2The following is the rule for determining the situations of these vases. If the theatre be of moderate size they must be ranged round at half its height. Thirteen cavities are prepared at twelve equal distances from each other, so that those tones above-named, producing netè hyperbolæon, are to be placed in the cavities at the extreme ends; second, from the ends, the vessels are to be of the pitch of netè diezeugmenon, bearing an interval of one fourth from the last mentioned. The third netè paramesôn, an interval of another fourth. The fourth, netè synemmenôn, another fourth. The fifth, mesè, a fourth. The sixth, hypatè mesôn, a fourth: in the centre of the range, hypatè hypatôn, a fourth.
2The arrangement of these vessels, with reference to the situations in which they should be placed, may be described as follows. If the theatre be of no great size, mark out a horizontal range halfway up, and in it construct thirteen arched niches with twelve equal spaces between them, so that of the above mentioned “echea” those which give the note nete hyperbolaeon may be placed first on each side, in the niches which are at the extreme ends; next to the ends and a fourth below in pitch, the note nete diezeugmenon; third, paramese, a fourth below; fourth, nete synhemmenon; fifth, mese, a fourth below; sixth, hypate meson, a fourth below; and in the middle and another fourth below, one vessel giving the note hypate hypaton.