Saturday, October 5, 2019

Book summary: A Thread Across the Ocean

A Thread Across the Ocean: The Heroic Story of the Transatlantic Cable

by John Steele Gordon

The most wonderful thing about the writing in this book is the constant impression that the author is a wide-ranging expert on everything about the history of this period, but he happened to choose to write about the transatlantic cable. The contextual asides and periodic tangents are so interesting and richly written that they bring the narrative more vividly to life rather than distracting from it, which is what usually happens to such tangents in the hands of less skilled historian-authors.

I had never really thought about how the transatlantic cable was laid. Among the things that surprised me, starting with the fact that it was privately funded—essentially by one man who spent his own fortune and raised huge amounts of money from others. A consummate entrepreneur, American businessman Cyrus Field was analogous to a theatrical producer: “The producer does not sing, act, or dance, but without him/her, neither does anyone else.”

The cable was laid at a time of great techno-optimism, but relatively little techno-savvy. Electricity wasn’t well understood yet—the discoveries and formulae of Ohm and Watt were roughly contemporaneous with the first attempts at cable-laying—and there was no real pushback to the idea that if you could shove an electrical (telegraph) signal through an underwater cable a few miles long (short-run telegraph cables had successfully traversed rivers and small bays), why not through a 2,000+ mile cable? There was telegraphy infrastructure in Newfoundland and Nova Scotia, so once news reached North America (typically by ship from Europe), it could propagate quickly; but Field wanted to reduce that latency by the 2 weeks or so it took to make the transatlantic crossing.

I also didn’t realize that Field consulted one of the leading British naval explorers of the time, Lt. Matthew Maury, whose explorations and soundings of the Atlantic revealed a long “shelf” connecting (roughly) the coast of Ireland to Newfoundland, moving the sea bottom a couple of thousand fathoms shallower than elsewhere and seemingly almost intended for a transatlantic cable to be laid.

That it took five attempts before a functioning cable was achieved is staggering, and each attempt was essentially brute force, though each attempt addressed mistakes of earlier attempts. Imagine piling 2000 miles of cable into a ship—even, in one attempt, a purpose-built ship—sailing away from Ireland, paying out cable as you go, hoping nothing breaks. That kind of chutzpah would not be seen again (in my view) until the manned moon landings. Indeed, the first attempt didn’t even use a steamship, but a sailing ship, notoriously difficult to control, and the ship was operated as a cruise for the investors and VIPs. Future endeavors used steam-powered ships instead of sailing ships, even at one point custom-building a ship with highly maneuverable dual steamer wheels, all manner of special equipment for unspooling and laying the cable without having it kink or tangle, and more. Vulcanized rubber was undiscovered, so gutta percha (a natural tree extract) was used instead, but it had problems of its own and the early cables made with it could kink and crack. 

At least two of the attempts ended with the cable snapping or being severed while paying out, and I can barely imagine the feeling of watching the end of a piece of cable sink to the ocean floor thousands of feet below after you’ve laid nearly a thousand miles of it and the other end is in Ireland.

Even more impressive was the (ultimately successful) attempt on one such mission to drag a hook along the ocean bottom to grapple the cable and pull it back up, splice the broken ends back together, and continue the attempt!

Of course, the first cables (which become operational in 1869) were only suitable for telegraphy; signal-to-noise considerations and signal propagation in the presence of parasitic capacitance and inductance were not well understood, so the signal bandwidth was barely sufficient for Morse code telegraphy, at a few words per minute and astronomical cost to the sender. But it worked, and future advancements in electronics led to AT&T laying a new cable with repeaters to boost the signal every few miles, allowing transatlantic voice communication.

Transatlantic cables were workhorses for longer than most people realized. Satellite communications were being used for long distance phone service up until the 1970s, when it became possible to lay fiber optic transatlantic cables; at which point the cost per bit fell so dramatically that satellites had no business model anymore. Today we take instantaneous global communication for granted, but it’s humbling to read about how one man—really, the Elon Musk of his time—had an audacious vision and made it happen. Every chapter is a cliffhanger, and it makes for a thoroughly entertaining and informative read for anyone interested in the history of communications or in the catalog of engineering marvels of a forward-looking age.

Book summary: A Thread Across the Ocean

A Thread Across the Ocean: The Heroic Story of the Transatlantic Cable by John Steele Gordon The most wonderful thing about the writ...