Excerpt from The Art of Illumination Since the first edition of this book was published profound and revolutionary changes have taken place in the available materials of artificial illumination. Among electrical illuminants entirely new types of are light have come into general use, and the carbon incandescent lamp is being rapidly pushed into obsolescence by the metallic filament lamps which now dominate electric lighting practice. In the field of gas lighting, the inverted mantle burners of both large and small capacity, and the high pressure mantle burners, have pushed their way to the front and radically changed the conditions of economy which previously existed. Auxiliaries of every kind, and particularly shades and reflectors of greatly im proved types, have been so multiplied as to meet almost every possible requirement. All these considerations have made necos sary a very complete revision of the parts of this volume dealing with practical lighting. Moreover, the art of illuminating engi neering has been enriched by a large amount of valuable experience within the past few years, and its principles are now founded on a more secure scientific basis. The general principles of the art, however, remain the same and its importance in practical life is at last being adequately appreciated. 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.