Moved by love for his native city of Florence, Dante gathers the scattered leaves and returns them to the bush, before continuing to follow Virgil toward the third ring of the seventh circle. The two poets come upon a desert surrounded by the forest they have just been walking through. Dante sees different groups of naked, suffering souls throughout the desert. Some lie supine on their backs, while others squat in the sand, and some wander about. The fewest souls were lying down, but Dante notes that their screams were the loudest.
Dante's love for his native city is another example of love as a positive motivating force. Indeed, love for one's nation or native city is important in Dante's conception of piety: those who betray their countrymen have (as we will later see) a specific part of hell.
All over the desert, "huge flakes of fire," (14.29) fall like snow, keeping the desert sands hot and burning the souls suffering there. Dante compares the falling fire to the fireballs that enemies of Alexander the Great shot at his army in India. Dante sees one gigantic man lying in the desert, "scorning the flame," (14.47) as if it does not burn him. The man himself answers, crying out that he will not let Jove (the king of the Roman gods) have the pleasure of vengeance. Virgil identifies him as Capaneus.
Dante's simile about snow tries to find an earthly comparison by which he can convey the strangeness of the fire falling from the sky here, even as it is stranger than anything Dante can compare it to.
Virgil explains to Dante that Capaneus was a king who besieged Thebes and made light of God. Even in hell, he resists and scorns god. Dante and Virgil continue walking around the edge of the desert (Virgil tells Dante to be careful not to tread on the burning sand). They come to where a red river begins to flow from the edge of the forest, with its banks turned to stone. Virgil tells Dante that this stream deserves Dante's wonder more than anything else they have seen in hell, as it puts out the flames on its riverbanks.
Capaneus is an interesting example of Dante's incorporation of classical characters into his Christian poem. Capaneus' scorning Jove, the king of the Roman gods, becomes here a denial of the Christian God. Part of Dante's achievement in Inferno is the detailed specificity of the hell he creates, which is on display here in the description of the river.
Virgil then tells Dante about the source of hell's rivers. Under the island of Crete there is a giant man with a golden head, silver arms and chest, a brass torso, iron legs, and one foot made of clay. His tears run down, gather, and flow underground into hell, forming Acheron, Styx, and Phlegethon, then Cocytus, the lake at the bottom of hell.
The giant man is an allegory for the ages of history (declining from the golden age to the iron age). The clay foot is often understood to represent the church, which Dante (among many others) considered to be corrupted or unstable. The fact that hell's rivers originate from just underneath the island of Crete suggests that hell (which is below earth's surface) and earth are closely connected.
Dante questions Virgil further, asking where Lethe, the other river of the classical underworld, is. Virgil answers that Lethe is beyond the pit of hell, in purgatory. There, souls wash off their guilt and sins. Virgil leads Dante along the banks of the river, cautioning him not to walk on the burning sands beyond the riverbanks.
Dante takes the Lethe, the river of forgetfulness in Greek mythology, and makes it function in his Christian conception of the afterlife as the way in which souls "forget" their sins in order to progress toward heaven.