Excerpt from Elements of Wave Motion, Relating to Sound and Light: A Text Book Prepared Expressly for the Use of the Cadets of the United States Military Academy, West Point The elements of character developed in the student by this sys tem of instruction, viz., confidence in his powers, reliance on individual effort, and capacity to appreciate truly his sources of information, are of essential importance in a career where he may be called upon in emergencies to exercise self-control, and to meet manfully unforeseen difficulties; and they offer a sufficient reason for the importance given to these studies in the curriculum of the Academy. Text-books are generally compilations. The subject-matter of this text has been gathered by the author from whatever source appeared to him best for the purpose in view. And as it is often desirable to refer to original treatises, for a better conception of the subject under discussion, a list of authors is appended to this Preface. 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.