Further information is derived from Aeschylus’ _Prometheus Bound_ (see pp. 166 f., above). (5) Supernumeraries may be employed for silent parts, e.g., that of Bia. (6) A part may be divided between a lay figure and an actor, as in the case of Prometheus himself. From the nature of things, this expedient would not be frequently employed; but an analogous device (6_a_) is common, viz., to give the silent portions of a rôle to a mute and the speaking portions to an actor. (7) The stubborn silence of the mutes and supernumeraries employed according to principles (5) and (6_a_) is sometimes extremely embarrassing and difficult to motivate. (4_a_) The interval required for a “lightning” change from one character to another was much shorter than the _Suppliants_ led us to suppose. Six verses and a slight pause in the action enabled the actor impersonating Hephaestus to withdraw by the side entrance after vs. 81 and to get in position to speak from behind the wooden figure of Prometheus at vs. 88. This conclusion is confirmed by certain evidence in Plautus’ translation of Greek comedies, which indicates that about thirteen lines would suffice.[276] Still other principles are derivable from Aeschylus’ _Persians_. The ghost of Darius having requested his widow to meet their son Xerxes with a change of raiment, Atossa replies (vss. 849 ff.): “I shall endeavor to meet my son ... and,” turning to the chorus, “if he comes hither before me, do you comfort him and escort him to his palace.” These words are clearly intended to prepare us for her failure to appear in the dénouement, and in fact she does not appear. But since one of the two actors is disengaged in the final scene, at first glance there seems to be no external reason for her absence. It is evident that Aeschylus valued the parts of Atossa and Xerxes so highly that he wanted them both played by the better of his two actors, the _protagonist_. If Atossa had appeared with her son, she must have been impersonated by a different actor than in the opening scenes. The poet preferred to sacrifice verisimilitude somewhat rather than to “split” Atossa’s rôle in this fashion. Hence, we must conclude (8) that at any cost star parts were reserved for the leading actor, (9) that split rôles were to be avoided, and (10) that sometimes for purely technical reasons the dramatist would unnaturally keep a character off the stage entirely in certain scenes.