4 MARCH 1876, Page 24

Telegraphy. By W. H. Preece, C.E., and J. Sivewright, M.A.

(Long- mane, Green, and Ce.)—Our artisans, for the most part, learn their trade from the observation of practised hands, and know little about the theory of their operations. In so important a matter, however, as that of establishing telegraphic communication, the employes should know more of the subject than what is required from an ordinary mechanic, and the work of Mr. Gulley is too costly for many of them to purchase. The authors have done good service to their department in publishing in a cheap form this easily intelligible treatise. The description of the methods and instruments is excellent, and the important parts of the mechanism are drawn to scale, which adds much to the value of the book. Nothing has been omitted from what should be known by all, from the departmental chief to the humblest pole-setter.