Excerpt from Physical Optics: Or the Nature and Properties of Light, a Descriptive and Experiment Treatise The author, on commencing an experimental study of Physical Optics more than a quarter of a century ago, found a want of experimental guidance in the treatises upon the subject, and this want has not yet been supplied. It is true that experimental results have been described, but not with the experimental detail which the student needs, in order to abridge his labour and facilitate his progress. Like other physical sciences, its development rests almost entirely upon the application of mathematical analysis, and accordingly the discussions of the original investigators are frequently too mathematical for general readers. Though the author, from the commencement of his experiments, had an adequate store of mathematical knowledge for application to his own researches, and to follow the researches of others, yet he has continually seen that the introduction of mathematical formulae into treatises upon Physical Optics must restrict the study of the science to a smaller class than was desirable; for many of the most expert experimenters have only slender acquirements in mathematical analysis. It has been the author's object to supply the want of a descriptive, experimental, and popular treatise on Physical Optics, and to point out the bearing of the different results upon the nature and properties of Light. 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."