This volume centres on a clock, known as Clock B, built in the mid-1970s that achieved considerable acclaim after an extraordinary performance in a 2015 peer-reviewed public trial at the Royal Observatory, Greenwich. The clock was built according to an understanding of John Harrison’s unique theoretical approach to making precision pendulum clocks, which defies the standard approaches to making accurate clocks. The clock represents the culmination of over forty years of collaborative research into Harrison’s writing on the subject, which is scattered across a number of manuscripts and a book, printed shortly before his death. Ostensibly, Harrison set out to describe how to make his precision pendulum clock, but it is a mixture of his peripheral interests. Horological information is almost completely lost among vitriolic sentiments relating to his experiences with the Board of Longitude. However, as one reviewer surmised: ‘we are sorry to say that the public will be disappointed’ and another concluded that ‘it can only be excused by superannuated dotage’. The chapters provides contextual history and documentation of the analysis and decoding of the cryptic written descriptions. It presents this in parallel to the modern horological story of making, finishing, and adjusting Clock B; the process of testing, using electronic equipment to monitor the its performance and reaction to changes in environmental conditions, and, indeed, the mechanics behind the various compensating features of the design.
