The Skylark of Space + Skylark Three

The Skylark of Space - Dick Seaton accidentally discovers a workable space drive in combining pure copper with a newly discovered element "X." Having failed to re-create the effect, Seaton realizes that the missing component is a field generated by DuQuesne's particle accelerator, his arch-enemy, and thereafter sets up a business with his millionaire friend, Martin Crane, to build a spaceship... Skylark Three - DuQuesne announces a long absence from Earth, to find another species more knowledgeable than the Osnomians allied with protagonist Richard Seaton. Shortly thereafter, DuQuesne and a henchman disappear from Earth...