accepted rules, the principal character does not appear upon the scene until after the beginning of the third act. But the conversation and disputes of the other dramatic personages have so inflamed our curiosity concerning him that we can scarcely wait to catch a glimpse of him, and his entrance finally is thrice as effective as if it had come earlier in the play. The erection of a scene-building about 465 B.C. somewhat relieved the difficulty of the playwrights’ problem. First of all the places of entrance were increased 50 per cent or more. Secondly, the new entrances were nearer the orchestra than were the parodi and enabled an actor to come in or depart more quickly. Thirdly, the presence of buildings almost required the scene to be laid in a town or city and correspondingly multiplied the possible motives for visiting it. And finally, since the doorways often represented the homes of certain of the dramatic characters, no elaborate motivation was needed to explain their passing in and out at frequent intervals. When his work was done, the useless actor could be temporarily eliminated with neatness and dispatch. These considerations and the introduction of the third actor at about the same time (see p. 167, above) soon doubled the amount of coming and going in the plays (cf. Mooney, _op. cit._, p. 54). The influence of the former factor appears in Euripides’ _Suppliants_, the action of which takes place before a temple. It so happens, however, that the temple doors in this case are not used for entrances and exits. Consequently of all Euripides’ tragedies this one has the least passing to and fro. On the other hand the influence of the second factor is seen in the fact that this piece and Sophocles’ _Oedipus at Colonus_ (see p. 227, above), both making practically no use of their back scene but both employing three actors, are higher in “action” than the corresponding plays of Aeschylus, which belong to the two-actor period.