The Astronomer Royal and the Hydrographer: the official relationship

Time balls were a common form of visual time signal that came into use during the nineteenth century. Many were built in strategic ports and dockyards to enable captains of ships moored nearby to observe any error in the timekeeping of their chronometers. Such errors might then be included in their longitude calculations during their journey and could significantly affect the accuracy with which they could locate their position at sea.Footnote ⁹ Nearly every day from 1833 onwards, the time ball on the Greenwich Observatory was raised to half-mast at five minutes before 1 p.m. and to its full height at two minutes before the hour, and then dropped at 1 p.m. precisely. Time balls continued to be used into the first quarter of the twentieth century, but were finally rendered obsolete in the 1920s when the widespread use of radio waves allowed accurate time to be transmitted directly to ships without a visible intermediary.

When the colonial government of Singapore was considering establishing a time ball in 1888, it took the advice of the master attendant of the harbour, who wrote,

These two institutions came to be the acknowledged authorities on time balls through their origins with respect to the navigational problem of marine location. The Royal Observatory in Greenwich was established in 1675 by order of Charles II for the purpose of providing accurate tables of the fixed stars and predictions of the position of the moon in order to calculate longitude while at sea.Footnote ¹¹ The Royal Navy Hydrographic Service was begun 120 years later by order of George III, with the aim of collating information from past and present coastal surveys and providing accurate charts for ships. More ships had been lost during the wars of the eighteenth century through shipwreck or being stranded than through enemy action, and a greater degree of knowledge of the seas was deemed necessary.Footnote ¹²

The two institutions were joined administratively in 1818. The Admiralty took responsibility for the financial and structural management of the observatory through the office of the Hydrographer. The observatory's historian Eric G. Forbes says that this arose from a suggestion by John Pond, Astronomer Royal between 1811 and 1835, ‘primarily on the grounds of administrative convenience’. Forbes views the Admiralty's acceptance of this as ‘highly desirable since [the Board of Ordnance] had become increasingly less competent to assess the importance of the work being done at Greenwich’.Footnote ¹³ From the Navy's perspective, Archibald Day's history of the Hydrographic Department summed up the purpose of the new administrative arrangements by referring to a Royal Society resolution on the matter. The minutes clearly intimated that the professional roles of the Astronomer Royal and the Hydrographer were such that they should be and were in fact in constant communication with each other.Footnote ¹⁴ From both perspectives it seems that observers at the time and afterwards viewed the juncture of these offices as very natural and mutually beneficial. It led to an increase in emphasis on the navigational work of the observatory, and in particular on the task of rating chronometers for the Admiralty. Forbes describes the establishment of the Greenwich time ball in September 1833 as symbolic of this same emphasis on navigation through the observatory's formalized connection to the Admiralty.Footnote ¹⁵ From its inception, the time ball was a solution to a practical navigational need of the Navy. As the primary source of accurate time the Royal Observatory was an obvious and important ally in providing time to Admiralty ships.

The provision of accurate time was to give this official relationship more advantages than mere ‘administrative convenience’. Within a few decades of collating and editing existing charts, the second Hydrographer, Thomas Hurd, in office between 1808 and 1823, realized that they would have greater control of their content and quality were they able to authorize coastal surveys as required and publish the charts for their own ships. On his initiative the Royal Naval Surveying Service was begun, with specialized training and pay for surveying officers.Footnote ¹⁶ The Admiralty charts produced from their work reached their widely acknowledged superiority in quality and accuracy during the leadership of the fourth Hydrographer, Francis Beaufort (served from 1829 to 1854). Their public accessibility, both nationally and internationally, was significantly increased under the fifth, John Washington, who served between 1854 and 1863.Footnote ¹⁷ By the end of the century there was only one private chart-printing company in Britain still able to remain in competitive business.Footnote ¹⁸

The Admiralty charts, produced for the most powerful Navy in the world to assist in its task of defining, navigating and defending the borders of the British Empire, were drawn from surveys using chronometers initially rated at the Royal Observatory.Footnote ¹⁹ In the latter part of the century time signals from Greenwich sent by telegraph wires were also used by the Hydrographic Department's surveyors to calculate specific longitudes for their charts. The accuracy of the charts was of obvious benefit to the Royal Navy, but the widespread use of these charts nationally and internationally also rewarded the Royal Observatory. The accolade of prime meridian of the world went to the observatory that was already referenced as longitude zero on the charts used by more than seventy per cent of the world's shipping.Footnote ²⁰ It is likely that a significant proportion of these were published by the Hydrographic Office of the Admiralty.Footnote ²¹ The increasing accuracy of the one repeatedly improved that of the other throughout the century, augmenting the status and authority of both. The relationship between the Hydrographer and the Astronomer Royal was more dynamic and productive than their administrative arrangements would suggest. The time ball is one of the key material witnesses to how they worked together; we will now consider a number of the time-signalling projects on which these officers collaborated.

George Airy and the Hydrographers: Beaufort, Washington, Richards and Evans

As Astronomer Royal, George Airy's association with time signalling is well known, seen clearly in his work to establish the Greenwich time service in the 1850s and in his continuous efforts to promote time signals throughout his long career.Footnote ²² That he became closely associated with the time ball in particular is seen in the Punch caricature of him as a time ball, published in 1883, shortly after his retirement.Footnote ²³ Here we examine the role of the four Hydrographers who worked with him on a range of time-signalling projects, as well as the impact on the time ball of Airy's introduction of galvanism into the processes of the observatory.

On becoming Astronomer Royal in 1835, Airy took on the management of the Greenwich time ball, then less than two years old, and of an observatory that was busy rating chronometers for the Admiralty. In Airy's opinion clock rating had become highly burdensome and he took determined action to ‘put the chronometer business in proper subordination to the scientific charge of the Observatory’, much to the annoyance of the Hydrographer, Francis Beaufort.Footnote ²⁴ The matter had to be referred to the Admiralty to bring about a resolution. Despite this conflict of interests, Beaufort's respect for Airy's expertise is apparent when the Admiralty was considering establishing a time ball at the Devonport Dockyards in Plymouth in 1847. As well as the ball, a transit instrument was required to calculate the local time from the stars. Beaufort wrote to the Admiralty that

This is one of the few references before 1850 in the Royal Observatory and Hydrographic Office archives to time balls other than that at Greenwich. The increase in volume after that date is largely due to Airy's adoption of galvanism, both within the observatory and externally. It is well known that Airy, while not the originator of these new techniques, was highly cognizant of the potential uses and benefits of electrical current in astronomy that were being devised in the United States and Britain during the 1840s. He used the new technology to instigate significant change in the practices of the Observatory, set up a system of regulated clocks that provided uniform accuracy from a single master clock, and replaced the ‘eye-and-ear’ method of observing transit times with a chronograph that was marked with the seconds of the sidereal clock and the moment of each observed transit. In liaison with members of the Electric Telegraph Company (ETC) and the South Eastern Railway (SER), he also facilitated the nationwide transmission of Greenwich time through their telegraph wires, thus coordinating a complex system of precision master and slave clocks, relays and local and national telegraph apparatus constructed for the railways and for general communication.Footnote ²⁶

In this context it seems a very small matter that amongst the many uses of electrical current adopted by the observatory was the ability to drop the Greenwich time ball automatically from the master clock, and, by extension, to drop another at a distance through a telegraph wire.Footnote ²⁷ But for the time ball, this was the beginning of a new era. First, the use of telegraphy elevated observers' perceptions of the reliability of the time balls. This is shown clearly in these 1855 instructions, written by the naval officer and nautical astronomer Charles Shadwell, on using them to rate chronometers: ‘When the fall of time-balls is regulated by galvanic apparatus with the Mean Time Clock of an established observatory [as at Greenwich and Edinburgh, for instance], the fall of the ball at the precise pre-arranged and expected moment may be implicitly depended on.’Footnote ²⁸ Shadwell's booklet became the standard reference on the use and management of chronometers, and was still recommended to surveyors in the key textbook Hydrographical Surveying in the 1880s and beyond.Footnote ²⁹ Whether this increased reliability was more imagined than real is debatable, but it is clear that time balls controlled by a telegraph signal were granted greater status than their manual counterparts.Footnote ³⁰

The second consequence was freedom from having to locate time balls near fixed observatories or transit instruments. The possibility of setting up a time ball on the Kent coast was originally the suggestion of C. V. Walker from the SER. Again, significant liaison between the observatory, the SER, the ETC and the Admiralty regarding logistical arrangements and location was required to set up the new time ball.Footnote ³¹ Established in 1855, its effectiveness was variable. Meadows reports that the Deal time ball was more inconsistent than its counterpart in Greenwich and subject to a greater number of technological failures.Footnote ³² While providing the opportunity to extend the reach of the Greenwich time signal, any part of the telegraph wire or relay system through which the signal had to travel was still liable to fail. Weak current or interruptions on the telegraphic connections could also prevent the ball from operating. These failures were managed through a return signal from Deal to Greenwich, the accuracy of which was reported annually to the Board of Visitors, and through a system for communicating with local observers to acknowledge inaccurate signals. But even with these physical limitations, the time ball signal was overall found to be of practical use. It was recorded in 1884 that ‘it is not an unusual sight to see numbers of ships lying to in the Downs waiting for the signal, in order to adjust their chronometers before putting out to sea’.Footnote ³³

Airy was certainly convinced of the benefits of repeating this elsewhere. In February 1856 he sent a six-page proposal to the Secretary of the Admiralty giving particulars of the telegraphic connections to the various principal dockyards (Chatham, Sheerness, Portsmouth and Devonport) and explaining in great detail what would be necessary to set up a similar time signal.Footnote ³⁴ He liaised with the Hydrographic Department to ensure he had the correct names and titles of the people he was trying to convince and personally visited the Devonport and Portsmouth dockyards to investigate the best locations for a time ball.Footnote ³⁵ In doing so, Airy clearly took the initiative to establish the technology that would allow the communication of accurate time to a larger number of ships.

The Admiralty was hesitant to follow up Airy's ideas because of the expense of building a time ball and the cost of laying the telegraph wires. The initial estimate that Airy provided in November 1856 gave a total cost of £623, with £425 for the time ball and apparatus.Footnote ³⁶ The Admiralty's response was to leave the question of constructing any further time signals until preparation of estimates for the 1858–9 year was under way.Footnote ³⁷ They continued to postpone serious consideration of the projects in the following few years, again largely due to financial considerations. Following a suggestion made by the Hydrographer, John Washington,Footnote ³⁸ when Airy began to prepare for the estimates of 1860–1 he proposed

Airy was not personally committed to the time ball itself. Given the opportunity both to save money and to make visual time signals more accessible he was ready to promote Washington's suggestion of semaphore beyond the Admiralty. The public, apparently, were less open to change. When the Thames Conservancy Board wrote to Airy in August 1860 about constructing a ball, he recommended they consider a different signal, as ‘it has long since appeared to me probable that an efficient construction might be made on the Semaphore principle, at a much smaller expense’.Footnote ⁴⁰ His correspondent followed up this suggestion to the extent of making a drawing of a semaphore signal to check with Airy, but noted that he found ‘a strong preference on the part of the Conservators for a Ball, as being the commonly recognized mode of exhibiting the signal’.Footnote ⁴¹ This exemplifies the kind of battle Airy was fighting to further the cause of time signals. Time balls had captured the public imagination as ‘the commonly recognized mode’ of showing time, and numerous parties were keen to build them, but their relative expense clearly told against them.

During the same period, Airy had begun work on a larger project of establishing a time ball at the Start Point on the Devon coast. A time signal on the south-west coast, in view of ships passing down the Channel, would provide them with the opportunity to calculate the seagoing rate of their chronometers, always slightly different from that found on land. As with the semaphore idea, this originated from Washington's suggestion in 1857 to put a time ball at Lizard Point on the Cornish coast, but it was Airy who adapted, developed and promoted it with Washington's support.Footnote ⁴² The basic idea was to set up a clock in the Devonport dockyards, near Plymouth, that was regulated by the Greenwich signal and reported its accuracy back to the observatory through a return signal. This clock would then be used to drop one time ball in the Devonport dockyards, of primary benefit to the Navy, and a second one at the Start. The latter would be set up to drop the ball every hour of the day to maximize its accessibility to passing ships. In developing a detailed proposal, Airy consulted closely with members of Trinity House who had a lighthouse at the Start Point, and also with Latimer Clark and C. T. Bright about the telegraph requirements. New telegraph wires would have to be laid between Dartmouth and the Start. The total cost was estimated at just over £2,000, with another £326 in maintenance costs per year.Footnote ⁴³

After being refused repeatedly over several years, Airy convinced the observatory's Board of Visitors to send a committee to visit both the First Lord of the Admiralty and the president of the Board of Trade in 1862. It was hoped to access funds outside the Admiralty for the project.Footnote ⁴⁴ While considering the proposal, the Board of Trade consulted with other relevant parties about the benefits of a time signal at the Start. Lloyds considered that the proposal would be of more interest to shipowners than to underwriters. Trinity House believed it would be advantageous to passing ships, but reluctantly declined the responsibility of being involved with the work as it was outside their remit. The South Shields, General and Sunderland Shipowners' Societies all expressed their belief that it would be of considerable advantage to shipping interests, while the London Local Marine Board were not in favour, on the grounds that the sailing time from London to the Start was too short to obtain a satisfactory seagoing rate, and that the chances of collision would be increased if more ships were drawn to the Start. Regardless of these generally favourable opinions, the Board of Trade was unable to release any funds from the Mercantile Marine Fund as they were limited by statute to the service of ‘seamarks’. As Trinity House was unwilling to connect the time balls with their lighthouses, there was no way to include time balls within the definition of ‘seamarks’.Footnote ⁴⁵

Further requests by Airy in late 1863 and the Board of Visitors in June 1864 to the Admiralty to consider funding were also rebuffed. Airy argued for the wide range of benefits of the project:

Airy lost a key supporter during this year when a new Hydrographer was appointed following Washington's death in 1863. George Henry Richards (served between 1864 and 1874) expressed his lack of support for the project in an unusually frank memorandum that was then cancelled, and rewritten with a more circumspect tone.Footnote ⁴⁷ In the original text, Richards acknowledged that from a scientific point of view the project was highly desirable, but he could not agree that the costs were necessary to spend in the interests of navigation. The Start was passed too early in any ship's journey to be able to give an accurate seagoing rate, and he did not believe that many merchant ships

This low opinion of the practical value of a time ball was not expressed in the final memorandum. Richards had nearly thirty years of practical surveying experience at a period when there were few time balls to use, which may account for his views.Footnote ⁴⁹ He went on to say that it was more likely that ships would calculate the alteration in their chronometer rates when they reached their first port. In both versions Richards affirmed the scientific point of view of the benefit of transmitting accurate Greenwich time to major seaports, but questioned whether it was not more important to establish telegraphic communication between such ports, garrisons and salient coastal points as a military measure, and then the transmission of time could follow. When this military need was deemed necessary, then it would be worth spending the money, and gaining accurate Greenwich time would be the added bonus.Footnote ⁵⁰ He thus reversed Airy's priorities: Airy would have laid the wires to transmit time, then let the military benefit from the infrastructure.

In spite of Airy's best efforts, he was unable to convince the Admiralty to set up a time ball at the Start, though he remained committed to the value of the project and spoke of it again in his report to the Board of Visitors as late as 1874.Footnote ⁵¹ Similarly, he failed to convince the Admiralty of the benefits of receiving the Greenwich time signal via the telegraph. When the Admiralty did erect time signals in Portsmouth (around 1856) and Devonport (in 1862), they were content to ascertain the time locally and acknowledge that their signals ‘cannot pretend to strict accuracy’.Footnote ⁵² This again shows the status accorded time signals that were delivered by a telegraph signal from Greenwich, as well as the Admiralty's decision that such accuracy was a luxury they were not prepared to pay for as yet.

Despite these setbacks, Airy's work promoting visual time signals was more successful than not, and by the end of his career there were such numbers of time balls in use that lists began to be printed to communicate their location and identifiable characteristics more widely.Footnote ⁵³ This came about through a series of international initiatives and requests for information, and demonstrates how Airy and Frederick Evans, Hydrographer from 1874 to 1884, played significant but unsuspecting roles in this multinational development.

Prompted by a request from the Prussian government for details of time balls in British colonies in 1879, Airy wrote to Evans requesting information held in the Hydrographic office, and to a colleague for details of those in South Africa.Footnote ⁵⁴ He provided a list of categories for each signal in a specimen form that included the location, time and nature of the signal. Airy then compiled the information from their replies, and sent the form to the Foreign Office on 11 September 1879.Footnote ⁵⁵ In February the following year Evans wrote to Airy requesting a copy of the list the Astronomer Royal had compiled, as the United States Hydrographic Office had asked him for a list of time signal stations in Great Britain, India and the colonies.Footnote ⁵⁶ Airy replied with some bemusement and wry humour at the request, providing a ‘history of the Report on Time-Signals, as known to me’. Having sent his report to the Foreign Office, ‘made with much personal labour’, he had heard no news since the previous September, so did not know if they had ever printed it. But ten days before Evans's current letter arrived, he had received a number of printed copies of a German report on time signals. ‘The form is entirely copied from mine’, he wrote, ‘but it includes the signals in all parts of the world’. The Foreign Office had sent the copies to him as the Prussian government wanted certain gaps in it to be filled. Airy continued,

This was a revelatory moment for the Hydrographer. Evans's reply announced that he was now preparing a list of time signal stations for publication ‘as completely as the resources of the Hydrographic Department will admit’.Footnote ⁵⁸ Having failed to realize that his office was the key collector of the vast bulk of this information, he could now see the use that a published list of these signals would be to ships' captains. This completed the circle of the exchanges of communication between three major seafaring nations and the multiple sources of ‘inspiration’ for publishing such a list.Footnote ⁵⁹

Marking a significant shift in the international awareness of the value of these signals, the Admiralty's List of Time Signals was published in 1881, the year of Airy's retirement. It provides a measure of their use, diversity and location, showing that by the end of 1880 there were twenty-four time signals in operation along Britain's coastline, twenty-nine in British colonies and forty-two in thirteen other countries.Footnote ⁶⁰ More than twenty-five nations were making use of such visual time signals as guns, discs, collapsible cones and semaphore, with the most prevalent being the time ball. The Royal Observatory had direct responsibility for only two of these: its own time ball at Greenwich and the one at Deal. Many of the other British time signals were operated by telegraph cable through the General Post Office (GPO), which had taken over the major telegraph companies in 1870 and was responsible for distributing the Greenwich time signal at 10 a.m. and 1 p.m. nationally. Others were connected to local observatories, such as in Edinburgh and Liverpool. Given that there were fewer than five time balls in operation in the world when Airy took up the office of Astronomer Royal in 1835, and the large numbers in use in Britain at the end of his term of office, the List of Time Signals marks the quantitative success of Airy's work in promoting their benefits.Footnote ⁶¹ It also marks the acknowledgement of the Hydrographic Department of its information resources and its acceptance of responsibility to make that information widely available to navigators.

The new Astronomer Royal: William Christie

William Christie's work as Astronomer Royal from 1881 further demonstrates Airy's success in establishing time signalling as an important part of that role. Christie quickly accepted Airy's responsibilities as the primary source of information for others' inquiries about how to set up a time ball in their own town or port.Footnote ⁶² He also took up Airy's proactive role in attempting to convince relevant groups to establish time balls in their particular port or coastal location. Encouraged by a suggestion from a member of Trinity House that Lloyds might be interested in establishing time balls at their signal stations, he even dared to resurrect Airy's Start project.Footnote ⁶³ Although never successful in its original objectives, Christie's work on this with William Wharton, Hydrographer from 1884 to 1905, was to be very productive.

While replying to a request from Lloyds to check their list of time differences between Greenwich and numerous ports, Christie mentioned the possibility of establishing hourly time signals at the Start Point. If the Committee of Lloyds were disposed to do this in conjunction with the time ball at Deal, he would do everything in his power to assist. He specifically offered to make arrangements with the Post Office Telegraphs to send the Greenwich signal automatically to their stations, free of charge, every hour for the drop of the time ball.Footnote ⁶⁴ The Secretary of Lloyds replied that the Committee would be ‘only too happy to establish a time ball at their signal station at Prawle Point, their nearest station to the Start, or at the Lizard, or St Catherine's Point, as may be considered most desirable’.Footnote ⁶⁵ This developed into an agreement in which Lloyds would take over the Deal time ball while the Admiralty set up the time balls at their south-western stations.

Meanwhile, Christie began negotiations with the GPO. Their response was less positive than that of Lloyds had been. Mr E. Graves wrote in early November,

He continued with a list of problems in setting up the connections. There was only one wire between London and Kingsbridge, shared with Salcombe and Dawlish. Communication from the three towns was directed through Exeter. In order to transmit time signals with sufficient accuracy, the London–Exeter wire would have to be transferred automatically from the ordinary instrument to unite it with the Kingsbridge wire, while cutting out the instruments at Salcombe and Dawlish to avoid interruptions. Once the time signal had gone through, the links would have to be reversed automatically to restore them to the normal arrangements. Such a procedure, repeated hourly, would be highly liable to error. It was certainly not something the Post Office was doing on any of its wires at that time, and Graves could not see how ‘the conduct of commercial business would possibly bear hourly interruptions, possibly in the middle of messages that were going forward’. He finished by saying,

Christie was quick to adapt his plans around these difficulties, and wrote the next day saying that under these circumstances a signal once or twice a day to correct a clock at Prawle Point would be sufficient, as the clock could then automatically drop the time ball at other hours of the day. He then asked whether, should the local connections have been completed, the Post Office would undertake to transmit the daily time signal to Prawle Point, with a return signal at a time convenient to themselves that would provide a useful check on the regulation of the clock.Footnote ⁶⁷ Graves was much more open to this suggestion; with the disturbance of ordinary communications reduced to this volume, he could see no difficulty in arranging what Christie wanted. A return signal sent within a minute or so of receipt of the time signal would be the simplest option, thus avoiding a second switching later on.Footnote ⁶⁸

It was at this point in the negotiations that Christie turned to the new Hydrographer, William Wharton, to discuss the practicalities of setting up a time ball as well as tactics in approaching the Admiralty regarding the negotiations with Lloyds. This was to be one of the first of many projects that they worked on closely together over a period of twenty years as the key representatives of the Royal Observatory and the Hydrographic Department, the longest pairing of these officers, only rivalled by that of Airy and Beaufort. But where the earlier pair had begun their work relationship in acrimony over the matter of rating chronometers, Christie and Wharton were better matched. They had reached the pinnacles of their careers at parallel points in their work and family lives, they shared scientific and research interests, and their family backgrounds provided points of common understanding. Their correspondence demonstrates a strong collaborative approach to solving the problems of time signalling, as well as a personal warmth and friendship. Their letters contain references to their families' health, personal greetings to and from their wives, and, lost to the historian, appointments to meet and discuss their projects in person.Footnote ⁶⁹ Only one example of a disagreement between them has been found, caused by a misunderstanding during the longitude measurement of Gibraltar in August 1885. The matter was quickly smoothed over by a personal, informal apology followed up with a more official letter the following day.Footnote ⁷⁰ It certainly seems to have been an isolated incident, as their correspondence on a second, concurrent project was not disturbed in any way. That project arose out of Christie's negotiations with Lloyds to set up a time ball near the Start Point. The proposal was to devise and trial a new clock and time ball mechanism in Devonport.

Christie, Wharton and the Devonport time ball and clock

Shortly after Christie's retirement in 1910 the observatory received a request from the Admiral Superintendent of the Portsmouth dockyard for information about the Greenwich time ball, as the one in Portsmouth was having problems with the release mechanism.Footnote ⁷¹ Dyson's reply was backed by a report from Mr T. Lewis, an assistant at the observatory, who wrote,

Lewis's notes claim that ‘90 per cent of recent time-balls are on the Devonport principle’, which would make it a very successful model in the world of time signals.

It was in February 1885, as Christie was making some progress on his revived project for a time ball near the Start, that Wharton suggested they try out their ideas at Devonport. In a series of letters marked ‘private’, the two men discussed the issues involved in making the project attractive to the interested parties, particularly the Admiralty. Christie's negotiations with Lloyds in late 1884 had developed as far as obtaining a definite offer from them to take over the Deal time signal, if the Admiralty would establish one for them at Prawle Point. There is some silence in the correspondence until 11 February 1885, when, perhaps after a verbal reminder, Wharton wrote that he had not realized that Christie wanted him to make the next move with the Admiralty, nor would he be able to do so at this point, as he had no information to present to them. While a plan for setting up a time signal at the Lloyds signal stations had been frequently put forward by Airy, the Admiralty had not been able to accept the expense associated with it as it would have been partly for the benefit of the Mercantile Marine. Wharton considered the deal being arranged by Christie to have a good chance of being taken up by the Admiralty. He said that if Christie raised the question again he would do all he could to make it go forward. Or, if Christie preferred, he could get Lloyds to write directly to Wharton himself, but then the matter would have to go back to Christie on points connected with the transmission of time and clocks.Footnote ⁷³ Christie replied the following day, saying he had not intended that Wharton approach the Admiralty at this point. The next step was to find out what a time ball would cost. Wharton had said he would make enquiries about the cost of one at Devonport and Gibraltar, and even whether a ball could be supplied by the dockyard. ‘I quite agree with you that it is better for me to bring the matter before the Admiralty’, he wrote, ‘and I will do so as soon as I can get information as to cheap time-balls’.Footnote ⁷⁴

The division of labour between the two is clear. Wharton was to look after the physical time ball and operating mechanism while Christie was to be in charge of the clocks and time distribution. Both of these notes also referred to meeting up with each other, and so it is likely that their discussion continued in person. Eleven days later Wharton wrote with his suggestion to use Devonport as a test case:

This part of his letter remained on his desk for two days, during which time a separate note from Christie arrived about a paper published by the US Signal Service describing the cheap and efficient time balls that were being constructed in the US using canvas and a simple dropping mechanism.Footnote ⁷⁶ Wharton then added to his earlier suggestion about Devonport that he would look up the American paper, and sent it off to the Astronomer Royal.

It is worth noting Wharton's opinion that the time arrangement at Devonport was ‘very bad’. Only twenty years earlier the Admiralty had installed a collapsible cone on Mount Wise, but had chosen not to invest in the telegraph wires that would have connected it directly to the Greenwich time signal. Their reasons for this are unclear, but presumably connected to the cost. Instead, they hired the services of a local watchmaker to take charge of their chronometers, who would also visit daily (except Sundays) to collapse the cone by hand. This level of service was now deemed by the Hydrographer to be well below standard. This change may have been due to increasing confidence in the telegraph system, or perhaps mirrored the greater emphasis on accuracy and precision measurement prevalent in the late nineteenth century.

In his annual report for 1885 Christie highlighted the Devonport project as a test model being developed in conjunction with Wharton, in order to implement Airy's original scheme of putting a time signal at the Start.Footnote ⁷⁷ He even encouraged others such as the Southampton Town Council to delay building their own time ball until the results of this project were complete.Footnote ⁷⁸ The clock was the chief responsibility of the observatory, and Christie liaised with E. J. Dent & Co, the makers of the Westminster Clock and long-time suppliers of astronomical clocks to the observatory, to organize the adaptation of a mean solar clock so that it could be regulated by a signal from Greenwich at one hour of the day, and then used to drop the ball at any other hour of the day. Christie described the regulating mechanism as follows:

Christie invested a great deal of his own time in ensuring this correction technique would work, conducting practical tests and going into detailed correspondence with Dent, who adapted one of the 1874 transit of Venus clocks as required.Footnote ⁸⁰ The value of having the clock corrected accurately each day was that it could then operate independently of the telegraph system. The second key modification was to add hourly contacts to the clock, enabling the clock itself to send a current automatically to the time ball each hour, causing it to fall if it had been hoisted up in preparation to give the time signal. This provided a unique service to both merchant and Navy ships when first introduced at Devonport, as captains could signal in their request to the harbour to have the time signalled at any daylight hour.

The clock was delivered to Devonport in October 1886 and entrusted to the care of Staff Commander Osborn, who was trained by one of Dent's employees to adjust the clock's pendulum to match the time signal, and given the task of monitoring its accuracy. Osborn took care of a number of serious problems caused by weather. The hut in which the clock was installed needed to be insulated carefully and then heated to a constant temperature and maintained at a constant humidity. After these modifications he was pleased to report in May 1887 that the clock was now keeping ‘splendid time’.Footnote ⁸¹

Osborn's other significant contribution was to the nature of the time signal eventually used at Devonport. As such, he revived the work of Captain Wauchope and demonstrated again the importance of the ‘practical navigation tradition’ in the development of time balls. After some consideration Wharton had thought it best to maintain the use of a collapsible cone. Problems with the ball at Deal made him reluctant to change the set-up. However, as early as 27 November 1886 Osborn was reporting problems with the cone and its spare. By 8 December they were both in rags. Explaining that the current design of the cone was not strong enough to withstand the extra demand on them made by being kept up and in place 365 days a year, he suggested an alternative design for a time ball:

Unfortunately there is no evidence as to whether Osborn was inspired by the designs being used in America, nor of any other source for his ideas. But with Wharton's permission he had the dockyard construct the time ball and it was trialled in early 1887. He reported on its continued satisfactory use in April 1887 and oversaw the installation that year of a time gun that was also run by the clock. The following February, Wharton and Osborn reviewed the situation in order to decide on the final, permanent signal form. Osborn wrote,

The second edition of the List of Time Signals, published in 1888, shows that a black ball with a diameter of three feet and eight inches was in operation.Footnote ⁸⁴ It appears from a later comment in Osborn's correspondence that Wharton may have been convinced by the ball's better ability to operate successfully in a strong gale.Footnote ⁸⁵

The final feature that also set this time ball apart from nearly all of its predecessors was the use of a return signal from the clock to the Royal Observatory at a specified time during the first minute after 1 p.m. This was done to monitor the accuracy with which the ball had been dropped, and had been used for many years to check the accuracy of the Deal time ball and the Westminster Clock. The arrival of the signal would be recorded and reported in the Astronomer Royal's annual report, giving an official measure of accuracy to the time signal.Footnote ⁸⁶

The reputation provided by the reported return signal came to be sufficiently highly prized that in 1901 a request was made by the Standard Time Company (STC) to have their clocks checked by the same procedure. The STC had been in business for twenty-five years, synchronizing clocks and transmitting time signals to clockmakers and others in London. Their own clocks were already regulated by the Greenwich signal via the GPO, but they were keen to have the same kind of record kept of their accuracy as was done for the Westminster Clock. ‘We are perfectly satisfied with the timekeeping of these Clocks’, they wrote, ‘but we desire to give them additional authority by having them connected directly with the Observatory at Greenwich’.Footnote ⁸⁷ Despite their willingness to pay for the service, and their argument of their business being of great public importance since many banks, railways, exchanges and large business houses received time from their clocks, Christie refused them this service as he considered that ‘it would not be proper to undertake to do this for private concerns which are carried on as commercial undertakings’.Footnote ⁸⁸

This did not deter the STC from making a second attempt to convince the Astronomer Royal of the public utility of their business some months later.Footnote ⁸⁹ In Lewis's briefing notes to Christie on the STC he commented that as a private time distribution company they were in direct competition with the Post Office time signal service and were able to provide the signal at lower cost: ‘If they can get an official recognition then the Post Office would be out of it altogether & so should we.’Footnote ⁹⁰ For their own business of signalling time, Greenwich had acknowledged the importance of the return signals by providing a separate wire between the observatory and the GPO for them in 1894, in order to reduce the risk of their failure.Footnote ⁹¹ By then they were responsible for recording the accuracy of three distant time balls in Deal, Devonport and Portsmouth (a copy of the system set up in Devonport), as well as their own. This official measure of accuracy meant that these time signals stood out from the others for their reliability, for as soon as a sensible error was noted (greater than 0.5 second), it was communicated to the dockyard concerned and the problem would be identified and dealt with.Footnote ⁹² Combining this with the ability to operate independently of the telegraph system and give a time signal at any hour of the day, Wharton and Christie had succeeded in providing ports and dockyards with a time signal that was cheap, efficient and flexible, and that communicated time under the authority of the Royal Observatory itself.

The transit instrument and the ‘embellishment’ of electrification

In the view of the historians Bartky and Dick, expressed in 1981, the time ball and clock developed at Devonport should be considered at best as an embellishment to the major principle of time signals.Footnote ⁹³ I suggest the system is more usefully seen as an example of further innovation in a technology in use and improved by adaptation to other technological innovations, such as the telegraph.Footnote ⁹⁴ It is worthwhile, therefore, to consider the difference that electrification made to the accuracy of the time signal given by the time ball and to the effort required to produce it. The best way of achieving this end is to examine the technical skill and mathematical and astronomical knowledge required to use a transit instrument, the apparatus through which time could be read from the stars.

The Greenwich Observatory was home to the Airy Transit, first brought into use in 1851, through which the time of transit of particular stars could be determined. These observations were made by trained and experienced observers, with checks on their reliability by their superiors, including the Astronomer Royal. The Airy Transit is an instrument of substantial size. Its position on its north–south meridian axis had to be carefully maintained to minimize errors in the readings. There were three standard sources of error taken into account in the calculations: the collimation, if the instrument were not at 90° to the horizontal axis; the level, if the axis were not quite horizontal; and the azimuth, if the axis were not exactly aligned east–west. The eyepiece was fitted with a series of crosshairs and the transit time of the star across each hair noted, the average being taken to help error reduction. With careful observation and due attention given to the possible errors inherent in some of the measurements, a time could be ‘reduced’ from the calculations that was as accurate as contemporary technology could provide, producing a high level of confidence in the outcome.Footnote ⁹⁵

However, for a time ball station that had no connection to Greenwich or to any other major observatory, a much smaller transit instrument would have to be used locally, by someone with less experience and with less support and accountability. Portable transits were used regularly for expeditions, such as the transit of Venus observations in 1874, and in smaller observatories. In his early days as Hydrographer, Wharton had expressed to Christie a desire to train his staff in using portable transit instruments, and in the following years a number of them did so.Footnote ⁹⁶

The difficulties of providing accurate time without an experienced, trained astronomer and a well-equipped observatory is demonstrated by the experience of Captain Roberts, who was trained up to ‘find his own time’ while in charge of the chronometer depot at Malta. Wharton wrote to Christie in 1903 to ask if he could take Roberts on as a student before he was sent out.Footnote ⁹⁷ By the late 1880s the port in Malta was in possession of two time balls, both of which were recorded as being unreliable.Footnote ⁹⁸ Wharton's goal in sending Roberts was not to increase the accuracy of the time signal provided by the time ball. Indeed, he makes clear in his letter to Christie that ‘the extreme accuracy of the time will not be very important’. This may account for his choice of Roberts, whom he described as a ‘dim man … & I expect will be rather slow at learning’.Footnote ⁹⁹ The key areas that made up Roberts's training at Greenwich were the setting up and operation of the transit, observations of the clock stars, recording of the transits and the reduction of the observations to a calculation of the time, accounting for the standard errors. Some time was taken working with the specific instrument he would take to Malta, and sending it to be refitted with a number of key parts.Footnote ¹⁰⁰

It was soon after Roberts had taken up his post that Wharton retired, and his successor, A. Mostyn Field, took up the office of Hydrographer (from 1904 to 1909). It is unclear whether Field had a different objective for Malta and did indeed wish to improve the accuracy of the time signal there. Yet it is certain that he was unhappy with the standard of Roberts's transit observations and management of the chronometers. Field asked Christie to design a record sheet that Roberts could complete and send back to London,

Christie supplied a draft of such a form. Later that year Christie headed to Sfax in Tunisia to observe a total eclipse; since he would stop in Malta en route he offered to visit Roberts on behalf of Field to inspect ‘the Time Ball arrangements and methods’.Footnote ¹⁰² Christie's report on his visit listed a catalogue of errors and difficulties with setting up the transit instrument so that it could be used effectively. He wrote,

By May 1906 Roberts had completed and returned a number of the record sheets to London. The observatory's analysis of them shows that he was only observing star transits to the nearest second, and only on one wire. A transit eyepiece is set up to track a star across a number of wires and should have been measured to the nearest tenth of a second. Roberts was also failing to collect the necessary information to correct for any of the standard errors. A report was produced indicating the particular deficiencies revealed by the record form, and instructions provided on how to improve.Footnote ¹⁰⁴

It was almost with relief that Field asked in September 1906 whether Christie would be able to take a new student at the observatory to replace Captain Roberts at Malta.Footnote ¹⁰⁵ Captain Hanning-Lee reported to the observatory for training later that month. The notes on his training and the correspondence between Hanning-Lee and Mr H. P. Hollis suggest that a much more productive relationship grew up.Footnote ¹⁰⁶ Hanning-Lee attended punctually every day (and on required evenings for observations), while Roberts had been erratic and had not informed the observatory of when he would not be attending. But even when the more diligent Hanning-Lee arrived in Malta he found other simple obstacles to overcome: there was only one lamp attached to the transit, the observation hut was a mile away from the main chronometer office, and his colleagues reported it had been raining continually for a month.Footnote ¹⁰⁷ None of these conditions were conducive to spending a night out observing the stars with careful accuracy.

The delivery of a time signal by telegraph from Greenwich (or any other well-equipped and staffed observatory) to a distant location could do away with problems of these kinds immediately. This was why the use of telegraph cables from the 1850s onwards was a major development in the history of visual time signals, and not merely an embellishment. Of course, the use of these wires introduced another set of problems that could also work to make the signal unreliable: weak current, interrupted signals and poor-quality cables could all cause the time signal to fail. The benefit of the system set up by Christie and Wharton was that these later problems could also be minimized, though not eliminated. By regulating a local high-quality clock, Greenwich time could be transplanted to distant locations, then operated through the clock independently of the telegraph system, dropping the ball at any required hour of the day while remaining accountable to Greenwich via the return signal. This was clearly an enormous improvement on the accuracy and reliability of the time signals that could be provided by a local non-professional astronomer and his portable transit.

Transplanting the Devonport time ball and clock

Although the original motivation for the Devonport project was to set up a time ball at one of Lloyds's signal stations, no evidence has been found that this was ever done. In late 1888 Wharton investigated the possibility of laying a telegraph wire from Devonport to the Lizard so that the Devonport clock could control a time ball there, but the GPO estimate of £850 for the cost and a £90 yearly maintenance fee proved prohibitive.Footnote ¹⁰⁸ Concerns over the terms on which the observatory supplied the time signals to the GPO and the accuracy with which they were then transmitted caused Christie to advise that any further action should wait until the agreements were more secure and reliable than at present.Footnote ¹⁰⁹ Lloyds made two further approaches to Christie regarding time balls in 1896 and 1899, but on both occasions the Astronomer Royal was preoccupied with other pressing business in the observatory and unable to give time to the project.Footnote ¹¹⁰

Instead, the first national copy of the Devonport time ball and clock was installed at Portsmouth in 1892 under Wharton's direction. It seems that the Royal Observatory was not involved until the final step of arranging a time for the return signal, which was then recorded and reported formally in the annual report to the Board of Visitors.Footnote ¹¹¹ Wharton and Christie played a significant international role as the sources of time signal information for the Colonial Government in Singapore, which led to them setting up copies of the Devonport time ball, but with the use of a local observer and a portable transit rather than a fully equipped observatory to provide the time calculations or record a return signal.Footnote ¹¹² To build the Singapore time balls, the original in Devonport was inspected on-site by members of the Crown Agents for the Colonies and engineers from Messrs Saxby and Farmer.Footnote ¹¹³ Their plan of Osborn's design was forwarded to later enquirers such as the harbour master in Brisbane, Australia.Footnote ¹¹⁴ Christie recorded in a letter on the establishment of a time ball in Ceylon that similar time balls to the Devonport model had also been established in Cairo, Port Said and Alexandria.Footnote ¹¹⁵ It would be difficult to calculate the accuracy of Lewis's claim that the Devonport model had been used in 90 per cent of recent time balls, but it is clear that it was sufficiently reliable to be reproduced elsewhere. With the Astronomer Royal's recommendation, it was almost certain to be taken up by those who inquired of him, but it is unlikely to have retained Christie's approval if it had not been maintaining an accurate standard of signal.

The Admiralty continued to set up copies of the Devonport time ball and clock in other locations, the furthest afield being Gibraltar in 1904.Footnote ¹¹⁶ This was a significant technical challenge, given the length of submarine cable involved and the associated problems of retardation, a slowing of the signal due to the changed dielectric surrounding the current while it was underwater. Sources of possible errors increased as the time signal from Greenwich now had to be transmitted through the submarine cables provided by the Eastern Telegraph Company (ETC) as well as the GPO telegraph system. More significant was the further limitation that since 1 p.m. was the busiest time of the day for the ETC, their cables could not be used for the purpose of time signals.Footnote ¹¹⁷ This meant Gibraltar had to rely on the accuracy of the 10 a.m. signal with neither check signal at 1 p.m. nor return signal.Footnote ¹¹⁸

The technology that would overcome the problems of telegraph wires in general and the long submarine cables in particular had already arrived, but it was some years before radio waves were actually used in Britain to transmit the time signal. The possibility of using wireless telegraphy was discussed by Christie and Field as early as October 1906 in the context of arrangements to train Hanning-Lee to replace Roberts. Since preliminary experiments using wireless signals for longitude determination had proved successful, Christie suggested that they could be used to send the Greenwich signal to both Malta and Gibraltar, thus solving the problems of both inept transit users and potentially unreliable busy submarine cables for time signals.Footnote ¹¹⁹ Field investigated further. He replied to Christie that while it was technically possible to get the wireless signal from the Marconi signal station at Poldhu, Cornwall, to both Gibraltar and Malta at night, the Admiralty's relations with the Marconi Company were not of sufficient warmth that this could be done without charge, and he did not think that the Admiralty would consider it a worthwhile investment at this stage.Footnote ¹²⁰ Day records that Field considered the expense unjustified, as the ships capable of receiving radio signals would be those with the best chronometers, thus least in need of regular rating checks.Footnote ¹²¹ While the two technologies overlapped for some years, the Deal time ball was formally decommissioned in 1927, providing one indication of the end of the time ball era.

Conclusion

This history of the time ball in Britain shows how collaboration between various Hydrographers and Astronomers Royal influenced and directed the development and dissemination of visual time signals throughout their period of use. The time ball demonstrates the creative and dynamic problem-solving partnership that existed between these two roles. In cases ranging from Beaufort's request for Airy's advice on location of a transit instrument in 1847 to Christie and Field's first discussions of the possible uses of radio waves in 1906, it is clear that this official partnership took a lead in defining problems and finding solutions to accurate and effective time signalling. The career of the time ball helps elucidate their relationship since it highlights a major dynamic between them: the demand for and supply of accurate time. As the use of chronometers became the accepted method to calculate longitude, the Royal Navy was in constant need of correct time. The Royal Observatory was able to provide it, and the Hydrographic Department was the conduit through which time was supplied to Her Majesty's ships in all its forms: chronometers rated before going to sea, surveys made and charts published that mapped time as longitude across coasts and oceans, and finally a visual form signalling the instant of 1 p.m. at strategic ports so that captains could check the error of their chronometers, without having to remove them from the ship, to help locate their position on their charts.

Amongst the various partnerships of Hydrographers and Astronomers Royal, this paper has focused on the twenty-year working relationship of William Wharton and William Christie as the most productive collaborators. The time ball and clock they pioneered together in Devonport was a highly successful model that solved a number of considerable problems, and could be reproduced in other places. First, it provided Britain and its colonies with a cheap and efficient form of time ball that meant financial restraints were much less of a concern to any wishing to establish a time signal. Second, it provided a modified clock that could be regulated daily by the Greenwich signal and then drop the time ball itself at any hour of the day as required. The sending of a return signal from the clock to be recorded at the observatory provided a public record of the accuracy of its time signal, which allowed its degree of precision to be monitored and certified. The warm friendship these men enjoyed augmented the sense of personal and professional satisfaction in the completion of a project that involved drawing together the technical expertise of skilled clockmakers, the resources of the Admiralty dockyards and the practical knowledge of Staff Commander Osborn, as well as public bodies such as the GPO that provided the telegraph wires through which the time signals could pass.

The importance of the telegraph system to the time ball should not be underestimated. Without it, it is likely that visual time signals would have remained few in number, restricted in location to pre-existing observatories or to wherever resources allowed a new observatory or at least a portable transit to be erected and staffed to ascertain the time with sufficient accuracy. With the telegraph, numerous time balls could be set up and run from one central, well-equipped observatory with well-trained and experienced staff. Given this, the introduction of telegraphy to transmit time signals directly from the Royal Observatory in the early 1850s is much more than an ‘embellishment’ on the standard operation of a time ball. And in an age characterized by an increasing fixation with precision measurement, stimulated both by the possibilities and limitations of telegraphy, the additional flexibility and accountability provided by the type of clock implemented by Christie and Wharton in the mid-1880s again increased the reliability and accuracy of the signal the time ball was able to provide.

This paper has highlighted the productive nature of the institutional connections between the Royal Observatory, the Hydrographic Office and the Admiralty. However, these relationships were not always smooth, and the tension between the scientific goals of the observatory and the practical needs of the Admiralty can be seen in Airy and Beaufort's clash over rating chronometers and Airy and Richards's differing views on the value of placing a time signal at the Start. Further conflict emerged around the control the Admiralty exercised over the observatory's budget and the demands it made of the observatory's services, limiting the extent to which Greenwich could therefore pursue scientific projects with sufficient resources. When arguing for an increase in resources in 1888, Christie was willing to hold the Admiralty to ransom over its need for accurate time, warning that ‘unless adequate provision be made for the primary objects of the Observatory, extraneous work, such as the supply of time-signals, may have to be dropped’.Footnote ¹²² These conflicting priorities affected the observatory from 1818 until it was formally separated from the Admiralty and placed under the auspices of the Science Research Council in 1965.Footnote ¹²³ Steven J. Dick's history of the United States Naval Observatory explores the work of an observatory managed by the Navy. Further research in a similar vein could evaluate both the fruitfulness of this relationship and the extent to which the struggles of the Royal Observatory to maintain an independent identity as a scientific institution while being ‘rated as a shore department of the Admiralty’ affected the direction and quality of its work.Footnote ¹²⁴