--The Physical Study of the World_

The natural world may be opposed to the intellectual, or nature to art
taking the latter term in its higher sense as embracing the
manifestations of the intellectual power of man; but these
distinctions--which are indicated in most cultivated languages--must not
be suffered to lead to such a separation of the domain of physics from
that of the intellect as would reduce the physics of the universe to a
mere assemblage of empirical specialities. Science only begins for man
from the moment when his mind lays hold of matter--when he tries to
subject the mass accumulated by experience to rational combinations.

Science is mind applied to nature. The external world only exists for us
so far as we conceive it within ourselves, and as it shapes itself
within us into the form of a contemplation of nature. As intelligence
and language, thought and the signs of thought, are united by secret and
indissoluble links, so, and almost without our being conscious of it,
the external world and our ideas and feelings melt into each other.
"External phenomena are translated," as Hegel expresses it in his
"Philosophy of History," "in our internal representation of them." The
objective world, thought by us, reflected in us, is subjected to the
unchanging, necessary, and all-conditioning forms of our intellectual
being.

The activity of the mind exerts itself on the elements furnished to it
by the perceptions of the senses. Thus, in the youth of nations there
manifests itself in the simplest intuition of natural facts, in the
first efforts made to comprehend them, the germ of the philosophy of
nature.

If the study of physical phenomena be regarded in its bearings not on
the material wants of man, but on his general intellectual progress, its
highest result is found in the knowledge of those mutual relations which
link together the general forces of nature. It is the intuitive and
intimate persuasion of the existence of these relations which at once
enlarges and elevates our views and enhances our enjoyment. Such
extended views are the growth of observation, of meditation, and of the
spirit of the age, which is ever reflected in the operations of the
human mind whatever may be their direction.

From the time when man, in interrogating nature, began to experiment or
to produce phenomena under definite conditions, and to collect and
record the fruits of his experience--so that investigation might no
long