A third picture of temptation is furnished by the episode of one of the Sirens who appears first repulsive and then seems to the poet sweet and alluring. Only when Virgil discloses her hideous nature does Dante see how easily he might have fallen a victim to her wiles. He tells us that in his sleep there appeared to him a woman with stammering utterance, squinting eyes, deformed hands. "I gazed at her, and as the sun restores the cold limbs made heavy by night, thus my look loosened her tongue, then straightened her all out in a little while and colored her wan face as love demands. When her speech was thus unbound she began to sing so that I could hardly have turned my attention from her. 'I am,' she sang, 'I am sweet Siren who bewitch sailors by mid-sea, so full am I of charm to hear. By my song I turned Ulysses from his wandering way. And whosoever abides with me seldom departs, so wholly do I satisfy him.' Her lips were not yet closed when a lady, swift and holy, appeared at my side to confound the other. 'O Virgil, Virgil, who is this?' she said proudly; and he advanced with his eyes fixed only on this modest woman." Virgil (Reason called by Conscience) comes to the rescue of the entranced poet and reveals the Siren in all her foul ugliness. At that Dante awakes from his dream more than ever convinced of the evil of sin and its hideousness. (Purg., XIX, 9.) Our poet, as we said, is firmly convinced that sin will be punished in Hell. But where is Hell? Popular tradition attributing an infernal connection with volcanic phenomena and moved by those passages in Holy Scripture which describe Hell as a place to which the reprobate descend, locates Hell in the interior of the earth. Dante not only follows this tradition for his Hell, but he does what no other writer before or after him ever did--he constructs a Hell with such rare architectural skill that the awful structure stands forth in startling reality, visualized easily as to form an atmosphere, and with a finish of detail that is amazing. Covered by a crust of earth it is situated under Jerusalem and extends in funnel shape to the very center of the earth. How it got this shape is told by the poet. When Lucifer was hurled from Heaven by the justice of God, he kept falling until he reached the center of earth, whence further motion downward was impossible. At the approach of Lucifer the earth is represented as recoiling and so making the cavity of Hell. The earth dislodged by the cataclysm was forced through an opening, a kind of nozzle of the funnel of Hell, to the antipodes and it there emerged, forming a mountain, which became the site of the Garden of Eden and Purgatory. The phenomenon made land in the northern and water in the southern hemisphere. Here is the description: