later practice of employing them at the end of a tragedy to solve the difficulties of the plot. He says that in a well-constructed play the conclusions should be the natural result of the preceding incidents, and there should be no need of any supernatural agency.[660] Euripides has generally been regarded as the chief offender against his rule, and as the author of the custom which he condemns. But it will be found, on examining his plays, that there are very few of them in which the god is really used as a last resort. There are only two instances in which he can be said to solve the problems of the situation. In the other cases he is introduced, not so much to set matters right, as to inform the characters of the destiny which awaits them. His function is confined to announcing the future course of events.[661] These, therefore, are what Aristotle would call permissible uses of the ‘deus ex machina’. § 8. _Other Mechanical Contrivances._ Several other devices in use upon the Attic stage are briefly mentioned by Pollux, but his descriptions are so meagre and obscure that little can be inferred as to their exact character. Charon’s Steps was a contrivance for bringing ghosts and spectres up from the other world. It can hardly have been anything else than a flight of steps leading out upon the stage from underneath. The ‘anapiesma’ was used by river-gods, Furies, and other subterranean beings for the purpose of appearing above ground. The word ‘anapiesma’ seems to mean something which was pushed back. It is probable, therefore, that the contrivance was merely the ordinary trap-door of the modern theatre, through which the spectral being was raised on to the stage.[662] Whether these two devices were used as early as the fifth century is somewhat doubtful. There are few occasions in the extant plays and fragments where they would have been serviceable, and none where they are absolutely necessary. The ghost of Darius in the Persae arises out of his tomb, and the ghost of Achilles in the lost Polyxena of Sophocles apparently revealed himself in the same way.[663] In these two cases it is needless to suppose any special apparatus beyond the tomb itself. The ghost of Clytaemnestra in the Eumenides, and that of Polydorus in the Hecuba, may possibly have risen from underground. But there is nothing in the text of the plays to show that this was the case, and an entrance in the ordinary manner would have satisfied all requirements. Some critics suppose that in the Prometheus the punishment which had been threatened by Hermes was actually carried out before the eyes of the spectators, and that the tragedy ended with the disappearance of Prometheus beneath the stage. But a melodramatic conclusion of this kind seems far from probable, and out of keeping with the character of the ancient drama. It is more likely that when the play was over the actor simply walked off the stage, or was concealed from view by a curtain. Or he may have remained in position