John Dalton's "Aha" Moment: the Origin of the Chemical Atomic Theory
My new paper on John Dalton’s laboratory notebook entries concludes he developed the atomic theory in 1803 to reconcile Cavendish’s and Lavoisier’s analytical data on the composition of nitric acid, not to explain the solubility of gases in water. Dalton's concept of atomic size dates back to 1801, when he visualized "spheres of influence" filled with material caloric. He used this idea to explain volumetric combining proportions, allowing him to assign molecular formulas according to his rules of greatest simplicity.
