Books › An Encyclopedia of the Violin, 1925 › scan 211
Scan 211
An Encyclopedia of the Violin, 1925
22 lines. Read by computer on 28 September 2026. Printed page 183. See the scan on archive.org.
1object is to define the properties and relations of sounds, distinguish between tones and noises, and determine the laws according to which sound propagates itself.
3Sound is generated by the movement given by percussion, or in any other way, to the molecules of some tone-producing body. The molecules of this body, whose equilibrium has been momentarily disturbed, return to their former position while executing rapid movements which constitute the vibrations already mentioned.
5These vibrations, in turn, generate sound. Hence sound in itself is not a body, but is produced by the molecular movements of various bodies.
7These vibrations may be easily determined. All that is necessary is to suspend a glass bevel from the extremity of a metal rod, of approximately .039 inches distant from its rim, in such wise that it can move. Then give the bell a light tap. Mingled with the resulting sound will be a noise produced by its striking the metal rod with its edges, which did not touch the rod before the production of the sound.
9We must remember that the atom is the last final element in any body. The atoms in the most complex bodies are simple, and do not, as a consequence, give a complete idea of the body to which they belong.
11The molecule is the combination or union of the system of atoms which compose the body. It is a complete sample of the body to which it belongs, and is the smallest one.
13The particle is a combination or union of molecules, a small portion of a body, yet one more or less considerable.
15Light, heat, magnetism and electricity are produced by atomic movement; sound is produced by molecular movement.
17Hence one may say, with Tyndall, that the production of sound is analogous to that of light or heat rays, which also, in actuality, move in waves. Like the sound waves, the heat and light waves spread indefinitely in space, diminishing in intensity in consequence of the same laws, and, like sound waves, they lose but very little of their intensity when they are propagated in tubes whose interior surface is highly polished. Incidentally, all experiments in light refraction have had results analogous to those given by sound refraction.
19It should be mentioned that a "vibration" as it is defined in America, England and Germany, comprises at one and the same time, a forward and backward movement. In France, the term "vibration" is applied to a single one of these movements, that is to say a French "vibration" is one half that of an English one. This complete vibration of the English and Germans is also known as an oscillation or undulation, a "wave"; while the French vibration is only half an oscillation or undulation, half a wave.
21E. F. Chladni (1756-1827) hit upon the idea of making sound waves visible by pouring sand on the surface of a vibrating body, and attacking it
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