# Elementary Text-book of Physics

ELEMENTARY
TEXT-BOOK OF PHYSICS.
BY
Prof. WM. A. ANTHONY, and Prof. CYRUS F. BRACKETT,
Of Cornell University. Of Princeton University.
REVISED BY
Prof. WILLIAM FRANCIS MAGIE,
Of Princeton University.
EIGHTH EDITION, REVISED.
FIRST THOUSAND.
NEW YORK:
JOHN WILEY & SONS.
London: CHAPMAN & HALL, Limited.
1897.
Copyright, 1897,
by
JOHN WILEY & SONS.
robert drummond, electrotyper and printer, new york.
PREFACE.
The design of the authors in the preparation of this work has been to present the fundamental principles of Physics, the experimental basis upon which they rest, and, so far as possible, the methods by which they have been established. Illustrations of these principles by detailed descriptions of special methods of experimentation and of devices necessary for their applications in the arts have been purposely omitted. The authors believe that such illustrations should be left to the lecturer, who, in the performance of his duty, will naturally be guided by considerations respecting the wants of his classes and the resources of his cabinet.
Pictorial representations of apparatus, which can seldom be employed with advantage unless accompanied with full and exact descriptions, have been discarded, and only such simple diagrams have been introduced into the text as seem suited to aid in the demonstrations. By adhering to this plan greater economy of space has been secured than would otherwise have been possible, and thus the work has been kept within reasonable limits.
A few demonstrations have been given which are not usually found in elementary text-books except those which are much more extended in their scope than the present work. This has been done in every case in order that the argument to which the demonstration pertains may be complete, and that the student may be convinced of its validity.
In the discussions the method of limits has been recognized wherever it is naturally involved; the special methods of the ​calculus, however, have not been employed, since, in most institutions in this country, the study of Physics is commenced before the student is sufficiently familiar with them.
The authors desire to acknowledge their obligations to Wm. F. Magie, Assistant Professor of Physics in the College of New Jersey, who has prepared a large portion of the manuscript and has aided in the final revision of all of it, as well as in reading the proofsheets.
W. A. Anthony, C. F. Brackett.
REVISER'S PREFACE.
By the courtesy of the authors and publishers of this book, I have beien given an opportunity to make a rather extensive revision of it. The principal changes which have been made, besides such slight corrections or supplementary statements as seemed necessary, are, an entire rearrangement and enlargement of the mechanics, and the addition of a discussion of the kinetic theory of matter and of a treatment of magnetism and electricity by the method of tubes of force. The omissions have been largely of statements that would naturally be made by the lecturer or of demonstrations in which the results reached did not warrant the expenditure of time and trouble necessary to master them. I trust that I have adhered throughout to the original design of the authors.
During the last few years I have been using with my classes Selby's "Elementary Mechanics of Solids and Fluids," and have availed myself in many places in the present revision of the suggestions which I received from that admirable book. The additions to the Magnetism and Electricity are based upon the treatment of the subject by J. J. Thomson in his "Elementary Theory of Electricity aud Magnetism."
W. F. Magie.
Princeton University,
February, 1897.