How does Douglass use rhetoric in the narrative?

"You are loosed from your moorings, and are free; I am fast in my chains, and am a slave! You move merrily before the gentle gale, and I sadly before the bloody whip! You are freedom's swift-winged angels, that fly round the world; I am confined in bands of iron! O that I were free!"

Douglass, p. 49

In this highly sentimental passage, Douglass offers a literary performance for his readers. Obviously this event has been embellished and inflated for the readers of his book; he would not have stood at the prow of the ship and uttered such words. His rhetoric, tone, and sentiment are supposed to rouse the emotions of his 19th-century readers. They are affected and artificial and strike the modern reader as unnecessary, but they would have resonated with contemporary readers. It was a speech that clearly pointed to the fact that the autobiography was composed in his adult years. It also evinced a very educated and highbrow rhetorical style that seemingly left the slave dialect behind. However, there is somewhat of a larger point here: Douglass was using a style of speaking and writing that white America had long denied him or thought him even intellectually capable of possessing.