Within recent years the subject of anodic oxidation has been very fully and minutely examined, notably by Bengough, Stuart, and Dr. Sutton, who was responsible for the large-scale experiments carried out at the Royal Aircraft establishment, Farnborough, and who, with his collaborators, has presented a number of excellent papers to the Royal Aeronautical Society, the Institute of Metals, and other bodies. In addition, scientists and industrialists at home and abroad are continuously adding to knowledge of aluminium, its uses and adaptability, and are giving a growing impetus to penetrations into spheres formerly exclusive to steel, brass, copper, tin and timber, each substitution calling for special consideration, so that it is well-nigh impossible for one to broach the subject without impinging somewhere upon the work ol others.