As the nautilus, a “ship of pearl […] / [s]ails” (Lines 1-2), it travels “gulfs enchanted” (Line 5). These waters are beautiful—but also potentially dangerous. Populated by mythic sea-people, traditionally ruled by the god Triton, the sea is also where a “Siren sings” (Line 5). In Greco-Roman mythology, the siren is a figure who is part human and part fish. Eventually, sirens became synonymous with sinister mermaids, or as Holmes’s speaker notes, “cold sea-maids” (Line 7). Sirens were said to lure sailors to their deaths with an irresistible song. They are featured prominently in the story of Jason and the Argonauts and in Homer’s The Odyssey. Here, Holmes’s speaker shows the symbolic ship of the nautilus is “wrecked” (Line 9) against the “coral reefs” (Line 6). Holmes uses the myth of the Siren to show one should not be guided by a seductive earthly song, but the “clearer note” (Line 25) of spiritual progress.

Holmes deliberately uses references to churchly architecture to emphasize that one’s interior life should be crafted like a holy site, much as the nautilus crafts each chamber of its shell. Each phase of life is as sacred as the next. The chambers are described as having “irised ceiling[s]” (Line 14) and the largest chamber comprises a “vast” space (Line 33) in the shape of a “dome” (Line 33).