The journey of one of the greatest scientific problem - Longitude's

Latitude lines, the parallels, stay parallel to each other, encircling the earth in concentric circles with decreasing radii. The meridians of longitude go the other way. The loop from the North pole to the South pole and back again in great circles and so they all converge at the ends of the Earth. These imaginary lines had been crisscrossing the Earth from ancient times, at least 3 centuries before Christ. By AD 150, the cartographer and astronomer Ptolemy had plotted them on the twenty-seven maps of his first world atlas. The equator marked the zero-degree parallel of latitude, as Ptolemy borrowed it from this knowledge from his predecessors. The sun, moon and stars pass almost directly overhead at the equator. Likewise the Tropic of Cancer and Capricorn, the positions which mark the northern and southern boundaries of sun’s motion around the year. Ptolemy, however, was free to decide his prime meridian, the zero-degree longitude line. He chose to run it through the Fortunate Islands (now called the Canary Islands) off the northwest coast of Africa. Later, mapmakers moved the prime meridian to the Azores and to the Cape Verde Islands as well as to Rome, Copenhagen, Jerusalem, St. Petersburg, Pisa, Paris and Philadelphia, before settling down in London.

The latitude remains fixed as the world turns and can be found with relative easy. The sailor can determine the latitude by measuring the length of the day or by the height of the sun or by guide stars above the horizon. On the other hand, longitude shifts with time, and this complicated the life of sea explorers many folds and made it the greatest scientific problem of the time. Due to lack of a practical method for determining the longitudes during the time, the age of exploration not only included searching unclaimed territories and newer routes but also exploring the explorers, who seldom used to get lost in the vastness of the oceans. The quest for a solution spread across entire Europe and included most crowned heads like George III and Louis XIV. The problem also rattled the brains of renowned astronomers like Galilio Galilei, Jean-Dominique Cassini, Christiaan Huygens, Sir Issac Newton, and Edmond Halley. Observatories were set up in Paris and London for the same and prizes worth 20,000 pounds was declared for the solution. In the end, the solution came from an unknown, self-educated and a simple man and an English clockmaker John Harrison. But as usual, every hero needs an anti-hero and so Harrison’s life was also adorned with such men.  

Due to the lack of guidance in the oceans, long-distance voyages usually used to be longer, which exposed the entire crew to several diseases. Scurvy was one such common curse. The ocean-diet was devoid of fresh fruits and vegetables which deprived them of Vitamin C, which led to the deterioration of connective tissues and their overall health. Their legs would swell, gums would bleed, and wounds refused to heal.

Apart from the human suffering, kingdoms also faced economically. Since determining location was nearly an impossible task, trade routes were constricted only to well-known passages, which were sometimes also used with notoriety. One such example is from 1592 when a squadron of six English men-of-war attacked and captured Madre de Deus, Portuguese ship from India carrying gold, silver, pearls, diamonds, amber, musk, tapestries, calico, ebony and hundred tons of spices. The total worth of this single ship was around half a million-pound sterling or approximately half the net value of the entire English Exchequer to that date. Due to this, sailors and kingdoms wished to find secret routes.

The sea captains in the fifteenth, sixteenth and seventeenth centuries relied on “dead reckoning” to gauge their positions. The captains would throw a log overboard and observe how quickly the ship receded from this temporary guidepost. They noted the crude speedometer reading in the ship’s logbook, along with the direction of travel from compass or stars, length of time using sandglass. Factoring the effects of ocean currents, winds etc they used to determine their longitudinal position.

Another method was through the use of celestial bodies and their relative positions. The skylights up marking day and night, phases of the moon marked passing months, solstice or an equinox marked season changes.

In the heavens, the constellations, especially Little Dipper with the North Star in its handle, showed them the way, but it was subjected to the clarity of the skies. During the day, the Sun gave a sense of direction and time. The Sun rises from the east and sets in the west, and when during the noon it reaches the peak and pauses to stretch, sailors turned their sandglasses. In this way they could calculate the local time, if only they could know time at some other location at that instant, they could calculate the longitude. This is because Earth takes 24 hours to traverse 360 degrees, which translates to 15 degrees longitudinal distance for 1 hour time difference.

Solar and lunar eclipses could have been used to determine this time difference. If sailors know the predicted time of eclipse at a particular place (say in London), they can witness the eclipse at their position and measure time and thereby calculate the time difference. However, the eclipses were too sporadic to be used by sailors, who travelled much frequently.

By 1514, the German astronomer Johannes Werner suggested using the moon for navigation. The moon travels nearly a distance equal to its own width every hour. At night, it travels through the field of stars and in the daytime (the moon is up in the daytime almost half of the month) it moves away or towards the sun. Thus, Werner suggested that astronomers should map the positions of the stars along the moon’s path and predict when the moon would be at which position in the stellar field from months to months for years. Additionally, they can map the relative positions of the sun the moon for navigation aid through daylight. Then they can publish all the moon meanderings, with the time of each star meeting predicted for one place – Berlin perhaps. Using this information, a sailor can determine the local time at which he witnesses the phenomenon and compares it with the reference point’s time. This was called as the lunar distance method. The main problem was that the positions of the stars were not well known. Also, no one knew the path of the moon and predict its position.

Clockmakers suggested that good clocks can resolve the longitude problem. Starting in 1530, Flemish astronomer Gemma Frisius hailed the mechanical clock as the first contender. However, the clocks in those times were very inaccurate. They were also delicate, which would go haywire when subjected to moisture’s and temperature change.

William Cunningham of England revived this idea again in 1559, recommending the use of watches, but they could gain or lose 15 minutes a day with ease.

In 1595, John Davis introduced back staff which immediately substituted cross-staff or Jacobs staff. The original sighting instrument required them to look directly to the celestial body to measure its height. Many sailors lost their eyesight to measure the height of the sun, which was used to calculate time and therefore aid in navigation back then. Backstaff provided some degree of relief since it did not require direct eye-contact with the celestial body.

Then there was a magnetic variation method. This method used the combined power of the North Star (which points towards actual North) and magnetic compass (which points towards magnetic north). As a ship travels from east to west along any latitude, the distance between the magnetic and the true pole changes. A chart was thus made to translate the distance between magnetic north and true north into longitudes. Although this method did not require time measurement, at the same time it had disadvantages. This method depended upon weather’s grace in order to see the North star. Also, accuracy was still the problem, rarely did the compass point to north at all times Results were also contaminated due to magnetic variations at different locations.

In 1610, almost a hundred years after Werner’s proposal, Galileo Galilei discovered another clock in the heavens. Galileo discovered mountains on the moon, spots on the sun, phases of Venus, moons around Saturn (which actually was its ring), and a family of four moons orbiting Jupiter. Galileo named these as Medicean stars, over Florentine patron, Cosimo de’ Medici. Over the years he calculated the orbital period of these moons and counted the number of times the bodies vanished behind the shadow of the giant. He proposed to create tables of each satellite’s expected disappearances and reappearances over several months which occurred over thousand times annually. He sent his proposal to King Philip III of Spain, who had promised fat pension for the solution. However, his idea was rejected because they realized it to be difficult to use telescope by sailors, and on top, when the ship floor is shaking. Further, it would not be possible to view in daylight due to its low brightness. Also, observations would be subjected to the weather. Despite the rejection, Galileo made a helmet – celastone – which could be worn and used to see the Jovian satellites. While testing the helmet, however, Galileo, himself realized that even the pounding of one’s heart can cause the whole Jupiter to jump out of telescope’s field of view. Galileo died in 1642, but his method was finally accepted in 1650 to measure longitudes on land. In 1637, Galileo came out with the first-ever design for the pendulum clock. However, he could not start building one. His son, Vincenzio, constructed a model from Galileo’s drawings, and the city fathers of Florence later built the same. 

Thus, it was then used to determine the length and breadth of kingdoms, with more accuracy. King Louis XIV of France, confronted with a revised map of his domain based on accurate longitude measurements complained that he had lost more territory to his astronomers than to his enemies. Despite this, he always had a soft spot in his heart for science. In 1666, he laid the supported building up of Academy of Royal Sciences. He also approved establishing an astronomical observatory in Paris to solve the longitudinal problem. The success of Galileo’s methods inspired other astronomers to refine his measurements in predicting eclipses of the Jovian satellites. In 1668, Giovanni Domenico Cassini, a professor of astronomer at the University of Bologna, published the best set yet, based on his carefully conducted observations. Cassini was invited to take the position of director of the astronomical observatory. Cassini called on observers from Paris, Uraniborg, Poland and Germany to cooperate and accurately calculate longitudes of these places using Galileo’s method. At the same time, Huygens’s was appointed the charter member of the Royal Academy of Sciences.

Huygens was a intellectual heir of Galileo. He discovered that what Galileo though as moons of Saturn was actually a ring, and also discovered Saturn’s largest moon Titan. Huygens is also believed to be the first horologist and claimed to arrive at the idea for the pendulum clock independent of Galileo. He developed his first pendulum clock in 1656 and two years later declared it fit for measuring longitudes in the sea. By 1660, Huygens completed another two marine timekeepers and sent them on different voyages for testing. Subsequent voyages revealed the problem with his clocks, to circumvent which, he developed the spiral balance spring-based clock and had it patented in France in 1675. However, Robert Hooke claimed that Huygens had stolen his concept and they remained in conflict over it for quite some time. The strife quenched when it was realized that none of the clocks could serve the purpose of longitudinal measurement at sea.

These efforts to solve the longitude problem led to other discoveries as well. For example, when Danish astronomer Ole Roemer was visiting the Paris Observatory, the realized that the eclipses of Jovian satellites vary in duration when the Earth is close to Jupiter than when it is far. He used this method to find the velocity of light in 1676 and just slightly underestimated today’s known values.

In England, King Charles II was worried as well with the longitudinal problem since he had the largest fleet in the world. The Frenchman, Sieur de St. Pierre, put forward Werner’s method, of using the path of the moon in the stellar field, to navigate ships. Intrigued by the idea, he redirected the efforts of his royal commissioners, which included Robert Hooke (one who coined the term cell, gave Hooke’s law in physics and many more), Christopher Wern (architect of St. Paul’s Cathedral). For the appraisal of Pierre’s theory, the commissioners called an astronomer John Flamsteed. He concluded that there exists no map for the moon and stellar system. At the same time, he suggested the King to establish an observatory with staff to carry out work to develop such maps. So, like the Paris Observatory, Commissioner Wren designed the Royal Observatory in Greenwich Park, which was completed in 1675. Flamsteed took up the residence in May and gathered instruments to start working in October. He ends up spending four decades here.

An interesting method was proposed by Frenchmen Sir Kenelm Digby in 1687. He claimed to have developed a magical powder, powder of sympathy, which could be used to heal the patient from the distance. The idea was to send aboard a wounded dog on the ship and leave a trusted individual on the shore who would dip the dog’s wound bandage in the sympathy powder every day at noon. As the person on the shore dip the bandage at a particular time (say noon), the dog on the ship would bark and the sailors on the ship would come to know the time at the port, thereby enabling them to calculate the difference.

In 1699, Samuel Fyler of Stockton in England came up with another way to draw longitude meridians on the night sky.  He suggested that someone well versed in astronomy could find twenty-four sets of discrete rows of stars, with each row arising above the horizon every hour. One can then chart the times at which the specific row of stars is visible in Canary Islands (the prime meridian then). The sailor can observe the star set, at mid-night and calculate the time-difference and thereby the longitude. However, again it was subjected to weather but also at the time the required astronomical data was absent.

The longitude problem had taken the lives of some great sea explorers. One such was Admiral Sir Clowdisley Shovell. He was returning home from Gilbraltar after skirmishes with the French Mediterranean forces when his fleet was enveloped by fog for days. Catering to lack of instrumentation to locate themselves, they sailed with their experiences, which unfortunately proved fatal as Association struck, followed by his entire fleet, drowning almost two thousands of Sir Clowdisley’s troops on October 22, 1707.

Without any solution to the problem, Newton and Halley grew impatient. They had been waiting for Flamsteed data which he had kept under seal in Greenwich. But somehow Newton and Halley managed to get the data and they published their own pirated version of Flamsteed’s star catalogue in 1712.

Two friends, William Whiston and Humphry Ditton then came out with their own amusing idea. Ditton reasoned that sounds might be used to serve as a signal. Whiston, in agreement, recalled that he could hear the sound of cannon nearly ninety miles away. So, they suggested, that if signal boats are placed at strategic locations and are made to fire at specific known times, ships can calculate the difference between the time they hear the fire on board and the specific time at which it was supposed to fire at the port, thus after factoring the speed of sound, it would tell them the time difference. However, after they were told unreliability of sound propagation in the sea, Whiston decided to combine sound with light. He proposed shooting fireball vertically upwards which would explode at specific times. Then all the navigator had to do was watch for signal flare at local midnight, listen to cannon’s roar, and sail on (based on the concept which we use today to measure the distance of approaching storm by looking at thunder). After watching the fireworks on the Thanksgiving Day for the Peace, on July 7, 1713, he was convinced that it would be visible for 100 miles. To shoot fireballs from strategic locations in the ocean, they proposed dispersing the fleet and anchoring them at 600-mile interval. While commenting on the anchoring, they also misstated the depth of North Atlantic, by a factor of approximately 10. Thus, they published their work in The Guardian. Critics quickly pointed out the obvious problems but on December 10, 1713, Whiston-Ditton proposal was published a second time, in The Englishman. Through their determination, public recognition, they united the shipping interests in London. In the spring of 1714, they got a petition signed by “Captains of Her Majesty’s Ships, Merchants of London, and Commanders of Merchant-men”. Thus, they pressurized the government to resolve the longitude problem by offering rich incentives. The merchants and seamen called for a committee to consider the current state of affairs and requested a fund for research and development of promising ideas.

The petition reached Westminster Palace on May 1714. In June, a parliamentary committee was set up to deal with the problem. The committee members sought expert advice from Sir Isaac Newton (by then 72 years old) and his friend Edmond Halley. Newton, in his report, reiterated the possible methods. He mentioned watches, Jupiter’s satellites, other astronomical methods which involved stars hiding behind our own moon, eclipses and the lunar distance method. He then mentioned that a handsome reward should be given to any individual who finds a practical solution. The Longitude Act was thus issued in the reign of Queen Anne on July 8, 1714. Since one degree of longitude measures about sixty nautical miles at the equator, even a fraction of error could correspond to large errors in distances and therefore the act had three prize segments: First prize of 20,000 pounds for the method which could determine longitude to an accuracy of half a degree of a great circle. Second prize of 15,000 pounds for the method which could determine longitude to an accuracy of two-thirds of a degree. Third prize of 10,000 pounds for the method which could determine longitude to an accuracy of one degree.. The Act also established panel of judges known as Board of Longitude. The board consisted of if scientists, naval officers and government officers. The astronomer royal served as an ex officio member, as did the president of the Royal Society, the first lord of the Admiralty, the speaker of the House of Commons, the first commissioner of Navy, and the Savilian, Lucasian, and Plumian professors of Maths at Oxford and Cambridge universities. (Newton had held Lucasian professorship for thirty years). This board was perhaps the world’s first official research-and-development agency. (even they acted like our present-day board, in the sense that by the time they were disbanded in 1828 they had disbursed funds in excess of 100,000 pounds). In order for commissioners of longitude to judge the accuracy of the methods, it had to be tested on Her Majesty’s ships as it sailed from Great Britain to any port in West Indies.

After the prize was declared, they received several solutions which included improving ships rudders, methods for purifying drinking water at sea, blueprints for perpetual motion machine and making sense of the value of pi. A good one amongst these came from Thacker of Beverly, England. Thacker developed a new clock enclosed in a vacuum chamber and he believed it to be the solution. He declared “In a word, I am satisfied that my Reader begins to think that the Phonometers, Pyrometers, Selenometers, Heliometers and all the Meters are not worthy to be compared with my Chronometer.” It was the first time chronometer word was introduced, and it is still synonymously used for timekeepers. The problem with Thacker’s clock was that it could not adjust to changes in temperature. To rectify this, he attached a thermometer with the clock. A mariner using the chronometer will have to make necessary calculations to adjust for the time shown with the temperature readings. However, this complicated the method which led to its rejection.

Very little is known about the early life of John Harrison.  He was born on March 24, 1693, in the county of Yorkshire, the eldest of five children. Not much is known about his family and their initials. Their home seems to have been on the estate, called Nostell Priory, where a rich landowner employed elder Harrison as a carpenter and custodian. Around his fourth birthday, for some reason, his family moved to Lincolnshire village of Barrow. Here, John Harrison learned woodworking from his father. As a teenager, he craved for book learning. In 1712, a clergyman lent him a textbook – a manuscript copy of a lecture series on natural philosophy delivered by mathematician Nicholas Saunderson at Cambridge University.  This along with Newton’s Principia strengthened his knowledge about the working of the natural world. Harrison completed his first pendulum clock in 1713 before he was twelve. Why he chose this project and how he completed it remains unknown. The clock is on display in the museum at Guildhall in London. Harrison made two more, almost identical clocks in 1715 and 1717. Sometime around 1720, he was hired by Sir Charles Pelham to build him a tower clock above his new stable at the manor house in Brocklesby Park. By then he had gained a local reputation. Harrison completed the project in 1722, which tells time still in Brocklesby Park. The mastery of the clock was the fact that it did not require any lubrication (unlikely in those days). This is because he used the wood from a tree which exudes its own grease. He was aware of the problem of dampness, and so wherever he had to install metal parts, he installed brass. When it came to fabricating toothed gears from oak, he invented a new kind of the wheel. He used a combination of wood in order to strengthen the structure, while also keep it lightweight. From 1725 to 1727, he (and now included his junior brother) built two more grandfather clocks. Two fancy inventions called the “gridiron” and the “grasshopper” ensured the accuracy of clocks. The gridiron was the special pendulum which consisted of metal strips. By combining metal strips of two different metals – brass and steel in one pendulum, Harrison eliminated the problem of thermal expansion or contraction of the pendulum that used to make them sensitive to temperatures. The two metal strips used to counteract, keeping the pendulum length constant. The grasshopper escapement was the part that controlled the heartbeats of the clock. His designed clocks never erred more than a single second in the whole month at the time when clocks used to deviate by one minute every day. By 1727, Harrison started thinking to solve the marine timekeeping problem to bag the prize. Later, in 1728, William, his first kid (of two) from the second wife (his first wife died of illness) was born.

Harrison had resolved most of the problems, temperature, lubrication, precision, corrosion etc. The one thing that remained was to replace the pendulum since it could not have survived in the rolling oceans. He spent almost 4 years to come up with a new design.

Harrison went to London in the summers of 1730 to show his designs for the maritime clock, but the Board of Longitude was nowhere found. Although the Board had existed for more than 15 years, it had no official headquarters, and in fact, had never met. Harrison, however, had heard of Halley who was the member of the committee, and so went straight to Greenwich to meet him. Halley had become England’s second astronomer royal in 1720, after Flamsteed’s death. Halley received Harrison politely and listened to his concept and suggested him to visit the well-known clockmaker George Graham. Halley knew that the Board, consisting of mostly astronomers, would not welcome a mechanical answer. Harrison met Graham, discussed his concept and by the evening the premier scientific instrument maker and a fellow of Royal Society, Graham, was impressed by him. Harrison then spent the next five years to make the first sea clock, also known as H-1 (Harrison’s No. 1).

Harrison produced his sea clocks precisely the same period when scientists finally understood the theories, instruments and information needed to make use of the clock of heaven. The clock of heaven, the lunar distance method, based on measuring the motions of the moon and Harrison’s timekeepers had the cut-throat competition. The two methods run parallel, perfecting with time from the 1730s to 1760s, trying to beat the other. On one hand, was Harrison, ever loner working with his machinery, and on the other side were the professors of astronomy and mathematics.

In 1731, two inventors John Hadley and Thomas Godfrey independently created instruments upon which the lunar method depended (later it was discovered that Newton and Halley had drawn plans for similar instruments). This instrument allowed mariners to measure the relative potions of objects along with their elevation. With detailed star charts and a trusty instrument, a good navigator could now stand on the deck of his ship and measure the lunar distances. Next, he consulted a table that listed the angular distances between the moon and numerous celestial objects for various hours of the day, as they would be observed from London or Paris. He then compared the time when he saw the moon thirty degrees away from the star Regulus, say, in the heart of Leo the Lion, with the time that particular position had been predicted for the home port. If, for example, this navigator's observation occurred at one o'clock in the morning, local time, when the tables called for the same configuration over London at A A.M., then the ship's time was three hours earlier —and the ship itself, therefore, at longitude forty-five degrees west of London. Hadley’s quadrant capitalized on the work of astronomers. Flamsteed alone conducted 30,000 observations. Halley, however, went to St. Helena in 1676 but could count only 341 new stars. Halley, during his tenure from 1720 to 1742 studiously tracked the moo day and night.

In 1735, Harrison carried H1 to London and delivered it to George Graham. Graham displayed Harrison’s great work to Royal Society, who welcomed the hero. H-1 weighted around 34 kilograms and measured around 4 feet in every dimension. Harrison. Despite all the appreciation, the Admiralty dragged the trial for a year. Then, instead of sending it to West Indies, as mentioned in the Longitude Act, Admiralty Sir Charles Wager ordered Harrison to board HMS Centurion captained by Proctor bound for Lisbon. Captain Proctor died as soon as they reached Lisbon. Captain Wills of HMS Orford received orders to bring Harrison back after 4 days. Upon reaching back, Wills gave the certificate to Harrison as an official pat on the back. The Board of Longitude convened for the first time – 23 years after it was created – citing this marvellous machine as the occasion. The Board sat, and everyone was impressed, except one, Harrison himself. The perfectionist still wanted to correct a few defects and believed that he could make the clock a lot smaller. He requested the Board to give him some time and funds to make the better machine. The Board agreed with the provision that after the return from the trial of the second machine, Harrison would have to surrender it and the first sea clock. He could have argued about this but chose not to.

In September 1740, Centurion set sail for the South Pacific under the command of Commodore George Anson, another great explorer and his tools - latitude readings, dead reckonings and good seamanship. By March 1741, the crew was stinking of scurvy and Anson decided to ship towards Juan Fernandez Island, which could soothe his crew. It was only after an additional two weeks of zigzag searching and losing extra eighty lives that he found land.

In January 1741, Harrison presented the board with H-2, but it wasn’t really an update. Harrison himself was disgusted with it. Resultingly it never went to the sea. The Board, however, rigorously tested H-2 in 1741-42 and it passed with flying colours, but Harrison was deaf to all the praise. He went back to work on H-3.

In January 1742, Halley’s astronomer royal chair passed to James Bradley. Bradley had determined a more accurate measurement of light speed than Roemer. He also determined the large diameter of Jupiter,, and detected tiny deviations in the tilt of Earth’s axis. From Paris Observatory meanwhile, Nicholas Louis de Lacaille headed for the Cape of Good Hope in 1750, to continue mapping the stars where Halley had left off. In this way, astronomers had established two of the three pillars: the positions of the stars and studied the motions of the moon; Instrument for measuring the distances and elevations of the celestial bodies. All that remained was the creation of detailed lunar tables that could translate the instrument readings into the longitude positions. Bradley received great interest in the lunar tables compiled by a German mapmaker, Tobias Mayer, who claimed to have provided the link. He had sent his idea to Lord Anson, who then passed it to Bradley. Mayer had created the first set of lunar tables for the moon’s location at twelve-hour intervals. He took a lot of help from Swiss mathematician Leonhard Euler, who designed elegant equations for studying the motions of the celestial bodies. Bradley tested Mayer’s predictions through his observations at Greenwich and was quite impressed. During this time, Nevil Maskelyne, while still a student, connected with James Bradley (third astronomer royal). Maskelyne was born in 1732 and was 45 years younger than Harrison. Unlike Harrison who was self-educated, Maskelyne went to the Universities of Westminster and Cambridge. Coming back, by late 1757 the method looked practicable. He then had it test at the sea by Captain John Campbell aboard the Essex. The testing continued despite the ongoing seven-year war. During the testing they realized the shortcomings of the method, like, the navigator was required to factor in the nearness of the object to the horizon, also they had to battle the problem of lunar parallax.

In comparison to all this, Harrison had proposed a simple solution inside a small box. Rather than accolades, he was subjected to rigorous trials when he presented H-3 in 1759. It took him 19 years to build. Between the completion and trial of H-3, Harrison presented H-4 to the board. Harrison worked diligently all this time, almost to the detriment of his health and family. Although he took some mundane job to keep his ends meet, his main income was from the board. The Royal Society’s member and his friend George Graham and other members insisted Harrison  accept the Copley Gold Medal on November 30, 1749 (later recipients of Copley Gold Medal include Benjamin Franklin, Henry Cavendish, Captain James Cook, Ernest Rutherford and Albert Einstein). But Harrison declined. He asked the membership to be given to his son, however, the membership is not transferrable. Anyways, William was duly elected to membership in his own right in 1765. The sole surviving son of John Harrison took up his father’s cause. He learnt the delicate works of the clock during H-3. Harrison originally came up with the idea of the bi-metallic strip, which is even found in today’s thermostats. After all this, Harrison still wasn’t satisfied with this performance. He still wanted to make it more compact. Thus, was H-4, unlike H-2 and H-3, a big leap forward. It was roughly five inches in diameter and weight only 3 pounds. However, he was unable to miniaturize the anti-friction wheel and so was forced to lubricate the watch. Harrison retracted H-3 and decided to board H-4 only for the trial. Thus, in November 1761, William boarded HMS Deptford captained by Digges with H4. The Atlantic crossing took three months and they arrived in Jamaica on January 19, 1762. Board’s representative John Robinson set up his astronomical instruments to synchronize time and check. They came back on board Merlin and reached in March 1762. It was found that the total, inbound and outbound combined error was just under two minutes. He had won but then tides turn. First, there comes evaluation of the trial by the board, in which three mathematicians were called to check and recheck the data on time determination at Portsmouth and Jamaica. The commissioners also complained that William had failed to follow certain rules, something William hadn’t realized he was required to do since it had not been mentioned to him.  Therefore, the final report in August 1762, denied the prize to Harrison. Instead of 20,000 pounds, he received just 1,500 pounds as recognition. Meanwhile, Maskelyne arrived in London on May 1762 after his expedition to St. Helena for data collection. Mayer died on February 1762, followed by Bradley in July. Nathaniel Bliss became the astronomer royal after Bradley. William corresponded with the board members and the new astronomy royal to vindicate the watch. But like Bradley, Bliss was also all for lunars and everything went against Harrisons. However, no one till this moment had any clue about the way the watch was made, and therefore, by early 1763 they started hounding Harrison to explain it to them. The French government dispatched a small contingent of horologists, Ferdinand Berthoud among them to London in hope that Harrison would reveal the watch’s workings. Harrison shooed the French and requested Englishmen to exercise privacy of his designs. Finally, in March 1764, the board decided to test H-4 onboard HMS Tartar to Barbados. Upon reaching, they found Maskelyne ready to test the performance of the watch. After the fractious second trial of the watch in summer of 1762, The board allowed months to pass without saying anything. Finally, they accepted H-4 but with conditions applied. The condition was that Harrison would have to supervise the production of two duplicates as proof that its design and performance could be duplicated.

In January 1765, Nathaniel Bliss passed away and his seat went to Maskelyne. As soon as he became the fifth astronomy royal, he brought four captains from East India Company and Maskelyne presented them as proof of the lunar method. He said that the captains could compute the longitude using The British Mariner’s Guide within four hours and so the tables should be widely published and distributed. In 1765, a new longitude act was passed from Parliament, This one officially called as the Act 5 George III cap.20 – put conditions on the original act of 1714, and applied specifically for Harrison. Harrison finally decided to bare all his descriptions and workings before a committee. Later on August 14, 1765, John Michell, William Ludlam, watchmakers, Thomas Mudge, William Mathews and Larcum Kendall (apprentice to John Jefferys. Harrison had a contract with various artisans in London, one of which was John Jefferys. In 1753, Jefferys made Harrison a pocket watch for his personal use based on Harrison’s designs. Some horologists consider Jefferys watch as the first true precision watch), scientific instrument maker John Brid, and Maskelyne arrived. Harrison dismantled watch piece by piece and explained each part to the committee. The board insisted that Harrison now reassemble the watch and surrender it to be kept at Admiralty, while also start working on building two replicas. They even took the original drawings and diagrams, which Maskelyne had delivered to the print shop to be published publicly. Meanwhile, Maskelyne produced the first volume of the Nautical Almanac and Astronomical Ephemeris in 1766 and went on supervising it until his dying day. He incorporated methods to reduce the number of arithmetic calculations from four hours to about thirty minutes. In order to put an end to doubt’s about H-4’s accuracy, the board decided to put H-4 in Royal Observatory under Maskelyne’s supervision. Within days of this, Maskelyne reached Harrisons and asked him to deliver the three timekeepers, as they had become public property. While taking away, one of Maskelyne’s workers while carrying H-1 outside, dropped it. By accident, of course. H-4 travelled by boat, accompanied by Kendall, while others went on an unsprung cart.

Harrison wanted captain James cook to take the original H-4 into the water for trial, but the Board said that H-4 will have to stay within the UK. H-4 which had sailed through the two sea trials applauded from three captains and even was nodded once by the entire board, apparently, had failed to work its ten-month trial at the Royal Observatory between May 1766 and March 1767, which had gained as many as twenty seconds a day. Maskelyne gathered statistics while pretending that the timekeeper was making six voyages to the West Indies each of six weeks duration, as per the Longitude Act of 1714. So the performance on the “voyage” was measured while H-4 stayed in the observatory. Thus, Maskelyne concluded that the watch cannot be trusted. However, to add words of praise he mentioned that it can be used for thirteen days when the moon only lights up the night sky but no measurements could be made in the day. In his opinion, the timekeeper might enhance the lunar distance method but never supplant it. Harrison issued a hailstorm of objections in a sixpenny booklet published at his own expense but Maskelyne did not answer to any. After being criticized by Maskelyne, Harrison expected a reunion with H-4, but the board declined. Instead, the board gave him, a couple of copies of the book containing his own drawings and description which Maskelyne had recently published, titled The Principles of Mr. Harrison’s Timekeeper with Plates of the same. The intent of the book was to enable anyone to reproduce the timekeeper. The board also hired watchmaker Larcum Kendall to attempt making an exact copy of H-4. Kendall finished his work, presenting K-1 in January 1770. Captain Cook, therefore, carried K-1 (since the board had grounded H-4) along with chronometers of John Arnold. Meanwhile, Harrison finished building the first of the two watches, H-5, the board had asked him to make. It took him five years to build and test. By this time he was seventy-nine and wasn’t sure if he could continue building the second watch. Concerned Harrison, thus reached out to the Majesty King George III. In January 1772, William wrote a letter to the king explaining the entire fiasco. He asked the king if he could lodge H-5 in his own observatory at Richmond. The king met William and agreed to keep H-5 with his private science tutor and Observatory director S.C.T Demainbray. The clock performed badly at first, but then the King realized that he had stored some lodestones near the watch station. After removing the stones, the H-5 worked precisely. After ten-week observation from May to July 1772, he was convinced about H-5’s precision. Thus, the king circumvented the board and reached the Prime Minister and the Parliament directly to give justice to Harrison. By the end of  June 1773, Harrison received nearly half the prize amount decided by the Longitude Act. Cook and HMS Resolution returned from his voyage in July 1775 and approved K-1. He reported, “Mr Kendall’s watch (which cost 450 pounds) exceeded the expectations of its most zealous advocate and by being now and then corrected by lunar observations has been our faithful guide through all vicissitudes of climates”.

Harrison died on March 24, 1776 and he held martyr status amongst the clockmakers. Some modern horologists even say that it was due to Harrison's work that the English could master the sea and create such a large empire. Maskelyne, from 1765 to 1811 published forty-nine issues of National Almanac. He figured all the lunar-solar and lunar-stellar distances from the Greenwich meridian. And so, starting with the very first volume in 1767, sailors all over the world who relied on Maskelyne’s tables began to calculate their longitude from Greenwich. In 1884, at the International Meridian Conference held in Washington, Greenwich meridian was declared the prime meridian of the world. However, the French continued to recognize Paris as their meridian, until 1911.

“With his marine clocks, John Harrison tested the waters of space-time. He succeeded, against all odds, in using the fourth dimension to link points on the three-dimensional globe.”

-       Thanks to Dava Sobel and William J. H. Andrewes for writing The Illustrated Longitude, Walker & Company, New York