Bauhaus-Universität Weimar

Die Sirenen. Ein Beitrag zur Entwickelungsgeschichte der Akustik. Teil 1
Robel, Ernst
eine Reihe damit zusammenhängender interessanter Beobachtungen darin erwähnt werden. Der 
hierauf bezügliche Passus soll nun vollständig mitgeteilt werden, nicht nur seines wichtigen sach¬ 
lichen Inhaltes wegen, sondern um auch dem'Leser Gelegenheit, zu geben, die Berechtigung gewisser 
Prioritätsreklamationen, die später für Robison gegen Cagniard-Latour erhoben wurden, selbst 
prüfen zu können. Die betreffende Stelle lautet: 
„It seems to be the general property of sounds which renders them susceptible of musical 
pitch, of acuteness, or gravity; and that a certain frequency of the sonorous undulations gives a 
determined and unalterable musical note. The writer of this article has verilied this by many ex¬ 
periments. He finds, that any noise whatever, if repeated 240 times in a second, at equal intervals, 
produces the note C sol fa ut of the Guidonian gamut. If it be repeated 360 times, it produces 
the G sol re ut etc. It was imagined, that only certain regular agitations of the air, such as are 
produced by the tremor or vibration of elastic bodies, are fitted for exciting in us the sensation 
of a musical note. But he found, by the most distinct experiments, that any noise whatever will 
have the same effect, if repeated with due frequency, not less than 30 or 40 times in a second. 
Nothing surely can have less pretension to the name of a musical sound than the solitary snap 
which a quill makes when drawn from one tooth of a comb to another: but when the quill is 
held to the teeth of a wheel, whirling at such a rate, that 720 teeth pass under it in a second, 
the sound of g in alt is heard most distinctly; and if the rate of the wheel’s motion be varied 
in any proportion, the noise made by the quill is mixed in the most distinct manner with the 
musical note corresponding to the frequency of the snaps. The „kind“ of the original noise deter¬ 
mines the kind of the continuous sound produced by it, making it harsh and fretful, or smooth 
and mellow, according as the original noise is abrupt or gradual: but even the most abrupt noise 
produces a tolerable smooth sound when sufficiently frequent. Nothing can be more abrupt than 
the snap just now mentioned; yet the g produced by it has the smoothness of a bird’s chirrup. 
An experiment was made, which was less promising of a sound than any that can be thought of. 
A stop-cock was so constructed, that it opened and shut the passage through a pipe 720 times 
in a second. This apparatus was fitted to the pipe of a conduit leading from the bellows to the 
windchest of an organ. The air was simply allowed to pass gently along this pipe by the opening 
ol the cock. When this was repeated 720 times in a second, the sound g in alt was most smoothly 
uttered, equal in sweetness to a clear female voice. When the frequency was reduced to 360, 
the sound was that of a clear but rather harsh man’s voice. The cock was now altered in such 
a manner, that it never shut the hole entirely, but left about one third of it open. When this 
was repeated 720 times in a second, the sound was incommonly smooth and sweet. When 
reduced to 360, the sound was more mellow than any man’s voice at the same pitch. Various 
changes were made in the form of the cock, with the intention of rendering the primitive noise 
more analogous to that produced by a vibrating string. Sounds were produced which were 
pleasant in the extreme. The intelligent reader will see here an opening made to great additions 
to practical music, and the means of producing musical sounds, of which we have at present 
scarcely any conception; and this manner of producing them is attended with the peculiar ad¬ 
vantage, that an instrument so constructed can never go out of tune in the smallest degree. But 
of this enough at present.“ 
Die Ergebnisse der gründlichen Robison’schen Versuche sind also folgende:


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