Note 10 — § 18. The Perfect System.
Reading edition
This observation was made by ancient writers, e.g. by Adrastus (Peripatetic philosopher of the second cent. A.D.): epêuxêmenês de tês mousikês kai polychordôn kai polyphthongôn gegonotôn organôn tô proslêphthênai kai epi to bary kai epi to oxy tois pro[:y]parchousin oktô phthongois allous pleionas, homôs k.t.l. (Theon Smyrn. c. 6).