have come to see that, while the universe is a place of ceaseless
change, the quantities of energy and of matter remain unaltered.

The foregoing brief sketch, which sets forth some of the important
conditions which have affected the development of science, may in a
way serve to show the student how he can himself become an interpreter
of Nature. The evidence indicates that the people of our race have
been in a way chosen among all the varieties of mankind to lead in
this great task of comprehending the visible universe. The facts,
moreover, show that discovery usually begins with the interest which
men feel in the world immediately about them, or which is presented to
their senses in a daily spectacle. Thus Benjamin Franklin, in the
midst of a busy life, became deeply interested in the phenomena of
lightning, and by a very simple experiment proved that this wonder of
the air was due to electrical action such as we may arouse by rubbing
a stick of sealing-wax or a piece of amber with a cloth. All
discoveries, in a word, have had their necessary beginnings in an
interest in the facts which daily experience discloses. This desire to
know something more than the first sight exhibits concerning the
actions in the world about us is native in every human soul--at least,
in all those who are born with the heritage of our race. It is
commonly strong in childhood; if cultivated by use, it will grow
throughout a lifetime, and, like other faculties, becomes the stronger
and more effective by the exertions which it inspires. It is therefore
most important that every one should obey this instinctive command to
inquiry, and organize his life and work so that he may not lose but
gain more and more as time goes on of this noble capacity to
interrogate and understand the world about him.

It is best that all study of Nature should begin not in laboratories,