PREFACE. THE problems in this book are intended to quicken a beginner's apprehension of the elementary principles of physics and to furnish a convenient means of testing his attainments. The subjects chosen are those at once usually taught in secondary schools and capable of easy illustration by quantitative experiments in the ordinary laboratory. While Statics and Dynamics, under Mechanics, receive special attention, because of their fundamental character, in the broad subject of Electricity only a few of the more important laws and of the commonest methods of measurement are illustrated. Though Static Electricity and Induced and Alternating Currents have not been attempted, some of the experiments involved in the other electrical problems included here are more elaborate than those in the earlier part of the book. The introductory sections review some portions of arithmetic which are needed in physical computations and which experience shows have to be presented in a new light before the average student can apply them with facility. Since explanations and statements of physical law take the shape of mathematical formulas wherever practicable, a good working knowledge of algebra and plane geometry is assumed. In general, algebraic methods are preferred to geometric, though not always. In the |