The Early History of Data Networks

The Early History of Data Networks by Gerard J. Holzmann and Bjorn Pehrson.

Book review from CCR: here.

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Most of us would consider the emergence of large-scale communication networks to be a twentieth-century phenomenon. The first true nationwide data networks, however, were being built almost two hundred years ago. At the turn of the 18th century, well before the electromagnetic telegraph was invented, many countries in Europe already had fully operational data communications systems, with alltogether close to one thousand network stations.

This book gives a fascinating glimpse of the many documented attempts throughout history to develop effective means for long distance communications. The oldest attempts date back to millenia before Christ, and include an ingenious uses of homing pigeons, mirrors, flags, torches, and beacons.

The book then shows how Claude Chappe, a French clergyman, started the information revolution in 1794, with the design and construction of the first true telegraph network in France. Included is also the first complete English translation of a remarkable document on the design of optical telegraphs that was written in 1796 by the Swedish nobleman Abraham Niclas Edelcrantz, the builder of the Swedish optical telegraph network.

Table of Contents

Preface vii

Chapter One -- Torches and Beacons

Chapter Two -- Claude Chappe

Chapter Three -- Abraham N. Edelcrantz

Chapter Four -- A Treatise on Telegraphs (from 1796)

Chapter Five -- Other Countries

Chapter Six -- About Invention

Appendix A -- Letters to Gentleman's Magazine

Appendix B -- Chappe's Design

Appendix C -- Edelcrantz's Design

Illustrations 241

Notes 245

Bibliography 273

Index 281

Colophon 291-304


It is hard to imagine what daily life must have been like two centuries ago, without radios, movies, telephones, or electricity. Marconi, Edison, Bell and Maxwell had not yet been born, and neither had their parents. The streets in the larger cities were lit by candles. In New York, for example, a city ordinance had been in effect since 1697:

. . . that the lights be hung out in the darke time of the moon within this citty, and for the use of the inhabitants; and that every 7th house doe hang out a lanthorn and a candle in it.
Mail was delivered by stagecoach in the United States, and by merchant vessels and mounted couriers throughout most of Europe. This system operated quite efficiently, also by today's standards. A letter or newspaper took only a few days to travel from London to Stockholm, and to get a piece of mail delivered within one of the larger cities took just hours. It was not unusual to extend a dinner invitation by regular mail in the morning, and to receive the response well in time to make the final preparations for that day.

An eyewitness described the dress code in 1789, when George Washington was sworn in as the first president of the United States, as follows:

There stood Washington, invested with a suit of dark silk velvet, of the old cut, steel-hilted small-sword by his side, hair in a bag and full powdered, in black silk hose, and shoes with silver buckles, as he took the oath of office.
This was the time of chamber music, of horse-drawn carriages, the time of Mozart, Haydn, and Beethoven, of Gauss and Fourier, and the time of James Watt, Claude Chappe, and Abraham Edelcrantz.

James Watt's work is well known. His improved steam engine designs gave a decisive push to the industrial revolution. The names of Chappe and Edelcrantz, however, are not nearly as well known, even though they had an equally revolutionary impact on society. In the eighteenth century they managed to develop the world's first nationwide data communications networks.

Let us go back to September 1794. Imagine Abraham Niclas Edelcrantz, a Swedish nobleman and scholar, in his library in the center of Stockholm, say in front of a nice big fireplace. He is reading Gentleman's Magazine. The September 1794 issue of this journal contained a report on a new French contraption that caught Edelcrantz's attention. This is, in part, what Edelcrantz read:

. . . a method to acquaint people at a great distance, and in very little time, with whatever one pleased. This method is as follows: let persons be placed in several stations, at such distances from each other, that, by the help of a telescope, a man in one station may see a signal made by the next before him; he immediately repeats this signal, which is again repeated through all the intermediate stations. This, with considerable improvements, has been adopted by the French, and denominated a Telegraphe; and, from the utility of the invention, we doubt not but it will be soon introduced in this country.
The invention was attributed to Claude Chappe.
The machines are the invention of Citizen Chappe, and were constructed before his own eyes; he directs their establishment at Paris.
The letter in Gentleman's Magazine described the telegraph that Chappe had developed for the construction of an optical telegraph line connecting Lille to Paris, over a distance of roughly 230 km (143 miles). The line was, by any standard, the first of its kind, and news of its construction was spreading quickly through Europe.

Edelcrantz began experimenting with his own optical telegraph designs the month that the article was published. Two months later he was able to demonstrate a first working version. Edelcrantz's first design still looked much like Chappe's, with articulated arms and flaps. Edelcrantz would later, after many experiments, switch to a shutter telegraph design that is similar to one of the first designs that Chappe had used in 1791 and 1792 and abandoned. There is no indication that Edelcrantz knew about these earlier experiments of Claude Chappe at this time. Why Chappe rejected the shutter principle and replaced it with semaphore arms, and Edelcrantz rejected the semaphore arms and replaced it with shutters is a mystery. Both designs were quite successful, and received much following.

For almost half a century, optical telegraphs became part of the landscape in Europe. They can be spotted in the background of many paintings from this period. They are also mentioned, at least in passing, in several novels and poems. Victor Hugo (1802-1885), for instance, wrote a long poem called Le Telegraphe. The Swedish poet Elias Sehlstedt dedicated a collection of poems to the optical telegraph, titled Telegrafen--Poetisk Kalender for 1858. The telegraphs also feature prominently in Stendhal's Lucien Leuwen, which was first published in 1842. The following passage appears in The Count of Monte Cristo, published in 1844:

``Thank you,'' said Monte Cristo, ``and now, please allow me to take leave of you. I'm about to go see something which has often made me thoughtful for hours on end.'' ``What is it?'' ``A telegraph. I was almost ashamed to say it, but now you know.'' ``A telegraph ?'' repeated Madame de Villefort. ``Yes, that's right. I've often seen those black shining arms rising from the top of a hill or at the end of a road, and it has never been without emotion for me, for I've always thought of those strange signs cleaving the air for three hundred leagues to carry thoughts of one man sitting at his desk to another man sitting at his desk at the other end of the line. It has always made me think of genii, sylphs or gnomes; in short, of occult powers, and that amuses me. Then one day I learned that the operator of each telegraph is only some poor devil employed for twelve hundred francs a year, constantly occupied in watching another telegraph four or five leagues away. I then became curious to see that living chrysalis at close quarters and watch the comedy he plays for the other chrysalis by pulling on his strings. ``What telegraph are you going to visit ?'' asked Villefort. ``Which line would you advise me to study ?'' ``Why, the one that's the busiest now, I suppose.'' ``That would be the line from Spain, wouldn't it ?'' ``Yes. But you'd better hurry; it will be dark in two hours and you won't be able to see anything.'' ``Thank you,'' said Monte Cristo. ``I'll tell you about my impressions when I see you Saturday.''
Monte Cristo proceeds to bribe a telegraph operator to transmit a false message to Paris. How likely or unlikely this might have been will become clear in the following chapters.


When optical telegraphs were superseded by electrical telegraphs, much of their history was forgotten. Today, at the bicentennial of the optical telegraphs, we would like to look back, and record the fascinating story of their discovery and use.
Distance Metrics

Unit Feet Meters
Swedish Mile 32,577 10,689 German Mile 25,000 7,620 French Mile 14,000 4,267 English (U.S.) Mile 5,280 1,609 League 15,840 4,827 Km 3,280 1,000 Fathom 6 1.83 Ell 1.948 0.594 Cubit 1.72 0.52

The first chapter gives an overview of the attempts made throughout history to come up with effective methods for long-distance communication. Apart from the more obvious courier and beacon systems, remarkably sophisticated devices were developed, in some cases more than two thousand years ago. In the second chapter we look at Claude Chappe's struggle to build a communications network in the late eighteenth century in France. The third chapter tells the story of Edelcrantz's attempts in Sweden to accomplish the same goal. Edelcrantz documented his design in a wonderful booklet called Treatise on Telegraphs that was first published in 1796. Almost immediately after its publication, the document was translated into French and German, but for some reason, it was never translated into English. Chapter Four contains our translation, which gives a glimpse of the world of a serious eighteenth century scholar attacking a twentieth century problem. In Chapter Five we take a closer look at the developments in some of the other countries, both in Europe and elsewhere. In most countries similar optical telegraph lines were built, though not quite on the same scale as in Sweden and France. Chapter Six concludes the book with a comparison of Chappe's and Edelcrantz's system and a brief look at the contributions that they each made to the art of signaling.

Three appendices contain documents on Chappe's and Edelcrantz's designs. Appendix A reproduces three letters that appeared in late 1794 in Gentleman's Magazine, recording the first reactions to Chappe's experiments from earlier that year. Appendix B has the instructions and regulations for the French optical telegraphs. Appendix C gives the station instructions and a penal code for the Swedish design.

The words telegraph, telescope, and semaphore, used throughout this book, have a Greek origin, though they are not part of the original language. Tele means ``at a distance,'' graphos means ``writer'' or ``signaler,'' and skopos means ``watcher'' or ``observer.'' Sema means ``sign'' or ``symbol,'' and phoros means ``bearer'' or ``carrier.'' Telescopes were invented in 1608 (see Chapter 1); the words telegraph and semaphore first entered the language in the late eighteenth century (Chapter 2), as a result of the experiments that we will describe.

The distance metrics in use today are considerably younger than many of the sources that we refer to in this book. In 1794 Swedish, French, German, and English miles all represented different lengths. Wherever possible, we use the metric system here, occasionally with the equivalent in U.S. (i.e., English) miles in parentheses. In all other cases, the distances are disambiguated with a country prefix. For reference, the relevant conversions are listed in the table of distance metrics shown above.

This book is the product of many years of enjoyable sleuthing into the history of communication systems. We have been helped by many wonderful people along the way, and it is a true pleasure to acknowledge them here. They include:

Stephane Baier, Jon Bentley, Bertil Bage, M. Blanloeil, Pierre Bosom, Jan Brans, Warren Burstein, Andre Butrica, Rosa Busquets, Lynne Bush, Patrice Carre, John Chaves, Lorinda Cherry, Gerard Contant, Dan Doernberg, Richard Drechsler, Maija Elo, Terje Ellefsen, Ari Epstein, Patrik Ernberg, Patrice Godefroid, Johan Goudsblom, Ron Hardin, Catherine Harris, Jay B. Haviser, Richard Q. Hofacker Jr., Lars Johannesson, M. Katz, Brian W. Kernighan, Srinivasan Keshav, Olga Lopez, Erik Ludwig, Jim Mais, M. Marchand, M. Douglas McIlroy, A. Beate Oestreicher, Helly Oestreicher, Nils Olander, Michel Ollivier, Judith A. Paone, Robert M. Papp, Craig Partridge, Rob Pike, Pilar Prieto, Marty Rabinowitz, Jim Reeds, Frank Reichert, Dennis M. Ritchie, C. van Romburgh, Johan Romstad (owner of the telegraph house in Furusund), Nelly Roussel, Carl-Erik Sundberg, Maureen Tate (Language Center New York), Teller, Chris Wagner, John Wait, Phil Winterbottom, Jan Zwijnenberg,
and of course the many dedicated researchers at the libraries, archives, and museums we visited in Amsterdam, Barcelona, Brulon, Grenoble, La Flêche, London, Nantes, New York, Paris, Pleumeur Bodou, Sacramento, San Francisco, Stockholm, The Hague, and Uppsala.

Our objective has been to provide an account that is both accurate and readable. To convince ourselves of the accuracy, we checked and double-checked every fact, by going back to the original sources where available. Nonetheless, it is possible that we have missed important details. We would be grateful to any reader who can correct the story, or add to it.

It was our privilege to present an early edition of this book to King Carl XVI Gustaf of Sweden on 22 June 1994, at the bicentennial celebration of the first experiments with optical telegraphs in Sweden.

Gerard J. Holzmann, gerard atsign spinroot dot com

Bjorn Pehrson, bjorn atsign