rs
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.

The aim has been to show that artificial light has become intricately
interwoven with human activities and that it has been a powerful
influence upon the progress of civilization. The subject is too
extensive to be treated in detail in a single volume, but an effort has
been made to present a discussion fairly complete in scope. It is hoped
that the reader will gain a greater appreciation of artificial light as
an economic factor, as an artistic medium, and as a mighty influence
upon the safety, efficiency, health, happiness, and general progress of
mankind.

M. LUCKIESH.

ACKNOWLEDGMENTS

It is a pleasant duty to acknowledge the cooeperation of various
companies in obtaining the photographs which illustrate this book. With
the exception of Plates 2 and 7, which are reproduced from the excellent
works of Benesch and Allegemane respectively, the illustrations of early
lighting devices are taken from an historical collection in the
possession of the National Lamp Works of the General Electric Co. To
this company the author is indebted for Plates 1, 3, 4, 5, 6, 9, 11, 15,
18b, 20, 21, 29; to Dr. McFarlan Moore for Plate 10; to Macbeth Evans
Glass Co. for Plate 12; to the Corps of Engineers, U. S. Army, for Plate
13; to Lynn Works of G. E. Co. for Plates 14, 16; to Edison Lamp Works of
G. E. Co. for Plates 17, 24; to Cooper Hewitt Co. for Plate 18a; to
R. U. V. Co. for Plate 19; to New York Edison Co. for Plates 22, 26, 30;
to W. D'A. Ryan and the Schenectady Works of G. E. Co. for Plates 23, 25,
31; to National X-Ray Reflector Co. for Plate 28. Besides the companies
and the individual