Some Remarks: Essays and Other Writing

by Neal Stephenson

  Many of the features that made Cornwall attractive to cable operators also made it a suitable place to conduct transatlantic radio experiments, and so in 1900 Guglielmo Marconi himself established a laboratory on Lizard Point, which is directly across the bay from Porthcurno, some 30 kilometers distant. Marconi had another station on the Isle of Wight, a few hundred kilometers to the east, and when he succeeded in sending messages between the two, he constructed a more powerful transmitter at the Lizard station and began trying to send messages to a receiver in Newfoundland. The competitive threat to the cable industry could hardly have been more obvious, and so the Eastern Telegraph Company raised a 60-meter mast above its Porthcurno site, hoisted an antenna, and began eavesdropping on Marconi’s transmissions. A couple of decades later, after the Italian had worked the bugs out of the system, the government stepped in and arranged a merger between his company and the submarine cable companies to create a new, fully integrated communications monopoly called Cable & Wireless.

  50˚ 2.602' N, 5˚ 39.054' W Museum of Submarine Telegraphy, Porthcurno, Cornwall

  On a sunny summer day, Porthcurno Beach was crowded with holidaymakers. The vast majority of these were scantily clad and tended to face toward the sun and the sea. The fully clothed and heavily shod tourists with their backs to the water were the hacker tourists; they were headed for a tiny, windowless cement blockhouse, scarcely big enough to serve as a one-car garage, planted at the apex of the beach. There was a sign on the wall identifying it as the Museum of Submarine Telegraphy and stating that it is open only on Wednesday and Friday.

  This was appalling news. We arrived on a Monday morning, and our maniacal schedule would not brook a two-day wait. Stunned, heartbroken, we walked around the thing a couple of times, which occupied about 30 seconds. The lifeguard watched us uneasily. We admired the brand-new manhole cover set into the ground in front of the hut, stamped with the year ’96, which strongly suggested a connection with FLAG. We wandered up the valley for a couple of hundred meters until it opened up into a parking lot for beach-goers, surrounded by older white masonry buildings. These were well-maintained but did not seem to be used for much. We peered at a couple of these and speculated (wrongly, as it turned out) that they were the landing station for FLAG.

  Tantalizing hints were everywhere: the inevitable plethora of manholes, networked to one another by long straight strips of new pavement set into the parking lot and the road. Nearby, a small junkheap containing several lengths of what to the casual visitor might look like old, dirty pipe but which on closer examination proved to be hunks of discarded coaxial cable. But all the buildings were locked and empty, and no one was around.

  Our journey seemed to have culminated in failure. We then noticed that one of the white buildings had a sign on the door identifying it as The Cable Station—Free House. The sign was adorned with a painting of a Victorian shore landing in progress—a line of small boats supporting a heavy cable being payed out from a sailing ship anchored in Porthcurno Bay.

  After coming all this way, it seemed criminal not to have a drink in this pub. By hacker tourist standards, a manhole cover counts as a major attraction, and so it was almost surreal to have stumbled across a place that had seemingly been conceived and built specifically for us. Indeed, we were the only customers in the place. We admired the photographs and paintings on the walls, which all had something or other to do with cables. We made friends with Sally the Dog, chatted with the proprietress, grabbed a pint, and went out into the beer garden to drown our sorrows.

  Somewhat later, we unburdened ourselves to the proprietress, who looked a bit startled to learn of our strange mission, and said, “Oh, the fellows who run the museum are inside just now.”

  Faster than a bit speeding down an optical fiber we were back inside the pub where we discovered half a dozen distinguished gentlemen sitting around a table, finishing up their lunches. One of them, a tall, handsome, craggy sort, apologized for having ink on his fingers. We made some feeble effort to explain the concept of Wired magazine (never easy), and they jumped up from their seats, pulled key chains out of their pockets, and took us across the parking lot, through the gate, and into the museum proper. We made friends with Minnie the Cable Dog and got the tour. Our primary guides were Ron Werngren (the gent with ink on his fingers, which I will explain in a minute) and John Worrall, who is the cheerful, energetic, talkative sort who seems to be an obligatory feature of any cable-related site.

  All of these men are retired Cable & Wireless employees. They sketched in for us the history of this strange compound of white buildings. Like any old-time cable station, it housed the equipment for receiving and transmitting messages as well as lodgings and support services for the telegraphers who manned it. But in addition it served as the campus of a school where Cable & Wireless foreign service staff were trained, complete with dormitories, faculty housing, gymnasium, and dining hall.

  The whole campus has been shut down since 1970. In recent years, though, the gentlemen we met in the pub, with the assistance of a local historical trust, have been building and operating the Museum of Submarine Telegraphy here. These men are of a generation that trained on the campus shortly after World War II, and between them they have lived and worked in just as many exotic places as the latter-day cable guys we met on Lan Tao Island: Buenos Aires, Ascension Island, Cyprus, Jordan, the West Indies, Saudi Arabia, Bahrain, Trinidad, Dubai.

  Fortunately, the tiny hut above the beach is not the museum. It’s just the place where the cables are terminated. FLAG and other modern cables bypass it and terminate in a modern station up at the head of the valley, so all of the cables in this hut are old and out of service. They are labeled with the names of the cities where they terminate: Faial in the Azores, Brest in France, Bilbao in Spain, Gibraltar 1, Saint John’s in Newfoundland, the Isles of Scilly, two cables to Carcavelos in Portugal, Vigo in Spain, Gibraltar 2 and 3. From this hut, the wires proceed up the valley a couple hundred meters to the cable station proper, which is encased in solid rock.

  During World War II, the Porthcurno cable nexus was such a painfully obvious target for a Nazi attack that a detachment of Cornish miners were brought in to carve a big tunnel out of a rock hill that rises above the campus. This turned out to be so wet that it was necessary to then construct a house inside the tunnel, complete with pitched roof, gutters, and downspouts to carry away the eternal drizzle of groundwater. The strategically important parts of the cable station were moved inside. Porthcurno Bay and the Cable & Wireless campus were laced with additional defensive measures, like a fuel-filled pipe underneath the water to cremate incoming Huns.

  Now the house in the tunnel is the home of the museum. It is sealed from the outside world by two blast doors, each of which consists of a foot-thick box welded together from inch-thick steel plate. The inner door has a gasket to keep out poison gas. Inside, the building is clean and almost cozy, and except for the lack of windows, one is not conscious of being underground.

  Practically the first thing we saw upon entering was a fully functional Kelvin mirror galvanometer—the exquisitely sensitive detector that sent Wildman Whitehouse into ignominy, made the first transatlantic cable useful, and earned William Thomson his first major fortune. Most of its delicate innards are concealed within a metal case. The beam of light that reflects off its tiny twisting mirror shines against a long horizontal screen of paper, marked and numbered like a yardstick, extending about 10 inches on either side of a central zero point. The light forms a spot on this screen about the size and shape of a dime cut in half. It is so sensitive that merely touching the machine’s case—grounding it—causes the spot of light to swing wildly to one end of the scale.

  At Porthcurno this device was used for more than one purpose. One of the most important activities at a cable station is pinpointing the locations of faults, which is done by measuring the resistance in the cable. Since the resistance per unit of length is a known quantity, a precise measurement of resistan
ce gives the distance to the fault. Measuring resistance was done by use of a device called a Wheatstone bridge. The museum has a beautiful one, built in a walnut box with big brass knobs for dialing in resistances. Use of the Wheatstone bridge relies on achieving a null current with the highest attainable level of precision, and for this purpose, no instrument on earth was better suited than the Kelvin mirror galvanometer. Locating a mid-ocean fault in a cable therefore was reduced to a problem of twiddling the dials on the Wheatstone bridge until the galvanometer’s spot of light was centered on the zero mark.

  The reason for the ink on Ron Werngren’s fingers became evident when we moved to another room and beheld a genuine Kelvin siphon recorder, which he was in the process of debugging. This machine represented the first step in the removal of humans from the global communications loop that has culminated in the machine room at cable landing stations like Ninomiya.

  After Kelvin’s mirror galvanometer became standard equipment throughout the wired world, every message coming down the cables had to pass, briefly, through the minds of human operators such as the ones who were schooled at the Porthcurno campus. These were highly trained young men in slicked hair and starched collars, working in teams of two or three: one to watch the moving spot of light and divine the letters, a second to write them down, and, if the message were being relayed down another cable, a third to key it in again.

  It was clear from the very beginning that this was an error-prone process, and when the young men in the starched collars began getting into fistfights, it also became clear that it was a job full of stress. The stress derived from the fact that if the man watching the spot of light let his attention wander for one moment, information would be forever lost. What was needed was some mechanical way to make a record of the signals coming down the cable. But because of the weakness of these signals, this was no easy job.

  Lord Kelvin, never one to rest on his laurels, solved the problem with the siphon recorder. For all its historical importance, and for all the money it made Kelvin, it is a flaky-looking piece of business. There is a reel of paper tape which is drawn steadily through the machine by a motor. Mounted above it is a small reservoir containing perhaps a tablespoon of ink. What looks like a gossamer strand emerges from the ink and bends around through some delicate metal fittings so that its other end caresses the surface of the moving tape. This strand is actually an extremely thin glass tube that siphons the ink from the reservoir onto the paper. The idea is that the current in the cable, by passing through an electromechanical device, will cause this tube to move slightly to one side or the other, just like the spot of light in the mirror galvanometer. But the current in the old cables was so feeble that even the infinitesimal contact point between the glass tube and the tape still induced too much friction, so Kelvin invented a remarkable kludge: he built a vibrator into the system that causes the glass tube to thrum like a guitar string so that its point of contact on the paper is always in slight motion.

  Dynamic friction (between moving objects) is always less than static friction (between objects that are at rest with respect to each other). The vibration in the glass siphon tube reduced the friction against the paper tape to the point where even the weak currents in a submarine cable could move it back and forth. Movement to one side of the tape represented a dot, to the other side a dash. We prevailed upon Werngren to tap out the message Get Wired. The result is on the cover of this magazine, and if you know Morse code you can pick the letters out easily.

  The question naturally arises: How does one go about manufacturing a hollow glass tube thinner than a hair? More to the point, how did they do it 100 years ago? After all, as Worrall pointed out, they needed to be able to repair these machines when they were posted out on Ascension Island. The answer is straightforward and technically sweet: you take a much thicker glass tube, heat it over a Bunsen burner until it glows and softens, and then pull sharply on both ends. It forms a long, thin tendril, like a string of melted cheese stretching away from a piece of pizza. Amazingly, it does not close up into a solid glass fiber, but remains a tube no matter how thin it gets.

  Exactly the same trick is used to create the glass fibers that run down the center of FLAG and other modern submarine cables: an ingot of very pure glass is heated until it glows, and then it is stretched. The only difference is that these are solid fibers rather than tubes, and, of course, it’s all done using machines that assure a consistent result.

  Moving down the room, we saw a couple of large tabletops devoted to a complete, functioning reproduction of a submarine cable system as it might have looked in the 1930s. The only difference is that the thousands of miles of intervening cable are replaced with short jumper wires so that transmitter, repeaters, and receiver are contained within a single room.

  All the equipment is built the way they don’t build things anymore: polished wooden cabinets with glass tops protecting gleaming brass machinery that whirrs and rattles and spins. Relays clack and things jiggle up and down. At one end of the table is an autotransmitter that reads characters off a paper tape, translates them into Morse code or cable code, and sends its output, in the form of a stream of electrical pulses, to a regenerator/retransmitter unit. In this case the unit is only a few feet away, but in practice it would have been on the other end of a long submarine cable, say in the Azores. This regenerator/retransmitter unit sends its output to a twin siphon-tube recorder which draws both the incoming signal (say, from London) and the outgoing signal as regenerated by this machine on the same paper tape at the same time. The two lines should be identical. If the machine is not functioning correctly, it will be obvious from a glance at the tape.

  The regenerated signal goes down the table (or down another submarine cable) to a machine that records the message as a pattern of holes punched in tape. It also goes to a direct printer that hammers out the words of the message in capital letters on another moving strip of paper. The final step is a gummer that spreads stickum on the back of the tape so that it may be stuck onto a telegraph form. (They tried to use pregummed tape, but in the tropics it only coated the machinery with glue.)

  Each piece of equipment on this tabletop is built around a motor that turns over at the same precise frequency. None of it would work—no device could communicate with any other device—unless all of those motors were spinning in lockstep with one another. The transmitter, regenerator/retransmitter, and printer all had to be in sync even though they were thousands of miles apart.

  This feat is achieved by means of a collection of extremely precise analog machinery. The heart of the system is another polished box that contains a vibrating reed, electromagnetically driven, thrumming along at 30 cycles per second, generating the clock pulses that keep all the other machines turning over at the right pace. The reed is as precise as such a thing can be, but over time it is bound to drift and get out of sync with the other vibrating reeds in the other stations.

  In order to control this tendency, a pair of identical pendulum clocks hang next to each other on the wall above. These clocks feed steady, one-second timing pulses into the box housing the reed. The reed, in turn, is driving a motor that is geared so that it should turn over at one revolution per second, generating a pulse with each revolution. If the frequency of the reed’s vibration begins to drift, the motor’s speed will drift along with it, and the pulse will come a bit too early or a bit too late. But these pulses are being compared with the steady one-second pulses generated by the double pendulum clock, and any difference between them is detected by a feedback system that can slightly speed up or slow down the vibration of the reed in order to correct the error. The result is a clock so steady that once one of them is set up in, say, London, and another is set up in, say, Cape Town, the machinery in those two cities will remain synched with each other indefinitely.

  This is precisely the same function that is performed by the quartz clock chip at the heart of any modern computing device. The job performed by the regenerator/retransmitter is
also perfectly recognizable to any modern digitally minded hacker tourist: it is an analog-to-digital converter. The analog voltages come down the cable into the device, the circuitry in the box decides whether the signal is a dot or a dash (or if you prefer, a 1 or a 0), and then an electromagnet physically moves one way or the other, depending on whether it’s a dot or a dash. At that moment, the device is strictly digital. The electromagnet, by moving, then closes a switch that generates a new pulse of analog voltage that moves on down the cable. The hacker tourist, who has spent much of his life messing around with invisible, ineffable bits, can hardly fail to be fascinated when staring into the guts of a machine built in 1927, steadily hammering out bits through an electromechanical process that can be seen and even touched.

  As I started to realize, and as John Worrall and many other cable-industry professionals subsequently told me, there have been new technologies but no new ideas since the turn of the century. Alas for Internet chauvinists who sneer at older, “analog” technology, this rule applies to the transmission of digital bits down wires, across long distances. We’ve been doing it ever since Morse sent “What hath God wrought!” from Washington to Baltimore.

  (Latitude & longitude unknown) Cable & Wireless Marine, Chelmsford, England

  [Note: I left my GPS receiver on a train in Bristol and had to do without it for a couple of weeks until Mr. Gallagher, station supervisor at Preston, Lancashire, miraculously found it and sent it back to me. Chelmsford is a half-hour train ride northeast of London.]