3.4. A COLLEGE TEXT-BOOK OF PHYSICS BY ARTHUR L. KIMBALL, PH. D. PROFESSOR OF PHYSICS IN AMHERST COLLEGE. Οὐ πολλά αλλά πολύ NEW YORK HENRY HOLT AND COMPANY PREFACE In offering this work to my fellow teachers, a word of explanation is due. The book was undertaken some years ago when the writer felt the want of a text-book adapted to the needs of students taking the general first year course in college. As the work has slowly progressed several text-books of very similar aim have appeared, and it must be admitted that the call is not so imperative now as formerly; and yet it is hoped that the treatment here presented may meet some still existing demand and so justify its existence. What may be called the physical rather than the mathematical method has been preferred in giving definitions and explanations, because it is believed that the ideas presented are more easily grasped and more tenaciously held when the mind forms for itself a sort of picture of the conditions, instead of merely associating them with the symbols of a formula. There are many minds that do not easily grasp mathematical reasoning even of a simple sort; and it is often the case also that a student who may be able to follow an algebraic deduction step by step has very little idea of the significance of the whole when he reaches the end. Algebra is not his native tongue and it takes considerable time and experience for him to learn to think in it. And while all will agree that for the more advanced study of physics, mathematics is quite indispensable, many will grant that in a general course, which is to furnish to most of those taking it all that they will ever know of physics as a science, the ideas and reasonings should be presented as directly as possible and in the most simple and familiar terms. This then has been the central aim in the preparation of this book; to give the student clear and distinct conceptions of the various ideas and phenomena of physics, and to aid him in thinking through the relations between them, to the end that he may see something of the underlying unity of the subject; and to |