Nehemiah Grew (1641–1712) and the Saline Chymistry of Plants

Abstract

In a series of lectures appended to his magisterial Anatomy of Plants (1682), Nehemiah Grew (1641–1712) explained the results of his own research into the saline chemistry of plants, following an established tradition in early modern chemistry. Members of the Royal Society such as Daniel Coxe were heavily involved in researching salt chemistry in the latter part of the seventeenth century, analysing the role of salts in spa waters, physiology, and as a fundamental element in iatrochemistry. Such researches of Royal Society members were often based upon the chemistry of Johann Van Helmont (1577–1634). As this paper will demonstrate, Grew's work drew from his microscopic research to elaborate and question some of Coxe's and hence Van Helmont's ideas about the principles of matter. Grew also used the results of his chemical research to draw conclusions about plant structure and colour, and applied his results to other areas in natural history such as meteorology, illustrating that chemistry was the basic analytical tool for seventeenth-century investigators of anatomy and natural history.     

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.     

Essay Reviews

Abstract

Liebig's 1831 paper that describes a new apparatus for the analysis of organic compounds and the results of several analyses using the apparatus is a justly famous contribution to the evolution of modern chemistry. In this paper, I look at the three separate components of Liebig's combustion apparatus that collect the water, carbon dioxide and nitrogen released by the combustion of six alkaloids. Gravimetric data included in the paper reveal that very accurate results could be obtained for water by absorption in a calcium chloride tube, and even better results for carbon dioxide resulted from use of the Kaliapparat. Volumetric measurement of nitrogen gave very poor results despite Liebig's efforts to improve it. Inaccuracies in nitrogen measurement made consistent construction of accurate molecular formulae for nitrogenous substances impossible, and only fortuitous decisions intended to bring molecular formulae into agreement with measured combining weights gave formulae in agreement with modern ones, as in the case for quinine.