>"Calcination refers to heating a solid to high temperatures in absence of air or oxygen, generally for the purpose of removing impurities or volatile substance

>"Calcination refers to heating a solid to high temperatures in absence of air or oxygen, generally for the purpose of removing impurities or volatile substances.[1]" [...] >"In alchemy, calcination was believed to be one of the 12 vital processes required for the transformation of a substance." [...] >"In some cases, calcination of a metal results in oxidation of the metal to produce a metal oxide. In the seventeenth century, Jean Rey noted that lead and tin when calcinated gained weight , presumably as they were being oxidized." PDS: Ah, but... Were lead and tin in fact being oxidized -- as Calcination refers to "heating a solid to high temperatures in absence of air or oxygen" ? (The Wikipedia editor's presumption of oxidation -- contradicts the definition of Calcination!) Or did they gain weight anomalously, without air or oxygen present? ? You see, this would be a great future research project... The smaller, less important thing that we are looking for -- is if lead or tin actually gained weight when heated in a vacuum... The larger, more important thing that we are looking for is: are there any anomalies that are known in Chemistry, that is, where the actual results of a chemical reaction or reactions -- differ from what's expected? In Chemistry (as well as any other science or system of logic!) -- always search for the proverbial "Minority Report"... Then do your own testing, and see if it's true... Then if it is, try to figure out WHY...