Original papers of Isaac Newton on his studies in alchemy have recently been rediscovered in the archives of the Royal Society in the process of recataloguing the collection. The papers had been lost since 1936, when they were sold at auction, and apparently not properly documented until now.
An example of his writing on the subject:
“It is therefore no wonder that – in their advice lay before us the rule of nature in obtaining the great secret both for medicine & transmutation. And if I may have the liberty of expression give me leave to assert as my opinion that it is effectual in all the three kingdoms & from every species may be produced when the modus is rightly understood: only mineralls produce minerals & sic de calmis. But the hidden secret modus is Clissus Paracelsi wch is nothing else but the separation of the principles thris purification & reunion in a fusible & penetrating fixity.”
Clear as mud!