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With 60 Plates and numerous Illustrations. Cloth. 34s. "A book of great professional usefulness."—Iron. CHARLES GRIFFIN & CO., Ltd., 12 Exeter Street, Strand, W.C. A Treatise ON ELECTRIC SWITCHGEAR AND SYSTEMS OF BY LEONARD ANDREWS, INSTITU ASSOCIATE MEMBER OF THE INSTITUTION OF CIVIL ENGINEERS, MEMBER OF THE INSTITUTION OF ELECTRICAL ENGINEERS, EX-MEMBER OF COUNCIL OF THE INCORPORATED MUNICIPAL ELECTRICAL ASSOCIATION, 93527 FEB 23 1906 TOL •AN2 PREFACE. 6983871 ELECTRICAL engineers have such an enormous library from which to select their technical literature that to increase its dimensions must be considered an offence, unless it can be shown that there is room for a new book on any particular subject. My excuse for so trespassing must be that, although many books exist on boilers, engines, electric generators, mains, transformers, lamps, etc., no one has dealt exclusively with that part of the system that has been rightly termed the 'nerve centre.' A reason for this apparent neglect of a very important section is to be found in the fact that such rapid advances in switchgear design are daily being made that it is almost impossible for a book, which necessarily is some months in passing through the press, to be absolutely up-to-date. It should be explained at the outset that the present work does not pretend to be purely a record of the best modern practice in switchgear design. Quite a large proportion of it is devoted to descriptions of various kinds of apparatus that have been abandoned, with, in many cases, a brief explanation of the reasons of failure. Some engineers claim that their time is too valuable to waste in endeavouring to understand failures, and they are quite content to be guided in the preparation of their schemes by the dictates of fashion. But to the engineer who, when he meets a difficulty, is not satisfied until he has got to the bottom of it-to the designer who will often make efficient use of a device that has failed by applying it to another purpose, and to the student who conscientiously wishes to prepare to deal with the difficulties he may meet with in his after career-the brief records given of difficulties that have been encountered in the evolution of modern switchgear will, I trust, prove of some assistance. There are certain classes of switchgear that I have not attempted to deal with, such as small installation switches, motor controllers, and automatic pressure regulating devices, all of which might have come within the scope of the work; but the subject as a whole is such an inexhaustible one that I have thought it best to confine my attention to |