Tracing Influence in Small Steps: Richard Kirwan's Quantified Affinity Theory

Abstract

This paper presents an attempt to negotiate the familiar historiographical difficulties of tracing influence in science without fear of accusations of whiggishness. Through a close reading of three papers presented to the Royal Society by Richard Kirwan in the early 1780s on specific gravity, proportions and affinity, it seeks to show that the search for the role of influence in the history of science need not be based on a present-centred value judgement of past science. Prevailing historiography tends to link Kirwan's work to notions of definite combining proportions, settling him firmly on the Proust side of the Berthollet–Proust debate and regarding his work as vaguely precursory to Dalton's atomic theory. My reading suggests, however, that these papers may well have had a surprising level of influence on Berthollet's Chemical Statics and should perhaps be viewed through a somewhat different historical lens. I hope to show that the tracing of historical influence can offer valuable insights to historians of science and that when influence is tracked in small steps only, and forwards rather than backwards, we can legitimately follow it without fear of present-centredness clouding our vision.