Vocabulary in The Chambered Nautilus

The description of “purpled wings” flung “on the sweet summer wind” is likely an elaboration on the nautilus-as-ship metaphor, presenting the tentacles of the nautilus as the sails driving the ship forward. Complicating the metaphor is the implicit, nested connection between sails and wings. This metaphorical vision of nautilus-as-ship runs deep into the scientific record of the animal—so deep, in fact, that the selected name, “nautilus,” was drawn from the Greek word for “sailor”: nautílos. Evidently, Holmes was not the first to consider the nautilus in nautical terms. The shell is the ship, the mollusc itself the sailor.

A “bark” is a small ship. The word has become antiquated, though it emerges from the same root as “barge”—the Latin barca. In most modern usage, “bark” is employed to provide a touch of poetic flair.

In this case, the noun “main” refers to the sea. This definition of “main” is a truncation of “the main sea,” meaning “the powerful sea.” To call the sea “unshadowed” is a tonal flourish, intended to evoke the fanciful vision of the sea that prevails over the course of the poem. In reality, the chambered nautilus is a frequent denizen of the marine layer known as the dysphotic—or “twilight”—zone, ranging down to depths of 1,000 feet where sunlight barely penetrates.