The brickmaker who tries to wrangle information out of Marlow about Kurtz adds to the conspiratorial air of the Central Station. From his conversation with Marlow, the reader learns that Kurtz has disrupted the brickmaker's plans to become assistant-manager. The brickmaker also reflects the Company's disorganization, for he makes no bricks at all; he also reflects the Company's avarice, for he wants to advance in rank without completing any actual work.
While the plot concerning Marlow's steamboat and rivets adds to Conrad's overall air of conspiracy, it also metaphorically enriches the novel as a whole. Rivets hold things together, and Conrad uses the rivets as symbols of the ways in which the Company, the Manager, Marlow, Kurtz, and Kurtz's fiancée (his Intended) attempt to "hold together" their beliefs and ideas. These ideological "rivets" are seen in numerous ways. For example, the Company wants to keep its operations running without criticism, inquiry or restraint; Marlow wants to believe his own naïve ideas about Africa; Kurtz wants to remain king of his private empire and disregard his "civilized" self; and the Intended wants to believe that Kurtz was a great man with a "generous mind" and "noble heart." Each character has his or her own "rivet," from the Company's implied belief that it is "civilizing" the Africans to the Intended's acceptance of Marlow's lie about Kurtz. Heart of Darkness is an oftentimes disturbing book because Conrad's suggestion that all of these "rivets" are simply lies — ideas, beliefs and assumptions used to excuse shameless profiteering (as with the Company) or sustain a false image of a loved one (as with the Intended). Only Marlow and Kurtz see that these metaphorical "rivets" are faulty: Marlow when he witnesses firsthand the atrocities perpetuated by the Company and Kurtz when he whispers, "The horror! The horror!" on his deathbed. Marlow's naïve belief that the Company was run only for profit and Kurtz's belief that he could escape his own "civilized" morality are both shown to be "rivets" that simply could not hold.
The final symbol found in Part 1 is the Eldorado Exploring Expedition, run by the Manager's uncle. This fictional expedition is based on an actual one: The Katanga Expedition (1890–1892). The fact that the Manager's uncle leads the expedition suggests that it is another example of White traders scrambling for riches in the Congo. Marlow dismisses them as "buccaneers" who do not even make a pretense of coming to Africa for anything other than treasure.
