2 JUNE 1923, Page 21

The third volume of Dr. Mellor's monumental work contains four

chapters, dealing exhaustively with six elements. A chapter is devoted to each of those industrially and financially important metals, copper, silver and gold, and the last chapter deals with the metals of the alkaline earths, calcium, strontium and barium. It would be difficult to overrate the value of Dr. Mellor's work for the advanced student. A specially useful feature is the very full list of references to original papers. The section on the physical properties of copper, for instance, covers thirty pages, and ten pages of references in small type are appended. Thus Dr. Mellor's work is not only a complete and lucid exposition, but an index to practically all the original research on which it is based.