The Mechanical Internet
There once existed a system for transmitting information across Europe in digital form without the use of electricity
It is sometimes claimed that before the advent of the electric telegraph, at about the same time that Queen Victoria came to the throne, information could be transmitted no faster than a galloping horse or sailing ship. Consider though the following incident, which occurred 40 years before the first practical, electric telegraph was introduced. In the late eighteenth century, conditions on board ships of Britain’s Royal Navy were appalling. The food was bad, living quarters dreadful and the discipline harsh and unremitting. Mutiny was a constant fear among the officers of the navy; the prospect that their men would rise up against them and take over the ship, as had happened during the mutiny on the Bounty in 1789. In the spring of 1797 the HMS Royal Sovereign was moored in the southern English port of Portsmouth; near that part of the channel of sea between the Hampshire coast and the isle of Wight which is known as Spithead.
A sailor on HMS Royal Sovereign told one of his officers privately that a mutiny was indeed about to break out on the ship. The warning was taken seriously, for the men of both this and other ships had lately drawn up petitions, which they had sent to the king; complaining about conditions on board the ships of the Royal Navy.
Unrest and rebellion can be contagious and so once it was known that one ship might be on the point of mutiny, it was vital to seek the advice of the Admiralty in London, so that orders might be received regarding the best way to deal with such a dangerous situation. On 1 April 1797, a signal was despatched to London as a matter of urgency. It was brief and to the point, reading, ‘Mutiny brewing in Spithead.’ The astonishing thing is the rapidity with which this brief message travelled the 70 miles to London. It took just three minutes from sending it until it was being read in London. The signal had travelled between the two cities at 1400 miles per hour or twice the speed of sound.
In the world of steampunk, mechanical devices regularly replace those which, in our own world, run on electricity. The Discworld novels of Terry Pratchett contain a perfect example of this sort of thing. Although the Discworld novels began as pure fantasy, they gradually developed over the years until some aspects of them were indistinguishable from steampunk. Indeed, the fortieth book in the series published in 2013, is called Raising Steam and actually features a steam engine. In earlier Discworld books, a chain of mechanical signalling stations very similar to that seen in Pavane makes an appearance. The ‘clacks’ are rickety wooden towers which have at the top a display of shutters. These can be either open or closed, and the various combinations are used to encode messages. The signal stations are on flat ground, positioned about eight miles apart from each other. Although when they are first mentioned, the clacks are really a type of telegraph system, they later evolve into something like a rudimentary internet. As the system grows, it becomes automated, with information being stored on punched tapes. A clockwork mechanism is also used; another popular means of powering devices in steampunk stories. So sophisticated did the clacks become, that they were ultimately able to transmit not only text, but also images.
In Going Postal, we are told that;
On the Tump, the old castle mound across the river, the big tower, one end of
the Grand Trunk that wound more than two thousand miles across the
continent to Genua, glittered with semaphore.
This is indeed, or so it would at first seem, an extravagant fantasy; a network of semaphore towers which stretches across an entire continent!
The ‘clacks’ were first mentioned in Pratchett’s The Fifth Elephant, which was published 10 years after The Difference Engine, and it has been speculated that his use of the word ‘clack’ was inspired by the earlier steampunk work; those operating the mechanical computers in The Difference Engine being known as ‘clackers’. It is equally possible that both words are derived from a common source. The expression ‘hacker’, in relation to computers, was already current when The Difference Engine first appeared in 1990.
Another imaginary world in which mechanical or optical telegraphs feature prominently is Pavane, by Keith Roberts. In Pavane, late twentieth and early twenty-first century Europe is wholly reliant upon such a method for rapid communication between cities. The Catholic Church rules supreme and has forbidden the use of electricity; branding it heretical. Instead of telephone and radio, a network of signal towers stretches across the world. These are fitted with large semaphore arms. Each tower is within view of two others and when one sends a message by semaphore signals, a man with a pair of field-glasses reads it out loud to a companion who is operating the arms of their own tower. In this way information about all sorts of things, ranging from the price of grain in London to an urgent appeal for military assistance, can be speedily transmitted across Europe and beyond.
The semaphore towers of the Guild of Signallers in Pavane are a thread running through the whole book. One chapter is devoted solely to this strange and seemingly primitive communications network, but it is mentioned in passing throughout the rest of the narrative. We are given to understand that even the church relies heavily upon the signallers to pass messages around the world. There is simply no other means of rapid communication.
All that has been described so far sounds like typical, fictional alternative worlds. The idea of sending complex information hundreds of miles by semaphore or an arrangement of shutters opening and closing really does not sound like a practical proposition. No wonder we know it only through the works of authors such as Terry Pratchett and Keith Roberts! It may therefore come as a surprise to learn that this mechanical internet did once exist in our own world and that the accounts found in Pavane and The Fifth Elephant are no more than the sober, historical truth. Two hundred years ago, a chain of semaphore towers did indeed straddle a continent; the continent of Europe! It was possible in the early nineteenth century to send a message swiftly from one end of Europe to the other by this means. The system ran from Amsterdam in the north to Venice in the south. More surprising still, the code used in some of these towers provided the basis for the transfer of written text across the internet today.
For almost the whole of recorded history, it has been impossible to transmit complex information other than by means of a physical message in the form of either a person carrying information in his head or by a written letter. Of course, beacons can be lit and a chain of such signal-fires can rapidly convey news of some event. This is known from classical times, when the Persians were fighting against Athens and news of the outcome of a battle was sent hundreds of miles in a relatively brief period of time. More recently, beacons on English hilltops carried news from Devon to London of the arrival of the Spanish Armada off the coast in 1588.
The disadvantage of signal fires is that they effectively carry only one piece of information; which has to be arranged beforehand. They are binary, having only two positions; on or off. Once a beacon in the West Country was ignited in 1588, somebody 10 miles or so away would see it and light another fire. In this way, the signal could be passed swiftly across the land. It contained no useful information though; other than that which had previously been agreed upon. To tell the people in London how many ships had been spotted and of what types, would have needed a letter to be carried on horseback for hundreds of miles. At least a couple of days were required to carry a message in that way across a few hundred miles. For thousands of years, that is how it was. Sending word from one place to another was a maddeningly slow process. As later as 1860, it took 24 days to get a message across America; from New York to California. This was because most of the distance was served only by mail coaches.
Of course, sound travels considerably faster than a galloping horse and a message can be carried on waves of sound; which take just under five seconds to travel a mile. Here too though, is the same problem that we saw with signal beacons. A loud sound can carry for miles but cannot relay anything other than a pre-arranged message. After the fall of France in 1940, for example, the ringing of church bells in Britain was banned by the government. It was made known that if church bells began to sound, this would be the signal that the invasion of Britain by Germany had begun. Again, this is a single binary code. Either the bells ring or they do not.
In the late eighteenth century, a Frenchman called Claude Chappe came up with an ingenious method which would allow him to send detailed information by sound waves which he would generate simply by banging an old copper cooking pot! He arranged with his brother Rene, that they would both be looking at two specially adapted clocks which Claude had devised. There were no minute or hour hands on these clocks; just a second hand, which had been tinkered with until it swept around the face at twice the usual speed.
To compensate for the time taken for sound to travel, the following procedure was adopted. With his brother several hundred yards away, Claude Chappe waited until the second hand on his clock was on twelve and then banged his cooking pot very hard. As soon as his brother head the sound, he started his own clock; with the hand on twelve. In this way, the two clocks were synchronised. It was now possible to send signals across a substantial distance. A code was devised, whereby numbers were used to signify the letters of the alphabet. As soon as Rene heard the clang of the cooking pot being whacked, he noted down the number which his second hand was passing. After a sequence of numbers had been transmitted in this way, he consulted a book in which he had the code written down and then knew what his brother was saying.
Claude Chappe’s system was an ingenious one, but it had obvious limitations; the chief of which was the distance that a loud noise could travel. One way of tackling this would be to make a louder sound, but it occurred to Chappe that a visual signal might be more effective. At first, he used a post with a panel which could be swiftly turned one way or the other. One side was painted white and the other black. Using the same clocks and code, Chappe found that he could now send a message much further; especially when the person receiving the signal was equipped with a telescope. On 2 March 1791, the Chappes used the new method to send a message dictated by an objective observer over a distance of 10 miles.
For most of us, the word ‘telegraph’ is inextricably linked with the electric wires used in the nineteenth century to carry messages in Morse code. It is interesting to consider the origin of the word and find that telegraphs were being talked about and used decades before Samuel Morse came up with his code. Indeed, the word was coined in 1791; the very year that Morse was born. When he successfully demonstrated his system over a long distance, Claude Chappe wished to find a name for his invention; something catchy and memorable. At first, he favoured ‘tachygraph’; Greek for ‘fast writing’. A friend persuaded him that ‘telegraph’, which means ‘far writing’, would be a better name and so the telegraph was born.
Had Chappe’s telegraph been invented just a few years earlier, it is altogether possible that nothing would have come of it. France was notorious for being the most hidebound and reactionary country in Europe, with no need for new ways of doing anything. However, the country was in the throes of revolution when Claude Chappe first demonstrated his telegraph and the time was ripe for radical ideas and new schemes. In 1793, the same year that Louis XVI went to the guillotine, the National Convention, the new body ruling France, set up a commission to investigate Chappe’s work and see if it could be of any use to the state. The commission suggested that money should be allocated to test the idea and see if the telegraph really could speed up communications across the nation, in the way that Claude Chappe claimed that it could.
The swivelling black and white panels and synchronised clocks had proved to be a laborious and cumbersome way of spelling out words and Chappe had teamed up with a clockmaker to produce a semaphore system which could be operated by one man. A tall mast bore a horizontal beam; at the end of which were two small arms, which could move independently. The whole array could be operated by levers from ground level. The main crossbar could be tilted and the smaller bars could each be moved to one of seven positions, meaning that the whole array could adopt a total of 94 separate and distinct arrangements; more than enough to signal numbers, letters of the alphabet, punctuation and a number of common syllables.
Three telegraph stations were constructed, stretching for 20 miles, between Belleville, on the outskirts of Paris, and Saint-Martin-du-Tertre, which was about 20 miles away. On 12 July 1793, a message was sent from one end of the line to the other; a process which took a little over 10 minutes. It was a fantastic achievement and the head of the commission which had been set up by the National Convention to look into telegraphy declared that this was a triumph for the French people and that henceforth France would be the nation to instruct Europe.
The real reason for the National Convention’s interest in building telegraph stations was purely pragmatic. With the country in turmoil, it was vital that the government in Paris could communicate swiftly with any part of France. Mutinies and insurrections were brewing in various districts and towns and strong leadership from the central government was essential if control was to be exerted over the entire nation. We saw earlier that in 1860, shortly before the start of the American Civil War, it took 24 days to get a message from one coast of America to the other. This meant that if the government in Washington wished to know what was going on in San Francisco, it would take 48 days simply to send a question and receive a reply. Under such circumstances, it was inevitable that some parts of the United States began to think of themselves as not being closely bound to the federal government, thousands of miles away. This state of affairs contributed to the tensions which led to the American Civil War. The revolutionary government in Paris had the same problem. They did not want it to take days to be able to find out what was going on in another part of the country; this sort of delay tended to make outlying towns feel that they were somehow independent from the capital and its authority.
It took nine months to construct the first section of the French State Telegraph network; which ran 150 miles from Paris to Lille in the north, near the present-day Belgian border. It was not long before the British became interested in the idea of telegraph lines. In their case, it was less about holding the country together under the reins of a central government, than it was establishing rapid communication between London and the naval bases on the south coast.
The first British telegraph network is worth examining in detail, because it is more than an historical curiosity. The method used by this telegraph linking London and Deal gave rise to the system which we use today for sending text around via the internet. It was a digital information network; almost identical to the ASCII code that computers now use to store and transmit written words in the twenty first century!
It was, surprisingly, a clergyman who invented the telegraph that the British Admiralty began building in 1795. George Murray was, in addition to being a man of the cloth, an enthusiastic, amateur scientist and also a lord. He was the second son of the Duke of Atholl. Murray’s idea did not entail the use of semaphore arms, but rather an array of six shutters; each about five feet high and with rods in the middle so that they could be rotated horizontally. In this way, each of the six shutters could be in one of two positions; either open or closed. This is of course a binary system; where things can be either one or zero, open or closed, on or off. It is the way that modern, digital devices work.
The array of shutters was capable of 64 combinations; more than enough to encode letters and numbers. So the letter ‘A’ was signified by;
- 0
0 0
0 0
‘B’ was:
0 -
0 0
0 0
and so on. It will be readily apparent that this can be expressed simply as a string of ones and zeros. Letter ‘A’ would be I00000, ‘B’ would be 0I0000. This is of course precisely how we encode text in the modern world. We use a universal protocol called ASCII; the acronym being pronounced ask-ee and standing for American Standard Code for Information Interchange. Just as with the Reverend Murray’s shutter telegraph, letters and numbers are reduced to strings of binary digits; ‘A’ is 1000001, ‘B’ is 1000010. In this way, all written material can be turned into sequences of digital information and sent through wires, along fibre-optic cables or through the air by radio waves and then reconstructed at the other end. Computers can also manipulate information in this form. It was an Anglican clergyman in the late eighteenth century who first used a binary code like this for practical, long-distance communications.
We return to Terry Pratchett’s ‘clacks’ for a moment. It will be recalled that the continent-wide chain of optical telegraph towers which ran 2000 miles from the city of Ankh-Morpork to distant Genua was supposedly capable of carrying not only text, but also pictures. It is not hard to see how this might be done and is indeed, in theory at least, quite possible. Just as individual letters are reduced to binary digits when being sent across the internet; so too are photographs and other images. In modern computers, these binary digits are usually manipulated in groups of eight; a byte. One byte is typically used to convey a single character. George Murray’s system used six binary digits for each character, but other than that, the arrangement is precisely the same. It would be a lengthy and time-consuming process to undertake, but a picture could be broken down into units of six digits and encoded; then sent along a mechanical telegraph line. The fantasy of Discworld, at least in this case, is not all that far-fetched!
The first telegraph line established by the Admiralty began to be set up set up in 1795 and started operation the following year. It ran for 70 miles from London to Deal on the Kent coast. There were 15 stations on the route. Because there had to be a clear line of sight between one station and another, the telegraphs were, where possible, situated on high ground or hills. There are a number of places in south east England known as Telegraph Hill for this reason; high ground, where once an optical telegraph stood. In London for example, Telegraph Hill Park, in the New Cross Gate district, is named after the shutter telegraph erected on the ridge which rises 150 feet above central London. Even with all the development of the area during the Victorian era, there is still a clear view across the whole of London from this point.
To this very day, a curious surviving relic of the Admiralty telegraph set up in 1795 may be seen in London. No 36 West Square, in the south London district of Lambeth was the first telegraph station from the Admiralty in Whitehall and it differs architecturally from neighbouring properties. It has a brick-built top story, rather than the tiled affairs which are seen on either side, and also an imposing bay window. This house was owned by the Inspector of Telegraphs and when first acquired, it was indistinguishable from all the other houses in West Square, which were built in 1794.
The Admiralty bought the lease on No 36 and erected one of Murray’s wooden shutter frames on the roof; from where there was a clear and unobstructed line of sight to the Admiralty in Whitehall. For the next 16 years, everything went smoothly. Then, in 1812, work began on the new Bethlem Royal Hospital, which was to be built in nearby St George’s Fields. The architectural plans for this asylum, which was to become known colloquially as ‘bedlam’, included a dome above the entrance which would, by ill fortune, obscure the line of sight between the Admiralty and the telegraph station in West Square. At first, the Admiralty suggested an ingenious plan. If they could be allowed to rent the roof of the new asylum, then the shutter could be erected there. Consideration was given to this idea, but ultimately rejected on the grounds that the constant clattering from the operation of the shutter could aggravate the condition of some of the more sensitive patients.
There was nothing for it but to adapt the property at No 36 West Square. A brick base was constructed on the roof, upon which a wooden platform was placed, which raised the shutter so that it would be visible from the Admiralty even when the new hospital was built. At the same time, an imposing bay window was built, to show that this was no common house, but the headquarters of the telegraph chain. The address is, over 200 years later, still known as Telegraph House. The Bethlem Royal Hospital too, remains a few hundred yards away, although it now houses the Imperial War Museum.
Fifteen telegraph stations linked the Admiralty in London with the port of Deal; which lies about 70 miles, as the crow flies, from the centre of the capital. Before the building of the telegraph line in 1795 and 1796, it would have taken a day’s hard riding to carry a message between London and Deal. Even then, it would have been a remarkable horse which could cover the distance in the space of 24 hours, because by road the distance is closer to 90 miles than 70. It is now that we encounter for the first time the truly astonishing speed at which optical telegraphs were able to transmit complicated information from one place to another; which might be many miles away. It took a mere 60 seconds to send a simple signal from London to Deal.
We pause for a moment to consider the implications of the fact that a signal could travel the 70 miles which separates London from Deal in just one minute. A simple calculation reveals something which leaves one gaping, open-mouthed, in disbelief. If a signal travels 70 miles in one minute, then it must be travelling at a speed of 4,200 miles per hour; more than six times the speed of sound! For the eighteenth century, this was, to say the least of it, quite a feat. Even more amazing is that this was by no means the top speed for the spreading of information by optical telegraphs. A few years later, another telegraph line in the north of England was sending information five times as fast as this.
The telegraph line from London to Deal needed 15 stations; each staffed by four men; a lieutenant, a midshipman and two assistants. Two were employed in watching the next stations in either direction, a third wrote down messages as they were received and the fourth man operated the shutters, so that the signals could be passed to the next in line. This meant that 60 men were occupied full-time, because the spotters had to be on duty throughout the hours of daytime, as nobody knew when a message might come through. At least 60 men were engaged constantly in maintaining the link between the Admiralty and the port. After the success of the Deal line, others were constructed. Dover, Sheerness, Great Yarmouth, Portsmouth and Plymouth all had their own lines connecting them to London. It was possible to send a message from the Suffolk town of Great Yarmouth, via London, all the way to Devon. By 1815, there were 65 of these telegraph stations dotted about on the hills of southern England.
Maintaining the shutter telegraph network which spread its tendrils across England in the late eighteenth and early nineteenth century was only made possible by the peculiar conditions which existed at the time. Between 1792 and 1815, Britain and France were at war almost continuously. The French Revolutionary Wars of 1792 to 1802 segued seamlessly into the Napoleonic Wars, which lasted from 1803 until 1815. The Napoleonic Wars have been called the first real world war, as the fighting took place from Scandinavia to South Africa, from the Middle East to the Caribbean and from Russia to the Indian Ocean. During that time it has been estimated that one sixth of British men were enrolled in the armed forces and the British economy was effectively on a war-footing for decades.
For over 20 years, Britain fought France and at one stage, there was even the threat of invasion from the continent. That being so, it was vital to have rapid and reliable communications between the ports from which the Royal Navy was operating and the Admiralty in London. The telegraph network which began to be set up from 1795 onwards was no luxury, but an essential part of the country’s defences. The peculiar circumstances of there being so many men enlisted in the army and navy also made it possible to operate the shutter telegraph cheaply, since wages were not a consideration. The 65 telegraph stations needed over 250 men to run them which, in the usual way of things, would have been an expensive business. When however, you already have hundreds of thousands of men under arms, it makes life far easier; you have virtually unlimited manpower available for building and operating something of this sort. Telegraphs of this sort, just like the one first set up in France, were never likely to be economically viable in peacetime.
There were though those who could see an exciting future for the telegraph; once it became a commercial, rather than a purely military, enterprise. The 1797 edition of the Encyclopaedia Brittanica suggested that one day the optical telegraph might be run like the ordinary postal service and that people would pay to send their messages along it. It would then become a self-supporting service. The encyclopaedia also foresaw diplomatic and political advantages, if the telegraph network grew and spread further across the world, saying that;
The capitals of distant nations might be united by a chain of posts, and the
settling of those disputes which at present take up months or years might then
be accomplished in as many hours.
When Napoleon Bonaparte seized control of France in a coup d’état in 1799, he inherited, among other apparatus of the state, the State Telegraph Service. He quickly realised the importance of this long-distance communication network and had it extended, until it stretched beyond the borders of France. It was Napoleon’s hope that the telegraph could even link Britain with continental Europe. At first, he authorised the building of a new line south; stretching as far as the Italian city of Milan. Then, when he was planning the invasion of England, he gave thought to setting up semaphore towers which might one day send messages across the channel. One was built at Boulogne, but when the invasion was cancelled, the scheme collapsed. It is intriguing to think that as early as 1805, Britain was nearly linked up with a continent-wide communications network!
We have seen that the chains of signal towers in books such as Pavane and Going Postal are not fantasies at all, but really a slightly exaggerated account of historical fact. Long before the electric telegraph, the mechanical telegraph ran across England and much of Europe. The French and British lines were not the only ones operating. In retrospect, the optical telegraph might seem to be a blind alley, but new lines were being built well into the 1850s; long after the electric telegraph had proved its efficiency. Optical telegraphs were especially popular in Scandinavia; Denmark, Norway, Sweden and Finland all constructed telegraph lines of this sort. Prussia and Russia too had telegraphs. The Russian line ran between Moscow and Warsaw and was the longest ever built, being over 700 miles long. Some of these networks used semaphores; others shutters. None of the systems were compatible with each other, which made it impossible for the different countries telegraph lines to connect with each other. Different numbers of shutters were used and various kinds of semaphore arms.
In both Canada and the United States, mechanical telegraphs were being built in the 1820s and 1830s. One line ran from Manhattan and another linked Martha’s Vineyard with Boston. Even Australia embraced the technology; the first line being opened in Sydney in 1827. It seemed that the mechanical telegraph was here to stay and every year saw innovations in existing systems, as well as completely new types of shutter or semaphore post.
The optical telegraph never developed into a connected, world-wide network, as the electrical telegraph did. There were several reasons for this. First, this form of telegraph had its origins in military and political necessity. It did not begin as a commercial enterprise and because it was so costly in manpower, those running the systems saw no reason to share them with others. Claude Chappe had a vision of his invention being used to carry news bulletins from one end of France to the other and also to advise on commodity prices; to bring about a unified, European economy. There was no appetite in the government though for such idea, although the winning numbers of the state-run lottery were eventually allowed to be sent across the country in this way. This greatly reduced fraud.
There was no possibility in Britain either of the telegraph lines being used for anything other than military traffic. The Admiralty had built them, their men were running the things; what reason would they have for sharing them with anybody else? Other countries were a little more relaxed about this and things like weather forecasts, news and commercial information began to travel at high speed around Europe. News that had once taken a week to reach a capital city could now be there in less than an hour!
After the Battle of Waterloo, the final defeat of Napoleon and end of the wars fought between the British and French, the Admiralty in London decided that their spider’s web of telegraph lines were surplus to requirements; a luxury which was no longer needed. The whole system was therefore dismantled. Only one line was wanted in peacetime and this was a link between London and the main British naval base at the Hampshire town of Portsmouth. For this, a new method was used. The shutters had worked well enough under ideal conditions and perfect visibility, but semaphores were more easily seen in gloomy or hazy weather. This was of course one of the great problems generally with optical telegraphs; the fact that in rain or fog, it could be hard to see with perfect clarity for eight or ten miles. For the British this was a particular difficulty, because of course their lines all ran to coastal ports and fog is more common near the sea than it is inland. For as many as 165 days a year in Britain, the weather is such that it is not possible to see clearly for 10 miles; even with a telescope or pair of field-glasses. The London to Portsmouth line was converted to semaphore.
Throughout the 1820s there was something of a boom in the building of telegraphs and in Britain a line was built which demonstrated just how fast an optical telegraph could be. In the early 1820s, Liverpool was a major port in England. Ships simply arrived unexpectedly and had to be directed to harbour as they came. This was a chaotic and unsatisfactory situation, which led to traffic jams of vessels lining up to be allocated permission to enter the port. If only the port authorities had some way of knowing when ships would be arriving. Since most of them sailed north through the Irish Sea to reach Liverpool, skirting the coast of north Wales in the process, it was thought that a telegraph line running from Holyhead, on the Isle of Anglesey, to Liverpool itself, might solve the problem.
In 1825 the Liverpool Dock Trustees managed to get an Act of Parliament passed which authorised them to;
establish a speedy Mode of Communication to the Ship-owners and Merchants
at Liverpool of the arrival of Ships and Vessels off the Port of Liverpool or the
Coast of Wales, by building, erecting and maintaining Signal Houses,
Telegraphs or such other Modes of Communication as to them shall seem
expedient, between Liverpool and Hoylake, or between Liverpool and the Isle
of Anglesey.
The following year, 12 signal stations were built, with living accommodation for those who would be operating them. 50 feet high ships’ masts were erected and three pairs of semaphore arms attached to them. The line of telegraph stations ran for 72 miles along the Welsh coast; via Rhyl, Colwyn Bay and Llandudno. An article in the Shrewsbury Chronicle on 21 October 1836 detailed precisely how quickly a message could be sent along the 72 miles of the line.
According to the logbook kept in the Liverpool station, it was the custom to send a message to Holyhead at exactly 1:0 PM each day; asking if there was anything to report. This would be sent to Holyhead and initially, a single word answer would be sent back; either ‘Yes’ or ‘No’. In other words, the message and reply would travel a total of 144 miles. According to the newspaper, if this took a minute; it was regarded as being very slow work on the part of the semaphore operators. A quick calculation tells us that if the message and reply took one minute to travel 144 miles, then the overall speed at which the information was being relayed was 8,640 miles an hour! In practice, the actual speed achieved was almost invariably far greater than this. The journalist writing the piece from the Shrewsbury Chronicle looked at the time taken in September 1836 and found that the five fastest questions and answers that month had take a total of two minutes and 36 seconds. Since the distance travelled by the messages in that time had been 720 miles; this worked out at 288 miles per minute or 17,280 miles per hour. This is approximately the speed at which the International Space Station is orbiting the Earth.
The speeds cited above are truly extraordinary for an arrangement of purely mechanical devices, but the fastest time of all for the enquiry to be sent from Liverpool and the reply received from Holyhead is simply staggering. On 10 September, it took only 25 seconds for the message to reach Holyhead and the reply to be received. This equates to a speed of over 20,000 miles per hour. A message sent from London to Moscow at this speed would take less than five minutes to arrive.
It is easy to see why the optical telegraph was thought to be perfectly satisfactory for all practical purposes and why, even when the electric telegraph began to be developed, there were those who were quite happy to stick with semaphores and shutters. True, there were problems in bad weather and it was impossible to send any messages at all in the hours of darkness, but the methods were reliable and extremely fast. By contrast, when the first telegraph wires were rigged up, they were prone to failure and very vulnerable to sabotage. A single wire which went across country for hundreds of miles seemed a very fragile and uncertain way of communicating. The slightest accident, let alone deliberate acts of sabotage or vandalism, would be enough to put it out of action.
Not only did electric telegraphs, when they began to appear, seem very feeble and delicate things when compared to the stout and highly visible optical telegraphs, there was widespread scepticism about them to begin with. Anybody could understand, simply by watching them in action, how the existing telegraph lines worked. Not so the electric lines, which caused a needle to twitch weakly or made a succession of buzzes. To begin with, the whole thing looked like some kind of scam and it required some very public demonstrations to persuade the average person that communication by electric wire was not just some elaborate confidence trick.
It was the development of electric telegraphs in the first half of the nineteenth century which spelled the end for optical telegraphy. In England, the installation of electric telegraph lines alongside railway lines coincided precisely with the dawn of the Victorian era, with Victoria's accession to the throne in 1838. Six years later, Samuel Morse demonstrated the capabilities of long distance communication by this method, when he sent the famous message 'WHAT HATH GOD WROUGHT?' from Washington to Baltimore in 1844.
In retrospect, the advantages of the electric, as opposed to the optical, telegraph are so blindingly obvious that it is a wonder that not everybody at the time saw them. Never the less, there was strong opposition to the electrical telegraph at first and many commercial enterprises preferred to stick with the familiar and more easily understood technology of mechanical arms and, on occasion, steam power. At the same time that the Great Western Railway was arranging for the laying of an electric telegraph line running 13 miles between West Drayton station and the terminus at Paddington, another railway company was rejecting electricity in favour of a pneumatic system which signalled with whistles. Ten years after the electric telegraph was linked up to London's Paddington station, the British army wished to set up a telegraph network on the Mediterranean island of Malta. Surprisingly, they opted for a purely mechanical system and semaphore towers were built across the island.
The eventual triumph of electrical telegraphs over semaphore towers took some decades and it was economic considerations which proved decisive in bringing about the end of the embryonic mechanical internet. Semaphore lines were very costly, both in terms of the physical structures needed and also in manpower. When Samuel Morse sent his message from Washington to Baltimore, only two people needed to be involved; one sending the words in Washington and another to receive and decode them 44 miles away in Baltimore. The average semaphore line covering such a distance would have needed six or seven stations, at intervals of about eight miles each, and each station would need a staff of at least three people. In other words, to send the simple message, 'What hath God wrought' would have needed perhaps 20 people, rather than just two. It was calculations of this kind which led inexorably to the decline and fall of optical telegraph networks.
Meanwhile, in the early years of the electric telegraph, optical telegraphs continued to forge ahead and to many people, they still looked like the future of telecommunications. In Russia, at the same time that Britain and America were tentatively experimenting with electric wires, a new line was completed in 1839 which connected St Petersburg with Warsaw. As late as 1854 a completely new design of optical telegraph was used for the construction of a line of eighty stations running along the southern coast of Finland. This ran from Helsinki to Turku and also into Russia.
Even when the electric telegraph had proved itself and was flourishing across the world, there was a reluctance to do away with the older telegraph stations. The Liverpool to Holyhead line, for example, continued operating until 1860. The last regular use of a European semaphore telegraph was in Sweden, which used one to communicate between the mainland and an offshore island until 1880.
The extensive lines of semaphores and shutters described in steampunk fiction have been shown to be no work of the imagination but rather a very real feature of the eighteenth and nineteenth centuries. Something about mechanical telegraphs seems to capture the imagination. They are to be found not only in steampunk novels, but also in stories of alternative history. A novel from 1939, Lest Darkness Fall by L Sprague de Camp, tells the story of a twentieth century American who is mysteriously transported back to the days of ancient Rome. The plot device is reminiscent of Mark Twain’s A Connecticut Yankee at the Court of King Arthur. The protagonist of Lest Darkness Fall determines to avert the Dark Age which occurred after the collapse of the Roman Empire in the sixth century AD. He introduces the Roman world to things such as printing and book-keeping. To maintain communications, the hero arranges for the construction of a semaphore chain.
The optical telegraph still crops up in modern science fiction. In the Safehold novels of David Weber, humanity is all but destroyed by an alien civilisation. The scattered remnants find refuge on a distant planet. Their only hope is to live quietly, without attracting the attention of the enemy by displaying any signs of technology or industrialisation. In order that radio waves do not leak out into space and thus betray their presence to the enemy, the colonists rely upon semaphore towers to communicate between towns. Terminal World, by Alastair Reynolds is a story set in the distant future, which tells of the last remaining great city. This is connected to outlying settlements by ancient semaphore stations.
There exists in Britain a lingering relic of the mechanical internet at which we have been looking. In the early 1840s, when optical telegraphs were at their height in Europe, an engineer called Charles Hutton Gregory wondered if it might be possible to adapt the semaphore telegraph and use it as a reliable form of indicating to railways trains when to stop and when to go; as well as a few other simple instructions and warnings. There were a variety of different ways at that time of signalling to trains, but no one accepted system. Gregory obtained permission to install semaphore signals on the London and Croydon Railway and they proved a great success.
In essence, semaphore signals as used on the railways were like a form of traffic light. When the arm was in one position; this meant go. In another and the engine driver knew that he should stop. Unlike the semaphore telegraphs, railway semaphores worked as easily at night. Oil lamps were lit and different coloured lenses moved to expose or obscure the appropriate light. For well over a century, semaphore signals were a regular feature of British railway lines and also those of many other countries. Since the end of the Second World War though, they have gradually vanished; replaced by more up-to-date electrical signs. A few remain, but they too will soon be replaced. Within a decade or so, the last visible sign of semaphore telegraphy will vanish.
There will still be semaphore signals, in use on the many heritage railways up and down the country, well into the future
Shout out for the West Somerset Railway from Bishops Lydeard to Minehead 👍.
This is a another truly interesting article on a subject to which, I must confess, I had never devoted a thought! This is another historical cranny delved into by Simon, for the benefit of all of us!