med Tyndall, who
was interested, among other things, in the study of sound. He studied
sounds of all kinds, made experiments with them, wrote down what he
observed, and out of it all he wrote a book,[11] useful to all who
desire to learn about sound and its nature.

One day, Tyndall and a friend were walking up one of the mountains of
the Alps.[12] As they ascended the path, Tyndall's attention was
attracted by a shrill sound, which seemed to come from the ground at
his feet. Being a trained thinker he was at once curious to know what
was the cause of this. By looking carefully he found that it came from
a myriad of small insects which swarmed by the side of the path.
Having satisfied himself as to what it was he spoke to his companion
about the shrill tone and was surprised to learn that he could not
hear it. Tyndall's friend could hear all ordinary sound perfectly
well. This, however, seemed to be sound of such a character as did not
reach his sense of hearing. One who like Tyndall listened carefully to
sounds of all kinds would quickly detect anything uncommon. This
little incident teaches us that sounds may go on about us and yet we
know nothing of them. Also it teaches us to think about tones, seek
them, and in the first days increase our acquaintance and familiarity
with them.

Men of science, who study the different ways in which the mind works,
tell us that habit and also a busy mind frequently make us unconscious
of many things about us. Sometimes we have not noticed the clock
strike, although we have been in the room on the hour; or some one
speaks to us, and because we are thinking of something else we fail to
hear what is said to us. It certainly is true that very many people do
not hear half of the sounds that go on about them, sounds which, if
but heeded, would teach people a great deal. And of all people, those
who study music should be particularly attentive to sounds of all
kinds. Indeed, the only way to begin a music education is to begin by
learning to listen. Robert Schumann, a German composer, once wrote a
set of rules for young musicians. As it was Schumann's habit to write
only what was absolutely needed we may be sure he regarded his rules
as very important. There are sixty-eight of them, and the very first
has reference to taking particular notice of the tones about us. If we
learn it from memory we shall understand it better and think of it
oftener. Besides that, we shall have memorized the s