In 1821 and 1822, the ball and cross that crowned the dome of St. Paul’s Cathedral were slated for replacement, and a scaffolding was erected around its summit. In this moment, the entrepreneurial surveyor Thomas Hornor spotted an opportunity. Installing himself on the scaffolding during the summer of 1821, he executed a series of sketches with the aim of publishing a series of panoramic engravings of London. A more significant vantage point from which to view the city could hardly be imagined: St. Paul’s was the very fulcrum around which London’s landscape unfolded. Yet, the cover of Hornor’s Prospectus for the set of engravings shows not the view from above but the silhouetted form of St. Paul’s dome and cross, above which floats an orb of light materialized by the reserve of the paper. Radiating from this orb, streaks of light penetrate and dispel the gloom of London’s atmosphere, inscribed as if by wiping accumulated soot from the page. The view “from above,” in this instance, is predicated on contending with air itself—a medium of vision that, in early nineteenth-century London, was an agent of obscurity rather than of transparence.