The Kabala, or Kabbala, is the body of mysticism growing out of the traditional Judaic interpretation of the Scriptures. Alchemy, which is based upon the same type of ideas, represents the physical side of this mystic philosophy, or so, at least, it was assumed to be by Swift. The opus magnum , in the next line, is the mighty experiment to which all the Alchemists' aims were directed. See p. 179, 1. 24.