yet another and another. But the progress is not indefinite. If all
the mechanical actions of the entire universe were to be formulated as
the results of a single law or cause, the cause of that cause would be
still to seek, as has been said.

We have every right to exult in the amazing achievements of Science;
but we have not understood them until we realize that the universe of
Science has strict limits, within which all its conquests must
necessarily be confined. Humility, and not pride, is the final lesson
of scientific work and study.

* * * * *

The choice of the selections printed in this volume has been
necessarily limited by many hampering conditions, that of mere space
being one of the most harassing. Each of the chapters might readily be
expanded into a volume. Volumes might be added on topics almost
untouched here. It has been necessary to pass over almost without
notice matters of surpassing interest and importance: Electricity and
its wonderful and new applications; the new Biology, with its views
upon such fundamental questions as the origins of life and death;
modern Astronomy, with its far-reaching pronouncements upon the fate
of universes. All these can only be touched lightly, if at all. It is
the chief purpose of this volume to point the way towards the most
modern and the greatest conclusions of Science, and to lay foundations
upon which the reading of a life-time can be laid.

[Illustration: Signature: Edward S. Holden]

UNITED STATES MILITARY ACADEMY, WEST POINT, _January 1, 1902_.