Francis Home and Joseph Black: the Chemistry and Testing of Alkaline Salts in the Early Bleaching and Alkali Trade

This paper considers the analytical work of two chemists in Scotland during the second half of the 18 century. It examines their efforts to understand and determine the strength of alkaline salts at a time when quantitative analytical measurement was beginning to be made in a form recognizable by present day chemists. In this period atomic weights and chemical formulae, which we now regard as essential aids in analysis, had not come into being. There is therefore a temptation for present day chemists to regard the period as one in which quantitative chemical analysis seemed almost impossible. It will be shown however that the analytical methods and chemical thinking of Francis Home (1719-1813) and Joseph Black (1728-1799) were adequate for the needs of the early alkali trade and the use of these alkaline materials in bleaching.