What is "sky-walk"

Sky-Walk (alternatively Sky Walk, Skywalk, etc.) is the first completed novel by Charles Brockden Brown. It was started in 1797 and completed by March 1798, when an “Excerpt” was published in The Weekly Magazine of Original Essays, Fugitive Pieces, and Interesting Intelligence. The novel was subsequently lost, though Brown’s later novel Edgar Huntly takes up the same themes as Sky-Walk, most notably, that of sleepwalking. Like Brown’s other novels, Sky-Walk is an example of the American Gothic novel.