The 7th episode, usually called Aeolus, parodies the format of a newspaper, with block headlines introducing short, punchy chunks of text. Since its "art" is rhetoric, it is also filled to the brim with figures of speech: formulaic patternings of words that capture attention and stir response. Of the hundreds of such figures that were identified by theorists of rhetoric in antiquity, metaphor is easily the most familiar, so it is fitting that Aeolus begins with one: "IN THE HEART" of a big city. This is precisely the kind of stale metaphor that modern men and women expect to encounter in newspaper headlines, but Joyce will breathe new life into the tiresome cliché before long.
In his "Rhetorical Figures in Aeolus," an appendix to Gifford's Ulysses Annotated, Robert Seidman offers an encyclopedic list of figures of speech, tagged by ancient rhetoricians with Greek (and occasionally Latin) names, that appear in the novel's newspaper episode. Metaphor, from Greek meta = over, across + pherein = to carry, has become a staple of the English language, but most others sound very foreign.
Seidman introduces his list by observing that "The 'art' of the Aeolus episode is rhetoric, the form of linguistic manipulation Joyce considered closest to the heart of the working press. In its concentration on this self-conscious way of organizing language, Aeolus is the precursor of the more complicated use of imitation and parody in Cyclops (Episode 12) and Oxen of the Sun (Episode 14). The earlier manuscript drafts of Aeolus in The Little Review suggest that Joyce added a great number of rhetorical figures in his revisions, deliberately larding the chapter with as many devices as possible. What remains continually impressive is not simply the presence of practically every rhetorical figure outlined by Quintilian and the classical rhetoricians, but the manner in which these contrivances are fitted into the chapter."
Seidman goes on to note the limitations of any such analysis. Many more examples of classical rhetorical figures might be identified in the chapter, and one particular arrangement of words on the page might be construed as an example of several different descriptive categories. The "insufficiency, overlap, and reduplication of categories," he observes, derives from the fact that the theoretical terms evolved to describe ancient oratorical practice, not the other way around. Even among the ancient rhetoricians "there was considerable uncertainty and much hairsplitting/headsplitting debate."
Stuart Gilbert was the first to comment (in James Joyce's Ulysses, 1930) on the abundance of rhetorical figures in this chapter, no doubt alerted to them by Joyce himself. Gilbert notes the resemblance to William Shakespeare, whose works employ many hundreds of rhetorical figures of speech. In Shakespeare's case, the reasons for writing in this way are very apparent. Since rhetoric was one of the three arts comprising the medieval trivium, and was regarded as particularly useful in the conduct of everyday life, the humanist educators of early modern grammar schools instructed boys in the use of such figures, and adult writers like George Puttenham and John Lyly made careers out of them. Where Joyce might have learned them is somewhat less clear, but the Jesuit ideal of a Christian Eloquentia Perfecta sprang from Renaissance humanist roots and was taught in Jesuit schools from the Renaissance through Joyce's time, so it seems likely that he gained his introduction to rhetorical tropes in the same way, and at much the same age, as Shakespeare did—i.e., in the Jesuit boys' school called Clongowes Wood College.
Quintilian's twelve-volume Institutes of Oratory (the complete text of which was recovered in 1416, spurring intense humanist study) is available in several English translations, including an important one completed by the Rev. John Selby Watson in 1856. A complete hypertext of Selby's translation, edited by Lee Honeycutt, can be found at http://rhetoric.eserver.org/quintilian.
My notes for the rhetorical figures in Aeolus will take their lead from Seidman, but diverge from him at many points. It should also be noted that many, many more passages in Joyce's chapter could be cited as examples of particular figures than appear in Seidman's list or my hyperlinks. For example, he does not cite "IN THE HEART OF THE HIBERNIAN METROPOLIS" as an example of metaphor, and I do not gloss it as an example of alliteration.