Neal Stephenson: Yeah. It started to come out in the twentieth century that Newton had devoted more of his time and energy to alchemy during his career than he had devoted to mathematical physics. That's a fact that is obvious enough if you look at his papers: he made no particular effort to conceal this. But it was sort of suppressed a little bit during the Enlightenment and Victorian era, when people didn't know what to make of it. They wanted to view Newton as this paragon of the scientific method, and it was difficult to fit alchemy into that structure.