Published texts, unpublished documents and, to a lesser extent, artefacts are the stuff from which historians of science fashion their interpretations of the past. From these residues we attempt to reconstruct the lost fabric of personalities, activities and institutions that constituted the practice of science, and to comprehend the flow of thought that was its substance. Like the sensory data of the empirical sciences, these raw materials are not pure chunks of reality. They must be interpreted in the light of contemporary discourse and practice of which they were part. Over time, and in the hands of different commentators they acquire new significance, sometimes of mythic proportions; moreover, they are inevitably viewed in the light of present suppositions and fashions, both scientific and historiographical.

‘Hitherto want of accuracy and definiteness have often been brought as a charge against geology, and sometimes only with too much justice’, wrote Archibald Geikie in a review of Sir Roderick Murchison's Siluria (1867). ‘We seem now to be entering, however, upon a new era, when there will be infused into geological methods and speculation, some of the precision of the exact sciences’. Geikie's judgement echoed an appeal made some thirty years earlier by William Hopkins (1793–1866) that the science of geology needed to be ‘elevated’ from a level of ‘indeterminate generalities’ to a rank among the stricter physical sciences. This paper aims to analyse, in the context of broader trends favouring measurement and mathematics in British scientific practice, Hopkins' role in the promotion of dynamical geology as a major new complement to stratigraphical geology such that, for example, in the first edition of Geikie's Textbook of Geology (1882) the dynamical and stratigraphical components each filled 376 pages.

The Century between the death of Copernicus (1543) and the birth of Newton (1642) witnessed a major reshaping of traditional ways of viewing the universe. The Ptolemaic system was challenged by Copernican heliocentrism, the Aristotelian world was assailed by Galilean physics and revived atomism, and theology was troubled by the progressive distancing of God from the daily operation of His creation. Besides earning this era the title of ‘the Scientific Revolution’, the intellectual ferment of these times offered many world systems as successors to the throne of crumbling Aristotelianism.

William Hampson, classics graduate and barrister, burst into science with his patent for air-liquefaction in 1895. Its success provided the means of isolating the rarer permanent atmospheric gases, and it formed the basis for multi-tonnage gas liquefaction. The British Oxygen Company acquired Hampson's patent interests.