Paper short abstract:

This paper will discuss representation in nineteenth century chemistry, focusing on John Dalton (1766-1844) and his work on the atomic theory. It will also briefly explore the tools and models used by some of his contemporaries in demonstrating molecular structure.

Paper long abstract:

In this paper I will highlight the use of representation in nineteenth century chemistry. The focus of the paper will be the visual and kinesthetic nature of John Dalton's chemistry, although I will also identify the tools and models used by some of his contemporaries.

In discussing representation in Dalton's work, I will examine the individual symbols presented in A New System of Chemical Philosophy (1808-1827) and attempt to categorise them according to design. I will then identify the two-dimensional representations of compounds Dalton drew using his individual symbols. In creating these compounds he assumed the simplest possible formulae, e.g. water as a binary compound, OH, rather than, as we now know, H2O. I will examine the ways in which he manipulated the symbols, looking at his spatial arrangements. I will include illustrations of the individual and compound symbols from Dalton's published work and pedagogic aids, such as handbills and posters. Looking at Dalton's three-dimensional teaching models will form the second part of my talk and I will include photographs of his actual models and my own recreations. I will show that visual thinking was apparent in his chemical work and teaching, through the media of his symbols and models.

Final conclusions will demonstrate that Dalton's wooden balls were not unique, but were the forerunners to the atomic models seen in the chemistry classrooms of today.