Latitude and longitude are how we navigate the globe. Latitude is set by the equator, a fixed point. That means, even out at sea, it’s simple to gauge your latitude by the length of the day or the position of the sun. But longitude is more dynamic, it moves as the Earth rotates. Every four minutes, longitude shifts one degree. So, determining longitude, especially at sea, was considered a problem as insoluble as finding the fountain of youth or turning lead into gold.
The longitude problem haunted sailors for centuries. Without being able to establish longitude, captains of ships were going off something they called “dead reckoning”, which essentially meant they were guessing, steering the ship with their gut, and ships were forced to stick to the few safe routes everyone knew.
Between 1550 and 1650, one in five ships was lost between Portugal and India. The issue reached a peak in the 17th century, when imperial conquest and colonialism relied on the sea trade. By the end of the century, nearly three hundred ships a year sailed between the British Isles and the West Indies to ply the Jamaica trade. Commodities and cargo, like sugar and cotton, were transported eastward across the Atlantic to meet consumer demand in Europe. The westward trade, however, was that of people who had been enslaved and forcibly transported to grow and harvest those commodities that fed the increasing European appetites [visit the National Archives website for more on this].
In 1714, merchants and sea captains banded together and brought a petition to the British Parliament to solve the longitude problem. The government paid attention and offered a hefty reward to anyone who could solve it. The Longitude Act, issued on July 8, 1714, offered up £20,000 prize (about £1.5m today) for a practical and useful method to determine longitude to an accuracy of half a degree.
Today, the motivations of the Longitude Prize are to address an intractable problem to better meet global health needs. Although the Longitude Prize was created in another epoch its ability to attract diverse types of people to work on intractable problems is as relevant today as it was in the 18th century.
Over a period of 14 years, the board in charge of judging received countless submissions, but it wasn’t until John Harrison arrived in London in 1735 that they had a real contender. Harrison was a carpenter from Yorkshire who had taken up clock-making just a year before the prize was announced. He had no formal training. In fact, his family was of limited means, and clocks were so expensive, it’s unclear whether he’d ever seen a clock outside of pictures in books, before he created one himself.
To calculate your longitude at sea, you need to be able to compare the time on the ship to the time at a port, where longitude is known. That meant keeping accurate time for days, which was impossible with eighteenth-century clock tech. But not for Harrison.
Harrison’s clocks were remarkably innovative. They were virtually frictionless and required no lubrication, which was unheard of at the time. Without oil, a clock had a much better chance of staying accurate at sea because there were no lubricants to get thicker or thinner as the temperature changed. No one was expecting a break-through from such an unusual challenger. As Dava Sobel writes in her book Longitude: “The only thing more remarkable than the Harrison clocks’ extraordinary accuracy was the fact that such unprecedented precision had been achieved by a couple of country bumpkins working independently.”
While Harrison was never awarded the full £20,000, he won the most money of all the contenders. Over almost 50 years, he brought the Longitude board four maritime clocks. The first, H-1, was incredibly accurate, but each was better than the last, and H-4 was a masterpiece.
Lieutenant Commander Rupert Gould of the Royal Navy, who rescued and repaired Harrison’s clocks in the 1920s, summed up Harrison’s genius perfectly in a 1935 speech, describing H-3: “It embodies several devices which are entirely unique—devices which no clockmaker has ever thought of using, and which Harrison invented as the result of tackling his mechanical problems as an engineer might, and not as a clockmaker would.” Harrison’s unique perspective, his lack of traditional expertise, gave him the ability to do something even Isaac Newton didn’t believe was possible.
