“THE works comprised in this series,” the editors tell us, “will all be composed with special reference to their use in school-teaching; but, at the same time, particular attention will be given to making the information contained in them trustworthy and accurate, and to presenting it in such a way that it may serve as a basis for more advanced study.” Practical Physics, Molecular Physics, and Sound. By Frederick Guthrie, Professor of Physics in the Royal School of Mines, London. (London: Longmans, Green, and Co., 1878.) [London Science Class-Books, edited by G. Carey Foster, F.R.S., and Philip Magnus, B.Sc., B.A.]