Sentence:  Sauveur divided the <WSD>heptameride</WSD> into two demi-<WSD>heptamerides</WSD>. One demi-<WSD>heptameride</WSD> is 1/602 of an octave, with frequency ratio 1:21/602 = 1.001 154 or 1.993 cents, very nearly 1/12 of a ditonic comma. 
Meaning of the word marked with <WSD> tags:  An interval of pitch equal to 1/7 of a meride, or 1/301 of an octave.