THE world to-day simply lives upon explosions: it moves and has its very being, in the air and on the roads, upon and under the waters, through the agency of flame. The publication of a book dealing comprehensively with a subject of such public importance, by a master-worker, is therefore most opportune. It is so well-written that it should rank as a ‘best-seller’ with Ludwig's “Napoleon” and gruesome “Jew Suss,” being as readable and exciting as a “Greenmantle” or a Mason ‘shocker’: though unfortunately the situations opened up are usually left unsettled and mayhap, even when ‘continued in our next,’ will still remain problematical. The plot, in fact, is seemingly one of fearful complexity and the detectives engaged in unravelling the story have been far from possessed of the logical training and mental agility needed to dissect out its many threads: still, that definite pathways are being cleared through the maze cannot be doubted. Flame and Combustion in Gases. By Prof. William A. Bone Dr. Donald T. A. Townend. Pp. xvi + 548 + 30 plates. (London: Longmans, Green and Co., Ltd., 1927.) 32s. net.