Final answer:
The figure of speech "sable divinity" in sentence 21 displays the characteristic of vivid imagery and personification in Romanticism.
Step-by-step explanation:
The characteristic of Romanticism displayed in the figure of speech "sable divinity" in sentence 21 is the use of vivid imagery and personification. The phrase "sable divinity" combines the contrasting colors of black and divinity, creating a powerful visual image.
The use of personification in referring to divinity as sable adds depth and emotion to the description, reflecting the Romantic emphasis on individual emotions and the sublime.