Excerpt from Principles of Physics, Designed for Use as a Textbook of General Physics It also presents the subject in the way in which it can most easily be apprehended. The progress of discovery has been along the lines of least intellectual resistance, and it is probable that what was easiest to discover once will now be the easiest to understand. It further enables us to pursue the argument whereby a physical law is established, sometimes almost in the words, and generally along the course of thought, of its original discoverer, so that the mind is brought into intimate relationship with the great minds of the past, and experiences the intellectual exhilaration which such a relationship always brings with it. A fairly faithful adherence to my plan has resulted in the necessary omission of many details of fact and theory which are commonly presented in textbooks of physics. For these the student must look to the course of experimental lectures or of laboratory practice, one or both of which should form part of a course of instruction in which this book is used. To illustrate the principles discussed and to introduce many important theorems without breaking up too much the continuity of the argument, I have made use of the examples which are placed in groups in various parts of the book. With the same purpose, some of the demonstrations of theorems which are of first importance in themselves, but the formal demonstration of which is of secondary importance for the student, have been put in fine print. The use of the historical outline accounts for what is nowadays the unusual order followed in the presentation of some of the subjects. It leads to a much fuller discussion of statics than is generally given, and to other peculiar features of the treatment, such as the use of the statical measure of force, the belated introduction of the relations of heat to energy, the use of the method of rays in geometrical optics, and to other minor divergences from common practice. In the alternative methods which are frequently employed, the true inductive order is either avoided or obscured, and the course of thought followed is neither natural nor that which would be followed by an investigator. I have ventured to name the book Principles of Physics, not to make a claim that it presents a complete and critical study of the foundations of the subject, but to indicate the object which, however imperfectly, I have tried to attain, that is, the exposition of the principal physical laws and theories in the light of the arguments by which they were established. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.