Longitude: The True Story of a Lone Genius who Solved the Greatest Scientific Problem of his Time 
by Dava Sobel.
Fourth Estate, 184 pp., £12.99, August 1996, 1 85702 502 4
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The curious Lilliputians guessed Gulliver’s pocket-watch must be ‘the God that he worships’, because ‘he assured us he seldom did anything without consulting it.’ The giant King of Brobdingnag had a different perspective: Gulliver must ‘be a piece of Clockwork (which is in that country arrived to a very great perfection)’. Any acute 18th-century reader of Swift would easily make sense of these timely jokes. Britain was then rapidly establishing world leadership in precision horology and its citizens increasingly seemed driven by the workings of the clock. Time management became a way of judging others – busy bourgeois, dawdling plebeians, languorous natives. Time discipline was imposed on workshops. Fine jewelling to reduce friction and ingenious machines to cut gears helped to make clocks of stunning accuracy. Pocket watches began to tell seconds, and, to assist the genteel Newmarket punters, even fractions of a second. Fashionable theologians preached that the Creation itself was best understood as godly clockwork.

The products and faith of this clockwork universe took the clockwatchers and their timepieces everywhere. In August 1773, after a 13-month voyage from Britain, the sloops Resolution and Adventure arrived on the north coast of Tahiti. For some on board, including their captain, James Cook, this was a return visit to the Pacific haven they called ‘King George’s Island’. The British were there, among other reasons, to check the performance of a small jewelled watch, barely more than five inches in diameter, carried with them all the way from London. This timepiece, finished by the expert clockmaker Larcum Kendall at the end of 1769 after 30 months of painstaking work, promised a solution to the enduring puzzle of longitude, the way of finding how far east or west a traveller was from home.

Latitude, the distance north or south of the equator, was comparatively easy to determine – just before being cast ashore on Lilliput, Gulliver’s shipmates have time during the storm to observe that they are in latitude 30°2’S. It was also long understood that, with a sufficiently reliable clock, such a traveller might be able to compare the local time with that in his place of departure, and thence translate time differences into true distance east or west. To get positions accurate to a mile at the equator, such a clock must err no more than four seconds over its whole voyage. But reliability of this order was scarcely to be achieved by any feasible clock. Only in the later 18th century did such clocks appear – and Kendall’s so-called K-1 was eminent among them. Tahiti was a good place to test its worth, since back in 1769 British astronomers had determined its longitude with care in order to observe the transit of Venus across the face of the Sun. Armed with pendulum clocks and sextants, the astronomers divined that ‘Point Venus’, as they called it, was 149°30’38" west of Greenwich, the home base of all British navigators.

Cook adored ‘our trusty friend the Watch’, relied on it absolutely, and told his Admiralty masters that K-1 had passed its tests with flying colours. The clock subsequently followed the British flag across the Pacific: with Cook to his death in Hawaii in 1779, then with Captain Arthur Phillip to the new penal settlement in Botany Bay in 1788. A second copy, rather less worthy, travelled on the Bounty with William Bligh and was taken by the mutineers to Pitcairn Island. Hence Umberto Eco playfully suggests at the end of his own recent longitude novel, The Island of the Day Before, that the documents on which his story is based must have been found by Bligh while adrift in the South Seas, who then delivered them ‘to the Admiralty in strictest confidence’. Tell-tale links between horology and the deeds that won the Empire were no coincidence. The Navy’s ability to sail by the most direct route across the open seas was crucial for the very survival of ships’ crews and the efficacy with which a worldwide maritime network was secured.

Yet precision clockwork was never truly indispensable to heroic seamanship. The Tahitians who encountered Cook’s men were also heirs of a culture of expert navigators. During the two millennia before 500 AD in European reckoning, the vast area of seas and islands stretching between Hawaii, New Zealand and the western coasts of South America had already been crossed by Polynesians, a feat far beyond any navigational skill then possessed by the ancestors of Cook. Some of the ‘experimental gentlemen’ on board his ships meditated on the Polynesian achievement, however little they knew of its true scope. ‘This exercise of their memories, and of other mental faculties confirming by their own experience the truth of the phenomena communicated to them by their parents and teachers gives them as it were a predilection for the examination of truth,’ opined a naturalist on board the Resolution. Such savants sought to compare the mental maps of Tahitian experts with their own charts, guessing at the oral traditions and astronomical lore of the natives they encountered. Thence developed the sense that European discoveries were merely revisitations to lands and seas already well-known to others. Cook himself contemplated some of the effects of the encounter between the two maritime cultures: ‘they cannot be restored to that happy mediocrity in which they lived before we discovered them if the intercourse between us should be discontinued. It has become in a manner incumbent on the Europeans to visit them once in three or four years,’ he judged, ‘in order to supply them with those conveniences which we have introduced among them.’ So did watchful Europeans imagine the change from timeless lassitude to punctilious commerce.

It was hard to tell which longitude schemes were feasible, which utopian. In 1687, one schemer proposed using a ‘powder of sympathy’, which when applied to a weapon could directly affect a wounded victim, however far away. So the longitude recipe involved putting a wounded dog on a ship, then using the powder on a knife in port every midday. The distant dog, its wound kept open, would promptly yelp on shipboard, telling its sailing companions when it was noon back home. A slightly more viable project, canvassed in 1714 with prestigious scholarly backing, demanded a worldwide network of moored hulks equipped with mortars to fire rockets at regular times. Its promoter, a renegade Cambridge mathematician, tried firing noisy bombs over Hampstead Heath to test the method and attract investors.

Satirists from Swift to Eco have found much matter in these schemes. But in more ponderous mood, such witty vexations form little part of the resolutely Anglocentric ‘true story’ recounted by Dava Sobel. Rather, her hero, the ‘lone genius’ of her ostentatious subtitle, is John Harrison, a dour Yorkshire carpenter and village choirmaster who spent half a century from the early 1720s trying to make clocks capable of determining longitude and to convince metropolitan grandees that he had done so. Kendall’s watch was a faithful copy of Harrison’s fourth such attempt, a device which beat the clock-maker’s main enemy, friction, with diamond jewelling and a lubricating oil which proved remarkably resistant to changes in temperature; it was itself tried on voyages to the West Indies during the earlier 1760s.

The romance has a neat shape. The humble autodidact Harrison, whom Sobel inevitably compares with Abraham Lincoln and the log-cabin heroes of her own American myths, but who rather shares the plodding devotion of his fellow-Yorkshireman Geoffrey Boycott, long battled alongside his loyal brother James and son William against the dandified prejudices of London and Oxbridge professors and bureaucrats. In 1714, Parliament had offered a remarkably large reward of £20,000 for any scheme capable of giving longitude within half a degree. Harrison kept on producing devices which apparently merited reward only to see his hopes dashed by committees which changed the rules, pushed their own favoured clients and methods, and requisitioned his clocks, then damaged or otherwise misused them. There were odious villains, such as the Astronomers Royal, James Bradley and Nevil Maskelyne, who used their Greenwich power base to orchestrate the conspiracy against Harrison. Maskelyne gloried in giving clockmakers ‘a bone to pick that would crack their teeth’. The day was saved by the King himself – mad George was something of an amateur horologist – so that, a month before Cook’s arrival off Tahiti in 1773, Harrison was awarded by Parliament more or less the balance of the sum he so richly deserved.

As with any satire of brave provincials battling London toffs eventually to win their just rewards, there’s more to this tale than superficial heroism. Period detail, especially knowledge of the London clockmakers, matters. A 1747 guide for ambitious parents keen on placing their sons in the right profession commended the watch-maker’s business: ‘we beat all Europe in Clocks and Watches of all sorts.’ Profits could be huge, though ‘all the branches require a mechanic head, a light nice hand and a strong sight. If he understands his Business, he may have Bread almost any where.’ Sobel is fairly reliable on horological technique and has some very good sources, too, notably the stunning lecture delivered in 1935 by the ex-naval officer Rupert Gould, who spent a dozen years after the First World War restoring all four of Harrison’s clocks to working order in the state they now enjoy in the splendid Time Gallery at the National Maritime Museum. So, for example, the third clock, which took Harrison 19 years to build, includes what Gould called ‘the only mechanically perfect remontoire I have ever met with’ – a spring device used to store up energy and deliver it at an ‘absolutely constant’ rate to the escape wheel. This was the work of an engineer, he reckoned, rather than a traditional clockmaker. According to Gould, the clock’s roller-bearings, designed to minimise friction, ‘look as though they have been taken out of a modern car’.

Modernity has much to learn from the longitude story. Sobel guesses that one reason Harrison was viewed with scepticism by the London astronomers was that his clock had ‘all the complexity of the longitude problem hardwired in its works’. The astronomers had their own perfectly viable method based on the motion of the Moon. They needed good instruments to measure distances between the Moon and nearby stars, and just such a quadrant was on sale in London from the 1730s. They also needed clocks good enough to keep time reliably over about eighteen hours, and the English produced them in abundance. Using these two devices a navigator could tell the position of the Moon at a fixed local time: accurate lunar tables, available under Maskelyne’s editorship from the 1760s, could then let him compare this time with that of Greenwich. The ‘method of lunars’ was viable, but it was scarcely simple and it nicely made apparent the dependence of navigators on the authoritative doctrine of metropolitan astronomy. There is a long tradition which rates such elegant complexity above the mundane quick-fix of a mechanical stratagem. Think of modern purists’ hostility to the displacement of their painstaking mathematical analysis by the bump and grind of powerful computers, or fashion’s search for authentic crafts in preference to mass-produced tat. The way Sobel tells it, Harrison’s story has the best of both worlds. His up-to-date engineering beat cloistered dons – and we reflect that Bill Gates dropped out of Harvard before exacting his revenge through Microsoft. At the same time, Harrison’s traditional craftsmanship beat the very best scientific expertise – compare the Campaign for Real Ale and its war on chemical fizz. These are two apparently contradictory morals which contemporary taste seems very ready to accept.

There are, however, more apt morals to be drawn from the longitude story. Heroic individualism is rarely a reliable guide to the workings of science and technology. No doubt prejudice in individualism’s favour partly explains why the shared skills of Polynesian navigators, or London artisans, have been ignored or minimised. The campaigns to make, test and distribute ways of navigating the oceans were above all collective enterprises. To build a clock portable yet reliable enough, Harrison worked closely with several other clockmakers, such as John Jeffreys, who supplied the Yorkshireman with his own pocket watch, one of the first genuinely accurate watches and the direct source of much of the design of H-4, the device which eventually won out. Kendall, who then worked out how to copy H-4, was one of Jeffreys’s best apprentices. Without this network, no horological solution to the longitude problem would have succeeded. The same is true of the many tests which Harrison’s devices had to pass. For a test to count, all must agree in advance that the conditions are sufficiently like the real-world situation in which, eventually the device will work. Getting this agreement is never easy and often relies on who has authority on their side – a principle which governs tests of food safety or missile accuracy or marine clocks. Whose kitchen is really like the labs where cook-chill packs are tested? The fierce fights Sobel describes around the tests of Harrison’s first and fourth watches are perfectly understandable in this light: it was never self-evident that voyages across the Atlantic, or up the Channel or in Maskelyne’s rooms in Greenwich, represented accurately enough the conditions any clock would encounter in everyday use on the high seas.

To get this kind of accuracy it was also crucial to produce large numbers of reliable timepieces. Understandably, Harrison never attempted this. What Sobel neatly calls ‘the mass production of genius’ was surely the key to the problem. Harrison’s genius may well have demonstrated the feasibility of a marine chronometer, but it didn’t produce the clocks mariners then used. It is remarkable that scarcely any of the innovations Harrison built into his clocks – and which Sobel describes in compelling detail – were taken over into the large-scale productions of the late 18th-century English marine chronometer industry. Instead, other masters and other workshops, led by the furious rivals John Arnold and Thomas Earnshaw, eventually won the day for the chronometer against the lunar method by simplifying clock design and applying a principle which a contemporary Scottish don, Adam Smith, had so tardily described – the division of labour in manufactures. While government manuals continued to instruct naval officers on the technicalities of lunar observation, thousands of clocks good enough for sailors’ purposes were made. And eventually, as has often been observed, this was why the British clock-trade shrank. Once saturated, the marine market simply could not sustain the intricate network of workshops and their output.

Harrison’s clocks and their aftermath in fact belong to a more exciting and challenging narrative than one of individual craft and purblind tradition. In Dombey and Son, much concerned with the new and shaky time-worlds of rail and steam, Dickens makes the ships’ instrument-maker Solomon Gills into a symbol of solid trust and sterling tradition. Above his shop door in Leadenhall Street is a wooden statue of a midshipman captured in the very act of taking an observation with his sextant. Gills himself uses a ‘tremendous chronometer, rather than doubt which precious possession he would have believed in a conspiracy against it on the part of all the clocks and watches of the City and even of the very Sun itself’. It seems tempting to treat such chronometers as benevolent emblems of a vanished world of ingenuity, solidity and trustworthiness, a fitting and amiable gift for aged servants when they retire. The temptation should be resisted, for in every detail the wheels of these cunning and beautiful devices turned in time with the processes of capital, empire and modernity.

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