270 reckoning of energy given out in alternating machines, 282 formula of coeffi- SIDGWICK, Mrs. H., 71, 242 Small resistances, measurement of, Specific resistance, 238 measurement of, 239-243 of mercury, 242 Speed of motor, relation of, to efficiency, 265 Standard cells, 151–157 use of, in graduation of galvano- meters, 156, 159 RICHARD CLAY AND SONS, LIMITED, LONDON AND BUNGAY. MESSRS. MACMILLAN & CO.'S PUBLICATIONS. BY THE SAME AUTHOR. ABSOLUTE MEASUREMENTS IN ELECTRICITY AND MAGNETISM, THE THEORY AND PRACTICE OF. Second Edition. In Two Volumes. Crown 8vo. Vol. I., 12s. 6d. Iron says: "This first volume includes the apparatus for measurement of angular deflection oscillations, couples, potential, resistance and specific inductive capacity. It is all very correct and exact. The book is deserving of the highest praise.' The Scotsman says:-"Students of electrical science will find it a thorough and helpful work. It also treats the mathematical theory of its subject in so com prehensive a manner as to form an admirable introduction to the abstract study of electrical science." The Cambridge Review says:-"The volume before us might easily have been called an introductory text-book of electrostatics, theoretical and practical, for practical electricians. The whole theory is worked out from the very foundation, nothing being assumed but the most elementary phenomena. Rather more than a third of this volume is occupied by the general theory of electrical attraction and so much of the theory of flow of electricity as is necessary for the understanding of the construction of electrometers and other statical instruments. The work next takes up the theory of units, harmonic oscillations, tortional vibrations, bifilar suspension, etc., thus clearing the way for the latter part, which is concerned with the theory, construction, and use of instruments connected with the measurement of static electricity. Here the author is at his best He has evidently made good use of the opportunities afforded him by a training in Sir William Thomson's laboratory, and the result is one of the most useful scientific works of recent years. The usefulness of the work as a work of reference for the laboratory is increased by the handy form and large clear type in which it is got up. We cannot too highly recommend this first volume, and look forward to the production of the next, which ought to be an even greater boon to practical electricians than its predecessor.' The Manchester Guardian says:-"There has been for some years a most distinct want of a book on electricity and magnetism which might take an intermediate place between Wiedemann's well-known work, which is descriptive and experimental, and does not attempt to deal with the general theory of the subject, and the more recondite treatise of Clerk-Maxwell. The present work is well designed for supplying this acknowledged want, and will, we believe, be welcomed by students and teachers, and the constantly increasing number of those who are engaged in the practical applications of electrical science, and who desire to obtain some knowledge of the theory of the instruments they are daily using." WORKS ON SCIENCE. NATURAL PHILOSOPHY. Airy.-Works by Sir G. B. AIRY, K.C.B., formerly Astronomer Royal. ON SOUND AND ATMOSPHERIC VIBRATIONS. With the Mathematical Elements of Music. Designed for the Use of Students in the University. Second Edition, revised and enlarged. Crown 8vo. 9s. A TREATISE ON MAGNETISM. Designed for the Use of Students in the University. Crown 8vo. 9s. 6d. |