When a tuning
fork, for example, is caused to vibrate, it is _assumed_ that the
supposed molecules in front of the advancing fork are crowded closely
together, thus forming a condensation, and on the retreat of the fork are
separated more widely apart, thus forming a rarefaction. On account of
the crowding of the molecules together to form the condensation, the air
is supposed to become more dense and of a higher temperature, while in
the rarefaction the air is supposed to become less dense and of lower
temperature; but the heat of the condensation is supposed to just satisfy
the cold of the rarefaction, in consequence of which the average
temperature of the air remains unchanged.
The supposed increase of temperature in the condensation is supposed to
facilitate the transference of the sound pulse, in consequence of which,
sound is able to travel at the rate of 1,095 feet a second at 0 deg.C., which
it would not do if there was no heat generated.
In other words, the supposed increase of temperature is supposed to add
1/6 to the velocity of sound.
If the tuning fork be a _Koenig C^{3}_ fork, which makes 256 _full_
vibrations in one second, then there will be 256 sound waves in one
second of a length of 1095/256 or 4.23 feet, so that at the end of a
second of time from the commencement of the vibration, the foremost wave
would have reached a distance of 1,095 feet, at 0 deg.
Pages:
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139