Sure, here are the paraphrases of the central idea and supporting details of the paragraph:
**Central idea:** The author was horrified by the prospect of being enslaved.
**Supporting details:**
* The author's complexion was different from the black people on the ship, and their language was also different.
* The author saw a large furnace or copper boiling, and a multitude of black people chained together.
* The author saw the black people's countenances expressing dejection and sorrow.
The author's fear of being enslaved is evident in the use of strong language, such as "horrors" and "anguish." The author's description of the black people on the ship is also notable, as it highlights their difference from the author and their enslavement. The author's fainting at the end of the paragraph suggests that they were overcome by their fear and anxiety.
Here is a more concise paraphrase of the central idea and supporting details:
The author was horrified by the prospect of being enslaved. They saw black people chained together and their countenances expressing dejection and sorrow. This confirmed their belief that they were going to be enslaved, and they fainted from fear and anguish.