The tone of Lord Jim is primarily wistful and tormented. This is because the person narrating the bulk of the novel—the aging sea captain Marlow—is telling the story after the death of his friend Jim (who was also something of a son to him). A sense of longing, grief, and regret is present throughout his narration. Take the following passage, for example, which comes at the conclusion of Marlow’s speech at the dinner party (before he continues the story in letters to the privileged reader):
“For me that white figure in the stillness of coast and sea seemed to stand at the heart of a vast enigma. The twilight was ebbing fast from the sky above his head, the strip of sand had sunk already under his feet, he himself appeared no bigger than a child—then only a speck, a tiny white speck, that seemed to catch all the light left in a darkened world. . . . And, suddenly, I lost him. . . .”
Marlow’s description of the last time he saw Jim has a distinctly wistful tone, as seen in phrases like “that white figure in the stillness of coast,” “a vast enigma,” and “a speck, a tiny white speck, that seemed to catch all the light left in a darkened world.” That this final goodbye is taking place at twilight also suggests the end of something, as night begins to fall. Conrad’s use of ellipses (which occur frequently throughout the book) also adds to the mournful tone of the passage.
There are moments, of course, when Marlow describes feeling annoyed with Jim’s immaturity and the tone of the story moves into a frustrated register. These moments are important, as they complicate the story that Marlow cherished Jim and show readers that Marlow understood Jim was a flawed person like everyone else.