• DOI:10.1086/348480
• Corpus ID: 144724805

The Origin of Dalton's Chemical Atomic Theory

@article{Nash1956TheOO,
  title={The Origin of Dalton's Chemical Atomic Theory},
  author={Leonard Kollender Nash},
  journal={Isis},
  year={1956},
  volume={47},
  pages={101 - 116}
}

• L. Nash
• Published 1 June 1956
• Geology
• Isis

M ANY explanations have been advanced as to how Dalton arrived at the chemical atomic theory.' None, including the one previously adopted by the present author,2 is completely satisfactory. Three major difficulties must be overcome. First, Dalton himself gave three mutually contradictory accounts of the origin of his theory none entirely consistent with information available elsewhere. Second, Dalton's papers bearing most importantly on the theory were not published in the Memoirs of the Manchester Literary and Philosophical Society until several years after they had been read before that body. As the Society's Secretary, Dalton was in a position to emend his work during the period between its presentation and its publication, and to bring it into conformity with his latest findings. He seems to have availed himself rather freely of that opportunity.3 Thus, an unequivocal account of the origin of the theory cannot be based solely on the sequence of ideas and data appearing in his publications. Finally, we cannot extract all the information we would like from Dalton's laboratory notebooks. His records are often fragmentary; some of the most important entries are not dated, and are difficult to date because their order is not purely chronological; and we have only an incomplete inventory of the contents of the notebooks, which were destroyed during the Second World War.4 Four major versions of the origin of the chemical atomic theory will now be examined, after which a new version will be proposed. The Thomson version. Thomas Thomson, the most effective publicist of the chemical atomic theory, visited Dalton at Manchester in August I804.5 Thomson reports Dalton asserted he had come upon the theory by pondering the significance of the instance of the law of multiple proportions presented by his analyses of methane and ethylene.6 But it is now generally agreed that this work on methane and ethylene was not performed until the summer of I804 -