THE
CIRCLE OF KNOWLEDGE

ESSENTIAL FACTS OF EVERYDAY INTEREST IN NATURE, GEOGRAPHY, HISTORY, TRAVEL, GOVERNMENT, SCIENCE, INVENTION, EDUCATION, LANGUAGE, LITERATURE, FINE ARTS, PHILOSOPHY, RELIGION, INDUSTRY, BIOGRAPHY, HUMAN CULTURE, AND UNIVERSAL PROGRESS

Easy to Read; Easy to Understand; Easy to Retain

EDITOR-IN-CHIEF
HENRY W. RUOFF, M.A., Litt.D., D.C.L.
Editor of “The Century Book of Facts,” “The Capitals of the World,”
“Leaders of Men,” “The Standard Dictionary of Facts,”
“Masters of Achievement,” “The Volume Library,”
“The Human Interest Library,” Etc.

NUMEROUS TEXT ILLUSTRATIONS, MAPS
TABLES, DUOTONE AND COLOR PLATES

Exclusive Publishers for Canada and
Newfoundland:
THE JOHN A. HERTEL CO., Ltd.
TORONTO, ONTARIO

THE STANDARD PUBLICATION COMPANY
BOSTON · WASHINGTON · CHICAGO
1917