Oceanus, the Titan representing the ocean the Greeks believed circled the entire world, enters on a flying beast. Getting straight to the point, Oceanus expresses his friendship for Prometheus, offers his pity, and insists on going to Zeus immediately to bail Prometheus out. Meanwhile, he suggests, Prometheus should keep silent and stop provoking Zeus. Prometheus refuses this offer categorically, replying that Oceanus can achieve nothing by standing up for him. When Oceanus persists, Prometheus says that he would rather not have anyone suffer at the hands of Zeus on his behalf, since it already pains him that his brothers suffer Zeus's wrath. Oceanus asks whether Prometheus does not know that words are best for healing, but Prometheus responds that words only heal when spoken at the proper time. If Oceanus interferes, he will only bring Zeus's wrath down on them both. With this, Oceanus departs.
The Chorus again repeats that they shed tears for Prometheus, and that the entire world that was old before Zeus mourns for the suffering of Prometheus and his Titan brothers at the hands of the new tyrant. They say they have seen only one other Titan bound and tortured in this way: Atlas, who holds the world. Prometheus replies by summarizing all he has done for humanity. He taught human beings how to use numbers and language so they could remember what they have learned. He showed the paths of the stars and taught the use of ships. He also first harnessed animals so that they could do the work of human beings. Prometheus also introduced medicine and prophecy and divination through dreams, birds, sacrifice, and fire. Finally, he showed how to draw metals from the earth. Prometheus insists that he is responsible for all the arts of humanity.
The Chorus suggests that Prometheus helped humanity too much without thinking of himself, but he replies that his suffering is necessary, and he must bow to necessity like everyone else including Zeus. Here Prometheus comes close to revealing his secret prophecy, but then explains that he cannot reveal it to the Chorus because it will free him in the end only if he keeps it secret. The Chorus affirms their commitment to following the laws of Zeus and sings that Prometheus should not have helped creatures who cannot help him back. Finally, they contrast the mournful songs they sing for him now with the songs they sang before to celebrate his marriage to their sister Hesione.
The exchange between Oceanus and Prometheus demonstrates further features of Zeus's servants, as well as Prometheus's character. Oceanus's sincerity in offering to help Prometheus does appear questionable. Prometheus, in any case, treats it with some sarcasm and is fairly terse in dismissing his would-be savior. Oceanus, meanwhile, does not get off his flying beast, and as he leaves even comments how eager his animal is to return home. Clearly Oceanus is drawn to offer help because of his bonds of kinship—Prometheus is a fellow Titan, as well as Oceanus's son-in-law. At the same time, however, Oceanus is clearly wary of opposing Zeus in any way. He chides Prometheus, urging him to be less rebellious, and leaves as soon as his offer to help is refused. Oceanus may be a somewhat unwilling servant, but he is a servant nevertheless. His attitude reminds us once again of the political nature of divine interaction. Oceanus knows the extent of his powers, and though he finds Zeus extreme, he values his place in the current order.
Prometheus, meanwhile, is far less open with Oceanus than with the Chorus. He simply mentions that intervention will be useless, without revealing anything about the prophecy. Prometheus also invokes two reminders of Zeus's power—the imprisonment of Atlas and the defeat of Typho—to convince Oceanus that involving himself is not advisable. Prometheus may simply want to avoid putting another at risk on his behalf as he says. If this is the case, it is not clear why he is willing to reveal so much more to the Oceanids. It seems more likely that Prometheus does not fully trust the politically minded Oceanus and wants to get rid of him. Oceanus uses the metaphor of words as medicine for Prometheus's illness, hoping that this approach will appeal to the intelligence of the rebel. But Prometheus dismisses this, replying simply that medicine must be administered at the right time without revealing his knowledge of when the right time will be. Oceanus mentions that Prometheus should take him as his schoolmaster, but Prometheus sarcastically returns this comment a little later, suggesting that Oceanus does not need him as a schoolmaster. The two part as friends, but some suggestion has been made that Oceanus's offer to help was only a matter of business he felt was required by tact, and that Prometheus knows how to exercise the restraint he feels proper to each situation.
Prometheus's list of his contributions to humanity demonstrates several interesting features. Though mention is made to language and numbers, Prometheus mostly refers to material contributions. He lists these contributions in two sets with similar structures. Both lists begin with Prometheus mentioning that human beings need something. He begins the first list by speaking of the need for shelter and guidance, while he begins the second with a need for drugs to stave off illness. From there, Prometheus goes on to first person accounts of what he contributed. The order in which the contributions in each set are listed is significant as well. The first set contains shelter, agriculture, numbers, husbandry, and shipbuilding. Apparently, Prometheus is attempting to give his audience a picture of progress. First, human beings are in desperate need. Once the initial need has been satisfied, by shelter and food, new devices are introduced to improve life. The order of the second list also mirrors the order of progress in civilization: first medicine, then divination, and finally minerals. Prometheus, having assured human progress, attempts to recapture that progress through the order in which he names his contributions. This structure is emphasized by the order in which he lists the metals he showed humans how to mine: bronze, iron, silver, and finally gold. This is an allusion to the four Ages of human existence mentioned by Hesiod. Hesiod had listed the Ages backward, from Gold to Bronze, attempting to show how far humanity has sunk. Aeschylus clearly wants to show the reverse: that the move from bronze to gold illustrates human progress.