The three sounds above this formed with the _a_ another tetrachord, _conjunct_, as it was termed. [Illustration: _The Added Trichord_ _d_ | tone | _c_ tone | _b_♭ ) hemitone *_a_ | tone | _g_ | tone | _f_ ) hemitone _e_ _The Original Tetrachord_] Continuing to plot out the scale on a vertical plan would not be of any advantage. The habit of the eye would perhaps require a diagonal line of ascent; I think, however, that showing the growth of the scale on a level line will best suit our general convenience. This then let us call the Terpander scheme for the scale to which the _seven-stringed lyre_ or Cithara was tuned. As we shall see, this became the classical lyre of Apollo, throughout the glorious period of Greek Art. ╭————————^———————╮╭————————^————————╮ _e_ ‿ _f_———_g_———_a_ ‿ _b_♭———_c_———_d_ * The _a_ I have marked with a star. It was called the _mese_ or _middle-note_, was considered the master-note of the lyre, and was compared to the sun as being the centre of the musical system. The original names of the strings of the four string lyre are lost, but it is quite obvious that until the extra three strings were introduced there could have been no _mese_ or middle string, so that the name originated with this condition, with this perfecting of the system. Before systems exists methods and rules have sway; and out of these methods and rules systems are constituted. The great poet-musicians renowned in the land, in teaching their successors in art according to their own practical experiences, and teaching _viva voce_, no doubt insisted upon the observance of certain methods, and laid down rules which on their authority as chief masters, became the traditions of the profession. The great repute of Terpander would have caused him to be regarded as one who spoke with authority, and I have sometimes thought that discrepancies in the accounts given by different authors, who wrote many centuries after the time of this musician, and from whom alone we have any knowledge of the doings in such early period, might be reconciled by the surmise that perhaps it was Terpander who first showed how the two tetrachords should be disposed and the tuning of the enlarged series of strings be regulated in the best way for the art of music, so that instead of being left to the caprice of different teachings, an uniform method should prevail. Some one in authority by his recognised supreme skill, would have been necessary to reduce to order the practices of the day as taught by the wandering minstrels in the land of Greece, and in the numerous settlements in Asia Minor, and it seems reasonable to suppose that Terpander may have been the first to formulate definite laws for the structure of the tetrachord in Greek music.