| +---+---+---+---+---+---+---+---+---+---
| Conically }| / | | | | / | / | / | | |
\ narrow at top. }| | | | | | | | | |
+---+---+---+---+---+---+---+---+---+---
Flute | / | / | / | / | | | | | |
+---+---+---+---+---+---+---+---+---+---
Violin | / | / | / | / | / | / | / | / | / | /
+---+---+---+---+---+---+---+---+---+---
Piano | / | / | / | / | / | / | / | / | |
+---+---+---+---+---+---+---+---+---+---
Bell | / | / | / | / | / | / | / | | |
+---+---+---+---+---+---+---+---+---+---
Clarionet | / | | / | | / | | / | | / |
+---+---+---+---+---+---+---+---+---+---
Bassoon | / | / | / | / | / | / | / | | |
+---+---+---+---+---+---+---+---+---+---
Oboe | / | / | / | / | / | / | / | | |
--------------------------+---+---+---+---+---+---+---+---+---+---

It must not be inferred that all of the overtones are of equal strength:
they are very far from that; but these differ in different
instruments, and it is this that constitutes the difference between a
good instrument and a poor one of the same name.

In a few of the spaces very light lines are made for the purpose of
indicating that such overtones are quite weak. For instance: the piano
has the sixth, seventh, and eighth thus marked; these tones being
suppressed by the mechanism, as described on a former page.

Only a few of the many forms of organ-pipes are given; but these are
sufficient to show what a physical difference there is between the
musical tones in such pipes.

As for the human voice, it is very rich in overtones; but no two voices
are alike, therefore it would be impossible to tabulate the components
of it in the manner they are tabulated for musical instruments.

In Helmholtz's experiments in the analysis of sounds, use was made of
the principle of resonance of a body of air enclosed in a vessel. In the
experiment with the tuning-fork to determine the wave-length, p. 78, it
is remarked that no response came until the volume of the air in the
tube was reduced to a certain length, which depended upon the vibration