constructing that picture of the growth
of the heavens and the earth, and the aim of the present volume is to
give, in clear and plain language, as full an account of the story as
the present condition of our knowledge and the limits of the volume will
allow. The author has been for many years interested in the evolution
of things, or the way in which suns and atoms, fishes and flowers, hills
and elephants, even man and his institutions, came to be what they
are. Lecturing and writing on one or other phase of the subject have,
moreover, taught him a language which the inexpert seem to understand,
although he is not content merely to give a superficial description of
the past inhabitants of the earth.

The particular features which, it is hoped, may give the book a
distinctive place in the large literature of evolution are, first, that
it includes the many evolutionary discoveries of the last few years,
gathers its material from the score of sciences which confine themselves
to separate aspects of the universe, and blends all these facts and
discoveries in a more or less continuous chronicle of the life of the
heavens and the earth. Then the author has endeavoured to show, not
merely how, but why, scene succeeds scene in the chronicle of the earth,
and life 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 wo