Constructing the ‘automatic’ Greenwich timesystem

In the context of the telegraphic distribution of Greenwich time, while the early experiments, the roles of successive Astronomers Royal in its expansion, and its impacts on the standardization of time in Victorian Britain have all been evaluated, the attempts of George Biddell Airy and his collaborators in constructing the Royal Observatory’s time signals as the authoritative source of standard time have been underexplored within the existing historical literature. This paper focuses on the wide-ranging activities of Airy, his assistant astronomers, telegraph engineers, clockmakers and others, which served to increase the reliability of the Royal Observatory’s time service between the 1850s and 1880s. Airy and his collaborators aimed to mechanize and automate their telegraphic time distribution system in order to improve its accuracy and reliability. The accomplishment of such technological innovations was disseminated via public lectures, journal articles and correspondence with experts, secondary distributors of standard time and the general public. These communications were used to build public trust in the Greenwich time service. The unexplored archival material used in the present paper provides fresh insight into the unstable nature of the Greenwich time system, including its clear limits in terms of its scale of automation and degree of accuracy.

In considering the Greenwich time service as the crucial driving force of change in the late nineteenth-century British temporal regime, it is interesting to see how Airy and his collaborators struggled to foment wide acceptance of the time signal as the most reliable source of time. The time system was not straightforwardly and widely adopted at the outset, but it was increasingly promoted through technological innovation, maintenance, public communications and the use of the Astronomer Royal’s authority. Airy’s factory mentality with regard to mechanization and automation extended to the works related to time measurement and public timekeeping, which can be seen as the most fundamental underlying driving principle. The aim of constructing an automatic time distribution system was to determine, adjust and transmit time without human intervention to the maximum extent in order to increase its accuracy and reliability. In addition, it also had a crucial effect on helping to distinguish the RO’s time from the time of other public clocks and time-signaling devices that either had no telegraphic connection with an astronomical observatory or required annual procedures.

Mechanization and automation not only were the main principles underlying technical innovations, but also were utilized to define the key features of the Greenwich time signal. Airy and his collaborators actively vouched for the social usefulness, credibility and accuracy of the time signal to garner the trust of experts and the general public. They used a wide range of media to disseminate knowledge regarding their timekeeping-related endeavors. In publications and lectures, Airy and his collaborators tended to avoid mentioning manual involvement, and instead placed the utmost emphasis on the accomplishment of mechanization and automation. From a broader viewpoint, these activities pertaining to technological innovations and public communications would, to a certain extent, result in the temporal hierarchy whereby the Greenwich time signal was the principal reference or authoritative source of standard time.

The users and secondary distributors of time were not passive recipients of the time signal and of knowledge related to it. Indeed, on a few occasions, these users attempted to strategically depend on the authority of the Astronomer Royal in building trust in their own time signalling machines. Moreover, some users reported scattered occurrences of errors and failures. Contrary to Airy’s ideal, however, in reality, the scale of automation and mechanization had clear limits. Monitoring, fault detection and maintenance by telegraph clerks, clockmakers and other engineers became massively important in order to continuously operate the time system. Without their monitoring and maintenance tasks, the Greenwich time system might have been much more unstable. Hence it is plain that Airy’s seemingly automatic time system needed to be complemented by manual operations and human observations on a regular basis.

Furthermore, discrepancies were some-times observed between the time signal and local time measurement, and on some occasions their causes could not be fully clarified. Yet, in most cases, the method used by Airy and his assistants to defend the accuracy of the time signal involved rejecting the validity of the user’s measurement of time. The fact that there was no definite techno-logical means to ultimately define which time was ‘correct’ might explain why they continuously relied on this simple logic. Without any detailed discussions or increasing doubts about these unstable features, the Greenwich time system continued to expand in use across the country and gradually became the principal standard of time among many other standard times in the late Victorian period.

Source: British Society for the History of Science

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