PREFACE The prime object of DRAKES ELECTRICAL DICTION- ARY is to bring together for convenient reference the words, terms and phrases used in the electrical world. The tremendous growth in interest in the electrical arts, trades and sciences makes some method of quick reference a practical necessity. It is hoped that the manner of presentation followed in this book will prove to be most advantageous. Many practical difficulties arise in arranging all words and phrases alphabetically. The single words fall into place naturally enough, but in placing the phrases the question of which word of the phrase is to have the alphabetic position is important. The general plan of using the first words of all phrases has been adopted. Thus an endless number of annoying cross references have been avoided. In any field of science in which growth has been and natural that words continues to be so rapid, it is only and terms are not absolutely fixed. Without making the work too voluminous, however, we have endeavored to include all those words and terms in common use, though many are used interchangeably. Every effort has been made to produce a book of the greatest practical utility to every one who has any in- terest in the subject of electricity.. A A. C. An abbreviation expressing an alternating current. Absolute. Complete by itself. Independent of any other element. Absolute Unit of Current. A current possessing a de- gree of strength, and which when transmitted through a wire which has been curved in the shape of an arc of a circle of one centimetre radius, will act on a one-unit power magnetic pole, stationed at the center of the arc, with a force equal to one degree. A 10 amperes current.Absolute Unit of Electromotive Force. The electro- motive force unit C. G. S. Absolute Vacuum. A void produced by the exhaustion of all residual gases. Absorption. The act of one form of material substance sucking or drawing in some other form of matter. The sucking in of water by a sponge or the draw ing in of vapors, gases, light, electricity, energy or heat by any other material substance. Absorption Power. A property peculiar to certain ma- terials by which they draw in gases through their pores and condense them. Acceleration. The increase or decrease of motion or action. The time period of mutation in velocity. Accumulated Siectricity.-r-Electricity confined or stored as in a condenser. Accumulating Electricity. Confining or placing elec- tricity in storage. Accumulation of Electricity. The gathering of electric charges in condensers or Leyden jars. An electric charge augmented by aid of a device term an accumulator. A charge produced by the use of an influence machine. The gathering of electricity by storage batteries or accumulators. Accumulator. A term sometimes used to designate a current accumulator. A condenser, a Leyden jar, a storage battery. Acetometer or Acidometer. A graduated hydrometer used to ascertain the strength of acetic acid or vinegar. Achromatic Lens. A lens producing images without false coloring. Acidometer. See Acetometer. Acoustic. Pertaining to the sense of hearing, or sound. Acoustic Absorption. The absorbing by one vibrating object or mass of the sound-wave energy created by another vibrating object or mass. Acoustic Interference. Mutual influence of soundwaves upon each other. Acoustic Synchronizer. A contrivance employed to mark the synchronism of twoalternating currents. An acoustic apparatus in which at synchronism silence is effected. Actinic…