slowly climbs from level to level. He has taken nature in the
past as we find it to-day: an interconnected whole, in which the
changes of land and sea, of heat and cold, of swamp and hill, are
faithfully reflected in the forms of its living population. And,
finally, he has written for those who are not students of
science, or whose knowledge may be confined to one branch of
science, and used a plain speech which assumes no previous
knowledge on the reader's part.

For the rest, it will be found that no strained effort is made to
trace pedigrees of animals and plants when the material is
scanty; that, if on account of some especial interest disputable
or conjectural speculations are admitted, they are frankly
described as such; and that the more important differences of
opinion which actually divide astronomers, geologists,
biologists, and anthropologists are carefully taken into account
and briefly explained. A few English and American works are
recommended for the convenience of those who would study
particular chapters more closely, but it has seemed useless, in
such a work, to give a bibliography of the hundreds of English,
American, French, German, and Italian works which have been
consulted.


CONTENTS

I. THE DISCOVERY OF THE UNIVERSE
II. THE FOUNDATIONS OF THE UNIVERSE
III. THE BIRTH AND DEATH OF WORLDS
IV. THE PREPARATION OF THE EARTH