Psychological analysis and theory of hearing / by Henry J. Watt.

  • Henry J. Watt
Date:
1914
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Licence: In copyright

Credit: Psychological analysis and theory of hearing / by Henry J. Watt. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    III. The relations of tones, vowels, and noises. There are pure tones and there are compound tones. The latter consist of many simultaneous tones which harmonize more or less with one another and with their fundamental component. If a tone does not last longer than the time of two vibrations, it is heard as a noise. Many tones of neighbouring pitch or generally inharmonic in relationship, sounded together, form a noise. The pitch of single noises is not very evident. But many noises contain distinguishable tones, and if noises are sounded one after another, their pitch becomes easily noticeable. Thus we obtain the propositions: (what is presumably) tone is some- times heard as noise; some noises consist of (what are presumably) tones; some noises contain tones. The net result of these is the proposition: many (phenomenal) noises are, or consist of, (real) tones. In reliance upon this, it has been usually inferred that all noises consist of tones or are tones of very indefinite pitch or are not yet tones, so that there is no special sense of noise1. This conclusion seemed to be confirmed by the rather vague and conflicting statements made about the tonal nature of vowel sounds. The synthesis of sounds by experi- mental means did not admit of a direct examination of the proposition : are there any unanalyzable noises of indefinite pitch ? This experimental question has been answered by Jaensch by the use of a selenium cell placed in the circuit of a telephone and illuminated by an arc lamp whose light was varied by the revolution of an obstruct- ing disc. The edge of this disc was cut out so that the variations in the length of its radius corresponded with the variations in height of any desired vibratory curve, pendular, periodic, or irregular. The results of these experiments are most acceptable. A constant rate of vibration produces a tone. The same average rate of vibration produces a vowel- like tone, if the mean variation from the average is still small. As the mean variation increases, the sound passes gradually into a vowel, then it takes on a noisy character, and when the mean variation is great enough, it may finally appear as pure noise. The average rates of vibration of the vowels m, u, o, a, e, i, and s are approximately octaves of one another2. These vowels do resemble certain tones, as Kohler maintains8. But they are not to be identified with them, as he pro- poses. The resemblance is close only between the lowest and highest 1 Cf. C. S. Myers, Textbook of Experimental Psychology, 2nd ed., Cambridge, 1911 25 f. 2 Jaensch, op. cit. 234 ff. Op. cit. esp. iviii. 91 ff.