In Joseph Conrad's "Heart of Darkness," the imagery of the sea and sky being "welded together without a joint" evokes a profound sense of unity and the vast, unbroken expanse of nature. This description illustrates the seamless connection between elements of the natural world, representing an all-encompassing environment that amplifies the themes of exploration and the unknown. Such harmonious imagery sets the stage for the unfolding journey into the depths of both the physical and psychological realms.

This phrase encapsulates the overwhelming experience of the protagonist as he embarks on his voyage. The blending of sea and sky hints at the ambiguity of his quest, where boundaries blur and distinctions fade, symbolizing the intertwining of civilization and savagery. In "Heart of Darkness," this imagery not only highlights the external landscape but also reflects the internal struggles faced by characters as they confront their own darkness amidst the sublime beauty of the world around them.