1. COLLONADES must be constructed behind the scaena, so that when sudden showers interrupt plays, the people may have somewhere to retire from the theatre, and so that there may be room for the preparation of all the outfit of the stage. Such places, for instance, are the colonnades of Pompey, and also, in Athens, the colonnades of Eumenes and the fane of Father Bacchus; also, as you leave the theatre, the music hall which Themistocles surrounded with stone columns, and roofed with the yards and masts of ships captured from the Persians. It was burned during the war with Mithridates, and afterwards restored by King Ariobarzanes. At Smyrna there is the Stratoniceum, at Tralles, a colonnade on each side of the scaena above the race course, and in other cities which have had careful architects there are colonnades and walks about the theatres.
2. The approved way of building them requires that they should be double, and have Doric columns on the outside, with the architraves and their ornaments finished according to the law of modular proportion. The approved depth for them requires that the depth, from the lower part of the outermost columns to the columns in the middle, and from the middle columns to the wall enclosing the walk under the colonnade, should be equal to the height of the outer columns. Let the middle columns be one fifth higher than the outer columns, and designed in the Ionic or Corinthian style.