Optical telegraph

An optical telegraph is a device designed to be seen at a great distance by configuring various signals through a mechanism operated by one or more people. By placing several towers in a chain, each tower could be made to repeat the message of the previous one, thus propagating and traveling great distances in a much shorter time than that required by a messenger on horseback. There have been different telegraph models throughout history, and in different countries, and the basic operating principle of all of them is practically identical. Etymologically, "telegraph" is a device for writing over long distances (sometimes, this device is also called "semaphore", from the Greek sema, sign or signal, and forum, carry).

Overview

The optical telegraph consists of a device located at visual distance from another similar device. The operator operates controls that place the telegraph elements in a position recognizable by the next tower. This repeats the message, which is read and reproduced by a third, and so on. However, the frequencies are marked by the material used in its construction.

History

It is very true that since the beginning of History, human beings have used optical means to transmit messages at high speed. Already in "The Orestíad", Aeschylus narrates how Agamemnon sends news to the palaces of Atrida by means of bonfires during the Trojan War. At the end of the 14th century, Peter IV of Aragon used a smoke system to communicate movements of enemy fleets or armies to his own. troops, and Henry III of Castile sends a message from Toro to Segovia to announce the birth of his heir. Furthermore, the smoke signal systems used by some Amerindian tribes are well known. However, these visual communication systems cannot technically be considered optical telegraphy because they do not form a unified system with homogeneous and regularized rules. This began to be a reality at the end of the XVII century.

Beginnings

Already in 1684 Robert Hooke presented to the Royal Society a system of optical telegraphy that was not very well received.

During the 18th century a series of social, political, scientific and technological advances occurred that would converge in the ideal conditions for the development of this technique. Specifically, the improvement of optics made it possible to build tools to improve vision at great distances, which made it possible to lengthen the spaces between each telegraph station and the next, making the laying of networks more economical. The new achromatic lenses (which did not present chromatic aberration) achieved much greater precision and their construction technique allowed them to be made larger and with more magnification power.

In addition, during the aforementioned century, Enlightenment thought was established throughout Europe, which caused all scientific-technological advances to be decisively promoted from the highest levels of power.

Thus, France is the first of the European kingdoms to be seriously interested in telegraphy. The climate of instability existing at the end of the XVIII century means that the crown finances a fast and effective communications system that allows improve territory control and maintain order. In 1792, already in the midst of the First Republic, the green light was given to the construction project of Claude Chappe and his brother Ignace Chappe, who collaborated, of the first telegraphy network. In 1793, Chappe, in France, was awarded the first world title of telegraph engineer in recognition of his work to put graphic sign repeater stations into operation and give them the name telegraph.

In 1794 the first telegram in history was transmitted from Lille to Paris, over 230 kilometers and 22 towers. The success of this first test is the definitive boost to the telegraphy that France will have throughout its network, an extension of almost 5000 kilometers.

Even before Chappe's success, reports of this technological advance were spread by information and espionage services, and numerous European countries were rushing to build their telegraph networks. The second to do so is Sweden, almost on par with Hungary. Spain, the United Kingdom and Germany also did not take long to provide themselves with this communication system. In the United States, a telegraphy network began on the East Coast at the beginning of the 19th century, although it would no longer be relevant. that will never cover an appreciable part of its territory.

Optical telegraphy in Spain

The first news reached Spain through La Gaceta de Madrid, which in its issue of October 14, 1794 published the results of Chappe's tests. Likewise, on November 4, the tests carried out by the team of the professor at the Royal Observatory of Madrid, Mr. Salvador Ximénez Colorado, were reported, in which the excellent results obtained with achromatic lenses were corroborated.

In 1799, several proposals for telegraph models were presented to Charles IV. Of all of them, it is worth highlighting that of Josef Fornell, consisting of 11 balls during the day or lanterns at night that would make up the different symbols. The detailed study of this proposal was entrusted to Agustín de Betancourt y Molina, who rejected it as too complex and prone to mechanical failures. Shortly after, Agustín de Betancourt himself, who thanks to his study trips knew the French (Chappe) and British (Murray) systems, and their defects and shortcomings, would design a system that surpassed Claude Chappe's system in speed, security, reliability and ease of reading and handling. It is worth noting that this system was presented to the Academy of Sciences of the Institute of France, which, meeting in commission, studied the Betancourt model and issued a very favorable judgment, although it was met with opposition from the French Director of Telegraphs., Chappe himself.

Network operation

The operation of the network began at the station from which the message was broadcast. The telegraph was placed in a preset alert or attention position to "warn" to the neighboring station and have it place its telegraph in position to capture the message. When the next station sighted this signal, it placed its telegraph in the ready or prepared position and the first telegraph knew it could begin transmitting. Once it began to be transmitted, each symbol had to be in position for at least 20 seconds so that the next station would read it correctly and place its telegraph in the same position, which indicated to the preceding station that it could transmit the next symbol. of the message.

Life in the tower

The working conditions were especially harsh. The staff of each telegraph station was made up of three or four people. During their work day, which lasted from dawn to dusk, as long as there was enough light to see a tower, the keepers had to regularly look at the front and back towers of the line to check if any of them were in position. attention. The operators did not know the nature of the message and simply limited themselves to what they saw in the previous tower, so that it could be copied by the subsequent one.

In addition to the harshness of the aforementioned factors, the life of the operators of each station was very hard. To the harshness of the climate we had to add that the towers were usually in high places, where conditions were harsh, also exposed to storm rays. This was added to the fact that budget deficiencies meant that on too many occasions many towers were supplied by the good will of the inhabitants of the surrounding towns.

In Spain, messages were sent encrypted according to a code existing in the code book, which was in the possession of the Line Commander, who was the only one authorized to encode and decode. The message sent the page number of the book, and then an alphanumeric code that referred to one of the words that appeared on said page. This made the transmission much faster, more efficient and more secure than if it were transmitted letter by letter.

Operation problems

One of the biggest problems that the optical telegraph presented was that the symbol or signal produced was flat, so it had to be read from the front. A telegraph seen from the side did not present any information, as can be imagined. This forced the routes to be almost straight and made taking a curve really complicated. Of all the systems existing in Europe, those designed by Betancourt and Mathé were the ones that allowed the greatest viewing angle (more than 45°), which is why both systems were highly praised in scientific circles on the continent.

But what was perhaps the greatest drawback of this communication system was the one derived from the logical inconveniences of its medium. At night it was unreliable and although experiments were carried out attaching lanterns to telegraphs, the truth is that none of the prototypes passed the test with satisfactory results in any country in Europe. On the other hand, with heavy rain, fog, snow or haze, the adjacent stations became practically invisible, so the transmission had to be interrupted.

The Betancourt project. The germ

Back in Spain, in 1798 Betancourt obtained from Charles IV a Royal Order (RO of February 17, 1799) by which the project to install optical telegraphy in Spain was approved.

The first projected line is Madrid-Cádiz, consisting of about 60 or 70 stations, endowed with one and a half million reais and directed directly by Betancourt himself. However, of this entire line, only the Madrid-Aranjuez section was built, which began to be operational in August 1800. In any case, the economic crisis that Spain was going through prevented Betancourt's dream from being completed.

The military telegraph of Cádiz

However, these experiences have set a precedent. In 1805, a military telegraph network began to operate, conceived by Lieutenant Colonel of Engineers Francisco Hurtado, consisting of four lines that linked Cádiz with Sanlúcar de Barrameda, Medina Sidonia, Chiclana de la Frontera and Jerez de la Frontera, with a section from this last location until Seville that operated temporarily. This network, in whole or in part, was in operation until 1820. The Main Telegraph that controlled the four lines and which was the only tower that operated from 1805 until its disappearance in 1820 has just been restored in Cádiz.

The network in the Royal Sites

In February 1831, the Navy officer Juan José Lerena y Barry, after a presentation of his project before the court, was commissioned to build a telegraph network between Madrid and the Royal Sites (RO of February 8, 1831). Three months later the construction of the 4 stations is completed (Torre de los Lujanes, Cerro de Los Ángeles, both in Madrid, Cerro de Espartinas in Valdemoro, and "Monte Parnaso" already in Aranjuez) of the Madrid-Aranjuez line, most likely based on the pre-existing Betancourt line.

On July 24, 1832, the Madrid-San Ildefonso line came into operation, with intermediate stations in the Puerto de Navacerrada and Hoyo de Manzanares.

In March 1834 the Madrid-Carabanchel Alto line began operating, in July 1834 San Ildefonso-Riofrío, and on August 28, 1834 the construction of the Madrid-El Pardo line began. This network is for private use by the Royal Family, who use it to stay up to date with the news that reaches Madrid when they are in one of their suburban residences.

The Carlist Wars

The role played by optical telegraphy during the Carlist Wars as a means of communication by the Elizabethan troops between Pamplona and Logroño deserves separate mention, as it is of special interest. During 1834, shortly after the First Carlist War began, the liberal army built a network of 13 to 15 telegraph stations starting from Pamplona, passing through Logroño and ending in Vitoria, thus surrounding the territory between the plain of Alava and the mountains that stand between this plain and the Ebro, an area occupied by the Carlist troops that made communication between the aforementioned capitals extremely difficult. Part of the line was: Lerín - Andosilla - Lodosa - Ausejo. In the Logroño bulletins of these war years it is common to find news that begins: "According to the telegraph from Ausejo, the telegraph from Lodosa has been received..." Through this line the first news of the mortal wound received by Zumalacárregui in June 1835 reached the Cristino countryside. In Lodosa there is a hill called "Telégrafo", leaving remains of the moat that surrounded the fort inside which it was mounted. the device. The hill is located going along the road from Lodosa to Alcanadre, on the left. It can be identified since its top resembles a nipple. Although it is noteworthy for the speed with which it was laid out and built, and the efficiency with which it was used, this telegraph line was not subsequently used due to the poor condition in which many of its towers were left after the fighting and because the route, expressly designed with a military purpose, it had little fit into the national telegraphy network.

Mathé's definitive project

But the largest project in optical telegraphy does not arrive until, perhaps, it is too late. In 1844, by Royal Decree of March 1, the framework was established for the new layout of optical telegraphy in Spain under the responsibility of the General Directorate of Roads, and José María Mathé Aragua, State Colonel, was one of the most responsible for the project. Mayor who had collaborated with Lerena on the latter's project, and author of the telegraph model that won the competition opened for this purpose.

The project, of titanic dimensions, sought to unite Madrid with all the provincial capitals of the peninsular territory. At a particularly turbulent stage in the History of Spain, this measure sought to provide the State with an instrument for maintaining order, as stated in the preamble of the aforementioned Royal Decree.

"The S.M. government has decided to seek, by all means, the strengthening of public order, so necessary for the peoples to enjoy a paternal and pre-visional administration..."

The decree was especially careful in the location of the towers. Thus, it is preferred that the lines follow the existing roads and paths, to facilitate the supply of telegraph stations, and if possible, as close to towns and localities, for the same reason. Pre-existing structures had to be used to save resources, where possible, and so castles, watchtowers and even church towers were used when possible. When this was not viable, ad-hoc towers had to be built, all identical and according to the standard set by Mathé, measuring 7 meters on a side and 12 meters high. Furthermore, the towers each had to be at a minimum distance of 2 leagues and a maximum of 3, from the next one. A shorter distance meant building more towers, which implied a higher cost. A greater distance meant greater difficulty in seeing the front or rear tower with the optical means of the time.

The tower designed by Mathé was intended as a fortress, so that in the event of war the enemy would have the greatest difficulty in interrupting the communications system. It consisted of 3 covered floors, and the telegraph was located on the flat upper deck. The towers sometimes had a wire from the first floor to the ground. On the first floor, at ground level, on each side there are two, three or four flared windows of disputed purpose. In some documents it is stated that they could be used to place the spyglasses oriented to the next tower, although the fact of being in such a low position, and of existing on all sides and not only on those oriented to the previous and rear towers, makes It is perhaps more logical to think that they were loopholes for the defense of the tower. On the second floor there was a window on three sides, while the door was on the fourth wall. The tower was accessed through this door located about 4 meters high by means of a wooden staircase that was removed and stored inside, leaving the tower inaccessible from the outside. On the third floor there were one window on each side on all of its walls, identical to those on the lower floor. From this third floor the controls of the telegraph located above were manipulated. The construction of the tower was essentially masonry and brick, and was sometimes whitewashed or plastered and painted ocher. However, although all the towers are practically identical, there are differences in the construction techniques in those that remain standing, surely subject to the availability or lack of different materials in the construction area, or to the criteria of the crews. in charge of raising the building. According to the inventory of an optical tower of the Andalusia Line, carried out at the end of 1857, the ground floor served as a kitchen and the third floor as an observatory.

The network designed by Mathé was large and national in size, as has been said, but only three lines were built:

• The line of Castilewith the Madrid-Irún route;
• The line of Andalusiawith the route Madrid-Cádiz, heir of that projected by Betancourt almost half a century before;
• The Catalan linewith the Madrid-La Junquera route.

The first of them, which began operating on October 2, 1846, had 52 towers and, using the aforementioned Madrid-San Ildefonso line as a base, passed through Valladolid, Burgos, Miranda, Vitoria and San Sebastián.

The second line, called "Andalusia Line", had 59 towers. The first Madrid-Puertollano section began operating in 1850, and was not complete, reaching Cádiz, until 1851, later expanding in 1853 with a last tower in San Fernando (Cádiz). It had stations in Aranjuez, Toledo, Consuegra, Ciudad Real, Puertollano, Montoro, Córdoba, Seville, Jerez de la Frontera, Cádiz and San Fernando. Some telegraph posts were installed in the Alcázar of Toledo, in the Royal Tobacco Factory in Seville and on the walls of Puerta de Tierra in Cádiz.

The third line never fully functioned. The Madrid-Valencia section came into operation in 1849, with 30 towers, it began with the telegraph of the Parque del Retiro in Madrid, a neomedieval construction, known as "El castillete" and currently in a state of ruin. This telegraph sent the signal to Vallecas (where the Santa Eugenia neighborhood is today) and later to Arganda del Rey until reaching the Valencia telegraph over 30 milestones. At various times the Valencia-Castellón, Barcelona-Tarragona, Barcelona-La Junquera and Tarancón-Cuenca sections operated.

The Catalan telegraph network

Due to the special direction that the Carlist question took in Catalonia in the middle of the 19th century, a dense network was built there telegraph that allowed the rapid communication of news and states to combat the persistent guerrilla war that the army of the Carlist claimant was carrying out from the Pyrenees to the entire Catalan territory. The Catalan network of this time is far from being homogeneous. In fact, part of the network uses the Mathé system, and other sections use other proprietary systems.

What makes this telegraphy network more special is that it continued to expand and operate even in the Third Carlist War (1872-1876) given that at that time large areas of Catalonia did not yet have electrotelegraph lines, and they were even built more than 150 telegraph stations. This large number is justified by the special orography of the region.

The decline of optical telegraphy

When in 1844 the necessary impulse was given to optical telegraphy in Spain, electric telegraphy was already known and had been experimented in Europe for 4 years, in some cases the optical telegraph installations coincided with that of the telegraph. electric in 1853. The harsh orography of the Iberian Peninsula was, once again, an almost insurmountable obstacle (as would happen later with the laying of the railway) for this advance in communications.

As early as 1854, the electric telegraphy line between Madrid and Irún was completed. A year later, in 1855, the equivalent optical telegraphy line stopped working, and in 1857 the last one in service of the national network, the Madrid-Cádiz line, was dismantled. The last telegraph stations that stopped working were probably part of the Catalan telegraphy network, at the end of the 19th century, such as has been mentioned above.

Current state in Spain

Nowadays, little or nothing remains of the original optical telegraphy network except for some of the towers in which the telegraphs were located. The Mathé towers, built in a fairly homogeneous way with brickwork chains and masonry complements (Toledan rig), were in many cases used by the locals as a quarry, after abandonment by the Administration.

The vast majority of the few that are still standing totally or partially, do so in a state of ruin to different degrees. Some are converted into housing (as is the case with the one in Torrelodones), others have been restored, such as Cabeza Mediana, near Collado Mediano. The Adanero tower, tower number 11 of the Madrid-Irún line, deserves special mention, which was restored in 2002 by a well-known Spanish mobile telephone company, also placing a telegraph on its top, thus recovering its original appearance. in the middle of the 19th century.

Today we also find an important trace of this technological advance in toponymy, and thus there are numerous hills or mountains that are called "del telegrafo" throughout of the entire Spanish geography, an unequivocal echo of the fact that an optical telegraph once stood at its summit.

Conclusions

Until the creation of the telegraph, the speed of information transmission had remained unchanged for dozens of centuries. In Spain, a horseback rider could take two or three days, in good weather and without any setbacks on the road or with his mount, to go from Madrid to the French border in Irun. With the optical telegraph, the same message took six hours to travel the same distance. The optical telegraph, and then the electric telegraph, shortened distances radically as had not been done since man got on the back of a horse to travel faster, several thousand years before. This advance in communications laid the foundations for the development of the modern State in the 19th century, which was driven by the bourgeoisie, newspapers and the stock market, all elements that benefited enormously from the greater speed in the transmission of news.