Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Tongue-in-Cheek
Just when you think something serious is going to happen, Melville will happily settle on some tongue-in-cheek observation of life's absurdities. Melville uses this quirky tone all the time, even when he's discussing the potential violence that might be done to a character who cannot walk. Or when it seems like some stockbroker has made off with $100 of a dying man's moolah.
Basically, whenever Melville has a chance to poke fun at his characters, his readers, or himself, he 100% will. And that's basically 100% of the time.