ABSTRACT
We have seen that Walker’s chemical conception of minerals was shared by Edinburgh’s literati as well as those who taught or studied in the medical school. The emphasis that such an environment placed upon material manipulation, combined with Walker’s own interest in systematics had a profound effect upon the way in which he approached the subject of geology. It is therefore the purpose of this chapter to explain the extent to which the logic of his chemical and mineralogical practices shaped how he understood the earth’s larger structure and composition. Throughout the chapter I emphasise that his geology was a product of his mineralogy and not vice versa. Since his geology blended the data of systematics with the evidence of civil history, the first section of this chapter unpacks several philosophical assumptions that guided his approach to the subject. In particular, I argue that his interest in classifying natural objects led him to be extremely suspicious of what he perceived to be unverifiable cosmological theories. As a consequence, long periods of terrestrial time were simply not a suitable topic for responsible scientific discussion. In pursuing this topic, my work falls in line with a number of recent works that aver, in the words of Martin Rudwick, that eighteenth-century mineralogy formed the ‘core and foundation of the science of the earth.’2 The second section then explains how Walker obtained his geological data from chemical, physical and historical ‘monuments’. Here I address how
L. Davies, The Earth in Decay (London: 1969); David R. Oldroyd, Sciences of the Earth (Aldershot: 1998); Rachel Laudan, From Mineralogy to Geology (Chicago: 1987). Related points are also made in Norma E. Emerton, The Scientific Reinterpretation of Form (Ithaca:
chemistry played an important role in the investigation of such monuments and how it allowed him to suspend certain types of temporal questions, especially those regarding the age of ‘primitive’ strata. I end by detailing how his emphasis upon physical and historical monuments encouraged a chronological approach to the earth’s age.
