本文將討論英國小說家康拉德在《黑暗之心》裡，如何運用河流的隱喻來表現出十九世紀末歐洲帝國主義興盛下，英國式帝國主義與比利時國王轄下進行殖民的非洲剛果自由邦在帝國殖民治理與文化等面向上的差異。藉由隱喻與敘事話語研究，本文將分析兩位敘事者對英國與剛果自由邦裡兩條河流的地景、生物與棲息該區域人群的活動等視覺印象的描述，檢視康拉德賦予英國帝國主義發達的榮光，與主要敘事者馬羅的西方種族與文明優越論和他漸次發展出的話語矛盾，並探討馬羅在批判比利時國王以暴力掠奪方式治理非洲剛果自由邦的同時，如何經由他的溯河救援行動經驗，賦予該流域在人文與地理景觀之外，一種看不見的、相當幽微的、彷彿是要阻擋與報復外來西方勢力的神秘肅靜力量。

This paper studies how Joseph Conrad uses the two rivers-the Thames, England and the Kassai, Congo-as two metaphors to signify the differences between the redeeming, humanitarian administrative methods asserted by the British colonial imperialism and the cruel invasion and looting in the Congo Free State privatized by Leopold II, King of the Belgians in the late nineteenth century in Heart of Darkness. The conflicts brought forth by the juxtaposition of the narratives of the two narrators about the rivers and their surroundings and the contradictory discourses derived partly from Marlow's delineation of the African natives based upon his European racial superiority and partly from his comments on the natives serving on the steamboat under his supervision will be discussed to see how the existence of mysterious stillness-which forms an invisible culture of heterogeneity in the Kassai valley-might be viewed as a vague and uncertain power of resistance implied by the metaphor of the Kassai, while Marlow, in his upper river journey, could dimly feel an implacable force ＂with a vengeful aspect＂ watching the intruding Europeans coming from the river in ＂Heart of Darkness＂.