NEW YORK
D. APPLETON AND COMPANY
1899
Copyright, 1872,
By D. APPLETON AND COMPANY.
Electrotyped and Printed
at the Appleton Press, U. S. A.
AMERICAN PREFACE TO THE INTERNATIONAL SCIENTIFIC SERIES.
The rapid development of science in the present age, and the increasing public interest in its results, make it desirable that the most efficient measures should be adopted to elevate the character of its popular literature. The tendency of careless and unscrupulous book-makers to cater to public ignorance and love of the marvellous, and to foist their crude productions upon those who are too little instructed to judge of their real quality, has hitherto been so strong as to cast discredit upon the idea of "popular science." It is highly important to counteract this evil tendency by furnishing the public with popular scientific books of a superior character. The publication of the present volume is the first step in carrying out a systematic enterprise of this kind. It initiates a series of such works on a wide range of scientific subjects, to be prepared by the leading thinkers of different countries, and known as the "International Scientific Series."