323. HIS MAGICK BOOKES AND ARTES. Monks engaged in scientific investigation, such as Friar Roger Bacon, were popularly supposed to use cabalistic books, and to make compacts with the Devil by means of necromancy, or the black art, as in st. xxxvii. Before the close of the century Marlowe's _Doctor Faustus_ and Greene's _Friar Bacon and Friar Bungay_, both based on the popular belief in magic, were presented on the London stage.