Her beams bemocked the sultry main,
Like April hoarfrost spread;
But where the ship’s huge shadow lay,
The charmed water burnt alway
A still and awful red.

These lines come from Samuel Taylor Coleridge’s narrative poem "The Rime of the Ancient Mariner," first published in 1798 in Lyrical Ballads (with Wordsworth) and later revised. They occur during the Mariner’s ordeal after the killing of the albatross, when the ship is becalmed in oppressive heat and the natural world takes on uncanny, punitive qualities. Coleridge, a central figure of English Romanticism, uses this episode to intensify the poem’s atmosphere of supernatural dread and moral consequence, blending seafaring detail with visionary imagery as the crew suffers under a curse-like stagnation at sea.

The passage juxtaposes deceptive beauty with hidden horror. The moonlight “bemocks” the “sultry main,” its pale sheen compared to “April hoarfrost,” suggesting a cold, illusory freshness laid over oppressive heat. Yet beneath the ship’s “huge shadow” the sea appears to “burn” a “still and awful red,” an image that fuses calmness with menace. The effect is to make nature seem morally charged and estranged: ordinary light becomes taunting, and the ocean—usually a symbol of life and movement—turns into a stagnant, blood-tinged presence. Coleridge thus externalizes guilt and punishment into the environment, making the Mariner’s inner transgression visible in the world around him.