by ageing at room temperature for five days, the tensile strength is lowered, but an elongation of 4r-6 per cent has been obtained. This modified alloy is called “Ceralumin D”. Sand castings give rather lower figures. The new alloy is claimed to give smooth castings, and to be suitable for many kinds of aeronautical and automobile purposes.