sovereignty." The mention of this possible release occasions a dialogue in which the connection of Io's fate with that of Prometheus is gradually disclosed:—
"Io. What! shall Zeus e'er be hurled from his estate?
Prom. 'Twould give thee joy I trow to see that fall.
Io. How should it not, when Zeus so foully wrongs me?
Prom. That this is so thou now may'st hear from me.
Io. Who then shall strip him of his sovereign power?
Prom. Himself shall do it by his own rash plans.
Io. But how?—tell this, unless it bringeth harm.
Prom. He shall wed one for whom one day he'll grieve.
Io. Heaven-born or mortal? tell, if tell thou may'st.
Prom. Why ask'st thou who? I may not tell thee that.
Io. Shall his bride hurl him from his throne of might?
Prom. Yea; she shall bear child mightier than his sire.
Io. Has he no way to turn aside that doom?
Prom. No, none, unless I from my bonds be loosed.
Io. Who then shall loose thee 'gainst the will of Zeus?
Prom. It must be one of thy posterity.
Io. What! shall a child of mine free thee from ills?
Prom. Yea, the third generation after ten."
Thus mysteriously is it foretold how Hercules, the thirteenth from Io, should be the means of Prometheus's freedom. Prometheus goes on, at the earnest request of Io herself and of the Chorus, to tell the rest of her wanderings and the manner of his own release. Through many strange countries she is to pass, and see many monsters—the three Graiæ, with the shapes of swans, and only one eye and one tooth between them; the three Gorgons, their sisters; the one-eyed Arimaspians who dwell by the ford of Pluto; and at last, passing the Ethiopians, she is to come to the land of
