tween the two
notes is so divided by musicians that from one to the other they
reckon eight different tones.

If the strings be of the length, two and three, the coincidence of
the pulses will happen less frequently, viz. at every third vibration
of the shorter string, and the concord will be less perfect. This
forms what is called a fifth. The less frequent the coincidence of
the vibrations, the less perfect will be the concord, or the less
pleasure will it afford to the mind; till the vibrations coincide so
seldom, that the sound produced by both strings at once is harsh and
disagreeable, and is called a discord.

The effects of music upon the mind, the power by which it moves the
heart, touches the passions, and excites sometimes the highest
pleasure, and sometimes the deepest melancholy, depend upon melody.
By a simple melody the ignorant are affected as well as those skilled
in music. The pleasures arising from harmony or a combination of
sounds are acquired rather than natural. Its pleasures are the result
of experience and knowledge in music; music affords a source of
innocent and inexhaustible pleasure, but its effects are different on
different persons: some are enthusiastically fond of it, while others
hear the sweetest airs with a listlessness bordering upon
indifference. This has been supposed to depend on a musical ear,
which is not given by nature to all. The cause of this difference is
by no means evident. It does not depend on the delicacy of the sense
of hearing, for there are some persons half deaf, who have the
greatest relish for music; while others who have a very acute sense
of hearing have no relish for music. In some instances I think a
musical ear has been acquired where it did not seem originally to
exist.

The force of sound is increased by the reflection of many bodies,
particularly such as are hard or elastic, which receive the waves or
pulses of the air and reflect them back again; these reflected
pulses, striking the ear along with the original, strengthen the
original sound. Hence it is, that the voice of a speaker is louder,
and more distinctly heard, in a room than in the open air. I said
that these reflected sounds entered the ear at the same time with the
original: this however is not strictly the case, for they must enter
the ear after the original, because the sound has a greater space to
move over: but they enter the ear so quickly after the original that
our sense cannot dist