Excerpt from Thick-Lens Optics: An Elementary Treatise for the Student and the Amateur This volume is the outcome of an attempt to answer certain questions regarding the optics of the microscope and telescope; questions to which no thoroughly satisfactory answer could be found in any literature accessible to the author. Many answers were found, but they were discordant and unusable for practical work, mainly by reason of their complexity and seeming contradictoriness and lack of co-ordination. The following pages seek to answer these questions in a manner so plain and simple that the average amateur can find out for himself what is going on optically in his camera, microscope, or telescope. To this end the mathematics is of the simplest kind, so that the busy man who has forgotten all or most of his mathematics can nevertheless work his way through, provided he can use the simplest kind of algebra, two theorems in elementary geometry and one in trigonometry. For the reader who has not had trigonometry, the few simple principles required are given in the text. So far as mathematical difficulties go, any high-school student is sufficiently equipped. As an aid to concreteness and clearness the investigations are based upon graphic principles as much as possible and along intuitive lines. 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.