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nydus/How it WorksPublic

Archibald Williams explains the scientific principles behind common mechanisms and physical phenomena such as steam, electricity, light, and hydraulics. The text focuses on the fundamental operation of everyday devices rather than specific models or detailed technical specifications.

Page 233 of 446
Table of Contents

HOW IT WORKS.

A1 to B and back again in half the time required to pass from A to B and back in Fig. 136, 1; therefore the note is an octave higher.

Fig. 137.
Fig. 137. —Showing how harmonics of an open pipe are formed, B , B 1 , and C are "nodes." The arrows indicate the distance travelled by a sound impulse from a node to a node.

THE OVERTONES OF AN OPEN PIPE.

The first overtone results when nodes form as in Fig. 137, 2, at points one-quarter of the length of the pipe from the ends, giving one complete ventral segment and two semi-ventral segments. The vibrations now are twice as rapid as before. The second overtone requires three nodes, as in Fig. 137, 3. The rate has now trebled. So that, while the overtones of a closed pipe rise in the ratio 1, 3, 5, 7, etc., those of an open pipe rise in the proportion 1, 2, 3, 4, etc.

WHERE OVERTONES ARE USED.

In the flute, piccolo, and clarionet, as well as in the horn class of

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