PROF. W. A. BONES address, Forty Years of Combustion Research, delivered on July 12 on the occasion of the presentation of the medal of the Society of Chemical Industry, was a brilliant review of experimental research in this field, and the clarity of its delivery no less than the lucidity and felicity of exposition which characterised it made the occasion one which will be long remembered by those present. A skilful picture of the position unfolded by Dixon in his lectures at Owens College, Manchester, when Bone entered the College in 1888, was followed by an account of the development of the theories of detonation, down to the development of the new technique for the investigation of spin in detonation which enables us to measure with precision periodic flame movements occurring with frequencies up to a million a second. Discussing research on the combustion of hydrocarbons, Prof. Bone referred to the recent quantitative proof of the hydroxylation theory, suggested by H. E. Armstrong in 1874, offered by D. M. Newitt and A. M. Blochs recent pressure-oxidation experiments on ethane and acetylene. Surface combustion, ignition phenomena and initial flame movements were touched upon in the same masterly manner, and a brief review given of the results obtained in gaseous combustion at high pressure, leading to the discovery of nitrogen activation in carbon monoxideair explosions, with the investigation of which Prof. Bone commenced his researches. Direct and cumulative evidence, chemical and spectrographic, all appears to lead to the conclusion that carbon monoxide can burn in two ways, directly, without any intervention of steam, and indirectly, either through steam or as a result of its intervention, pressure favouring the former. In concluding, Prof. Bone emphasised the need for the elaboration of an adequate technique, and the dependence of progress on accurate and completely analytical operations under experienced guidance.