25 AUGUST 1894, Page 24

Electro-Magnetism and the Construction of Dynamos. By D. C. Jackson.

(Macmillan.) — Text-books on the construction of dynamos are always welcomed now ; the dynamo is the most important engine the mechanical engineer has to construct nowa- days. The technical details and formulee of their working are elaborately and carefully discussed by Mr. Jackson. The book, which seems expensive, is illustrated by curves and diagrams.