Answer:
Paraphrase the central idea: The narrator strongly believes that the differences in appearance, language, and treatment of the people on the ship confirm the horrifying reality of their own situation.
Paraphrase the supporting details: The people on the ship have different complexions, long hair, and speak a language unfamiliar to the narrator. The sight of a large boiling furnace and numerous black people of various descriptions, all chained together and expressing sadness, further solidify the narrator's realization of their fate. The intense horror and distress caused the narrator to lose consciousness and collapse on the ship's deck.