DR. THOMAS'S book on “Complex Salts” is a small volume of about 120 pages, intended more especially for students reading for final and honours degrees. It differs from a recent book by Schwarz on “The ...

DR. L. C. JACKSON'S letter in NATURE of June 27, p. 981, points out the fact that an iron atom, known definitely to be ferrous, can have at least four distinct magnetic moments; namely, 26, 26.5, 27, ...