To identify the figures of speech you need to look at the dream that the slave has as he lies on his plantation, near death. Consider the way that, as he rides his horse, a metaphor is used to describe the reins as being like "golden chains" that serve to emphasise the wealth and nobility of his life before he was transported to work as a slave. The "blood-red flamingoes" are described using a simile as being "like a blood-red flag," just as the sounds of the "water-horse" passing are described as being "like a glorious roll of drums." The setting of this free Africa is personified in the following stanza:
The forests, with their myriad tongues,
Shouted of liberty;
And the Blast of the Desert cried aloud,
With a voice so wild and free...
Note how the forests are compared to people shouting of "liberty" and the Desert likewise is able to cry out with "a voice so wild and free." Lastly, a metaphor is used to describe the body of the slave in the final stanza, as it is said to be "a worn-out fetter" that the soul had left.