Produced by K.D. Thornton, Karina Aleksandrova and the Online Distributed Proofreading Team at http://www.pgdp.net Transcriber's Notes: 1. Subscripts have been marked with an underscore character in front with text surrounded in curly braces, for example: H_{2}O (formula of water). 2. Inconsistent hyphenation of words preserved. 3. Several misprints fixed. A full list of corrections can be found at the end of the text. [Illustration: LIGHT AND LIBERTY] The Century Books of Useful Science ARTIFICIAL LIGHT ITS INFLUENCE UPON CIVILIZATION BY M. LUCKIESH DIRECTOR OF APPLIED SCIENCE. NELA RESEARCH LABORATORY, NATIONAL LAMP WORKS OF GENERAL ELECTRIC COMPANY Author of "Color and Its Applications," "Light and Shade and Their Applications," "The Lighting Art," "The Language of Color," etc. _ILLUSTRATED WITH PHOTOGRAPHS_ NEW YORK THE CENTURY CO. 1920 Copyright, 1920, by THE CENTURY CO. DEDICATED TO THOSE WHO HAVE ENCOURAGED ORGANIZED SCIENTIFIC RESEARCH FOR THE ADVANCEMENT OF CIVILIZATION PREFACE In the following pages I have endeavored to discuss artificial light for the general reader, in a manner as devoid as possible of intricate details. The early chapters deal particularly with primitive artificial light and their contents are generally historical. The science of light-production may be considered to have been born in the latter part of the eighteenth century and beginning with that period a few chapters treat of the development of artificial light up to the present time. Until the middle of the nineteenth century _mere_ light was available, but as the century progressed, the light-sources through the application of science became more powerful and efficient. Gradually _mere_ light grew to _more_ light and in the dawn of the twentieth century _adequate_ light became available. In a single century, after the development of artificial light began in earnest, the efficiency of light-production increased fifty-fold and the cost diminished correspondingly. The next group of chapters deals with various economic influences of artificial light and with some of the byways in which artificial light is serving mankind. On passing through the spectacular aspects of lighting we finally emerge into the esthetics of light and lighting.