PROF. DINGLE's two small books form a balanced course of physics, not including mechanics. They begin at the post-matriculation stage, assuming a slight knowledge of mechanics and of the calculus, and they attain a level, on the standard of the University of London, somewhere between the physics of Intermediate Science and that of the General B.Sc. They treat ordinary academic physics and are not specially “aero”. The explanations are easily read and almost all very clear, the diagrams abundant and satisfactory, the paper good, the print excellent, and the price low. There are indexes and exercises. A welcome addition to the usual course of physics is a chapter on sidereal and solar time, with diagrams of the celestial sphere. An original feature is the broad grouping of the subject-matter into “mechanical” and “sub-atomic” books ; the former including gravitation, elasticity, surface tension, viscosity, heat and sound ; whereas the “sub-atomic” book includes optics, electricity and magnetism. In explanation of this arrangement the second book has a chapter on the structure of the atom. But it is placed at the beginning, at a stage where the student cannot yet understand the experimental evidence. This dogmatic chapter may whet the appetite of some students, but discourage others. Mechanical Physics By Prof. Herbert Dingle. (Nelson's Aeroscience Manuals.) Pp. 248. (London and Edinburgh: Thomas Nelson and Sons, Ltd., 1942.) 5s. net. Sub-Atomic Physics By Prof. Herbert Dingle. (Nelson's Aeroscience Manuals.) Pp. 272. (London and Edinburgh: Thomas Nelson and Sons, Ltd., 1942.) 5s. net. University Physics By Dr. F. C. Champion. Part 5: Electricity and Magnetism. Pp. vii + 246. (London, Glasgow and Bombay: Blackie and Son, Ltd., 1942.) 7s. 6d. net.