John Dalton’s puzzles: from meteorology to chemistry

Historical research on John Dalton has been dominated by an attempt to reconstruct the origins of his so-called “chemical atomic theory”. I show that Dalton’s theory is difficult to define in any concise manner, and that there has been no consensus as to its unique content among his contemporaries, later chemists, and modern historians. I propose an approach which, instead of attempting to work backward from Dalton’s theory, works forward, by identifying the research questions that Dalton posed to himself and attempting to understand how his hypotheses served as answers to these questions. I describe Dalton’s scientific work as an evolving set of puzzles about natural phenomena. I show how an early interest in meteorology led Dalton to see the constitution of the atmosphere as a puzzle. In working on this great puzzle, he gradually turned his interest to specifically chemical questions. In the end, the web of puzzles that he worked on required him to create his own novel philosophy of chemistry for which he is known today.