In the Greek scales, the chief strangeness to us is that the keynote lays not at the beginning, but within the scale; and it was called the _mese_, or middle note. Nevertheless, its position was not always in the middle, but was shifted higher or lower in the octave according to the mode for the time employed. The scale originated in the tetrachord, and the octave resulted from the combination of two tetrachords; in the old system these were conjunct, and in the new system disjunct, and the two systems were exemplified in the octave lyre. The primary rule in the disjunct system was that the separation between the two tetrachords should consist of a whole major tone. Another rule insisted upon by every Greek writer was that there should be an interval of a whole tone, at least, immediately below the _mese_ note; and, as Aristotle says, “_Mese_ is the leader and sole ruler of the scale.” I make no pretence of discoursing upon the Greek musical systems; all I desire is to fix your attention upon certain peculiar features unfamiliar to us, but upon which the _structure of the flutes_ depended. I have previously alluded to the special importance of a curious interval of a minimum minor third, and maximum minor third, in the Greek measures, not our intervals. The historic record, together with an exposition of the growth of these scales, and their bearing upon the development of the system of music, will be given in a later chapter. Now look back at our mon-aulos; it has six holes, and is governed by the fingers of two hands, with the thumb added, and this is the first instance of the thumb being employed in flute playing. Now look at our _Bombyx-plagiaulos_ (if such name be accepted), it has the same number of holes, and the thumb hole lying underneath between the upper two holes. One can understand how in the longer _Bombyciæ_ (of which I shall have to discourse in the next chapter) there was an obvious advantage in having movable sections of a cylinder to shut off notes, simply for the reason that the fingers could not manipulate thirteen open holes. But the puzzle with the shorter _Bombyx_ is that it shows no advance beyond the mon-aulos in the demand made upon the fingers, which could cover the holes as required, without any need to have particular holes shut off mechanically. I could not comprehend, and the question persistently arose, what was the utility of the new invention? Look at the relative positions of the two lowest holes of the mon-aulos; in each instrument the peculiarity of relation is noticeable, and yet there is a difference in each. Why? The conclusion I arrive at is that there is something traditionally imperative as to the unequal division of one tetrachord in the octave; that originally it was the lower tetrachord that was thus subject to custom; that afterwards more licence was taken, and, still subject to rule, there was choice as to where that tetrachord might be; and I find in the