Excerpt from The Optical Defects of the Eye, and Their Consequences, Asthenopia and Strabismus In the course as actually delivered by me at the Ophthalmic Hospital, Southwark, all the leading phenomena of optical science, as the laws of reflection and refraction, &c., were fully discussed but as these subjects are but imperfectly intelligible without such experimental illustrations as I then produced, I have omitted them in the lectures as now published, proceeding at once to the consideration of optical lenses, a knowledge of which is. 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.