Alongside his theology, Newton conducted decades of serious, sustained alchemical experimentation, filling notebooks with recipes, observations and coded terminology drawn from the older alchemical tradition, work he treated with the same rigor and secrecy he applied to his mathematics and optics rather than as a separate, lesser pursuit. This body of work remained almost entirely unknown to the public until a large collection of his private papers was sold at auction in 1936; the economist John Maynard Keynes, who purchased a substantial portion of the alchemical manuscripts, famously remarked afterward that Newton was not the first of the age of reason but the last of the magicians, a judgment later historians of science, including Betty Jo Teeter Dobbs in her detailed study of the alchemical papers, have treated as a serious and largely accurate assessment rather than mere rhetoric.
Newton also devoted substantial effort late in life to biblical chronology and prophecy, publishing after his death The Chronology of Ancient Kingdoms Amended and Observations upon the Prophecies of Daniel, and the Apocalypse of St. John, works attempting to date ancient events precisely from scriptural and astronomical evidence and to interpret apocalyptic prophecy through the same careful, evidence based method he applied to physics. The atlas records alchemy, prophecy interpretation and anti-trinitarian theology together as genuine, extensively documented strands of Newton's intellectual life, not as embarrassing footnotes to his scientific achievement.