I just saw an ad for a Nova program called "Newton's Dark Secret", and had to google to find details. It turns out, startlingly, that Newton was secretly practising alchemy and trying to find the legendary "Philosopher's Stone", a kind of mythical catalyst that could transform one element into another. http://www.pbs.org/wgbh/nova/newton/alch-newman.html In his day there wasn't alot of separation between alchemy and chemistry. It would be nice to have found out he was trying to bring chemistry into the light of science as he did with motion and optics, but it seems he wasn't. He was, apparently, convinced there was something real about the ancient alchemical legends, and put alot of effort into trying to uncover how to transform one element to another. He left a great deal of writing on this subject, but it seems that no one who knows about it has wanted to bring it to anyone's attention. At the link they talk about the driving impulse behind all of this as being the desire to have control over Nature. It's hard to square his very brilliant insights of a purely realistic kind with his persuit of this sort of unrealistic pseudo-science. Newton of all people! It makes me wonder about the sense of reality of all scientists and physicists, and to what extent it can be erroded by their underlying motives.