THESE papers make a stately volume of considerably more than 700 pages, and our thanks are due to the editors, Mr. Guy Barlow and Dr. Shakespear, for the ability with which they have performed their work, a work which, as old pupils of Poynting, must have been to them a labour of love. The volume contains an excellent portrait, and the type, paper, and binding are worthy of the Cambridge University Press. I think everyone, even though he may have thought himself well acquainted with Poynting's work, will find here something which he sees for the first time, for the volume includes not only papers from such normal sources as the Transactions and Proceedings of the Royal Society and the Philosophical Magazine, but also others from the India Rubber Journal, the Hibbert Journal, the “Encyclopaedia of Biblical Literature,” the Mason College Magazine, and the Inquirer. In addition to the classical papers on the flow of energy in the electromagnetic field, on the pressure of light, and on the density of the earth, there are others on the drunkenness statistics of the large towns, on the fluctuations in the price of wheat, on the experiences of one who overtook the waves of light, a criticism of Herbert Spencer's “First Principles,” and a paper on physical law and life. To those who knew Poynting, these informal papers have a special charm, for they will find in them much that will recall memories of long-past talks; they recall his quiet humour, the freshness of his views, his courtesy in debate, his dread of saying or doing anything that could hurt the feelings of anyone who did not hold his own views on the point at issue. Among the seventy papers in this book, there are not more than two or three that could be called controversial, and it is characteristic of these that he criticises his opponent as if he loved him; and, even when the author under notice has laid himself more than usually open to criticism, Poynting is not content with pointing out the unsoundness of his statements; he suggests that he must really have meant something else, something much more reasonable. Collected Scientific Papers. By Prof. J. H. Poynting. Pp. xxxii + 768. (Cambridge: At the University Press, 1920.) Price 37s. 6d. net.