When the Time-ball at Greenwich was first erected, it was, as you are aware, dropped by hand. The error of a clock placed near to the ball trigger having been previously ascertained, suppose it to have been 1s.4 fast, the assistant, a few seconds before 1h placed his thumb on the trigger, and counting the seconds of the clock, he, at 1s.4 after 1h clock time, discharged the ball by sharply pressing down the trigger. Now, on showing this to my friend Mr. Babbage, a man gifted with a greater far-seeing faculty than most people are aware of, he used to say to me, ‘Why do you not make the clock discharge the ball mechanically?’ And my answer always was, ‘Yes, but how am I to get the clock right’. The problem was, having a clock wrong by 1s.4, how is it quickly to be got right. And this was long a difficulty, and I spent a great deal of time in endeavouring to arrange some scheme to effect the desired object.
George Biddell Airy's speech at a public lecture for the British Horological Institute, 1865Footnote 1Introduction
In 1865, George Biddell Airy, the Astronomer Royal at the Royal Observatory Greenwich (hereafter RO), chaired a public lecture organized by the British Horological Institute. William Ellis, his assistant astronomer in charge of time-signalling matters, presented a paper to explain how the RO disseminated standard time through extensive networks of telegraph lines. At the end of the lecture Airy delivered a brief speech on his experience of innovating the telegraphed time distribution. The epigraph above, which was part of the speech, illustrates his fundamental principle underlying such innovations: mechanization. It also reveals that Airy's pursuit was partly inspired by Charles Babbage, who is known for having strived towards the mechanization of intellectual labour. This paper focuses on how Airy's attempts at mechanization and automation influenced the design of his time-signalling system and the wider implications of mechanization and automation on the justification of the Greenwich time service between the 1850s and 1870s.
The crucial features that characterized public timekeeping in the Victorian age were the adaptations of telegraphic time signalling, time balls, time guns and synchronized electric clocks. The most important of this newly emerged temporal regime was the RO's time service, which was being provided by Airy and his collaborators from the early 1850s. The scholarly literature on telegraphic time distribution has demonstrated the nature of the RO's early experiments, the roles of successive Astronomers Royal in its expansion, and its impacts on the standardization of time.Footnote 2 However, there is more to know, especially regarding the workings of the time service and how users and the general public came to rely upon it. Comparatively little is known about the ideas that inspired such technological innovations. While historians of science have generally agreed that a significant characteristic of the RO under Airy's superintendence was its transformation into a factory-like scientific institution, it is unclear how this ideal can be seen in the construction of the time-signalling project.Footnote 3 There has also been no detailed discussion of the ways in which Airy interacted with the users and the secondary suppliers of Greenwich time, nor his strategies on public communication regarding time signalling.
Notably, previously historians have tended to implicitly assume that the increase in temporal accuracy and the standardization of time faced no noticeable obstacles and was accomplished directly through technological improvements, in particular the reception of telegraphed time signals. However, the recent studies by Hannah Gay, David Rooney and James Nye have shown that telegraphic time distribution was unreliable even until the early twentieth century, owing to occasional failures and errors that occurred in its day-to-day running.Footnote 4 Moreover, the adaptation of the newly established synchronizing-clocks method devised by Airy did not advance smoothly from the outset. As Edward Gillin has indicated, Airy's plan to set up a series of electric clocks and use the RO's time signal at the Palace of Westminster met steady opposition from other horological experts in the late 1840s and the 1850s.Footnote 5 However, as this paper will establish, an increasing number of users and suppliers of standard time, as well as the general public, gradually depended on the Greenwich time service between the late 1850s and the 1870s. Therefore questions remain about how Airy and his collaborators promoted the Greenwich time system as the most authoritative source of standard time in the few decades following its launch.
A closer look at Airy's works on time measurement and public timekeeping reveals his struggles to maintain and justify the telegraphic distribution of Greenwich time. It focuses on how he and his collaborators pursued mechanization and automation as their primary objective to develop accuracy and reliability. The development of mechanization and automation had a marked effect on the relationship between time-service provider and users, as Airy and his collaborators tried to attach these technological features and meanings to the time signal and highlight its reliability through various media. Therefore, in addition to the technological innovations, this study will shed light on the approaches they employed in public communications and their interactions with users. Nevertheless, it is important to bear in mind that, although Airy and his collaborators were promoting their innovations, thereby allowing them to expand their adaptations of the time signal, the time system had clear technological limitations, especially its scale of automation and degree of accuracy. An investigation of these issues will demonstrate the ideal and actualities pertaining to the initial phase of the Greenwich time system.
The transformation of temporal infrastructure in Victorian Britain
Mid- to late nineteenth-century Britain witnessed a large-scale transformation of its temporal infrastructure. The advent of railways, electric telegraphs and steamships significantly fostered communication, transport and mobility, which resulted in a growing demand for accurate timekeeping.Footnote 6 Precise timekeeping was also instrumental in the world of large factories, where a stricter time regime was enforced in tandem with the division of labour and the increase in production.Footnote 7 While the local public clock would remain the most fundamental tool for knowing the time, the addition of time balls, time guns and public clocks connected with an astronomical observatory created a new dimension of time-telling plurality. Although the RO had already been used as the initial meridian in the Ordnance Survey maps and the British Nautical Almanac since the eighteenth century, the expansion of railway networks led to the adoption of Greenwich time across the country after the late 1840s.Footnote 8
During these shifts in temporal infrastructure in the Victorian age, Airy and his collaborators, in particular Charles Shepherd (clockmaker), Edwin and Latimer Clark (telegraph engineers at the Electric Telegraph Company, hereafter the ETC), Charles Walker (telegraph engineer at the South Eastern Railway) and assistant astronomers at the RO made a concerted effort to launch, maintain and expand the Greenwich time service from 1852. Specifically, at several predetermined times, such as at 10 a.m. and 1 p.m., an electric time current was sent from the RO to London and provincial cities via telegraph networks. By the middle of the 1870s, its signal reached around sixty different locations.Footnote 9 After the 1870s, more than six hundred local post offices were connected via telegraph lines with the General Post Office (GPO) in London, and consequently received the time signal.Footnote 10 By the late 1860s, many English railway companies, including the Great Northern, Great Western, London and South Western, Midland and North British railways, employed it to share a standard time on their respective lines.Footnote 11 Once the time signal was received at their principal stations, these railways further disseminated the time through rail conductors who would bring watches on board, or through electric telegraphs to synchronize the clocks located at each station.
The observatory time was also intended to contribute to seafaring communities. As Britain's commercial, maritime and imperial supremacy was highly dependent on overseas trade and naval power, precision timekeeping as an indispensable tool for speedy and safe navigation became increasingly important.Footnote 12 Throughout the century, it was increasingly common for ocean-going vessels to be equipped with the marine chronometer, which was used to determine the longitude at sea. Knowing the time accurately before departures was required to regulate the timepiece. Although the time ball was invented for this purpose and was first used in Portsmouth in 1829, until the early 1860s only five such time balls operating in connection with the Greenwich time current had been established. They were located at the RO, a naval yard in Deal, the ETC's branch offices in Liverpool and the Strand, and on the premises of French, a clockmaker in London.Footnote 13 This situation contrasts with that of the late 1890s, when nine time balls and nine time guns were maintained in the principal seaports. Among them, the devices at Sheerness, Deal, Portsmouth, Devonport, Southampton, Portland, Falmouth, Swansea, North Shields, Cork and Queenstown were using the RO's time signal.Footnote 14
After the nationalization of telegraph companies by the British government in 1870, the GPO, which took over all of the inland telegraph business, except the submarine telegraphs, began disseminating the time signal from the RO and launched a venture for providing standard time by setting prices for private lines. In provincial cities, for instance, to receive a time signal at ten o'clock, the annual rent was set as twelve pounds within a quarter-mile from a local post office, fourteen pounds within half a mile and seventeen pounds within a mile. This service allowed private individuals or companies that needed an accurate time to use the RO's signal. Such an enterprise of ‘commodifying standard time’ was also launched after the late 1870s by several private firms that relied on the time received from the GPO and further transmitted it to their own subscribers.Footnote 15 Among those projectors, the best-researched to date is the Standard Time Company (STC), which mechanically corrected a subscriber's domestic clock by sending an hourly electric current. Moreover, it is well known that Maria Belville and her daughter Ruth visited the RO each week to check their chronometer which was then used to deliver Greenwich time for their customers around London.Footnote 16 These commercial ventures attracted a growing number of subscribers, largely because they charged less expensive fees, and most of them, including the STC and the Belville family, relied on Greenwich time as the standard.Footnote 17
In brief, the temporal infrastructure was largely reorganized on a nationwide scale in the second half of the nineteenth century. To a greater extent, it was founded on the basis of the Greenwich time signal, since most railway transport, postal and telegraph communications, naval and merchant shipping, municipal corporations and private projectors in the time-telling business became increasingly reliant on time supplied by the RO. This led to the emergence of a pyramidal system of authority and trust in the standardization of time by the late nineteenth century; at the top of that pyramid lay the RO's time as the primary standard, and below it was the chain of standard times that other secondary distributors provided.Footnote 18 Although a few civic or university observatories, notably in Liverpool, Edinburgh and Glasgow, as well as commercial ventures that sold time, provided standard time (i.e. Greenwich Mean Time) for local or regional areas, only the RO disseminated time on a national scale.Footnote 19 However, this does not imply that its wider acceptance was straightforward or rapid. On the contrary, to maintain the public time service as reliably and accurately as possible, Airy and his collaborators had to face a wide range of obstacles and use various approaches to solve them.
The pursuit of automatic time signalling
While no drastic change occurred in the basic technological framework of time distribution by the RO in the nineteenth century, it did not remain entirely static. On the whole, Airy made relentless efforts to increase the efficiency of the RO and enhance public accountability.Footnote 20 To that end, he regularly upgraded the material basis of the astronomical sciences by designing and installing the latest instruments, such as the altazimuth (1847), transit circle (1850), reflex zenith tube (1851), chronograph (1854) and large visual refractor (1859).Footnote 21 One of Airy's primary purposes in this regard was to further mechanization in observing, recording and other practices to minimize human error and misconduct. As a central aspect of his introduction of a ‘factory mentality’ into the RO, this approach clearly encompassed innovations connected to time measurement and signalling. Indeed, a series of changes in the observatory techniques of astronomical time determination and dissemination of the time signal occurred at Airy's initiative.Footnote 22
First, the barrel chronograph was installed due to the collaboration of Airy and E.J. Dent for recording observations via the transit circle, which was used to determine time.Footnote 23 The chronographic method replaced the traditional ‘eye-and-ear’ method, whereby the observer listened to the beats of the transit clock and mentally counted the time when the image of the star crossing over the meridian would appear on the fixed wires in the telescope view. The new device, in contrast, meant the observer only needed to tap a key to mark the precise time of the transit of stars on paper covering a rotating drum in less than a tenth of a second.Footnote 24 This mechanical recording reduced the ‘personal equations’, differences of observing timing caused by variations in the observers’ reaction speeds. Edwin Dunkin, an assistant at the RO, claimed that the possible errors of transit observations using the chronograph were only a third to a half of those carried out by the eye-and-ear method.Footnote 25
The chronograph improved the precision of time measurement, as the results of those transit observations were used for correcting a small fraction of the errors in the RO's principal regulator, commissioned from Shepherd in 1852. Although the adjustment of time was initially conducted by the regulation of the clock's pendulum by hand, Airy found that setting the clock below one-tenth of a second using this method was highly demanding. As a result, in 1860, he devised a method based on the principle of synchronizing clocks invented by R.L. Jones, an engineer in Chester.Footnote 26 This invention involved attaching a magnet on the bottom of a clock's pendulum and placing a coil of wire just underneath the magnet. An observer who knew the amount of the clock's error sent a battery current to the coil to accelerate or slow the movement of the pendulum in order to adjust the time.Footnote 27 This method, according to Airy, considerably reduced the dependency on manual skills.
Shepherd's master clock was vital to Airy's time-signalling programme. It controlled other secondary clocks established at the RO, such as the ones in the rooms for chronometers and computing; automatically discharged the time ball on the observatory building; and sent the time signal to telegraph lines, for instance those of the ETC, which transmitted the time signal extensively among other companies, the Magnetic Telegraph Company and the London and District Telegraph Company by the 1860s. Furthermore, the clock became synchronized with other high-precision clocks, namely the ones at London Bridge and Ashford stations of the South Eastern Railway, which transferred the time signal to the company's other stations; a public clock at the British Horological Institute; and several clocks at the factory of Warren De La Rue, an entrepreneur and astronomer in London.Footnote 28
In 1864, Cromwell Varley, a leading telegraph engineer, installed a machine called the chronopher to mechanize the process of widely distributing time signals at the ETC's central telegraph station. This was clearly an important innovation because upon receipt of the time current from the RO, the device automatically produced the time signals in one-tenth of a second and passed them to relevant telegraph lines.Footnote 29 Ellis described the machine as ‘an elaborate system of switches and relays provided with an accurate clock for opening and closing the switches at the proper times, and forming together a complete automatic system’.Footnote 30 In 1873, after a further technical innovation was implemented in the machine, Airy conducted an experiment that involved sending an electric impulse from Shepherd's regulator to the chronopher, which was then automatically returned. At the RO, the return current was checked through two galvanometers placed adjacent to each other showing the outgoing current and returning current. Airy described the results based on his observation.
I have myself watched them in several instances. And the result is, that the delay is imperceptibly small. We have never seen any for which we could answer. We are habitually accustomed to estimate tenth-parts of a second of time, and I am certain that the delay is very far below 1/10 of a second of time.Footnote 31
Ellis also mentioned in his article that ‘there was no sensible difference in their indications. It follows, therefore, that entire confidence can be placed in the distribution by the chronopher’.Footnote 32 Thus, together with Shepherd's clocks, Airy and his collaborators viewed the chronopher as the fundamental basis of the accuracy and reliability of the time service.
Through telegraph networks, the Greenwich time signals were provided with time balls, time guns and public clocks established elsewhere across Britain. One of the earliest such examples was a time ball attached to the ETC's Strand branch in 1852. The company's objective was to advertise their commercial business by showcasing it as the latest technology.Footnote 33 Their employment of the Greenwich signal expanded with the establishment of a time ball at their Liverpool branch in 1853. Further, in 1855, due to Airy's initiative, a time ball in Deal in receipt of the RO time current began to be automatically operated. He proudly reported to Admiralty officials that ‘it is a beautiful specimen of engineers’ work, and is in all respects perfectly efficient’.Footnote 34 One more notable instance was the working of the time guns introduced in Newcastle and South Shields in 1863. The time current was sent from the chronopher to regulate the time of a clock in Newcastle, which then operated these guns.Footnote 35
At the early stage of its operation, the time service was maintained with no external means to judge whether an electric current was being correctly transmitted. Nor could the receivers ascertain this information, except by measuring time using their own clock or watch. This assurance problem came to the fore in 1853, when John Hartnup, the director of the Liverpool Observatory, questioned the accuracy of the time signal. He would use a chronometer to measure the drop of the ETC's time ball in Liverpool and published the error data in a local newspaper, which caused the machine to be out of service for several months.Footnote 36 To overcome this difficulty, Airy and Edwin and Latimer Clark devised a method called a return signal system: once a time signal arrived in Liverpool, the drop of the ball automatically caused an electric impulse to be sent to the central telegraph station in London, where clerks observed its accuracy.Footnote 37 In fact, the idea for using the transmission of an electric current to the RO for verifying accuracy had already been suggested by Airy when he first began working on the public-clocks project at the Palace of Westminster in 1846.Footnote 38
Airy wasted no time in expanding the use of a return current. When the GPO asked him to establish a network of office clocks to be synchronized with the master clock at the RO in 1855, he proposed that ‘one or several clocks must be regulated directly by the Greenwich current, and one or more must automatically send signals back to inform me at Greenwich how they are going’.Footnote 39 This scheme was accomplished by Shepherd, who installed the synchronized clocks at the GPO. Indeed, for the time ball in Deal and the tower clocks at the Palace of Westminster Airy relied on the return current to monitor them for fault detection. The daily observations of the return signals from these lines were recorded and used to identify any error or failure.Footnote 40 Using an operation system called the time desk established inside the RO by the early 1860s, assistant astronomers could not only observe a return current, but also control all of the steps necessary for the telegraphic distribution of time.Footnote 41
There are two notable reasons why Airy and his collaborators sought to construct a whole system composed of ‘automatically’ driven machines and devices to transmit electrified time. The first reason related to Airy's vision of mechanization. Airy was a keen admirer of the factory system and imposed its principle on the RO by promoting the mechanization and instrumentation of scientific practices, as well as by creating hierarchies and a rigid division of labour among its staff.Footnote 42 He shared this enthusiasm for using machines for intellectual work with a number of influential figures in contemporary British science, including Babbage and John F.W. Herschel.Footnote 43 Similar to Babbage's challenge of replacing the human manual task of making astronomical tables with a calculating engine, Airy regarded mechanization as instrumental to minimizing the vagaries of human conduct in time signalling. He initially displayed this stance in the early 1850s, during his first experiments with the time service.Footnote 44 As the test proceeded, Airy became increasingly more reliant on machines than on those who monitored how an electric current moved. Further, from a technical viewpoint, Airy and those engaged in constructing the time system believed that the transfer of a time signal would meet delay or even failure if human actions were involved. Since the dissemination of time signals evidently needed a large number of transmitting steps in the telegraph networks, with the aim of reducing human intervention, it is not surprising that they continued to foster the pursuit of mechanization and automation in all possible areas of time signalling.
This in turn illustrates another key point: as long as the effectiveness of the timekeeping and time-signalling system was thought to be critically contingent on removing human intervention, manually operated time signals and timekeeping devices would be distrusted for being less accurate and less reliable. When Airy noticed that a time ball was being dropped manually at the Portsmouth dock in 1878, for example, he strongly criticized what he saw as improper timekeeping. In this instance, two time balls were inside the dock area; one of them was established in an astronomical observatory where the time signal from the RO was observed, and the other was attached to a flag located at a different point that communicated time more widely. In reaction to the drop of the first ball, the second one would drop. Due to the unavoidable delay occurring between the former and the latter, the former was enacted 0.5 second earlier than standard time. Airy expressed his critical views about these procedures in a letter to the Secretary of the Admiralty:
The communication to the Public Time Signal is far from good. First, a man's hand drops a little ball; then another man's eye sees that drop and his hand drops a large ball. I hope that no foreign officer will see this. Not to mention Greenwich and Deal, those drops of balls at Edinburgh, and the gun fires at Hartlepool, Shields, Dundee, Kendal, Swansea, Edinburgh, Liverpool are greatly superior. I see no remedy for this except in the erection of a proper Time Ball or other signal, subject to galvanic action, and put in motion by post office current in the same manner as is the Time Ball at Deal by Greenwich-current, without the agency of human senses.Footnote 45
This statement illustrates Airy's perception that human agency was the principal cause of errors and failures in the function of the machinery and telegraphic time service. To avoid this, for Airy, there was no option but to construct a system of automatic transmission of time. Mechanization and automation introduced new means of differentiation among standard times.
Communicating the credibility of observatory time
The extension of the mechanization and automation of the time system affected how Airy and his collaborators interacted and communicated with users and the general public. Not only did they pursue technological innovations, but they also emphasized the accuracy and reliability of the time signal through official reports, public lectures, journal articles and other media.Footnote 46 On many occasions, Airy utilized his annual official report to communicate his own views, such as those relating to the division of labour in astronomical-observation programmes and the representation of the RO as a practically oriented scientific institution.Footnote 47 As an administrative document published as both a pamphlet and a part of Greenwich Observations, most of its contents reached the wider public, as abridged versions were published in scientific journals and popular magazines, notably the Literary Gazette, Athenaeum and the Monthly Notice of the Royal Astronomical Society.Footnote 48
Airy regularly discussed how the time system was used in society and maintained in an efficient condition. In the report of 1853, for example, he emphasized the accuracy and public benefit of the time service:
It [Shepherd's master clock] sends galvanic signals every day along all the principal railways diverging from London. It drops the Greenwich Ball and the Ball on the Offices of the Electric Telegraph Company in the Strand; and the correctness of the last of these operations is tested by means of a galvanic signal-needle upon the case of our transit-clock. All these various effects are produced without sensible error of time; and I cannot but feel a satisfaction in thinking that the Royal Observatory is thus quietly contributing to the punctuality of business through a large portion of this busy country.Footnote 49
The report of 1865 includes Airy's expectation and ambition of improving public timekeeping in Britain and its empire:
I can hardly doubt that there will soon be movements in London, as in other great cities of our Empire, for more perfect regulation of public clocks, and for other exhibitions of Time Signals. The business of the Royal Observatory, in reference to such proposals, will consist mainly in the transmission of currents accurately at every hour, or every minute, or every second, to definite offices in London; and to this I shall be prepared to give all the attention which it can require.Footnote 50
By giving the impression that the synchronization of clocks was in progress elsewhere, Airy not only promoted more extensive adaptations of the time service, but also demonstrated his responsibility, as the government astronomer, for sending accurate time, and his assurance that he would do so. His 1868 report also refers to reliability by noting that ‘the Motor-Clock [Shepherd's master clock], and the entire apparatus for maintaining the action of sympathetic clocks, regulating distant clocks, distributing time-signals through the country, dropping time-signal-balls, firing time-signal-guns, &c., are in a perfectly efficient state’.Footnote 51
By disseminating information about how widely the time service was applied in provincial cities, Airy stimulated a sense of competition regarding the adaptations of the time signal, time ball and time gun as public utilities. From the late 1850s to the end of the century, wide-ranging authorities in provincial cities established time balls and time guns, since the time service and these apparatuses came to be perceived as fundamental to improving the temporal infrastructure. This phenomenon can be seen as part of a broader growth of urban infrastructure and civic culture since the mid-century, through the mushrooming of public museums, libraries, art galleries and town halls, as well as clean water, gas systems and improved housing. This was largely because of the rise in material expressions of civic pride, and hence the notable role played, and the investment made, by various municipal authorities.Footnote 52
The public lecture given by Ellis in 1865, referred to in the introduction, was also a crucial opportunity to ascertain increased reliability of the time system. As the time service had been launched only a decade previously, it was imperative that its technical expertise be communicated to those involved in the business of the watch and clock trade. Ellis used some model instruments, provided by Varley, Airy and Shepherd, to demonstrate the working of the time system. Another notable fact is that Ellis began his talk by drawing attention to automation:
I may say at the outset that the whole of the system is automatic. The apparatus is itself distributed in various places but works together as one complete whole … Signals pass also to control clocks and correct clocks, and signals are received from corrected clocks, time balls also are discharged, and all by automatic means.Footnote 53
As we will see in the next section, although the correction of public clocks and the operations of time balls and time guns generally required manual operation, Ellis emphasized the creation of an ‘automatic’ time system. In his paper published in Nature in 1876, he again referred to the construction of an automatic transmission of Greenwich time.Footnote 54
Moreover, during the public lecture, Ellis and Airy drew attention to the fact that the RO was a state-sponsored scientific institution. By doing so, they implied that the reliability of the time signal was firmly guaranteed. Ellis maintained the following:
Greenwich Observatory supplies signals as required to those who, possessing the means of communicating with distant parts of the country, are willing to forward the work of distribution, and it is this joint action alone which maintains in existence a system by which the country almost unconsciously benefits, one which, having its origin in the National Observatory, has thereby sufficient guarantee for that which is fundamental.Footnote 55
After Ellis's talk, Airy also stated, ‘I have indeed always considered it a very proper duty of the National Observatory to promote by utilitarian aid the dissemination of a knowledge of accurate time which is now really a matter of very great importance’.Footnote 56 This declaration reflects Airy's self-consciousness as a scientific civil servant.Footnote 57 These claims played a role in distinguishing the RO time signal from many other time-signalling devices and public clocks that were superintended by other diverse institutions, time-selling projectors and private individuals.
Apart from these publications and lectures, Airy utilized the inquiries from potential users and others to vouch for the accuracy and reliability of the time signal. When Hugh Childers, MP and Secretary of the Treasury, requested information on the current condition of time signalling in 1866, Airy answered that the loss of time in the transfer of the time current from the RO throughout the country was less than ‘one-twentieth of a second of time’.Footnote 58 Another strong instance is an enquiry from Dublin in 1866, in which Airy was asked to provide information about the possibility of receiving the Greenwich time signal there. He responded, ‘I have to state that you may rely confidently on the time signal received from the Electric and International Telegraph as giving Greenwich Time correctly to one-tenth of a second of time, if the state of the sky has permitted observations to be made at Greenwich’.Footnote 59
Airy and his collaborators also attempted to guarantee the reliability of specific time-signalling devices. For instance, when the time ball at the ETC's Strand branch began its operations, Edwin Clark vouched for its trustworthiness in an article published in The Times: ‘The time ball already acts with the great precision … Absolute reliance may at all times be placed on the correctness of the signals whenever they are given’.Footnote 60 The time ball was particularly essential for Clark, as he planned to extend its technology and introduce it in principal towns in England. Contrary to Clark's remark, however, occasional failures arose, primarily attributable to the weakness of an electric current from the RO and the error of the time signal. In the early 1850s, electrically operating an apparatus placed at a distant location was highly demanding. In June 1853, a chronometer-maker in London complained to the ETC that the time ball at the Strand might be operating with two-minute delays.Footnote 61 Upon encountering these errors and complaints, Clark wrote to Robert Main, the chief assistant at the RO: ‘The public attribute the numerous failures to our incompetency’.Footnote 62 This situation placed Airy in a position where he had to defend the reliability of the time ball, as the importance of the Strand project was clear for Airy as well, given that the time service was beginning to gain social acceptance. Consequently, he created and circulated a printed ‘Notice to chronometer makers and to the public’:
The system of dropping the Time-Signal-Ball on the buildings of the Electric Telegraph Company, 448, Strand, by a galvanic current from the Royal Observatory, Greenwich, having, after the experience of several months, been found perfectly efficient (interrupted only by occasional repairs of the apparatus); Chronometer makers and others are informed that, when no extraordinary signal is exhibited, implicit reliance may be placed on the accuracy of the time given by the drop of the ball.Footnote 63
The notice was intended to add the Astronomer Royal's authority for ensuring the machine's trustworthiness.
From the viewpoint of the secondary distributors of standard time, such testimony of the Astronomer Royal was perceived as a powerful tool in generating public trust in their time-signaling devices. In March 1856, French, a chronometer-maker operating at Cornhill, in London, established a time ball based on the time signal transmitted from the ETC. To gain the public's reliance on the apparatus, French asked Airy to provide a certificate, similar to the one for the time ball at the Strand.Footnote 64 However, Airy declined the proposal on the grounds that the telegraph connection between the RO and French's time ball had not been directly established.Footnote 65 Thus Airy himself could not verify its accuracy, and instead he stated that the ETC should issue the certificate. Naturally, French became eager to form a direct connection ‘with the view of perfecting its utility to the public and of establishing their complete confidence in it’. He also wrote to Airy, ‘it appears to me that the public and more especially the other chronometer makers, whom it most concerns, would naturally place much more reliance upon a certificate from you’.Footnote 66 Although the request was made in the hope of using the weight of the Astronomer Royal's authority, Airy continued to decline because of his view that the ball was not accurate enough to do so.Footnote 67 He appears to have distanced French's time ball from the time balls and signals that he was directly responsible for.
Similar to French's case, Airy's authority was accepted by those involved in the time gun project in Newcastle. Immediately after the time gun began its operation, in 1864, Nathaniel Holmes, a projector of time-signalling ventures, claimed in a local paper that the time current was not in reality coming from the RO and that Airy was not concerned with this project. Holmes stated that since Airy had nothing to do with the time gun, the credibility of the machine was doubtful. To contradict these claims, James Mather, who had collaborated with Airy in the establishment of the time guns, provided a local paper with a detailed account of how the time current came from the RO and further stated, ‘it is thus clear that the time-guns of the Tyne are under the direct influence of the Greenwich Observatory; and this I may add, that no means will be spared by the proper authorities to render them accurate and perfect’.Footnote 68
To reinforce his argument, Mather asked Varley to supply a written note by Airy that declared that the time signal from the RO to Newcastle had been sanctioned.Footnote 69 Varley wrote to Airy requesting his testimony:
If you would also kindly favour either Mr. Mather or myself with a line stating that correct time currents are sent from Greenwich to this office and that those signals are re-transmitted automatically from this station to the gun and that the loss of time of such transmission which involved one relay at this station and another at Newcastle does not exceed but a small portion of a second it would be published in the paper and then let the Captains and others who visit Newcastle and the River Tyne know that the signals emanate from Greenwich and are reliable.Footnote 70
Varley admitted that Airy's statement would be effective to generate trustworthiness. In fact, in his official report of 1864, Airy had already referred to the establishment of the time gun. Therefore, as evidence indicating Airy's recognition, the information from this report was communicated to Varley and Mather.Footnote 71 Airy's report only notes the following: ‘time-signals are sent daily to great distances, [such] as Glasgow and Cardiff, and on the principal railways in various directions. Time-signal-guns are fired daily at Newcastle and Shields’.Footnote 72 This short passage was published in a local paper by Mather to put an end to the debate.Footnote 73
Thus Airy and his collaborators relied on various means to build public trust in the Greenwich time signal. Similar to newly invented technologies, such as the steamship, electric telegraphs and railways, the Greenwich time service needed to be made credible through public communications.Footnote 74 Information on the technological characteristics of the devices, experiments with them and current uses of time signals was provided to experts and the general public. In contrast to such widely propagated features and results, however, the occasional occurrences of errors and failures were rarely mentioned in these lectures, correspondences and publications. Airy attempted to assure the reliability of specific time devices by issuing a public certificate. His authority, based on his horological expertise and position as the government astronomer, clearly made him the appropriate provider of such certificates, as indicated by the cases of French and the time gun in Newcastle. The authority of the Astronomer Royal and the RO was not only used by Airy himself, but also, on occasion, utilized by the secondary distributors of time in order to increase the credibility of their devices. The dispute in Newcastle would also indicate that, in spite of their antipathy, both sides shared a common belief that a time-signalling device was more reliable if it was telegraphically connected with the RO. Simultaneously, this example illustrates that a device without any connection to the RO might be viewed as less reliable and less accurate, a view that was also constructed and circulated among users and the general public. While it cannot be easily concluded that these notions were created as a direct result of the public communications of Airy and his collaborators, it can be safely assumed that the spread of these beliefs was key to establishing the RO's time signal as the principal standard.
The limits of the ‘automatic’ distribution of Greenwich time
Despite his innovation and promotion, however, Airy's ideal of automatic time distribution had a clear limitation in terms of scale and accuracy, as sporadic failures and errors continued to occur. On more than a few occasions, no time signal reached the sites of primary partners, such as the ETC's offices or the stations served by the South Eastern Railway. A wide range of causes were detected, including the error of Shepherd's master clock, owing to bad weather that prevented astronomical observations and defective telegraph connections, wires and batteries.Footnote 75 Airy and his collaborators struggled to identify the causes, but their efforts sometimes yielded no results, as finding the sources of errors or failures somewhere in the complicated connections of telegraph relays, clocks and other mechanical devices was extremely difficult. This uncertainty itself was one of the principal technical limits.
Moreover, it is important to note that Airy and his collaborators were far from completely successful at automating and mechanizing all the parts of telegraphic distribution of time. In reality, many areas were yet to be mechanized and automated, specifically the operations relating to public time signalling and fault detection. For most of the time balls, time guns and local public clocks elsewhere, the releasing, firing and adjusting of these machines according to the RO's time signal required manual procedures. Most local post offices and railway stations required clerks to adjust the timekeeping devices or transmit time by hand after receiving the time signal. At the principal London railway termini, the signal was redistributed by hand to regulate most of the railway clocks throughout the country.Footnote 76 At the telegraph office at Paddington Station of the Great Western Railway, for example, a diary note was used to record the arrival of the time currents; the record was indicated using ‘Time see’ or ‘Time not see’, and after checking the rate of the clock established there, ‘Clock right’, ‘Clock 1 min or mins fast’, or ‘Slow’ was indicated.Footnote 77 The signal was then manually retransmitted to their stations. Thus, beyond central London, automatic connections, apparatus or operations were rarely established, except for a few time balls and time guns.
As a means of fault detection, the return current could certainly be entrusted to identify any errors and failures. Ellis stated the following about the time ball in Deal:
The success with which it is worked is due principally to the establishment of the ‘return signal’, the non-receipt of which immediately shows that something has gone wrong, thus giving the earliest possible notice of the existence of some fault requiring correction if possible before the following day.Footnote 78
However, apart from specific lines and points where the return current was employed, there was no established route to estimate the accuracy of the time signal that an end user received. In order to address this matter, in practice, at the central sites of the time system, such as London Bridge Station, the GPO, the central telegraph station, the Strand and the Palace of Westminster, telegraph engineers and post office and railway clerks regularly monitored telegraph lines and devices connected to time signals.Footnote 79 If a failure or error was detected, Walker, Clark, Varley and other principal collaborators reported the information to Airy, inspected the components and, if necessary, repaired the telegraph wires and timekeeping devices. Without these human observations and reports, grasping how the time current operated, even in the central London area, would have been difficult for Airy. This network of experts and their cooperation were key to maintaining the time service in a satisfactory condition.Footnote 80
Maintenance was indeed vital to appropriately working the time system.Footnote 81 When the time ball at Deal began to be used regularly in 1855, for instance, its operation was interrupted by the derangement of the apparatus. Airy's report tells us how he managed to solve the problems:
I sent an Assistant and workman to put it in order, and since that time it has generally acted very well. Since March there have been three failures; one of these arose from the Ball hanging on the clips, which were not properly oiled, and one from the turning off of the current on the Railway line; the cause of the third has not been traced out with certainty.Footnote 82
Similarly, repairs were needed in 1858, when four telegraph wires connected with the RO were damaged, due presumably to the thunderstorm.Footnote 83 In 1861, as most of those wires became useless, Airy said, ‘we have taken up parts and replaced them by new wire, but apparently, the whole of the gutta percha has perished. No special fault has been found, but every yard is faulty’.Footnote 84 As a result, he had to establish new open-air wires. Similar to the maintenance of these telegraph wires, Airy also reported in 1864 that Shepherd's master clock had been cleaned.Footnote 85
The time current's accuracy was also a matter of concern. The letters exchanged between Airy, Ellis and Varley in 1861, for instance, exemplified the degree of errors that they were expecting. Their discussion indicates that errors within a few seconds were recently emerging during the ten o'clock time signals. When asked by Varley about the possible errors, Ellis said the following, referring to the previous five days: ‘10h current was erroneous by more than 1 second but less than 2. On one occasion the error was greater than 2 seconds, but on all other occasions it was less than 1 second and generally under half a second’.Footnote 86 They clearly understood that an error of more than a second was not uncommon. On the whole, it was highly demanding to avoid making this degree of error at that time, even after the invention of the chronopher.
These small-scale errors and sporadic failures were observed by users as well. In a newspaper in 1855, Horatio Finer, a chronometer-maker, publicly criticized the fact that neither the time balls at the Strand nor the one at the RO were being appropriately and accurately maintained. He cast doubt on their workings, stating that ‘if the Astronomer Royal cannot keep those balls in better working condition, the sooner they are abolished the better’.Footnote 87 Likewise, in 1865, Reid & Son of Newcastle, a local clockmaker who received the time signal, complained to Varley that they had observed discrepancies of two seconds on two successive days from the time gun and a needle indicator whose deflection indicated the arrival of the Greenwich current. Reid stated, however, that this was ‘a very uncommon occurrence’.Footnote 88 This claim suggests that a user in a provincial city could reasonably expect to receive the time signal within the error of two seconds. In response, Airy explained that as astronomical observations to determine the time could not be carried out for three days, a notable number of errors that had accumulated in the master clock had resulted in the errors afflicting Reid & Son.Footnote 89
On another occasion, Reid & Son reported errors of 1.5 and 2 seconds. Ellis replied that ‘the time sent from the Observatory on the days in question was perfectly accurate’.Footnote 90 The clockmaker also complained in 1868,
We regret to say that the time signals are very incorrect just now, some days they are correct and other days nearly 2 seconds out. In fact, we have no dependence on these. Could you telegraph for an accurate current at one o'clock today. It is most important they should be accurate.Footnote 91
This remark suggests that the clockmaker could not tolerate the two-second error, since he would usually receive a signal with an error below this degree. On this occasion Airy noted in his reply to an ETC engineer,
The sky was not seen here for five days, and during that time the error in carrying on our clock rates amounted to 1s. The remaining discordance noted by Messrs. Reid arose from their own error … This is not the first instance of Messrs. Reid's frivolous complaints, and I will have nothing more to do with them.Footnote 92
This comment clearly illustrates that the cause of discrepancies regarding the time signal and the local time measurements could not be satisfactorily explained by the time provider; instead, all Airy could do was to reiterate that the RO signal was being correctly dispatched and to reject the criticism.
This inquiry from Newcastle was not an isolated example. Rather, Airy occasionally dealt with letters from users on the inaccurate or unreliable supply of standard time. A typical case was that of Edwin Langford, a watchmaker in Bristol, who, in 1874, informed Airy about daily errors between 0.5 and 1 second, noting that he measured the interval of time between the two successive arrivals of the time currents using fifty chronometers to detect that minute error.Footnote 93 Airy responded with simple logic:
The signals as they reach Bristol from the chronopher are undoubtedly the most accurate that human means can produce. If the signal is given to you from the chronopher signal by touch of finger or anything similar, I cannot answer for the accuracy. But if you receive it direct by wire from the chronopher, the discordance certainly arises from error on your side.Footnote 94
Thus Airy devised a ready-made explanation: he attributed such discrepancies to the user's measurements. His logic made it very difficult for the watchmaker to further criticize Airy, since Langford would then have to prove that his time measurement had been correctly performed. Despite this, Langford again wrote to Airy the next year stating, ‘I consider it my duty to report to you another irregularity in the time current as received by me on Monday last at 10. Time being 2.0 or 2.3 seconds slow’.Footnote 95 One of Airy's assistants answered in a manner similar to Airy's first response:
The time signals from the Royal Observatory have gone out with perfect accuracy; and, as the apparatus at the General Post Office is automatic, there is no reason to doubt but that the signals are, by it, transmitted with the same accuracy. The Astronomer Royal has no doubt that, whatever of fault there is, it is at Bristol.Footnote 96
Whenever necessary, the policy of denying users’ observations was regularly adopted.
Further, in 1877, Commander Swainson, who oversaw an astronomical observatory and naval chronometers at the Portsmouth dock, investigated the accuracy of the time signal by comparing it with a high-precision regulator for ninety days during the year. He claimed to have discovered the following errors and failures (the number of days in the brackets): failures (eight), error of 11 seconds (one), error of 10 seconds (one), error of four seconds (one), error of three seconds (six), error of two seconds (thirty), error of one second (thirty-nine), and error of less than one second (four).Footnote 97 He reported these observations to Admiralty Hydrographer Frederick Evans, who contacted Airy about the possible failures and errors. Airy responded, in a letter to Evans, that ‘signals go from Greenwich with perfect accuracy’ with relatively minor occurrences of errors below one second, adding the following:
The Greenwich signals are immediately distributed out automatically from the Post Office by an instrument called the Chronopher without sensible loss of time. I have verified this by causing the Chronopher to send the Greenwich currents back to Greenwich. I have no information whether the Portsmouth Observatory receives one of these Chronopher currents direct. If it does so, the Post Office signals at Portsmouth are certainly accurate. If the hand of man intervenes anywhere, there is no certainty for the accuracy.Footnote 98
Again, Airy's distrust of human intervention in the time system and his reliance on the chronopher can be observed. Based on this understanding, he rejected the claims that errors and failures arose in the time signals.
After the Secretary of the Admiralty asked Airy to scrutinize the cause, an assistant at the RO examined the chronopher, telegraph cables between London and Portsmouth, electric devices used in telegraph stations and the time ball in the dock.Footnote 99 The examination included the assistant's observation of the time current at the local telegraph office and the observatory in Portsmouth. The report from the assistant showed that no technical failure was discovered in either the chronopher or the London–Portsmouth cable and that both the local telegraph office and the dock observatory correctly received the time current. The assistant astronomer concluded, ‘I have no doubt that the Greenwich signal arrives at the Dockyard Observatory without any sensible loss of time as far as the transmitting and receiving apparatus is concerned’.Footnote 100 Based on this report Airy justified the RO–GPO's procedures and implied that the fault was with the measurement of astronomical time at Portsmouth. Although Swainson objected to Airy's observation by further asserting his doubts about the delays in the telegraphed time signal, in the end the underlying cause of the disparity of time between the RO signal and the time determined by the local transit observations remained subject to uncertainty.
The cases discussed above demonstrate the fundamental technological limitations of the RO time system between the 1850s and the 1870s. The progress of automation was rather limited within the time signal network in the central London area and within a few time balls and time guns established at other locations. The ambitious programme of mechanization and automation was, in the significant aspects of fault detection and maintenance, complemented by human observations and repairs. However, small-scale errors of the time signal, within a few seconds, could not be entirely avoided. In general, Airy and his collaborators could not explain the cause of the discrepancy between the time current and the user's locally measured time. As a result, when replying to complaints from the users, if they could not discover any source of errors or failures, they tended to reject the reliability of local time measurements. These limits and problems remained inherent in the time system, without being fundamentally resolved, yet they were not widely communicated or known to users and the general public.
Conclusion
In considering the Greenwich time service as the crucial driving force of change in the late nineteenth-century British temporal regime, this paper has illustrated 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. My evidence has illustrated that 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-signalling devices that either had no telegraphic connection with an astronomical observatory or required manual 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. Although the existing literature has paid little attention to this issue, 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 endeavours. 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. Nevertheless, 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 sometimes 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 technological 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.
