whole domain of knowledge. The entire world of matter, as distinguished
from the world of mind, would be presented to us in a comprehensive
study of physics.

I shall consider in this discussion only a limited part of this great
subject. Phenomena modified by the action of the vital force, either in
plants or in animals, will be excluded; I shall not, therefore, consider
such subjects as botany or zooelogy. Geology and related branches will
also be omitted by restricting our study to phenomena which take place
in short, definite, measurable periods of time. And lastly, those
subjects in which, as in astronomy, the phenomena take place beyond
the control of student and teacher, and in which their repetition at
pleasure is impossible, will not be considered. Natural philosophy, or
physics, as this term is generally used, and chemistry, will, therefore,
be the subjects which we will consider as sources from which to draw
matter for lessons for the children in our schools.

The child's mind has the receptive side, the sensibility, the most
prominent. His senses are alert. He handles and examines objects about
him. He sees more, and he learns more from the seeing, than he will in
later years unless his perceptive powers are definitely trained and
observation made a habit. His judgment and his will are weak. He reasons
imperfectly. He chooses without appropriate motives. He needs the
building up and development given by educational training. _Nature
points out the method._

Sensibility being the characteristic of his mind, we must appeal to him
through his senses. We must use the concrete; through it we must act
upon his weak will and immature judgment. From his natural curiosity we
must develop attention. His naturally strong perceptive powers must be