New York
D. Appleton and Company
1901
Copyright, 1901,
by D. Appleton and Company.




TO THE MEMORY OF WILLIAM JAY YOUMANS.




PREFACE


The point of view of this book is human interest in the other worlds
around us. It presents the latest discoveries among the planets of the
solar system, and shows their bearing upon the question of life in those
planets. It points out the resemblances and the differences between the
earth and the other worlds that share with it in the light of the sun.
It shows what we should see and experience if we could visit those
worlds.

While basing itself upon facts, it does not exclude the discussion of
interesting probabilities and theories that have commanded wide popular
attention. It points out, for instance, what is to be thought of the
idea of interplanetary communication. It indicates what must be the