The history of chemistry includes the development of quantitative methods for identifying substances and explaining chemical change. A decisive experimental advance was accounting for gases as material participants: a solid can gain mass during heating while the corresponding enclosed gas loses material to it.
Work on different kinds of air, combustion, and chemical composition helped replace a single undifferentiated view of air with experimentally distinguishable gases. Lavoisier's account of mercury and air records a closed-system interpretation in which only part of the air is consumed, connecting chemical explanation to measured material balance.[ref]
Elements of Chemistry by Antoine Lavoisier. Part I, Chapters III–V, mercury-air experiment and oxygen interpretation
A historical account in which burning and related processes involved the release or transfer of a supposed principle, phlogiston. Its interpretation of metallic calces differed from the later account of oxidation.
The Chemical Revolution was the late-eighteenth-century transformation associated with new explanations of combustion, chemical composition, and nomenclature. Oxygen-based accounts and careful mass measurements displaced many uses of the earlier phlogiston framework.
In Lavoisier's mercury-air experiment, heating mercury in communication with a confined quantity of air formed a red solid while reducing the gas volume; decomposing that solid recovered a gas with distinctive combustion-supporting behavior. This connected a reversible chemical transformation with the composition of air, rather than treating a mass gain as a property of heat alone.[ref]
