The sensory basis and structure of knowledge / by Henry J. Watt.

  • Henry J. Watt
Date:
[1925]
Catalogue details

Licence: In copyright

Credit: The sensory basis and structure of knowledge / by Henry J. Watt. Source: Wellcome Collection.

    62/272 (page 46)
    CHAPTER IV THE HIGHER SENSES—HEARING SOUNDS fall obviously into two classes—noises and tones. Both occur in great variety, and the question at once arises what is the relation between them. The general tendency hitherto has been to regard the noises as really consisting of a great many tones. For there are far many more kinds of noise than of tone. It is very difficult to suggest any scheme or arrangement which will give every kind of noise its proper place, but for any kind of instrument the tones it produces clearly form a regular series. Compared together the series from different instruments are partly the same, partly different; for while we can play the same melody on many instruments —violin, voice, or piano, we can still recognise the instru¬ ment used by the kind of tone it produces. Thus our first special problem is to show the relation between the different series of instrumental tones. By simple experiment we can find that an instrumental tone is not as simple as it seems, but really consists of a small group or blend of tones. These are called partials of the whole instrumental tone. In all tones of the same pitch from different instruments there is an identical component, called the “ fundamental/’ It is the lowest in pitch of all the partials of the tone. It is this lowest component that gives the whole blend an apparent pitch. In every instrumental tone the fundamental is accompanied by various other higher components, called upper partials. These commonly bear a certain relation to the fundamental that is determined by the physical vibrations of the instrument used. When an instrument is intentionally brought into one rate of vibration, as when you strike a certain note on the piano or sing a certain pitch, it falls at the same time into other rates of vibration that are