Text: Musical Thirds What do we know about Thirds? Why are they important? 1) Major Third 5:4 2) Minor Third 6:5 2.1) Augmented Third 125:96 2.2) A major third consists of four semitones, a minor third of three. A major tone is the whole tone having the ratio 8:9; a minor tone, that having the ratio 9:10. Intervals have had the term major applied to them in a conflicting manner. A Dictionary of Musical Terms. 3) Both occur for the first time in the third octave. 4) Are probably resultant, summation or compound tones. 5) Any two thirds make a Fifth, of which there are several: Diminished Fifth 64:45 Diminished Fifth 36:25 Perfect Fifth 3:2 Augmented Fifth 25:16 6) They play a key role in the simplest chords: Triads, of which there are three types a) Major b) Minor c) Diminished (The material of which music is made is tone, in recognizable, orderly chord groups. The simplest chord group is the Triad, or three tone chord. The Triad always consists of fundamental (root), third and fifth. A Triad may be constructed upon every degree of the scale, Major and Minor. Upon the Major Scale tones the Triads of the key, in C Major, are shown above. These seven Triads occur in exactly the same form in every Major Key. There are three different Triad groupings in the above: Major Triad: Major 3rd and Perfect 5th on the 1st, 4th and 5th degrees. Minor Triad: Minor 3rd and Perfect 5th on the 2nd, 3rd and 6th degrees. Diminished Triad: Minor 3rd and Diminished 5th on the 7th degree.) DEFINITIONS 1) The interval between a fundamental tone and the third diatonic tone above. 2) The interval comprised by two notes written on adjacent lines or spaces. A major third has two whole tones, a minor third a tone and a semitone, and a diminished third a whole tone. The mode of a triad is determined by its third, as is the mode of a scale, since the sixth and seventh degrees are treated as variable in the harmonic minor and melodic minor scales. The diminished third is most often used as the inversion of the AUGMENTED SIXTH, INTERVAL, IMPERFECT INTERVAL. Collin's Music Encyclopedia, 1959 3) Progressive Thirds: The ultimate test of a good temperament on any piano is a smooth change of the beat rates as progressive thirds are played -- both in the bearings octave, and outside it. (no reference) 4) Diatonic Thirds: "The sympathetic acoustic impulses are: the DOMINANT - a diatonic third - the HARMONIC - the connective "sixth" - and the ENHARMONIC - or diminished seventh - which Keely calls a ninth - inducing "infinite trajective velocity" or "neutral radiation" from neutral centers." Snell Manuscript.

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