In the following passage from Act 1, Prometheus angrily curses Jupiter, using simile as a means of describing Jupiter's soul:
What ruin
Will hunt thee undefended through the wide Heaven!
How will thy soul, cloven to its depth with terror,
Gape like a Hell within!
In order to emphasize the extent of his suffering and his just craving for retribution, Prometheus states that Jupiter’s soul will “Gape like a Hell within”—a phrase that is self-evidently ironic, on account of whom Prometheus is addressing. Particularly in a Christian context, a soul is traditionally regarded as inherently sacred. It is situationally ironic, then, given Shelley's context, that Jupiter, as a god who lives in the sacred realm of heaven, would have a soul that gapes "like a hell within."
While Jupiter is no pillar of morality within the Greek and Roman myths, the God of Christianity is supposed to be utterly holy, with no hellish soul or sinful misdeeds in sight. To imply that God is impure or immoral in Christianity would be heresy; in Greek and Roman mythology, however, it was not uncommon for gods to act immorally. Jupiter, for instance, was known to frequently cheat on his wife, siring demigods with an untold number of mortal women. In Prometheus Unbound, Shelley blurs the lines between so-called "heathen" religions and Christianity, muddying the waters in terms of how to regard godly morality.
The following passage, spoken by the Third Voice (from the Air) in Act 1, recounts Prometheus's imprisonment and the effect it had on the natural world. Utilizing simile, the voice specifically recounts the aftermath of Prometheus's curse:
By such dread words from Earth to Heaven
My still realm was never riven:
When its wound was closed, there stood
Darkness o’er the day like blood.
According to the speaker, the day was dark, and that darkness blotted out the daytime "like blood." This simile, while not directly alluding to the Bible, does form a connection between Shelley's imagery and the imagery of Christianity—in particular, the plagues God sends to punish Egypt, which included three days of darkness. At the end of the three days, God sent an angel of death to kill all of the firstborn sons in Egypt, sparing only those Israelites who painted their doors with lamb's blood beforehand. Shelley's simile in the above passage calls on the similarities between God's divine punishment of the Egyptians and Prometheus's own punishment at the hands of a different god. While Prometheus's bodily wounding and imprisonment were two such affronts causing this darkness, it was the curse itself—the promise of vengeance, instead of forgiveness—that brought about the wound.
In the following excerpt from Act 1, Mother Earth/Gaia speaks to her son, Prometheus, advising him to seek out knowledge of his prior curse against Jupiter at the inception of his imprisonment. The Earth pushes for this outcome because she wants revenge on behalf of her children, the Titans, who were all imprisoned by Jupiter. The Earth imagines what that vengeance might look like in figurative terms, using metaphor to describe it to Prometheus:
Ask, and they must reply: so the revenge
Of the Supreme may sweep through vacant shades,
As rainy wind through the abandoned gate
Of a fallen palace.
The simile in the passage above compares the vengeful acts of the "Supreme" to rainy wind entering into an abandoned dwelling, disturbing the otherwise vacant and quiet spaces. This bit of figurative language implies that speaking the truth of Prometheus's oppression will be both an act of freedom and an act of disturbance. Rainy wind blowing through an abandoned or fallen place is hardly a pleasant image; such weather would cause more discomfort than anything. While this simile hardly presents a happy picture of freedom, it does clarify Shelley's view on the matter. Freedom will always result in a disturbance, or upset, of the status quo, which is meant to make those in power uncomfortable. The Earth's description affirms this.
During a particular scene in Act 1, Mercury addresses Prometheus, whom he has been sent to converse with on Jupiter’s behalf. While he takes this mission seriously, Mercury makes it clear that this task brings him no joy. In the following passage, Mercury sheds some light on his outsider’s perception of Prometheus’s imprisonment, using simile to describe the situation:
Alas! I pity thee, and hate myself
That I can do no more: aye from thy sight
Returning, for a season, Heaven seems Hell,
So thy worn form pursues me night and day,
Smiling reproach.
In this excerpt, Mercury juxtaposes heaven and hell, comparing the two through simile in an attempt to explain the emotional and moral turmoil he experiences upon viewing Prometheus’s predicament. According to Mercury, whenever he returns from visiting Prometheus, the beauty of his surroundings in heaven (or Mount Olympus) is diminished by his memory of Prometheus's suffering, and the role of the gods in said torture. Mercury is so tormented by this guilt that it makes his beautiful, heavenly surroundings into a living hell. In his mind, the glory and moral quality of heaven are tarnished by the horror of what Jupiter has done to Prometheus, such that Prometheus's vengeful spirit even seems to haunt the halls of Mount Olympus.
In the following passage from Act 1, Prometheus describes what he wishes to happen to Jupiter. This description comes from a place of anger and occurs before Prometheus elects to hear his curse in full; thus, the passage below comprises Prometheus's thoughts on Jupiter before he decides upon forgiveness. Using simile, an angry and vindictive Prometheus describes the retribution his foe will face:
And yet to me welcome is day and night,
Whether one breaks the hoar frost of the morn,
Or starry, dim, and slow, the other climbs
The leaden-coloured east; for then they lead
Their wingless, crawling Hours, one among whom
—As some dark Priest hales the reluctant victim—
Shall drag thee, cruel King, to kiss the blood
From these pale feet, which then might trample thee
If they disdained not such a prostrate slave.
The image and simile used by Prometheus here are quite dark: he envisions Jupiter, brought low, dragged before him as a "dark Priest" who brings a sacrifice to the altar, forced to kiss the blood from Prometheus's wounded feet. This portrait of revenge is particularly apt for a god, who no doubt is used to having priests singing his praises and spreading his doctrine. Again, Shelley uses figurative language as a means to upset pre-established power hierarchies.
The following excerpt from Act 2, Scene 3 is from the end of the sirens' song, which Asia and Panthea hear as they attempt to enter the realm of the Demogorgon. In their song, the sirens use a simile to describe the fate of those who "descend" into "the deep":
We have bound thee, we guide thee
Down, down!
With the bright form beside thee;
Resist not the weakness—
Such strength is in meekness
That the Eternal, the Immortal,
Must unloose through life’s portal
The snake-like Doom coiled underneath his throne
By that alone!
In the above passage, the sirens speak about dragging someone down to their doom, using the phrase "snake-like" to describe this "doom." This simile is likely intended to reference the image of a snake coiled in on itself, eating its own tail—a common image used to signify the cycle of life. This visual motif is repeated on such important artifacts as the Rod of Asclepius, commonly associated with healing and medicine. The image of a snake coiled around a rod can still be found in many hospitals worldwide.
This particular simile seems to indicate that the "doom" these sirens are referring to is the Underworld rather than the bottom of the sea. Death, after all, is part of the cycle of life.
In the following passage from Act 2, Scene 4, Asia addresses the Demogorgon, seeking out an answer to the oft-asked question: who is responsible for the suffering of humanity? Asia herself does not seem to know the answer to this question, wondering about Jupiter's role in human suffering but questioning, through simile, his capacity for such cruel action:
Not Jove: while yet his frown shook Heaven, aye, when
His adversary from adamantine chains
Cursed him, he trembled like a slave. Declare
Who is his master? Is he too a slave?
In this address, Asia wonders who could now be the cause of all human suffering, given the fact that Prometheus is imprisoned, and Jupiter is afraid of him. Asia quite clearly does not consider Jupiter a strong contender for the source of humanity's suffering, viewing him instead as an oppressor who fears the one he subjugates. The simile in the above passage, which states that Jupiter trembles "like a slave" at the thought of Prometheus's release, actually turns the oppressor/prisoner dichotomy on its head. Whereas Prometheus is Jupiter's slave physically, being chained to a rock and tortured, Jupiter is a slave to Prometheus psychologically, fearing the loss of his power should Prometheus be freed. Asia simply does not believe that one so afraid of their rival would have the brazen cruelty to heap such suffering upon humanity.
In the following excerpt from Act 2, Scene 5, Asia, Panthea, and the Spirit of the Hour pause in their flight across the sky. At this moment, Panthea remarks on Asia's visage, asserting that there is love in the air because of her presence. With this comment comes the implication that Asia's appearance is a good omen foreshadowing the positive change to come. Asia replies to this comment, using simile to describe the state of the world around her:
Common as light is love,
And its familiar voice wearies not ever.
Like the wide Heaven, the all-sustaining air,
It makes the reptile equal to the God:
They who inspire it most are fortunate,
As I am now; but those who feel it most
Are happier still, after long sufferings,
As I shall soon become.
Asia contemplates the feeling of love as it arises, remarking through simile that it is as ubiquitous and commonplace as light, and undoubtedly just as essential. Importantly, Asia further notes that love "makes the reptile equal to the God." This observation again ties ephemeral emotional/moral concepts to nature, implying that these things—love, joy, virtue—are just as essential to the world as the natural law that governs light and biology.
