Is there a reason to expect that someone who wanted to investigate the laws of the composition and reactivity of matter, in the late 1600s/early 1700s, would end up studying chemistry rather than alchemy? Sure, Boyle had introduced “chemistry” as an idea in 1661 (before Newton was born), but I imagine that alchemy would still be quite active in the late 1600s as an academic “field”, with many contributors already late in their careers studying it; whereas chemistry would have been just getting off the ground, without many potential collaborators.

Your point has been brought up before -usually as an attempt by established institutions to whitewash and explain away Newton's idiosyncrasies- but there is no evidence whatsoever to back it. On the contrary, what we know (and there is a lot we do know thanks to his writings) about Newton and alchemy absolutely indicates him being immersed in the Hermetic worldview and alchemical paradigm. Clearly, Newton was practicing alchemy not as a way to look for novel techniques or as a way to bridge the old and new worlds together, but primarily because he was a devout believer.

Newton -a profound genius- stood at the threshold of two worlds colliding. He was also a groundbreaking scientist in optics/mechanics/mathematics. He was aware of Boyle's chemical research. Knowing all of that, he _absolutely_ chose to dedicate his life to alchemy. That is immensely interesting.

"Much of Newton's writing on alchemy may have been lost in a fire in his laboratory, so the true extent of his work in this area may have been larger than is currently known. Newton also suffered a nervous breakdown during his period of alchemical work, possibly due to some form of chemical poisoning (perhaps from mercury, lead, or some other substance)."

https://en.wikipedia.org/wiki/Isaac_Newton%27s_occult_studie...