J. M. W. Turner captured the Romantic sublime in watercolors, oils, and prints, his visions of elemental power—sky, wind, water—pushing toward abstraction and modernity. “Light is therefore color,” he once said. He also declared, enigmatically, “The Sun is God.” Meanwhile, John Constable, whose life was marked by loss, became known for his turbulent landscapes. “The sky is the source of light in Nature,” he observed, “and it governs everything.” Now, these contemporaries—born just 14 months apart—are shown side by side to mark the 250th anniversary of their births. —Elena Clavarino