SPEAKER_00: Amazing, fascinating stories of inventions, ideas and innovations. Yes, this is the podcast about the things that have helped to shape our lives. Podcasts from the BBC World Service are supported by advertising.
SPEAKER_04: 50 Things That Made The Modern Economy with Tim Harford
SPEAKER_03: It was October the 3rd, 1744. A storm was brewing in the English Channel. With sails set for home after chasing a French fleet off the coast of Portugal, a squadron of English warships led by Admiral Sir John Balkan was heading straight for trouble.
SPEAKER_01: We met with a hard gale of wind, which tore all our sails and rigging, that we were obliged to submit to the mercy of the waves. That's the account of one sailor whose ship made
SPEAKER_03: it back to harbour, but only just.
SPEAKER_01: On the 4th we had ten feet in our hold, which made our condition very bad, and the dread of death appeared in every face, for we momentarily expected to be swallowed up.
SPEAKER_03: One ship was swallowed up. The flagship, HMS Victory, commanded by Admiral Balkan himself. It sank 100 metres to the seabed, 80 kilometres south of Plymouth, taking with it 1,100 men, and so rumour had it, quite a lot of Portuguese gold bullion. There the wreckage lay until a decade ago, when treasure hunters located it. They were hoping to find the gold, but there was something else on board the ship that has proved much more economically significant. The first known attempt to apply an idea that's now used to guide everything from submarines to satellites, from rovers on Mars to the phone in your pocket. The man behind that idea was John Cersun, and a year before the wreck he'd been invited on board a Royal yacht near London to explain it to two high-ranking naval officers and an eminent mathematician. Cersun was a sea captain, he was barely literate, but he was an ingenious mechanic, as the Gentleman's Magazine later put it. His idea was inspired by a child's toy, the spinning top. The problem he wanted to solve was this. Sailors worked out a ship's position by using a quadrant to take an angle from the sun to the horizon, but you couldn't always see the horizon for haze or mist. Cersun wondered if he could create an artificial horizon, something that would stay level even as a ship lurched and swayed around it. The Gentleman's Magazine explained. He got a kind of top made, whose
SPEAKER_02: upper surface perpendicular to the axe was a circular plane of polished metal, and found, as he had expected, that when this top was briskly set in motion, its plane surface would soon become horizontal. If the whirling plane were disturbed from its horizontal position, it would soon recover it again. The officers and the mathematician were impressed. In their
SPEAKER_02: opinion, Mr Cersun's contrivance was highly deserving their encouragement, as likely to prove very useful in foggy weather. The Navy asked Cersun to make further observations aboard
SPEAKER_03: the HMS Victory. And so perished poor Mr Cersun. But his idea lived on. Others made versions of
SPEAKER_03: his device. One was sold to the French Academy of Sciences, much to the disdain of the Gentleman's Magazine. As it turned out, insignificant alterations weren't enough. Cersun's whirling speculum proved of sadly limited practical use. But it was France, a century later, that gave us a more successful take on the same principle. It was a spinning disk mounted in gimbals, which are a set of pivoted supports that allow the disk to maintain its orientation, regardless of how the base might be tilting around. The physicist, Leon Foucault, called his device a gyroscope, from the Greek words for turn and observe, because he used it to study the Earth's rotation. Then electric motors came along, meaning the disk could spin indefinitely. And practical applications came thick and fast. Ships got workable artificial horizons. So did aeroplanes. In the early 1900s, Hermann Anschutz-Kemper and Elmer Sperry figured out how to align the spin to the Earth's north-south axis, giving us the gyrocompass. Combine these instruments with others – accelerometers, magnetometers – and you get a good idea of which way up you are and in which directions you're heading. Feed the outputs into systems that can course correct and you have an aeroplanes autopilot, a ship's gyro-stabiliser, and inertial navigation systems on spacecraft or missiles. Add in GPS and you know where you are. There's a limit to how small you can make spinning disks in gimbals, but other technologies have miniaturised the gyroscope. Vibrating micro-electromechanical gyroscopes measure just a few cubic millimetres. Researchers are making a laser-based gyroscope thinner than a human hair. As these and other sensors have got smaller and cheaper, and computers faster, and batteries lighter, they've found uses from smartphones to robots, gaming consoles and virtual reality headsets. And another technology around which there's a particular buzz. The drone. Drones are now commonplace, from surveying to movie-making. They get urgent medical supplies to hard-to-reach places. But it's the routine everyday uses that promise to be truly transformative. Flying our online shopping to us, or even flying us. The Chinese company Ehang is pioneering drones that can carry human passengers. In rural China, delivery drones are starting to look like a leapfrog technology, one that catches on most quickly where there isn't a competing established infrastructure. In this case, an infrastructure of big box retail stores and roads for van deliveries. Zhangwei, for example, is a village in Jiangsu province, where few people own cars, and only half have fridges, but everyone has a phone, and they use their phones to place orders at online retailer JD.com for everything from disposable nappies to fresh crabs. About four times a day, warehouse workers dispatch the village's orders on a drone that carries up to 14 kilograms at 45 miles an hour. Everyone's happy, except for the woman who runs the village shop. If drones are to take off more widely, we'll need solutions to the last mile problem. In Jiangwei, JD.com employs a human to distribute the crabs and the nappies to the villagers who ordered them. But in countries where labour is pricier, the last mile is where delivery costs are concentrated. Automate it, and some believe bricks and mortar stores could cease to exist altogether. But nobody's sure precisely how that might work. Do we want our online purchases parachuted into our back gardens, or plunked on the roofs of our apartment buildings? How about smart windows that can open to let drones in when we're not at home? Then there's another problem, the one that did for John Cersun. The weather. If we're going to rely on airborne deliveries, they'll have to work in all conditions. Will drones ever navigate storms that could sink a battleship? Perhaps then, the promise of the gyroscope will truly have been fulfilled. The sad story of John Cersun's whirling speculum is told in volume 24 of the
SPEAKER_04: Gentleman's Magazine and Historical Chronicle for the year 1754.
