London 1600-1800: communities of natural knowledge and artificial practice.

This essay introduces a special issue of the BJHS on communities of natural knowledge and artificial practice in seventeenth- and eighteenth-century London. In seeking to understand the rise of a learned and technical culture within a growing and changing city, our approach has been inclusive in terms of the activities, people and places we consider worth exploring but shaped by a sense of the importance of collective activity, training, storage of information and identity. London's knowledge culture was formed by the public, pragmatic and commercial spaces of the city rather than by the academy or the court. In this introduction, we outline the types of group and institution within our view and acknowledge the many locations that might be explored further. Above all, we introduce a particular vision of London's potential as a city of knowledge and practice, arising from its commercial and mercantile activity and fostered within its range of corporations, institutions and associations. This was recognized and promoted by contemporary authors, including natural and experimental philosophers, practical mathematicians, artisans and others, who sought to establish a place for and recognition of their individual and collective skills and knowledge within the metropolis.

Mathematicians on board: introducing lunar distances to life at sea.

Nevil Maskelyne, the Cambridge-trained mathematician and later Astronomer Royal, was appointed by the Royal Society to observe the 1761 transit of Venus from the Atlantic island of St Helena, assisted by the mathematical practitioner Robert Waddington. Both had experience of measurement and computation within astronomy and they decided to put their outward and return voyages to a further use by trying out the method of finding longitude at sea by lunar distances. The manuscript and printed records they generated in this activity are complemented by the traditional logs and journals kept by the ships' officers. Together these records show how the mathematicians came to engage with the navigational practices that were already part of shipboard routine and how their experience affected the development of the methods that Maskelyne and Waddington would separately promote on their return. The expedition to St Helena, in particular the part played by Maskelyne, has long been regarded as pivotal to the introduction of the lunar method to British seamen and to the establishment of the Nautical Almanac. This study enriches our understanding of the episode by pointing to the significant role played by the established navigational competence among officers of the East India Company.

Early modern mathematical instruments.

In considering the appropriate use of the terms "science" and "scientific instrument," tracing the history of "mathematical instruments" in the early modern period is offered as an illuminating alternative to the historian's natural instinct to follow the guiding lights of originality and innovation, even if the trail transgresses contemporary boundaries. The mathematical instrument was a well-defined category, shared across the academic, artisanal, and commercial aspects of instrumentation, and its narrative from the sixteenth to the eighteenth century was largely independent from other classes of device, in a period when a "scientific" instrument was unheard of.