50 HAND-BOOK OF ACOUSTICS.
This is also the difference between a Major and a Minor Third, for
The interval between the Greater and Lesser Chromatic Semitones will be
which is usually termed the Comma or Komma.
Referring to the first table of vibration numbers on page 46, we have 1 = 480, and r = 324; therefore
and thus, as noticed above, it is not a Perfect Fifth. To form a Perfect Fifth with 1, a note rx would be required, such that
It is easy to find the vibration number of this note if that of 1 be given, thus:—
This note has been termed rah or grave r, and may be conveniently written, r\ Similarlyis not a true Minor Third, for its vibration ratio is
but | *» is a true Minor Third, forits vibration ratio is
The interval between r and rv is the comma, its vibration ratio being evidently
The sounds used in Music He within the compass of about eight Octaves.
The vibration ratio or vibration fraction of an interval, is the ratio of the vibration numbers of the two sounds forming that interval.
The vibration ratios of the principal musical intervals have been exactly verified by Helmholtz's modification of the Double Syren.