Article - Issue 6, November 2000
The second industrial revolution: the role of communications
Professor Laszlo Solymar FRS
Since there is no generally accepted definition of the Second Industrial Revolution it might be worthwhile to start with possible definitions. The First Industrial Revolution may be said to have come to assist our muscles whereas the Second Industrial Revolution has come to assist our brains. With a slight change in emphasis we could also say that the First Industrial Revolution made muscles redundant whereas the Second Industrial Revolution is in the process of making our brains superfluous. I am sure that many other definitions are possible but all would suggest a radical change both in the way industry works and in the manner society responds.
The Atlantic telegraph cables
So how did it all start? I wish to claim that the starting point was a paper in 1856 by William Thomson (later Lord Kelvin) in which he calculated the spread of an electric pulse sent along a long cable. The need for such calculations was provided by the Atlantic cable, a gigantic enterprise, a demonstration of the courage and confidence of our Victorian forefathers.
The mechanical engineering problems were daunting (just consider how to store in a ship three thousand miles of cable, or how to build the paying out apparatus) but familiar. The electrical problem of pulse spreading was entirely new. Nobody had the slightest idea of how to reduce the spread: they did not even know whether the cable should be made thicker or thinner. Clearly, the way to learn how the pulse spreads is by doing experiments. However no cable long enough existed and sending pulses to and fro along a shorter cable had its experimental pitfalls. So Thomson set up a second order partial differential equation known today as the telegraphist’s equation, solved it and out of it came the dependence of the pulse spread on the various cable parameters. It was a momentous time in history. For the first time ever a practical, and very significant, engineering problem was solved with the aid of a partial differential equation. Thomson’s calculations were of course regarded as quite irrelevant at the time. E. O. W. Whitehouse, who was a little later in charge of all the electrical engineering problems in the Atlantic cable project wrote:
… I can only regard it as a fiction of the schools, a forced and violent adaptation of a principle in Physics good and true under other circumstances but misapplied here.
The coming of the telephone
Thomson was proved right in the end, and the second and eventually successful cable, laid in 1865, was designed according to his specifications. The telegraphist’s equation became part of conventional wisdom. But circumstances changed. In 1864 Maxwell published his equations, in the 1870s the telephone appeared on the scene. It led to a major clash between believers of the old system (based on the telegraphist’s equation) and of the new one at the 1888 meeting of the British Association. The promoters of the new kind of thinking were Heaviside and Lodge. They thought that some of the newly discovered phenomena (in particular current in a lightning conductor) could only be explained if a new term was added to the telegraphist’s equation standing for self-inductance.
William Preece, Chief Engineer of the British Post Office from 1877 to 1899 had the following to say about self-inductance:
The practical man with his eye and his mind trained by the stern realities of daily experience, on a scale vast compared with that of the little world of laboratory, revolts from such wild hypotheses, such unnecessary and inconceivable conceptions, such a travesty of the beautiful simplicity of nature.
The fierce debate between Preece and Lodge ended, according to Electrical Plant, with the victory of Preece, who managed to slay his opponent (see cartoon). Preece was of course wrong and Lodge and Heaviside were right. The proof came a little later. Using sophisticated mathematics Heaviside proved that the range of telephone lines could be very much extended if self-inductances were inserted at periodic intervals. Preece refused to let the paper be published. But the Americans at Bell Laboratories and at Columbia University took up the idea. It was duly patented, coils were added periodically to the lines, and lo and behold the range of telephone lines could be extended by a factor of two. The New York–Denver line was inaugurated in 1911 using the new technology.
So this was another proof that great engineering advances could be made by relying on the predictions of sophisticated mathematical calculations. It needs to be emphasized that the mathematics was not merely used to have more accurate design equations. It was used to arrive at a completely new solution, a solution not backed by any kind of intuition. Once the line was built engineering intuition could again occupy its rightful place but this time the new intuition was based on a mathematical solution.
The point I wish to make is that for the Second Industrial Revolution to be successful a necessary condition was the development of a three-way interaction between Engineering, Physics and Mathematics, and as it happened, that interaction came about because of the need for improved communications.
The electron, amplifiers and semiconductors
Luckily, for the Second Industrial Revolution, the electron was discovered in the last decade of the nineteenth century. It could have remained the plaything of physicists for a long time had not the communications engineers wanted an efficient detector of radio waves. In 1904 Ambrose Fleming used the diode for just that purpose. A few years later Lee de Forest added another electrode turning the diode into a triode. It turned out to have some extraordinary properties: it could amplify electronic signals. By inserting these amplifiers into the telephone line the last limitations were removed. In 1915 it became possible to phone San Francisco from New York . In the electronic revolution mathematics played only a minor role. The advances were mostly based on engineering intuition and clever experimental research. And it was all driven by the needs of communications.
The electronics industry, based on vacuum tubes, reached great sophistication by the end of the Second World War. But tubes were big, clumsy, likely to burn out and used a lot of power. What could take their place? In the 1920s Julius Lilienfeld working in Leipzig took out a patent for a solid state amplifier. It still used electrons but now the electrons moved in a solid. The principles were admirable but the device did not work. The reason was simple. In the twenties very little was known about the properties of electrons in solids. However solid state physics was born in the next decade. By the end of the Second World War it was still in its infancy but the infant was quite robust. There was no doubt that it would soon reach maturity. Research started in earnest at Bell Laboratories under the leadership of William Shockley. In a couple of years their labour brought forth a solid state semiconductor amplifier that they called the transistor. The subsequent celebrations were fully justified but they were somewhat marred by the fact that they had no idea how their new device worked. Then came again that interaction; this time it was between engineering and physics with mathematics offering a helpful hand. Shockley sat down at his desk and based on his knowledge of solid state physics he set up a mathematical model for the operation of an amplifier consisting of two semiconductor junctions. When built, and after the elimination of some hitches, it worked as predicted. This was the moment when the Second Industrial Revolution became unstoppable. After the individual transistor came integrated circuits and the tendency for the circuits to become smaller and more powerful each year.
I have just argued that with the development of semiconductor technology the Second Industrial Revolution became unstoppable. Perhaps not, perhaps one more component was needed, the amazing advance of optical techniques which run nowadays under the name of photonics. The crucial invention was of course that of the laser whose properties were predicted by Schawlow and Townes and found experimentally by Maiman. But at the time the laser was a solution without a problem. Nobody knew what the new device could be used for. Nonetheless research went on and new types of lasers were constructed in quick succession. Some applications slowly appeared but the really big one was communications.
How did optical and communications technology meet? Optical signals have been used of course from time immemorial in the form of fire and smoke signals so the question is rather how did these techniques meet in modern times? It was the intuition of Alec Reeves at Standard Telecommunications Laboratories which started the whole thing off. He became convinced at the end of the 1950s that optics would be the eventual winner in the longdistance communications race and entrusted a small group with the task of looking into the various possibilities. For Reeves the invention of the laser came as an unexpected boon. His men were already running along the right track when a bandwagon suddenly appeared. They jumped upon it without losing any time while the rest of the world was not even aware that there were any bandwagons on the move. The dielectric waveguide in the form of a fibre, invented well back in the 1890s for transmitting light, was one of the candidates. Toni Karbowiak, who was by 1964 in charge of the transmission medium studies at Standard Telecommunications Laboratories concluded in a paper read to the Institution of Electrical Engineers in London that
Of all the guides known to-date the fibre guide appears to hold the most promise, if due to advances in material technology, it becomes possible to manufacture cladded fibres having effective loss tangent about two orders of magnitude better than at present.
Progress was of course slow. It was bound to be slow because there was no chance at the time of using even a fraction of the enormous capacity of optical fibres. The demand was simply not there. The rest of the story is that of triumphal advance. There were two milestones on the way. The reduction of losses below 16 db/km by Corning Glass Works around 1970 and the invention of the fibre amplifier by David Payne in 1987. The technology as it has developed can now genuinely reduce the globe to a village. Without optical fibres the potential of the Internet would have never been realized.
What about computers? Was the impetus for the development of computers also given by the demands of communications? Not in the very beginning when Charles Wheatstone worked on telegraphy and Charles Babbage on his difference engine. But in modern times, yes. Colossus, the first electronic computer built by the British Post Office in 1943, had a lot to do with communications. Its very existence came about because of the wartime effort to decypher German communications. And of course the components needed by computers were already available thanks to the efforts of the communications industries. The tubes used for amplification could also be employed as switches in computer circuits. Colossus used 2,500 vacuum tubes and consumed 4.5 kW of power. Admittedly, computers have been used after further development for lots of purposes e.g. industrial control, scientific calculations or business accounting, and it is also likely that in the near future every appliance, from washing machine to credit card, is going to have a computer inside. Does that mean that the role of communications has declined? On the contrary, it is on the increase. In modern systems it is impossible to say where computers end and communications equipment starts. They all work on the same principle: they are digital systems using solid state electronic devices. And we should not forget that the spectacular increase in the number of computers has also been driven by the demand for easier and faster communications. The main function of a Personal Computer nowadays is to send and receive instantaneous mail from all the world over, and to surf the Internet, i.e. to communicate interactively with supermarkets, travel agencies, libraries, museums, etc. in order to make use of the vast amount of information stored around the world. I wish to conclude with the thought that the driving force behind most new developments was the desire to improve communications. In the practical arts it was communications which first led to sophisticated mathematical models, it was communications which recruited electrons into our service, and it was communications which brought us semiconductor technology and photonics. And the demand for more and more communications is still there. Will it saturate? Sometime in the future, certainly, but not as yet. Will the new technology merely assist our brains or will it replace them? It’s too early to say.
This is the last of three articles on the history of point-to-point communications based on the author’s research for the book Getting the Message: A History of Communications (Oxford University Press, 1999).