Dalton's disputed nitric oxide experiments and the origins of his atomic theory.
In 1808 John Dalton published his first general account of chemical atomic theory, a cornerstone of modern chemistry. The theory originated in his earlier studies of the properties of atmospheric gases. In 1803 Dalton discovered that oxygen combined with either one or two volumes of nitric oxide in closed vessels over water and this pioneering observation of integral multiple proportions provided important experimental evidence for his incipient atomic ideas. Previous attempts to reproduce Dalton's experiments have been unsuccessful and some commentators have concluded the results were fraudulent. We report a successful reconstruction of Dalton's experiments and provide an analysis exonerating him of any scientific misconduct. But we conclude that Dalton, already thinking atomistically, adjusted experimental conditions to obtain the integral combining proportions.
Usselman
Melvyn C
MC
Department of Chemistry, University of Western Ontario, London ON N6A 5B7, Canada. usselman@uwo.ca
Leaist
Derek G
DG
Watson
Katherine D
KD
D002627:Chemistry, Physical / Q000266:history*; D049672:History, 19th Century; D008956:Models, Chemical; D009569:Nitric Oxide / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry*
D014867:Water; D009569:Nitric Oxide; D010100:Oxygen