In Chapter 1, Captain Graveling uses a metaphor to describe Billy Budd to Lieutenant Ratcliffe:
The master broke the silence; and there lurked a rueful reproach in the tone of his voice: “Lieutenant, you are going to take my best man from me, the jewel of ’em.”
The Captain makes the unlikely comparison of Budd to a jewel. His phrasing is of course not literal and is an example of metaphor. The Captain refers to Billy as a "jewel" to reflect how Budd is regarded as the most precious or valuable member among his crew. The Captain's use of figurative language also suggests that Budd possesses exceptional qualities, skills, and traits that make him stand out among his peers. In having the Captain use such an evocative phrase, Melville emphasizes the high esteem in which the speaker holds Billy. The Captain's phrase is also emotionally resonant and conveys a sense of affection on the part of the Captain.
Throughout the novella, Melville uses figurative language like the metaphor above to emphasize Billy's character traits and present him as admirable and morally good. Billy's goodness is central to the novella's events, as that goodness comes into question when Claggart accuses Billy of mutiny. But rather than simply explaining or describing Billy's goodness, Melville expresses it to the reader in an evocative and memorable way.
