student should obtain some idea as to the ways in which men have been
led to the knowledge which they possess concerning the world about
them. Therefore it will be well briefly to sketch the steps by which
natural science has come to be what it is. By so doing we shall
perceive how much we owe to the students of other generations; and by
noting the difficulties which they encountered, and how they avoided
them, we shall more easily find our own way to knowledge.

The primitive savages, who were the ancestors of all men, however
civilized they may be, were students of Nature. The remnants of these
lowly people who were left in different parts of the world show us
that man was not long in existence before he began to devise some
explanation concerning the course of events in the outer world.
Seeing the sun rise and set, the changes of the moon, the alternation
of the seasons, the incessant movement of the streams and sea, and the
other more or less orderly successions of events, our primitive
forefathers were driven to invent some explanation of them. This,
independently, and in many different times and places, they did in a
simple and natural way by supposing that the world was controlled by a
host of intelligent beings, each of which had some part in ordering
material things. Sometimes these invisible powers were believed to be
the spirits of great chieftains, who were active when on earth, and
who after death continued to exercise their power in the larger realms
of Nature. Again, and perhaps more commonly, these movements of Nature
were supposed to be due to the action of great though invisible
beasts, much like those which the savage found about him. Thus among
our North American Indians the winds are explained by the supposition
that the air is fanned by the wings of a great unseen bird, whose duty
it is to set the atmosphere into motion. That no one has ever seen the
bird doing the work, or that the task is too great for any conceivable