ELECTRICITY CONTROL. NET BOOK.-This book is supplied to the Trade on terms which will not allow of Discount to the Public. CHARLES GRIFFIN & CO., LTD. ENGINEERS AND OTHERS. CENTRAL ELECTRICAL STATIONS: Their Design, Organisation, and ELECTRICAL RULES AND TABLES: For the use of Electricians and M. Inst. M.E. Crown 8vo. ELECTRO-METALLURGY: Embracing the application of Electrolysis to the Plating Depositing, Smelting, and Refining of various Metals, and to the Repro. duction of Printing Surfaces and Art Work. By WALTER G. MCMILLAN, F.I.C., F.C.S. SECOND EDITION. Revised and Enlarged. Large Crown Svo. Price 10s. 6d. one of the BEST AND MOST COMPLETE manuals hitherto published on Electro-Metallurgy."-Electrical Review. 64 An excellent treatise ELECTRIC SMELTING AND REFINING: A Practical Manual of the Extraction and Treatment of Metals by the Electrical Methods. W. BORCHERS. Translated by W. G. MCMILLAN, F.I.C., F.C.S. Large Svo. Handsome cloth. THIRD EDITION. 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"This is UNDOUBTEDLY the MOST VALUABLE and MOST COMPLETE handbook of reference on the subject WHICH NOW EXISTS."-Marine Engineer. GAS, OIL, AND AIR ENGINES: A Practical Text-book on Internal By HENRY ROBINSON, M. Inst.C.E., F.G.S. THIRD EDITION. Thoroughly Revised and Enlarged. With 60 Plates and numerous Illustrations. Cloth. 348. "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, 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, PREFACE. 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 |