I marvelled exactly how patination is both art and chemistry; regulated oxidation, acids

https://www.scribd.com/document/1042029003/The-Heritage-of-Hand-Fabricated-Metal-Customized-Leader-Boxes-Designed-to-Endure-a-Century-198695

I marvelled exactly how patination is both art and chemistry; controlled oxidation, acids, and waxes create living coatings that evolve with weather yet stay protectively secured.