In revising the first edition of Power Plants the author decided to greatly enlarge it in the hope that it will have a still greater success than the first one. The section on theory is thoroughly revised. A complete chapter on Standard Wiring including new tables and original diagrams added. The National Fire Underwriters' rules condensed and simple explanations given. Direct and alternating current motors have been given a special chapter and modern forms of starting rheostats described at length. The principles of alternators have been considered also transformers and their applications. Modern testing instruments and their use are given a separate chapter. New matter has been added to storage batteries including charging of automobile batteries, 10 new tables, and 137 new illustrations. SYNOPSIS OF CONTENTS OF CHAPTERS. 1. THE ELECTRIC CURRENT; series and multiple connections; resistance of circuits; general explanation of formulas. 2. STANDARD WIRING; wiring formulas and tables; wiring systems; cut-outs; conduits; panel boxes; correct methods of wiring. 3. DIRECT AND ALTERNATING CURRENT GENERATORS; management in the power house; windings; selection of generators. 4. MOTORS AND MOTOR STARTERS; various forms of motors; controllers; care of motors and their diseases; rules for installing. 5. TESTING AND MEASURING INSTRUMENTS; voltmeter testing and connections; instruments used; switchboard instruments. 6. THE STORAGE BATTERY; different kinds; switchboards for charging fixed and movable batteries; management of battery. 7. THE INCANDESCENT LAMP; various methods of testing; life of lamps. 8. ENGINEERING NOTES; belts and pulleys h.p. of belts. Tables. Contents. Index. 290 pages, 203 illustrations. 12mo., cloth, $1.50. Full limp leather, $2.50. * * * * * Design of Dynamos BY SILVANUS P. THOMPSON, D. Sc., B. A., F. R. S. EXTRACTS FROM PREFACE. "The present work is purposely confined to continuous current generators. The calculations and data being expressed in inch measures; but the author has adopted throughout the decimal subdivision of the inch; small lengths being in mils, and small areas of cross-section in sq. mils, or, sometimes, also, in circular mils." CONTENTS OF CHAPTERS. 1. DYNAMO DESIGN AS AN ART. 2. MAGNETIC DATA AND CALCULATIONS. Causes of waste of Power. Coefficients of Dispersion. Calculation of Dispersion. Determination of exciting ampere-turns. Example of Calculation. 3. COPPER CALCULATIONS. Weight of Copper Wire. Electrical resistance of Copper, in cube, strip, rods, etc. Space-factors. Coil Windings; Ends; Insulation; Ventilating; Heating. 4. INSULATING MATERIALS AND THEIR PROPERTIES. A list of materials, including "Armalac," "Vitrite," "Petrifite," "Micanite," "Vulcabeston," "Stabilite," "Megohmite," etc. With tables.