The first of these is the natural world round about us. We are immersed
in Nature; it touches us on every side; it addresses us through all our
senses; it speaks to us every day with a thousand voices. Nature is the
great teacher of the human race. She knows everything; she waits to
impart her love to all who will receive it; she is very patient; her
lessons are not forced upon unwilling pupils, but whosoever will may
come and take of her treasure. Longfellow said of the childhood of
Agassiz, that--

"Nature, the old nurse, took
The child upon her knee,
Saying: 'Here is a story-book
Thy Father has written for thee.

"'Come, wander with me,' she said,
'Into regions yet untrod;
And read what is still unread
In the manuscripts of God.'"

It is not the child Agassiz alone whom Nature thus invited; to the whole
human race, in its childhood, its adolescence, its maturity, she has
always been saying the same thing. She has been seeking, through all the
ages, to disclose to us all the mysteries of this marvelous universe. We
have been slow learners; it took her a great many centuries to get the
simplest truths lodged in the human mind. The cave-dweller, the savage
in his teepee, were able to receive but little of what she had to give.
Yet before their eyes, every day, she spread all her wonders; with
infinite patience she waited for the unfolding of their powers. All the
marvels of steam, of electricity, of the camera, of the telescope, the
microscope, the spectroscope, the Roentgen rays,--all the facts and