From alchemy to atoms

Robert Boyle: The Sceptical Chymist 1661 John Dalton: A New System of Chemical Philosophy 1808 1600 1700 1800 1637 René Descartes: Discours de la méthode 1789 Antoine Lavoisier: Traité Élémentaire de Chimie 1779 Joseph Proust: law of definite proportions

chemistry …a scientific art, by which one learns to dissolve bodies, and draw from them the different substances on their composition, and how to unite them again, and exalt them to a higher perfection. (Christopher Glaser, 1663, Traite de la chymie) … the art of resolving mixed, compound, or aggregate bodies into their principles; and of composing such bodies from those principles. (George Stahl, 1730, Philosophical Principles of Universal Chemistry)

Proposition I. It seems not absurd to conceive that at the first production of mixt bodies, the universal matter whereof they among other parts of the universe consisted, was actually divided into little particles of several sizes and shapes variously moved. Proposition II. Neither is it impossible that of these minute particles divers of the smallest and neighboring ones were here and there associated into minute masses or clusters, and did by their coalitions constitute great store of such little primary concretions or masses as were not easily dissipable into such particles as composed them. Proposition III. I shall not peremptorily deny, that from most such mixt bodies as partake either of animals or vegetable nature, there may by the help of the fire be actually obtained a determinate number (whether three, four, or five, or fewer or more) of substances, worthy of differing denominations. Proposition IV. It may likewise be granted, that those distinct substances, which concretes generally either afford or are made up of, may without very much inconvenience be called the elements or principles of them

Joseph Proust (1754-1826) Law of definite proportions „Proust had studied tin oxides and found that their masses were either 88.1% tin and 11.9% oxygen or 78.7% tin and 21.3% oxygen…”