Critical discussions of the bubbles that make fleeting but memorable appearances in several well-known Romantic-era poems—most notably, Samuel Taylor Coleridge’s “The Eolian Harp” (1796), Anna Letitia Barbauld’s “Washing-Day” (1797), and George Gordon, Lord Byron’s Don Juan (1818-1824)—tend to take the bubble’s properties and associations for granted. To do so is a mistake because the eighteenth century—the century of both Isaac Newton’s Opticks (1704) and the South Sea Bubble (1720)—redefines what bubbles mean. Inspired by the bubble’s redefined material and figural status, the three aforementioned poems articulate a poetics of the bubble that envisions aesthetic experience as a form of speculative play involving both illusion and disillusionment. By appropriating the bubble as a figure of aesthetic play, Barbauld, Coleridge, and Byron embrace a ludic imperative that is also at the heart of late seventeenth- and eighteenth-century natural philosophical experiments with soap-bubbles. In so doing they reveal how Romantic aesthetics is as much continuous with as it is self-consciously distinct from Enlightenment science.