"Lost at Sea - The Search For Longitude"

PBS Airdate: October 6, 1998
Go to the companion Web site

NARRATOR: During the following program, look for NOVA's Web markers, which lead you to more information at our Web site.

Tonight on NOVA: In the days when sailors had to find their speed in knots and dead reckoning could be fatal...

VOICE OF __: It was very easy for the pirates to catch the cargo ships.

NARRATOR: An unknown genius discovered the key to navigating the open seas—time. Now, based on the best selling novel by Dava Sobel, "Lost at Sea - The Search For Longitude."

Major funding for NOVA is provided by the Park Foundation, dedicated to education and quality television.

And by Iomega, makers of personal storage solutions for your computer, so you can create more, share more, save more and do more of whatever it is you do. Iomega, because it's your stuff.

NARRATOR: This program is funded in part by Northwestern Mutual Life, which has been protecting families and businesses for generations. Have you heard from the quite company? Northwestern Mutual Life.

And by the Corporation for Public Broadcasting and viewers like you.

[THE EYE OF THE WIND—LONELY SHIP AT SEA]

VOICE OF FISHERMAN: Oh, God, thy sea is so great, and my boat is so small.

NARRATOR: To be lost at sea meant wandering an empty ocean. A lonely ship, far from shore and never finding safe harbor. These perils were the stuff of legend since ships first sailed beyond the sight of land. But until just over 200 years ago, there was no sure way of knowing the position on the high seas. Navigation because the greatest scientific challenge of the age of sail.

[PARIS OBSERVATORY—EMBOSSED STONEWORK OF INSTRUMENTS WS GREENWICH EXTERIOR AND OCTAGON ROOM]

Any nation which found the method of accurate navigation could rule the economy of the world. In Paris and at Greenwich, observatories were built, to chart the sky in an effort to learn if the moon and stars could help guide a ship at sea. It was, of course, assumed that the answer would come from these royal institutions or great universities.

[VILLAGE OF BARROW/COTTAGE WINDOWS—SOUND OF LATHE/RECREATION—HARRISON WORKING]

NARRATOR: But far away, in a remote English village called "Barrow-on-Humbar," a carpenter named John Harrison was teaching himself clock making. He had no formal education, but his clocks were highly original. Harrison learned his craft while observing village life around him.

[CU CLOCK PENDULUM/BELLS SWINGING]

JOHN HARRISON: I, from being a bell ringer since a boy, had saw the bell swinging in an enormous arc, 250 degrees or more.

[CLOSE SHOT—THE TENOR BELL/CU CHILD RINGING THE BELL—HANDS ON ROPES]

VOICE OF JOHN HARRISON: And when I went to plot out the pendulum of my first timekeeper, I knew that proper point in the swing where to best apply the force. I speak from strictly due experience, which is the best proof of usefulness, notwithstanding what University men may write or do.

[BELLS]

NARRATOR: Neither a university man nor an astronomer, having never been to sea, what role could John Harrison have in solving the greatest technical enigma of his time?

[THE CREW LETTING OUT THE LOG WITH WILL ANDREWES]

NARRATOR: Consider the problems of the sailors and navigators of the 1700s. On the training vessel Eye of the Wind, the passengers and crew are about to experience the challenges of being at sea on board a tall ship and finding their way across vast reaches of open ocean. Will Andrewes, Curator of Harvard University's Collection of Historical Scientific Instruments, has joined the crew in this exploration of ancient navigation. They're trying out a replica of a typical log and line of the early 1700s.

WILL ANDREWES VO: It was a triangle of wood which was called the log, and onto that was tied the line. It was a knotted line, knots tied at intervals of about 48 feet 3 inches. The navigator would throw the line over the side of the ship. And the first 50 feet of line would be clear, but as soon as the marker on the line passed through the navigator's fingers, the navigator would shout "Turn" and count the number of knots flowing through his fingers in the time it took a 28-second sand glass to flow through. This would give the speed of the ship in knots.

NARRATOR: Measuring the speed with knots was one of the techniques of dead reckoning. It was a crude method, and it didn't allow for currents or cross winds, which could easily push a ship off course. But it was then the only way to estimate distance traveled at sea.

[ANIMATION 1—DEFINE LATITUDE AND LONGITUDE]

NARRATOR: For centuries map makers have used grid lines to indicate points on the surface of the earth. This grid system evolved into lines of latitude and longitude. Latitude is represented by parallel horizontal lines circling the earth, with the Equator as the line of zero degrees latitude.

Longitude is depicted by the vertical lines, or meridians, running from Pole to Pole.

Any point on earth can be defined by a degree of latitude and a degree of longitude. But 300 years ago only the latitude was measurable, and that with great difficulty.

[EYE OF THE WIND—WILL USES CROSS STAFF]

NARRATOR: Navigators knew that the height of the noon-day sun varies. On the equator, it would be high in the sky, but in the far north, the sun remains low on the horizon.

By measuring the angle between the sun and the horizon, latitude could be calculated—if the navigator could survive the hazards lurking in his own instruments.

[EYE OF THE WIND—WILL USING CROSS STAFF]

WILL ANDREWES VO: As a cross staff, this was actually designed for use on land, and it was adapted for use at sea. One of its problems is that one has the staff held against one's eye and, with the ship moving up and down you not only get blinded by the sun, but you also get badly bruised on the eye bone. so it's not the easiest of instruments to use.

NARRATOR: But without any means of figuring longitude - their east-west position—latitude was all navigators could hope to use.

DAVA SOBEL: The safest way to go was to get to the right latitude in waters that had favorable currents and winds and then just go. Except that everybody else knew that you'd be going that way. So it was very easy for the warring nations to lie in wait for each other or for the pirates to catch the cargo ships. And it was an untenable situation, but what else could you do? If you struck out on a new route, you were just as doomed.

[GRAY SEAS - PAN TO ROCKS]

NARRATOR: On a damp October day in 1707 a fleet of British warships was returning home from battle with the French. They were just a day's sail from England.

[ANTIQUE MAP ILLUSTRATES THE ROUTE]

NARRATOR: Although they had no way of determining their exact position, they believed they were safely clear of the treacherous Scilly Islands off the English coast.

[SEAS AND ROCKS]

NARRATOR: But as the ships sailed on, a crash was heard on the lower decks of the flagship.

[PAINTING OF THE DISASTER]

NARRATOR: They had run aground, and the hull had been severed below the water line. One by one, four ships hit the rocks. And one by one, they sank. In a matter of minutes, thousands of men drowned and an important part of England's fleet was lost.

[MEMORIAL STONE/WS AISLE OF CHURCH, CHURCH WINDOWS]

NARRATOR: The wreck of Admiral Shovell's fleet was a national tragedy. There were days of mourning, official inquiries. If England was to be master of the seas, how could such a disaster have happened in her home waters?

An official of the Royal Navy, Samuel Pepys, had expressed the nations alarm:

[PORTRAIT - PEPYS]

VOICE OF SAMUEL PEPYS: It is most plain from the confusion all these people are to be that it is by God's almighty providence and the wideness of the sea that there are not a great many more misfortunes in navigation than there are.

[LONGITUDE ACT DOCUMENTS]

NARRATOR: The unfortunate situation had been exposed, and an outcry finally forced some action. In 1714 Parliament offered a reward to anyone who could solve the key problem of navigation—how to find longitude at sea.

The prize was big enough to capture the attention of the nation: L20,000, equivalent to millions today.

Proving voyages to the West Indies would be required to test the method, and a distinguished board would pass judgement.

DAVA SOBEL: Sir Isaac Newton, one of the—the Prime Commissioner, showing just how important the problem was and high-powered the board was. There were—the top scientists were on it, the top admirals, members of parliament. This was a blue ribbon panel, if ever there was one.

NARRATOR: But if Newton and the Board expected that the huge prize would quickly produce and answer, they were frustrated by the rush of loony, half-backed pamphlets which flooded the book stalls of London.

[CRANK PROPOSALS]

VOICE OF CRANK #1: The Only Method for Discovered Longitude, Humbly Proposed for the Consideration of the Publick.

VOICE OF CRANK #2: Longitude Explained, or Taking the Time on Tiptoe

[HOGARTH ETCHING: LUNATICS]

NARRATOR: William Hogarth's etching shows a pack of Longitude Lunatics searching for solutions within their asylum walls. Finding longitude, in the public's mind, had become the work of madmen.

[RECREATION—CLOSE SHOTS OF HARRISON—HANGS PENDULUM]

NARRATOR: For John Harrison, at the age of twenty, clock making had become a passion. He was obsessed with accuracy and, by about 1720, he too had become intrigued with the problem of longitude at sea.

[CU HARRISON'S JOURNAL]

NARRATOR: Although he was mostly unschooled, Harrison kept a detailed journal. Some of his writings have survived, and his own words reveal how quickly he grasped the essence of the longitude problem—its connection to time.

[HARRISON NEAR WALL BESIDE HUMBER]

JOHN HARRISON VO: I suppose that the difference of longitude betwixt a ship at sea and the port it sailed from might be as nearly known as its latitude if the ship had along with it a machine or watch that would exactly point out what time it was at the home port.

But it is said by all the—the motion of the ship has rendered all such machines as have been tried so irregular as to be of no service to the seaman in the matter of the longitude.

[ANIMATION OF GLOBE WITH LONGITUDE MERIDIANS]

NARRATOR: In theory, a clock should work. The earth turns a full 360 degrees in 24 hours, or 15 degrees each hour.

[ANIMATION 2 - FINDING LONGITUDE MEANS FINDING TIME]

NARRATOR: To know the longitude, one must know the time in two places at once. If a sailor knew when it was noon at the home port—Greenwich England, for example—and then had to wait one our until it was high noon on board his ship, he would know that the ship was 15 degrees west of Greenwich. If the sailor had to wait two hours for the sun to reach its high point, he was 30 degrees west. The challenge was knowing the time at the home port while sitting hundreds or thousands of miles away.

[HARRISON BESIDE HUMBER]

JOHN HARRISON VO: I judged that my intended sea clock will indeed require a regularity, a performance, as has not been seen before. A nicety of two or three seconds a month.

[BROCKLESBY PARK STABLES]

NARRATOR: Harrison understood that an exceptionally accurate timekeeper which would work at sea could solve the problem. But few clocks had reached the level of accuracy, even on land. Here, above the stables of the great English country house at Brocklesby Park, one of Harrison's first machines still keeps time. Each Thursday morning the estate's carpenter winds the movement.

[HARRY WINDS THE MECHANISM]

HARRY VO: I've been coming here to wind this Harrison clock for 30 years or thereabouts. My predecessor, he was winding it for 50 years. As far as I know, it's been very little trouble since 1722, when Harrison installed it.

[CLOCK MECHANISM, CU GRASSHOPPER, THE PENDULUM AND WOODEN BEARINGS]

NARRATOR: It was a wooden clock, like all of Harrison's early timekeepers. Its sturdy frame disguises its extraordinary accuracy and innovative features.

Harrison refined the mechanisms found in other clocks of the period. Tick by tick, the gear wheels rotate as their driving weights descend.

On each side of the toothed wheel, the unique grasshopper escapement transfers its impulses at the start of each swing.

All of this as the pendulum provides a constant measure of time.

HARRY VO: Being a joiner myself, I appreciate the quality of the timber that he used. The wood has a natural oil in it, so the clock is virtually maintenance-free. The materials that Harrison used are still in perfect condition, considering the time—1722—he didn't do a bad job, really.

[RECREATION—HARRISON TURNING SPINDLE ON LATHER/PULL FOCUS TO CU HARRISON]

NARRATOR: As a carpenter, Harrison knew the properties of wood. And this led him to anew way of reducing friction, which all clock makers knew was the enemy of accuracy.

ANDREW KING VO: Harrison had to deal with the problems of friction. The oils of the early 18th century were terrible. They'd dry out, they'd gum up very, very quickly. The main wood Harrison used to reduce friction was a tropical wood called "lignum-vitae." It's found in the Caribbean and South America. And it has natural resins in it, which never, never dry. For the top of the clock and the last wheel of the wheel tray, instead of suing a plain bush, Harrison pivots the wheel on little—these little rollers made of lignum-vitae, which reduce friction enormously. It was the first time this had ever been done.

[EYE OF THE WIND—STORMY SEAS]

NARRATOR: But could a clock based on these methods work at sea?

WILL ANDREWES VO: There are enormous problems in trying to make a precision piece of clockwork performs accurately at sea. There's the humidity. There are changes in atmospheric pressure. There's different gravity and different latitudes. There are enormous variations in temperature, from the cold North Sea to the blazing suns of the Caribbean. These affect the materials out of which the timekeeper is made. And then, of course, the most obvious of all is the rocking of the ship, the tremendous shocks that the ship receives when it moves from one wave to the other. All these things made it virtually impossible for a timekeeper to keep time at sea, or so they though in the 18th century.

NARRATOR: But some way of keeping the time at sea had to be found.

[GRAPHIC—WHISTON-DITTON PAMPHLET]

NARRATOR: Desperate problems invite desperate solutions. One fantastic scheme was presented by Professors William Whiston and Humphry Ditton.

[ANIMATION OF WHISTON-DITTON METHOD]

VOICE OF WILLIAM WHISTON: All that would be needed is a straight row of 20 or 30 warships somehow permanently anchored across the Atlantic. At midnight each night, the ships would fire off large sky rockets, which could be seen or heard for 100 miles around. With the explosions, mariners will always know when it is midnight in Greenwich and will be able to determine their longitude by comparing Greenwich time to the local time on board their ship.

NARRATOR: If sky rockets were impractical, the sky itself might provide time signals if one knew where to look.

[GRAPHICS—PORTRAIT OF GALILEO AND CHARTS]

NARRATOR: Using a primitive telescope, in 1610 the great astronomer Galileo discovered four moons circling the planet Jupiter.

[ANIMATION—TABLE AND ANIMATION OF MOONS OF JUPITER]

NARRATOR: He carefully charted their motions. The four moons would become a celestial timekeeper when tables were eventually drawn, to show their positions at seven o'clock each night, precise to within a few minutes.

[PARIS—FOUNTAIN AND OBSERVATORY]

NARRATOR: By the 1660s the Italian disciples of Galileo were close to perfecting his method of telling time with Jupiter's moons. News of this breakthrough reached the Paris Observatory, which was soon to become the home of the greatest Italian astronomer since Galileo—Giovanni Domenico Cassini.

[CAFE D'OBSERVATOIRE—UP TO STREET SIGN: RUE CASSINI/DRAWING—LOUIS XIV WITH CASSINI/DR. SUZANNE DEBARBAT WALKS UP STAIRS]

NARRATOR: Using the moons of Jupiter to find longitude promised to revolutionize map making. And, hoping to provide better maps for his busy map collectors, King Louis XIV set his new Italian astronomer to work.

[DR. SUZANNE DEBARBAT WALKS THROUGH OBSERVATORY]

NARRATOR: Cassini would start by measuring the distance from the Paris meridian to the coasts.

[CASSINI'S MAP OF FRANCE]

SUZANNE DEBARBAT VO AND ON-CAM SYNC: In 1671, an operation of measuring the position of the French coast began. VO: Cassini was observing the eclipses on the meridian line and astronomers were doing the same observations along the coast of France. The measurements of—by the astronomers made a big difference in the coast, and the areas of France diminished of about 20 percent.

NARRATOR: When the stunned Louis XIV first saw the new, highly accurate map of his diminished kingdom, he is said to have exclaimed "I have just lost more territory to my astronomers than to all my enemies."

[STATUE OF CASSINI/LES HYPOTHESES ET LES TABLES DES SATELLITES DE JUPITER]

NARRATOR: Cassini's method relied on the best telescopes of the day. It has a high level of accuracy—perhaps a bit too high for the King. But could the same system be used at sea?

SUZANNE DEBARBAT VO: It's impossible to do the same at sea because of the motion of the boat.

[EYE OF THE WIND AT NIGHT]

SUZANNE DEBARBAT VO: To observe the eclipse of the satellites with good accuracy, you need to be stable, which is not the case on a boat.

[RECREATION—TELESCOPES AT SEA]

NARRATOR: With Jupiter unable to be used as a clock at sea, there seemed to be two alternatives. Either find a different astronomical clock, or build a mechanical one. And Newton and the Board of Longitude were skeptical of mechanical clocks.

[PORTRAIT—NEWTON]

VOICE OF ISAAC NEWTON: I have told the world oftener than once that longitude is not to be found by watchmakers but by the ablest astronomers. I am unwilling to meddle with any other method than the right one.

DAVA SOBEL VO: Newton really prejudiced the Board by saying in no uncertain terms that no clock would ever succeed in finding the longitude.

[HARRISON LOOKING OUT AT SKY]

NARRATOR: Working in isolation, John Harrison never heard Newton's doubts; and the labor to perfect his clocks went on.

He now needed to check the accuracy of his timekeepers to within seconds a day, but the village sundial wasn't good enough.

[RECREATION—HARRISON CHECKS STARS]

ANDREW KING VO: Harrison quite simply looked at the stars. But there were no time standards whatsoever, but it's quite possible to get—to—to take star readings. As the world rotates, the fixed stars come into your vision every day at a certain time. But they arrive three minutes 54 seconds earlier every day. And Harrison managed to take sightings from his house.

[HARRISON USES HIS WORKSHOP WINDOW TO VIEW THE SKY AS IT PASSES HIS NEIGHBOR'S CHIMNEY/HARRISON LINES UP CHIMNEY/CHIMNEY - SUPER STARS—MIX TO SECOND HAND ON CLOCK/WS HARRISON]

JOHN HARRISON: I fashioned a true way of setting my clocks by the apparent motion of the fixed stars, with a large sort of an instrument of about 25-yard radius, composed of the west side of my neighbor's chimney and the east side of my own window frames. By which the rays of a star are taken from my sight almost in an instant. And counting the seconds of the clock, beginning a little before the star vanish. And so I observe at what second it vanisheth.

[WS HARRISON VIEWING STARS]

NARRATOR: John Harrison's living room had become a genuine scientific laboratory.

[RECREATIONS—WORKSHOP/HARRISON WORKING WITH IRON AND BRASS WIRES]

DAVA SOBEL: If this was a period of scientific revolution, Harrison was a real revolutionary character, a lone genius, totally uncaring about what everyone else was doing. He invented everything he needed.

NARRATOR: Of the many factors which could degrade a clock's performance, none was worse then the effect slight changes in temperature had on the speed of the movement.

VOICE OF JOHN HARRISON: The pendulum must always retain the same length. But there's no metal whatever whereof to make a pendulum that is not continually altering its length according to the degrees of heat and cold.

DAVA SOBEL: Harrison's achievement represents a fundamental issue in science—whether science proceeds by theory or by the hands-on work of an experimenter.

[RECREATION—WIRES AND PENDULUM]

NARRATOR: Searching for a pendulum which would not be affected by temperature, Harrison noticed that heat caused brass and iron wires to expand at different rates. Making use of this observation, he combined wires of the two metals to compensate for expansion, producing and perfecting his gridiron pendulum.

ANDREW KING VO: He developed testing methods. These clocks were incredibly accurate. He tested one clock against another, which is totally unheard of in his own day.

[RECREATION—TEMPERATURE EXPERIMENTS/PAN FROM PENDULUM TO HARRISON WORKING IN COLD HALLWAY]

JOHN HARRISON VO: Two clocks, placed one in one room and the other in another, in very cold and frosty weather, I made one room very warm with a great fire, whilst the other is very cold.

NARRATOR: He would succeed only when there was absolutely no time difference between the two clocks, whether hot or cold. It was brilliant science requiring astonishing feats of observation.

VOICE OF JOHN HARRISON: I could stand in the doorstead, and I could hear the beats of both pendulums, by which means I could have the difference of both clocks to the 20th part of a second—less—and thus I proved the operation of my pendulum wires and adjust the same...

[CLOSE SHOT PENDULUM]

ANDREW KING: The very thought that, uh, you could produce a precision timekeeper of a wooden clock seems quite, quite out, out of order, as well. And yet, Harrison claimed that these clocks were accurate to a, uh, accurate to within a second a month. This is something that wasn't even thought of until the 1880's. Harrison was 150 years ahead of his time. He was incredible.

[RECREATION: HARRISON PACKING UP PAPERS]

NARRATOR: By 1730, John Harrison had collected enough information on the effects of temperature, friction, and gravity to convince himself that he could really build a sea clock accurate and reliable enough to win the Longitude Prize.

[GREENWICH - EXTERIOR/PORTRAITS: HALLEY AND GRAHAM]

NARRATOR: For the first time in his life, he ventured beyond the vicinity of Barrow, traveling to London to present his proposal to the esteemed Astronomer Royal, Dr. Edmond Halley, predictor of the comet which bears his name. Halley arranged an introduction to London's most famous clock maker, George Graham.

[RECREATION: HARRISON WALKING BESIDE HUMBER/HARRISON RETURNS HOME]

NARRATOR: After a stay of several weeks Harrison returned to his village. His journals describe his London adventures, and give a glimpse of the country carpenter meeting England's most distinguished scientists. His plain-spoken memoirs suggest that he was less than impressed by the work of the celebrated George Graham.

[RECREATION: HARRISON DESCRIBES HIS LONDON VISIT]

JOHN HARRISON: Dr. Halley, advised me to go to Mr. Graham, advice which went very hard with me, for I thought it a step very improper to be taken. But he told me Mr. Graham was a very honest man and would do me no harm as by pirating anything from me.

Mr. Graham began, as I thought, very roughly with me, which occasioned me to become rough too. But, we uh, we got the ice broke and we reasoned the cases more than once. And our reasoning, or as it were sometimes debating, held from about ten o'clock in the forenoon till eight o'clock at night. I had along with me some drawings of the principal parts of my pendulum clock, and also my intended timekeeper for the longitude.

While Mr. Graham proved indeed a fine gentleman, if truth be told, I was taken aback by the poor little feeble motions of his pendulums...the small force they had like creatures sick and inactive. But I, um, commented not on he folly in his watches.

JONATHAN BETTS: When Harrison knocked on the door, here was a, um, a joiner's son from Lincolnshire with no formal education, and here he was producing plans for a clock with wooden wheels of all things. You can imagine how Graham must have, uh, reacted to that. But, there's no doubt that as soon as Harrison got out his drawings of his gridiron pendulum and showed Geor, three, George Graham that, he would have been incredibly impressed because we know that George Graham has been trying to design just such a temperature compensated pendulum himself some years before and had failed. So, this must have been the turning point for Graham. This was no time waster.

[RECREATION—TRACK PAST BRASS CLOCK UNDER CONSTRUCTION/MIX TO WIDE SHOT]

NARRATOR: Harrison's meeting with George Graham was indeed a turning point. With Graham's support development money began to flow, allowing Harrison to build his first longitude timekeeper, the sea clock known today simply as H-1.

[H-1—WOODEN GEARS BRASS BALANCES AND SPRINGS]

NARRATOR: One by one, Harrison attacked the problems of adapting his clocks to go to sea. Working in brass for the first time, he continued to use wheels of oak to engage rollers of ignum vitae. To overcome the motion of the ship Harrison replaced his long pendulum with two rocking balance arms with springs to maintain their oscillations.

JONATHAN BETTS: And in this way, he got round all of these problems and produced, arguably, one of the most remarkable marine timekeepers of all time.

[H-1 AT GREENWICH—FRONT VIEW, THEN TILT UP MECHANISM/MIX TO EYE OF THE WIND/HEAVY GRAY SEAS]

NARRATOR: In 1736, Harrison accompanied his first sea clock on a preliminary testing voyage to Lisbon on board The Centurian. The stormy five-week journey was to be the only ocean trip of John Harrison's life.

WILL ANDREWS: VO: On the return voyage from Lisbon there were storms and the ship lost its position. The crew kept a rough idea of where the ship was by dead reckoning. Harrison was maintaining its location as best he could by the timekeeper, and when land was sighted, the South Coast of England was sighted, there was a dispute as to what point of land it was. They knew they were not far from the Scilly Isles where Sir Clowdseley Shovels' fleet had been wrecked. Sync: As land got closer the crew realized that Harrison was right. His timekeeper was proved to be a practical invention.

[RECREATION: HARRISON EXAMINES BALANCE ARMS]

JOHN HARRISON: My clock has been on a voyage, a very rough one. Upon my meeting the Captain, he said to me that the difficulty of measuring time with the motion of the sea gave him concern, and he felt I'd attempted impossibilities. He later wrote a report and said, Mr. Harrison was sea sick throughout, but the motion of the sea was not in the least detrimental to his sea clock keeping true time.

JONATHAN BETTS: We believe it performed very well, although we don't know the exact performance of H-1, but we have reason to believe it was well within five to ten seconds a day, which would not have won he is not the great Longitude Prize, but it was far better than most people had expected and it gave Harrison great cause to believe that he was on the right track.

[GREENWICH: TRACK FROM H-1 TO H-2]

NARRATOR: Without even asking for additional tests Harrison put H-1 aside and took on the job of producing what he hoped would be an improved model, H-2.

JONATHAN BETTS VO: In working on H-2, Harrison must have employed other workmen and he would only have given one individual a small amount of work to do so that no single person could claim to have made any of it and, therefore, be entitled to any of the prize money. We know Harrison was paranoid about the idea of other people taking his ideas.

NARRATOR: After two years of painstaking work Harrison noticed a fatal flaw. When subjected to a specific extreme movement the accuracy of his bar balances was corrupted.

JONATHAN BETTS: Being a very ruthless man with himself, he simply then set the machine aside and moved straight on to his third machine. There was no way he could improve it, so he simply left it.

[TRACK AROUND ABANDONED H-2]

NARRATOR: Harrison's development of his large sea clocks was bogging down. Years passed as his quest for perfection led up many blind alleys. For a man obsessed with time, his own time meant nothing to him.

And while Harrison stumbled, his rivals, the astronomers, were attempting to win the Longitude Prize by telling time using our own moon. Their method was beginning to show promise.

[GRAPHIC: ASTRONOMERS TAKING READINGS]

NARRATOR: Both moon and stars move across the night sky. Astronomers knew that the position of the moon against the stars was unique for every minute of every day. They had the makings of a true celestial clock if someone could work it all out in advance. Enter the forceful champion of this lunar method, the Very Reverend Nevil Maskelyne.

[PORTRAIT: MASKELYNE]

DEREK HOWSE: Nevil Maskelyne, uh, he was a bit pompous. The fact he was a reverend, of course, doesn't come into it because all scientific people who wanted to get on in science had to take holy orders at that time, so we can forget that one. But, he was pompous, a bit of a prig, I think, probably.

[PORTRAIT: MASKELYNE (another)]

NARRATOR: If John Harrison was the perpetual outsider, Nevil Maskelyne was the perfect insider. As a well bred, ambitious young astronomer from Cambridge, Maskelyne set out to make a name for himself within the scientific establishment.

DAVA SOBEL: I find Maskelyne a particularly unpleasant character. He did a great deal for navigation, but here is somebody who kept track of every dime...

DEREK HOWSE: ...every penny that he spent for about forty years is, in fact, recorded...

DAVA SOBEL: ...but he took that same maniacle meticulousness and applied it to his astronomical work, and that's where he did a great good service, and perhaps he couldn't have done it without that sort of attention to detail.

[GREENWICH: TELESCOPES AND QUADRANTS (USE WITH OLD PRINT)]

NARRATOR: Laboring at Greenwich, Maskelyne observed the motion of the moon against the background of stars. Eventually, he could predict its position for every minute of every day. Using these predictions, Maskelyne produced a set of astronomical tables.

[ANIMATION - LUNAR DISTANCE]

NARRATOR: Unlike Jupiter, no powerful telescopes were needed. From his ship, a navigator would measure the angle between the moon and certain stars. Then, in theory, he could use Maskelyne's tables to find the time at Greenwich, if he had clear weather, precise instruments, and after hours of calculations.

[EYE OF THE WIND AT NIGHT]

NARRATOR: But from a rolling deck just keeping site of the moon was a difficult chore, even without the lengthy computations.

SUZANNE DEBARBAT: The method of lunar distances was based on very long calculations. I've read that it needs about four hours of calculation after one observation to obtain the longitude. Four hours of calculations, and during these four hours the boat ....went during that time. If you use the clock like it was proposed by Harrison it's enough, more or less, to read the clock.

[DR. DEBARBAT WALKING AROUND CORNER OF LITTLE OBSERVATORY]

NARRATOR: But the Board of Longitude still would not accept that the clock was the answer, and it controlled the funds Harrison desperately needed to work on his difficult H-3.

DEREK HOWSE: I think that it was a question that these new fangled gadgets, uh, should we rely on them. Uh, the method was perfectly satisfactory. If you had a clock or a watch which could keep absolute time over all these times, then, of course, that's fine. But would it?

[RECREATION: JOHN HARRISON LOOKING AT HIS CLOCK]

JOHN HARRISON: They said, a clock can be but a clock, and the performance of mine, though nearly to truth itself, must be altogether a deception.

I say, for the love of money, these professors or priests have preferred their cumbersome lunar method over what may be had with ease, for certainly Parson Maskelyne would never concern himself in such a matter if money were not bottom.

...and yet, these university men must be my masters, knowing nothing at all of the matter, farther than that one wheel turns another; my mere clock being not only repugnant to their learning, but also the loss of a booty to them.

[GREENWICH—TRACK TO H-2 25:32:44/H-3—VARIOUS SHOTS 25:47:07]

NARRATOR: Harrison continued to work. In his H-3 he replaced his swinging bar balance with large balance wheels. Almost as an aside he invented the caged roller bearing, a friction reducing device still widely used today. And yet, his new clock continued to prove troublesome. Perhaps Harrison's large timekeepers had reached a dead end.

[INTERCUT WITH HARRISON WATCHMAKING WORKBENCH]

JONATHAN BETTS: SYNC: It was while he was struggling with H-3 that he made the breakthrough that he was desperately looking for. VO: He knew for many years that it would be extremely useful to him if he could improve these dreadful things called pocket watches, and in 1753, he instructed a watch maker, called John Jefferys, to make a watch for him to his own design, to Harrison's own design.

[INTERCUT WITH HARRISON WATCHMAKING WORKBENCH/CLOSE SHOTS OF THE WATCHES HE WAS EXAMINING/PLANS OF H-4—HE PLACES THE COMPONENTS AGAINST HIS DRAWINGS]

JONATHAN BETTS: VO: The going of the Jefferys watch far exceeded Harrison's wildest dreams and he began to realize maybe he had been barking up the wrong tree for all these years and he should have been working on watch development, not these large machines.

[CLOCKS, WATCHES, PLANS WORKBENCH/HANDS HOLDING SMALL COMPONENTS]

NARRATOR: This was an extraordinary change of direction. Now Harrison was prepared to reject 25 years of his own work and move ahead on an almost untried technology, struggling to make smaller what he had always assumed should be made larger.

JONATHAN BETTS: The result, of course, was H-4 which was finished in 1759 and which positively proved to Harrison that he had solved the problem.

[EYE OF THE WIND—RECREATION PROVING VOYAGE/BURNT OUT SHOTS, MOVEMENTS FROM SEA UP TO FIGURES]

NARRATOR: The Board of Longitude ordered H-4 to be tested on a proving voyage from Portsmouth, England to the island of Barbados.

[SEA AND REPEAT THROUGH THE SEQUENCE/CABIN INTERIOR H-4 BOX]

NARRATOR: Locked in its new protective box the precious watch had been carefully set to the correct time at Portsmouth using the sighting of the sun at noon.

[CREWMAN]

NARRATOR: For 46 days The Tartar sailed southwest across the Atlantic.

[RECREATION: WA (OVER SHOULDER) TAKES SEXTANT READING OF LOW SUN/THE CLOCK IN ITS CASE IS ASSIDUOUSLY WATCHED OVER/CLOCK IS BROUGHT FOR INSPECTION/ BCU KEYS/WAITING OFFICERS/ON DECK/ROUGH SEAS - PAN TO DECK OFFICER/HELMSMAN CHECKING COMPASS]

NARRATOR: The ship passed from the chill of the English Channel to the tropical Caribbean—a temperature difference of 50 degrees.

[INTERIOR CABIN]

Except for winding, the watch remained untouched in its box throughout the voyage. John Harrison was now 71 years old, and the burden of this test had passed to his son, William.

[SUN/SAILING OFF LAND]

NARRATOR: After a month and a half at sea, on the morning of May 13, 1764, the Tartar dropped anchor off Bridgetown, Barbados.

[MIX TO LONG BOAR HEADING FOR SHORE]

NARRATOR: The watch was rowed ashore to be examined.

[BARBADOS—SEA SHORE 09:43:41/WALLS OF OLD FORT, WAREHOUSES/BARBADOS—PAN TO PARLIAMENT BUILDING/ GRAPHIC: PANORAMIC PAINTING OF BRIDGETOWN HARBOR, CIRCA 1760.]

NARRATOR: To know if H-4 has passed the test the exact longitude of Bridgetown itself had to be determined to a new level of accuracy. this was clearly work for an astronomer.

[PORTRAIT: MASKELYNE/RECREATION: LOCAL WORKMEN CONSTRUCT AN OBSERVATION TENT/BRASS TELESCOPE IS SET UP IN TENT/ MIX TO/DUSK—TILT DOWN TO TENT/SHADOW OF ASTRONOMER'S PROFILE SEEN THROUGH TENT]

NARRATOR: In a great irony Nevil Maskelyne, Harrison's chief rival, had been sent to Barbados months earlier to make careful land-based, moons of Jupiter observations for the purpose of determining the correct longitude.

Maskelyne was quick to accept the assignment, but he had his own agenda. He planned to use the trip as a trial of his lunar method.

Working away in the tropical night, Maskelyne toiled with his instruments. It was reported that several of Barbados prominent citizens heard him boast that his lunar distance system was superior to any clock and might itself win the $20,000 (English pound) Longitude Prize when he returned to England.

Besides the glory, there was a great deal of money at stake.

WILL ANDREWES IN CHURCHYARD: The misunderstanding begins when Harrison arrives in Barbados in May 1764.

[BARBADOS COAST AT SUNSET?]

WILL ANDREWS VO: the principal purpose of this voyage was to test his father's timekeeper, which his father had taken a lifetime to build.]

NARRATOR: The testing of the clock in Maskelyne's hands was bound to be thorough, but would it also be fair and objective?

WILL ANDREWES IN CHURCHYARD: SYNC: William and his father, John Harrison, knew that Nevil Maskelyne was very interested in the lunar distance method. He was a good astronomer and they didn't complain before the voyage that he had been chosen as the principal person to make the observations on the island to determine the success of his timekeeper. However, when William Harrison arrived in May 1764,

[MASKELYNE'S TENT, HIS TELESCOPE AND PORTRAIT]

VO: he found out that Maskelyne had been talking a great deal about the lunar distance method. William Harrison created quite a scene. He didn't want Nevil Maskelyne to do any observations. This was an enormous slur on Maskelyne's character and Maskelyne resented it bitterly.

NARRATOR: Maskelyne's boasting had created an appearance of conflict-of-interest. A century-long quest for longitude had come down to a contest between the work of two stubborn men on the beaches of a remote tropical island.

[RECREATIONS: OPENING BOX BCU KEYS IN LOCK/BOX IS OPENED AND CUSHIONS PULLED BACK TO REVEAL H-4/CLOSE ON MINUTE HAND OF H-4/MIX TO MECHANISM]

NARRATOR: At the moment of noon, just as the sun reached its highest point over Bridgetown, William Harrison prepared to unlock H-4's case. The clock had not been reset for forty-six days. At that same moment the watch indicated that it was 3:55 PM back in Portsmouth. At fifteen degrees of longitude per hour, the clock placed the Harbor at Barbados just under sixty degrees west of Portsmouth, only a few miles from what we now know to be its actual position.

[ZOOM INTO WATCH]

ANDREW KING: When you imagine that the most accurate watch that you could buy in the 18th century was accurate within only a minute a day, Harrison produced this watch. It went to the West Indies and back, and after a six week voyage this thing was accurate to within about 30 seconds of time. This is just unheard of.

WILL ANDREWES: At the meeting of the Board of Longitude in January 1765, along the with the official news of the success of John Harrison's fourth marine timekeeper came the devastating news to Harrison that Nevil Maskelyne was to be appointed Astronomer Royal.

[RECREATION - BOARD OF LONGITUDE (DESK)]

NARRATOR: With Maskelyne now able to influence the Board, Harrison's hope that H-4's performance would quickly gain him the prize began to fade.

To the members of the Board, the clock's very accuracy was cause for suspicion.

ANDREW KING: SYNC: They were either government appointees or from the Royal Navy, or professors from universities,....

[H-4 WORKINGS]

ANDREW KING VO: ...they just didn't understand mechanics; I think they were frightened of it. It was a system of solving the longitude problem that they couldn't really cope with. They could understand an astronomical problem, but the SYNC: the very idea of a mechanical timekeeper that was so good that it was just too good to be true. They couldn't accept it.

[RECREATION - BOARD OF LONGITUDE (DESK)]

JONATHAN BETTS: VO: As far as the members of the Board of Longitude were concerned there was no particular vendetta against Harrison. In some ways, these people were far too boring for that kind of exercise, but at this stage they really believed that their summation was best and that these tick-tock clocks simply could not be believed.

ANDREW KING: Just imagine today that the government introduced award of, say, a million pounds for someone who could produce a 2-liter motor car that could do a thousand miles to the gallon. We'd all laugh at the idea. But supposing someone from the remote regions of the country comes down to London with a car and says to the government, "This car will do a thousand miles to the gallon. Where's my million pounds"? And so they say, oh come on, what's under the bonnet? "I want my million pounds then I'll tell you". And so the arguments start. He's not going to tell you what's under the bonnet because he knows perfectly well somebody's going to pinch the idea. And Harrison was in exactly the same position.

[RECREATION—BRIEF CLOSE SHOTS OF BOXES, CART WHEELS ON COBBLES]

NARRATOR: On the instructions of Nevil Maskelyne, Harrison's timekeepers were carted away for further tests. This left Harrison deeply discouraged.

JOHN HARRISON: Justice, as touching my reward or encouragement, has been scandalously frustrated.

Mr. Graham said to several gentlemen that I deserved the 20,000 pounds, yet the Board has turned me into a slave.

Well, they took great care about my watch, for they also locked it up for some time in a closet at the Admiralty because it had performed to voyages so well. And so they would keep it as a piece of treasure for feat nobody else would ever be able to make another. It's a fair sign indeed that they did not understand it. Nay, my timekeeper is beyond the reach of both the Latitude and the Longitude of these villainous priests of Cambridge and Oxford.

The trouble which these lunar men of occasion be.

NARRATOR: Finally, in 1772, Harrison's son wrote a letter to George III, pleading on behalf of his father. The two Harrisons were soon granted an audience with the King of England.

The Monarch must have been moved by the mens' story because he whispered to an aide these two people have been cruelly wronged. And then, turning to face father and son, he cried out for all to hear, "By God, Harrison, I shall see you righted."

DAVA SOBEL: I think it was very difficult for Harrison, and I think after all those years of willing struggle to have finally succeeded and met many unfair demands to push the project through extra trials and repeat replica performances, to get the money grudgingly but never the full trumpet fanfare, yes you did it, well done, must have left him feeling terribly bitter and disappointed, because it was always the principal of the thing with him.

NARRATOR: And so, forty-three years after a young John Harrison first travelled to London, a reluctant Parliament at the insistence of the King, awarded him the full 20,000 pounds.

JOHN HARRISON: I can boldly say that no timekeeper, whether in the pendulum way or that of the balance can never be able to go any truer or better than mine. And now, at sea, longitude may be had with great certainty and exactness. I've indeed had a long deal of labor, but I thank God I've got it free.

NARRATOR: In 1995, the first truly world-wide navigation system was realized. GPS, the Global Positioning System now provides navigators their latitude and longitude within a few feet anywhere on Earth. As 24 satellites orbit ten thousand miles overhead, their atomic clocks are monitored for almost perfect accuracy.

[TRANSMITTING DOWN 29, .... ZERO HOURS, 35 MINUTES EXACTLY/THE RESULTS ARE 29]

NARRATOR: Today, just as it was three hundred years ago the secret of knowing where you are is knowing what time it is.