Jack and Mark build an airship and head North, hoping to find a rare plant that grows only in Alaska. But a freak earthquake causes a chunk of the Earth, along with our protagonists, to fly into outer space.

Roy Rockwood was a house pseudonym used by the Stratemeyer Syndicate for boy's adventure books. The name is mostly well-remembered for the Bomba, the Jungle Boy (1926-1937) and Great Marvel series (1906- 1935). The Stratemeyer Syndicate was the producer of a number of series for children and adults including the Nancy Drew mysteries, the Hardy Boys, and others. The Stratemeyer Syndicate was the creation of Edward Stratemeyer, whose ambition was to be a writer la Horatio Alger. He succeeded in this ambition (eventually even writing eleven books under the pseudonym "Horatio Alger"), turning out inspirational, up-by-the-bootstraps tales. In Stratemeyer's view, it was not the promise of sex or violence that made such reading attractive to boys; it was the thrill of feeling "grown-up" and the desire for a series of stories, an "I want some more" syndrome. Works written under that name include: Five Thousand Miles Underground; or, The Mystery of the Centre of the Earth (1908), Jack North's Treasure Hunt (1907) and Lost on the Moon; or, In Quest of the Field of Diamonds (1911).