Tells of the dangers of longitudial errors in the age of exploration, the creation of the longitude prize, astronomical attempts at solution, and John Harrison's development of a chronometer-based solution.
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00:00Tonight on NOVA.
00:02In the days when sailors had to find their speed in knots,
00:07and dead reckoning could be fatal.
00:10It was very easy for the pirates to catch the cargo ships.
00:15An unknown genius discovered the key to navigating the open seas.
00:20Time.
00:22Now, based on the best-selling book by Dava Sobel,
00:26Lost at Sea, The Search for Longitude.
00:31O God, thy sea is so great, and my boat is so small.
00:50O God, thy sea is so great, and my boat is so small.
00:57To be lost at sea meant wandering an empty ocean,
00:59a lonely ship far from shore and never finding safe harbor.
01:05These perils were the stuff of legend,
01:08since ships first sailed beyond the sight of land.
01:12But until just over 200 years ago,
01:14there was no sure way of knowing the position of a ship on the high seas.
01:18It was the first time that ships sailed beyond the sight of land.
01:20But until just over 200 years ago,
01:22there was no sure way of knowing the position of a ship on the high seas.
01:26Navigation became the greatest scientific challenge of the age of sail.
01:41Any nation which found a method of accurate navigation
01:56could rule the economy of the world.
01:59In Paris and at Greenwich,
02:02observatories were built to chart the sky in an effort to learn
02:06if the moon and stars could help guide a ship at sea.
02:10It was of course assumed that the answer would come
02:13from these royal institutions or great universities.
02:25But far away in a remote English village called Barrow-on-Humber,
02:28a carpenter named John Harrison was teaching himself clockmaking.
02:33He had no formal education, but his clocks were highly original.
02:45Harrison learned his craft while observing village life around him.
02:49I, from being a bell ringer since a boy,
02:54had saw the bell swing in an enormous hour, 250 degrees or more.
02:59And when I went to plan out the pendulum of my first timekeeper,
03:03I knew that proper point in the swing where to best apply the force.
03:08I speak from strictly due experience,
03:12which is the best proof of usefulness,
03:14notwithstanding what university men may write or do.
03:18Neither a university man nor an astronomer,
03:24having never been to sea,
03:26what role could John Harrison have
03:28in solving the greatest technical enigma of his time?
03:32Slack away the tank, forward!
03:35Slack away the tank, forward!
03:37Thuristic on the tank!
03:39Consider the problems of the sailors and navigators of the 1700s.
03:45On the training vessel Eye of the Wind,
03:50the passengers and crew are about to experience the challenges
03:53of being at sea on board a tall ship,
03:57and finding their way across vast reaches of open ocean.
04:00Will Andrews, curator of Harvard University's collection of historical scientific instruments,
04:14has joined the crew in this exploration of ancient navigation.
04:19They're trying out a replica of a typical log and line of the early 1700s.
04:24All set, Tiger. Standing by.
04:27Ready?
04:29It was a triangle of wood, which was called the log,
04:32and onto that was tied the line.
04:34It was a knotted line, knots tied at intervals of about 48 feet 3 inches.
04:39The navigator would throw the line over the side of the ship,
04:44and the first 50 feet of line would be clear.
04:47But as soon as the marker on the line passed through the navigator's fingers,
04:51the navigator would shout,
04:53Turn!
04:55and count the number of knots flowing through his fingers
04:58in the time it took a 28-second sand glass to flow through.
05:02This would give the speed of the ship in knots.
05:06Measuring the speed with knots was one of the techniques of dead reckoning.
05:10It was a crude method, and it didn't allow for currents or crosswinds,
05:14which could easily push a ship off course.
05:17But it was then the only way to estimate distance traveled at sea.
05:25For centuries, map makers have used grid lines
05:28to indicate points on the surface of the Earth.
05:31This grid system evolved into lines of latitude and longitude.
05:36Latitude is represented by parallel horizontal lines circling the Earth,
05:42with the equator as the line of zero degrees latitude.
05:48Longitude is depicted by the vertical lines, or meridians, running from pole to pole.
05:54Any point on Earth can be defined by a degree of latitude and a degree of longitude.
06:02But 300 years ago, only the latitude was measurable, and that with great difficulty.
06:09Navigators knew that the height of the noonday sun varies.
06:14On the equator, it would be high in the sky.
06:18But in the far north, the sun remains low on the horizon.
06:23By measuring the angle between the sun and the horizon,
06:26latitude could be calculated,
06:28if the navigator could survive the hazards lurking in his own instruments.
06:32As a cross-staff, this was actually designed for use on land,
06:36and it was adapted for use at sea.
06:38One of its problems is that one has the staff held against one's eye,
06:43and with the ship moving up and down,
06:45you not only get blinded by the sun,
06:47but you also get badly bruised on the eye bone.
06:49So it's not the easiest of instruments to use.
06:5218 degrees above the horizon.
06:57But without any means of figuring longitude, their east-west position,
07:02latitude was all navigators could hope to use.
07:07The safest way to go was to get to the right latitude
07:12in waters that had favorable currents and winds,
07:16and then just go,
07:18except that everybody else knew that you'd be going that way.
07:21So it was very easy for the warring nations to lie in wait for each other,
07:27or for the pirates to catch the cargo ships.
07:31And it was an untenable situation,
07:34but what else could you do?
07:36If you struck out on a new route, you were just as doomed.
07:45On a damp October day in 1707,
07:48a fleet of British warships was returning home from battle with the French.
07:53They were just a day's sail from England.
07:57Although they had no way of determining their exact position,
08:00they believed they were safely clear of the treacherous, silly islands off the English coast.
08:05But as the ship sailed on, a crash was heard on the lower decks of the flagship.
08:15They had run aground, and the hull had been severed below the waterline.
08:19One by one, four ships hit the rocks.
08:23And one by one, they sank.
08:26In a matter of minutes, thousands of men drowned.
08:31And an important part of England's fleet was lost.
08:34The wreck of Admiral Shovel's fleet was a national tragedy.
08:36There were days of mourning, official inquiries.
08:39If England was to be managed,
08:41they would have been destroyed.
08:42The wreck of Admiral Shovel's fleet was a national tragedy.
08:46There were days of mourning, official inquiries.
08:51If England was to be master of the seas,
08:54how could such a disaster have happened in her home waters?
08:58An official of the Royal Navy, Samuel Pepys, had expressed a surprise.
09:01The wreck of Admiral Shovel's fleet was a national tragedy.
09:04The wreck of Admiral Shovel's fleet was a national tragedy.
09:06There were days of mourning, official inquiries.
09:09If England was to be master of the seas,
09:11how could such a disaster have happened in her home waters?
09:14An official of the Royal Navy, Samuel Pepys,
09:20had expressed the nation's alarm.
09:23It is most plain from the confusion all these people are to be,
09:27that it is by God's almighty providence and the wideness of the sea
09:32that there are not a great many more misfortunes in navigation than there are.
09:37The unfortunate situation had been exposed,
09:42and an outcry finally forced some action.
09:45In 1714, Parliament offered a reward
09:49to anyone who could solve the key problem of navigation,
09:53how to find longitude at sea.
09:57The prize was big enough to capture the attention of the nation,
10:0120,000 pounds, equivalent to millions today.
10:06Proving voyages to the West Indies would be required to test the method,
10:11and a distinguished board would pass judgment.
10:16Sir Isaac Newton, one of the prime commissioner,
10:20showing just how important the problem was,
10:25and how high-powered the board was.
10:28The top scientists were on it, the top admirals, members of parliament.
10:34This was a blue ribbon panel, if ever there was one.
10:38But if Newton and the board expected that the huge prize would quickly produce an answer,
10:43they were frustrated by the rush of loony, half-baked pamphlets,
10:47which flooded the bookstalls of London.
10:50The only method for discovering longitude,
10:53humbly proposed for the consideration of the public.
10:58Longitude explained, or taking the time on tiptoe.
11:05William Hogarth's etching shows a pack of longitude lunatics
11:09searching for solutions within their asylum walls.
11:14Finding longitude in the public's mind had become the work of madmen.
11:26For John Harrison, at the age of 20, clock-making had become a passion.
11:31He was obsessed with accuracy, and by about 1720,
11:35he too had become intrigued with the problem of longitude at sea.
11:43Although he was mostly unschooled, Harrison kept a detailed journal.
11:48Some of his writings have survived,
11:50and his own words reveal how quickly he grasped the essence of the longitude problem,
11:55its connection to time.
12:00I suppose that the difference of longitude patricks the ship at sea,
12:06and the port it sailed from, might be as nearly known as its latitude,
12:11if the ship had along with it a machine or watch,
12:15that would exactly point out what time it was at the home port.
12:19But it is said by all that the motion of the ship
12:25has rendered all such machines as have been tried so irregular
12:29as to be of no service to the seaman in the matter of the longitude.
12:37In theory, a clock should work.
12:40The Earth turns a full 360 degrees in 24 hours, or 15 degrees each hour.
12:50To know the longitude, one must know the time in two places at once.
12:55If a sailor knew when it was noon at the home port, Greenwich, England, for example,
13:00and then had to wait one hour until it was high noon on board his ship,
13:04he would know that the ship was 15 degrees west of Greenwich.
13:09If the sailor had to wait two hours for the sun to reach its high point,
13:13he was 30 degrees west.
13:15The challenge was knowing the time at the home port
13:19while sitting hundreds or thousands of miles away.
13:22I judge that my intended sea clock will indeed require a regularity,
13:32a performance that has not been seen before,
13:36a nicety of two or three seconds a month.
13:47Harrison understood that an exceptionally accurate timekeeper
13:50which would work at sea could solve the problem.
13:54But few clocks had reached that level of accuracy, even on land.
13:59Here, above the stables of the Great English Country House at Brocklesby Park,
14:04one of Harrison's first machines still keeps time.
14:08Each Thursday morning, the estate's carpenter winds the movement.
14:13I've been coming here to wind this Harrison clock for 30 years or thereabouts.
14:22My predecessor, he was winding it for 50 years.
14:27As far as I know, it's been very little trouble since 1722,
14:33when Harrison installed it.
14:36It was a wooden clock, like all of Harrison's early timekeepers.
14:42Its sturdy frame disguises its extraordinary accuracy and innovative features.
14:48Harrison refined the mechanisms found in other clocks of the period.
14:53Tick by tick, the gear wheels rotate as their driving weights descend.
15:01On each side of the toothed wheel, the unique grasshopper escapement transfers its impulses at the start of each swing.
15:13All of this as the pendulum provides a constant measure of time.
15:18Being a joiner myself, I appreciate the quality of the timber that he used.
15:34The wood has a natural oil in it, so the clock is virtually maintenance-free.
15:41The materials that Harrison used are still in perfect condition.
15:50Considering the time, 1722, he didn't do a bad job really.
15:58As a carpenter, Harrison knew the properties of wood.
16:11And this led him to a new way of reducing friction,
16:15which all clockmakers knew was the enemy of accuracy.
16:19Harrison had to deal with the problems of friction.
16:23The oils of the early 18th century were terrible.
16:25They'd dry out, they'd gum up very, very quickly.
16:27The main wood Harrison used to reduce friction was a tropical wood called lignum vitae.
16:34It's found in the Caribbean and South America,
16:38and it has natural resins in it, which never, never dry.
16:42At the top of the clock, in the last wheel of the wheel train,
16:45instead of using a plain bush, Harrison pivots the wheel on these little rollers made of lignum vitae,
16:52which reduced friction enormously.
16:54It was the first time this had ever been done.
16:57But could a clock based on these methods work at sea?
17:15There are enormous problems in trying to make a precision piece of clockwork perform accurately at sea.
17:24There's the humidity.
17:26There are changes in atmospheric pressure.
17:28There's different gravity and different latitudes.
17:31There are enormous variations in temperature, from the cold North Sea to the blazing suns of the Caribbean.
17:38These affect the materials out of which the timekeeper is made.
17:42And then, of course, the most obvious of all is the rocking of the ship.
17:46The tremendous shocks that the ship receives when it moves from one wave to the other.
17:51All these things made it virtually impossible for a timekeeper to keep time at sea, or so they thought in the 18th century.
18:00But some way of keeping the time at sea had to be found.
18:05Desperate problems invite desperate solutions.
18:08One fantastic scheme was presented by Professors William Whiston and Humphrey Ditton.
18:15All that would be needed is a straight row of twenty or thirty warships, somehow permanently anchored across the Atlantic.
18:27At midnight each night, the ships would fire off large sky rockets, which could be seen or heard for a hundred miles around.
18:37With 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.
18:51If sky rockets were impractical, the sky itself might provide time signals if one knew where to look.
18:59Using a primitive telescope, in 1610 the great astronomer Galileo discovered four moons circling the planet Jupiter.
19:08He carefully charted their motions.
19:11The four moons would become a celestial timekeeper, when tables were eventually drawn,
19:16to show their positions at seven o'clock each night, precise to within a few minutes.
19:22By the 1660s, the Italian disciples of Galileo were close to perfecting his method of telling time with Jupiter's moons.
19:37News of this breakthrough reached the Paris Observatory,
19:40which was soon to become the home of the greatest Italian astronomer since Galileo, Giovanni Domenico Cassini.
19:49Using the moons of Jupiter to find longitude promised to revolutionize map making.
19:57And hoping to provide better maps for his busy tax collectors,
20:03King Louis XIV set his new Italian astronomer to work.
20:08Cassini would start by measuring the distance from the Paris Meridian to the coasts.
20:14In 1671, an operation of measuring the position of the French coast began.
20:23Cassini was observing the eclipses on the Meridian line,
20:27and astronomers were doing the same observations along the coast of France.
20:33The measurements by the astronomers made a big difference in the coast,
20:40and the area of France diminished of about 20 percent.
20:46When the stunned Louis XIV first saw the new, highly accurate map of his diminished kingdom,
20:53he is said to have exclaimed,
20:55I have just lost more territory to my astronomers than to all my enemies.
21:04Cassini's method relied on the best telescopes of the day.
21:08It had a high level of accuracy, perhaps a bit too high for the king.
21:13But could the same system be used at sea?
21:16It's impossible to do the same at sea because of the motion of the boat.
21:22To observe the eclipse of the satellites with good accuracy,
21:28you need to be stable, which is not the case on a boat.
21:33With Jupiter unable to be used as a clock at sea, there seem to be two alternatives.
21:40Either find a different astronomical clock, or build a mechanical one.
21:45And Newton and the board of longitude were skeptical of mechanical clocks.
21:52I have told the world, oftener than once, that longitude is not to be found by watchmakers,
21:59but by the ablest astronomers.
22:02I am unwilling to meddle with any other method than the right one.
22:07Newton really prejudiced the board by saying, in no uncertain terms,
22:13that no clock would ever succeed in finding the longitude.
22:20Working in isolation, John Harrison never heard Newton's doubts.
22:27And the labor to perfect his clocks went on.
22:30He now needed to check the accuracy of his timekeepers to within seconds a day.
22:35But the village sundial wasn't good enough.
22:40Harrison quite simply looked at the stars.
22:42There were no time standards whatsoever.
22:44But it's quite possible to take star readings.
22:49As the world rotates, the fixed stars come into your vision every day at a certain time.
22:55But they arrive three minutes, 54 seconds earlier every day.
22:58And Harrison managed to take sightings from his house.
23:02I fashioned a true way of setting my clocks by the apparent motion of the fixed stars
23:08with a very large sort of an instrument, about a 25-yard radius,
23:13composed of the west side of my neighbor's chimney and the east side of my own window frames,
23:20by which the rays of a star are taken from my sight almost in an instant.
23:26And counting the seconds of the clock beginning a little before the star vanish,
23:31and so I observe at what second it vanisheth.
23:37John Harrison's living room had become a genuine scientific laboratory.
23:42If this was a period of scientific revolution, Harrison was a real revolutionary character,
23:51a lone genius, totally uncaring about what everyone else was doing.
23:58He invented everything he needed.
24:01Of the many factors which could degrade a clock's performance,
24:05none was worse than the effect slight changes in temperature had on the speed of the movement.
24:11The pendulum must always retain the same length,
24:16but there's no metal whatever we're of to make a pendulum
24:19that is not continually altering its length according to the degrees of heat and cold.
24:25Harrison's achievement represents a fundamental issue in science,
24:32whether science proceeds by theory or by the hands-on work of an experimenter.
24:39Searching for a pendulum which would not be affected by temperature,
24:48Harrison noticed that heat caused brass and iron wires to expand at different rates.
24:54Making use of this observation, he combined wires of the two metals to compensate for expansion,
25:02producing and perfecting his gridiron pendulum.
25:11He developed testing methods. These clocks were incredibly accurate.
25:15He tested one clock against another, which is totally unheard of in his own day.
25:20Two clocks placed, one in one room and the other in another, in very cold and frosty weather.
25:30I make one room very warm with a great fire, whilst the other is very cold.
25:35He would succeed only when there was absolutely no time difference between the two clocks, whether hot or cold.
25:45It was brilliant science, requiring astonishing feats of observation.
25:50And I can stand in the doorstead and I can hear the beats of both pendulums.
25:55By which means I can have the difference of both clocks to the twentieth part of a second.
26:02Less!
26:04And thus I prove the operation of my pendulum wires under just the same.
26:23The very thought that you could produce a precision timekeeper for wooden clocks seems quite out of order as well.
26:30And yet Harrison claimed that these clocks were accurate to within a second a month.
26:35This is something that wasn't even thought of until the 1880s.
26:38Harrison was 150 years ahead of his time. It was incredible.
26:43By 1730, John Harrison had collected enough information on the effects of temperature, friction and gravity
26:50to convince himself that he could really build a C-clock, accurate and reliable enough to win the longitude prize.
27:00For the first time in his life, he ventured beyond the vicinity of Barrow,
27:05traveling to London to present his proposal to the esteemed astronomer royal, Dr. Edmund Halley,
27:11predictor of the comet which bears his name.
27:15Halley arranged an introduction to London's most famous clockmaker, George Graham.
27:20After a stay of several weeks, Harrison returned to his village.
27:42His journals describe his London adventures and give a glimpse of the country carpenter meeting England's most distinguished scientists.
27:54His plain-spoken memoir suggests that he was less than impressed by the work of the celebrated George Graham.
28:01Dr. Halley advised me to call to Mr. Graham.
28:08Advice which went very hard with me, for I thought it was a step very improper to be taken.
28:13And he told me Mr. Graham was a very honest man and would do me no harm as by pirating anything from me.
28:19Mr. Graham began, as I thought, very roughly with me.
28:34This occasioned me to become rough too, but we, er, we got the ice broke.
28:40And we reasoned the cases more than once.
28:47And our reasoning, or as it were sometimes debating,
28:51held from about ten o'clock in the full moon to eight o'clock at night.
28:56I had along with me some drawings of the principal parts of my pendulum clock
29:02and also my intended timekeeper for the longitude.
29:07Well, Mr. Graham proved indeed a fine gentleman.
29:15If truth be told, I was taken aback by the poor little feeble motions of his pendulums.
29:21The small force they had.
29:24Like creatures, sick and inactive.
29:28But I, er, commented not on the folly in his watches.
29:32When Harrison knocked on the door, here was a, er, a joiner's son from Lincolnshire with no formal education.
29:45And here he was, producing plans for a clock with wooden wheels, of all things.
29:50You can imagine how Graham must have, er, reacted to that.
29:53But there's no doubt that as soon as Harrison got out his drawings of his gridiron pendulum
29:59and showed George Graham that, he would have been incredibly impressed.
30:03Because we know that George Graham had been trying to design just such a temperature-compensated pendulum himself
30:08some years before and had failed.
30:10So this must have been the turning point for Graham. This was no time waster.
30:13Harrison's meeting with George Graham was indeed a turning point.
30:20With Graham's support, development money began to flow,
30:25allowing Harrison to build his first longitude timekeeper,
30:29the sea clock known today simply as H1.
30:33One by one, Harrison attacked the problems of adapting his clocks to go to sea.
30:39Working in brass for the first time, he continued to use wheels of oak to engage rollers of lignum vitii.
30:51To overcome the motion of the ship, Harrison replaced his long pendulum
30:56with two rocking balance arms with springs to maintain their oscillations.
31:00And in this way he got round all of these problems and produced arguably one of the most remarkable marine timekeepers of all time.
31:13In 1736, Harrison accompanied his first sea clock on a preliminary testing voyage to Lisbon on board the Centurion.
31:34The stormy five-week journey was to be the only ocean trip of John Harrison's life.
31:49On the return voyage from Lisbon, there were storms and the ship lost its position.
31:54The crew kept a rough idea of where the ship was by dead reckoning.
32:00Harrison was maintaining its location as best he could by the timekeeper.
32:05And when land was sighted, the south coast of England was sighted, there was a dispute as to what point of land it was.
32:11They knew they were not far from the Silly Isles where Sir Cloudsley Shovel's fleet had been wrecked.
32:15As land got closer, the crew realised that Harrison was right.
32:21His timekeeper was proved to be a practical invention.
32:28My clock has been on a voyage.
32:31A very rough one.
32:34Upon my meeting the captain, he said to me
32:36that the difficulty of measuring time with the motion of the sea gave him concern.
32:43And he felt I'd attempted impossibilities.
32:46He later wrote a report and said,
32:49Mr. Harrison was seasick throughout,
32:52but the motion of the sea was not in the least detrimental to his sea clock keeping true time.
32:58We believe it performed very well, although we don't know the exact performance of H1.
33:08But we have reason to believe it was well within five to ten seconds a day,
33:13which would not have won him the Great Longitude Prize,
33:15but it was far better than most people had expected.
33:18And it gave Harrison great cause to believe that he was on the right track.
33:24Without even asking for additional tests,
33:26Harrison put H1 aside,
33:29and took on the job of producing what he hoped would be an improved model,
33:33H2.
33:35In working on H2, Harrison must have employed other workmen,
33:39and he would only have given one individual a small amount of work to do,
33:43so that no single person could claim to have made any of it,
33:46and therefore be entitled to any of the prize money.
33:49We know Harrison was paranoid about the idea of other people taking his ideas.
33:52After two years of painstaking work, Harrison noticed a fatal flaw.
33:59When subjected to a specific extreme movement, the accuracy of his bar balances was corrupted.
34:06Being a very ruthless man with himself, he simply then set the machine aside and moved straight onto his third machine.
34:12There was no way he could improve it, so he simply left it.
34:16Harrison's development of his large sea clocks was bogging down.
34:21Years passed as his quest for perfection led up many blind alleys.
34:26For a man obsessed with time, his own time meant nothing to him.
34:33And while Harrison stumbled, his rivals, the astronomers, were attempting to win the longitude prize by telling time using our own moon.
34:43Their method was beginning to show promise.
34:45Both moon and stars move across the night sky.
34:51Astronomers knew that the position of the moon against the stars was unique for every minute of every day.
34:58They had the makings of a true celestial clock if someone could work it all out in advance.
35:04Enter the forceful champion of this lunar method, the very reverend Neville Maskelin.
35:10Neville Maskelin, he was a bit pompous.
35:15The 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.
35:28But he was pompous, a bit of a prig, I think, probably.
35:34If John Harrison was the perpetual outsider, Neville Maskelin was the perfect insider.
35:42As a well-bred, ambitious young astronomer from Cambridge, Maskelin set out to make a name for himself within the scientific establishment.
35:51I find Maskelin a particularly unpleasant character.
35:58He did a great deal for navigation, but here is somebody who kept track of every dime.
36:06Every penny that he spent for about 40 years is in fact recorded.
36:10But he took that same maniacal meticulousness and applied it to his astronomical work, and that's where he did a great good service.
36:20And perhaps he couldn't have done it without that sort of attention to detail.
36:25Laboring at Greenwich, Maskelin observed the motion of the moon against the background of stars.
36:35Eventually, he could predict its position for every minute of every day.
36:41Using these predictions, Maskelin produced a set of astronomical tables.
36:47Unlike Jupiter, no powerful telescopes were needed.
36:53From his ship, a navigator would measure the angle between the moon and certain stars.
37:00Then, in theory, he could use Maskelin's tables to find the time at Greenwich.
37:06If he had clear weather, precise instruments, and after hours of calculations.
37:14But from a rolling deck, just keeping sight of the moon was a difficult chore, even without the lengthy computations.
37:21The method of lunar distances was based on very long calculations.
37:33I've read that it needs about four hours of calculation after one observation to obtain the longitude.
37:42Four hours of calculations, and during these four hours, the boat went during that time.
37:53If you use the clock like it was proposed by Harrison, it's enough, more or less, to read the clock.
38:04But the Board of Longitude still would not accept that the clock was the answer.
38:11And it controlled the funds Harrison desperately needed to work on his difficult H3.
38:16I think that it was a question that these newfangled gadgets, should we rely on them?
38:26The method was perfectly satisfactory.
38:29If you had a clock or a watch which could keep absolute time over all these times, then, of course, that's fine.
38:35But would it?
38:40They said, a clock can be but a clock.
38:44And the performance of mine, though nearly to truth itself, must be altogether a deception.
38:50I say, for the love of money, these professors or priests have preferred their cumbersome lunar method over what may be had with ease.
39:03For certainly, Parson Maskeline would never concern himself in such a matter if money were not at bottom.
39:08And yet these university men must be my masters, knowing nothing at all of the matter farther than that one wheel turns another.
39:18My mere clock being not only repugnant to their learning, but also the loss of a booty to them.
39:33Harrison continued to work.
39:34In his H3, he replaced his swinging bar balance with large balance wheels.
39:41Almost as an aside, he invented the caged roller bearing, a friction-reducing device still widely used today.
39:49And yet his new clock continued to prove troublesome.
39:53Perhaps Harrison's large timekeepers had reached a dead end.
40:04It was while he was struggling with H3 that he made the breakthrough that he was desperately looking for.
40:11He knew for many years that it would be extremely useful to him if he could improve these dreadful things called pocket watches.
40:19And in 1753, he instructed a watchmaker called John Jeffries to make a watch for him to his own design, to Harrison's own design.
40:30The going of the Jeffries watch far exceeded Harrison's wildest dreams.
40:34And he began to realize maybe he'd been barking up the wrong tree for all these years, and he should have been working on watch development, not these large machines.
40:43This was an extraordinary change of direction.
40:48Now 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.
41:01The result, of course, was H4, which was finished in 1759, and which positively proved to Harrison that he had solved the problem.
41:21The Board of Longitude ordered H4 to be tested on a proving voyage from Portsmouth, England, to the island of Barbados.
41:30Locked in its new protective box, the precious watch had been carefully set to the correct time at Portsmouth, using a sighting of the sun at noon.
41:42For 46 days, the Tartars sailed southwest across the Atlantic.
41:49The ship passed from the chill of the English Channel to the tropical Caribbean, a temperature difference of 50 degrees.
41:56Except for winding, the watch remained untouched in its box throughout the voyage.
42:03John Harrison was now 71 years old, and the burden of this test had passed to his son, William.
42:10After a month and a half at sea, on the morning of May 13th, 1764, the Tartar dropped anchor off Bridgetown, Barbados.
42:25The watch was rowed ashore to be examined.
42:32To know if H4 had passed the test, the exact longitude of Bridgetown itself had to be determined to a new level of accuracy.
42:49This was clearly work for an astronomer.
42:57In a great irony, Neville Maskelin, 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.
43:12Maskelin was quick to accept the assignment, but he had his own agenda.
43:22He planned to use the trip as a trial of his lunar method.
43:27Working away in the tropical night, Maskelin toiled with his instruments.
43:37It was reported that several of Barbados' prominent citizens heard him boast that his lunar distance system was superior to any clock,
43:46and might itself win the twenty-thousand-pound longitude prize when he returned to England.
43:54Besides the glory, there was a great deal of money at stake.
44:02The misunderstanding begins when Harrison arrives in Barbados in May 1764.
44:08The principal purpose of this voyage was to test his father's timekeeper, which his father had taken a lifetime to build.
44:17The testing of the clock in Maskelin's hands was bound to be thorough.
44:22But would it also be fair and objective?
44:25William and his father, John Harrison, knew that Neville Maskelin was very interested in the lunar distance method.
44:32He was a good astronomer, and they didn't complain before the voyage that he had been chosen as the principal person
44:40to make the observations on the island to determine the success of his timekeeper.
44:47However, when William Harrison arrived in May 1764, he found out that Maskelin had been talking a great deal about the lunar distance method.
44:58William Harrison created quite a scene.
45:01He didn't want Neville Maskelin to do any observations.
45:05This was an enormous slur on Maskelin's character, and Maskelin resented it bitterly.
45:10Maskelin's boasting had created an appearance of conflict of interest.
45:17A century-long quest for longitude had come down to a contest between the work of two stubborn men
45:24on the beaches of a remote tropical island.
45:31At the moment of noon, just as the sun reached its highest point over Bridgetown,
45:36William Harrison prepared to unlock H4's case.
45:40The clock had not been reset for 46 days.
46:02At that same moment, the watch indicated that it was 3.55 pm back in Portsmouth.
46:12At 15 degrees of longitude per hour, the clock placed the harbor at Barbados just under 60 degrees west of Portsmouth,
46:20only a few miles from what we now know to be its actual position.
46:32When you imagine that the most accurate watch you could buy in the 18th century was accurate within only a minute a day,
46:37Harrison produced this watch.
46:39It went to the West Indies and back.
46:41And after a six-week voyage, this thing was accurate within about 30 seconds of time.
46:46This is just unheard of.
46:48At the meeting of the Board of Longitude in January 1765, along with the official news of the success of John Harrison's fourth marine timekeeper,
47:00came the devastating news to Harrison that Neville Maskelyne was to be appointed astronomer royal.
47:07With Maskelyne now able to influence the board, Harrison's hope that H4's performance would quickly gain him the prize began to fade.
47:16To the members of the board, the clock's very accuracy was cause for suspicion.
47:23They were either government appointees or from the Royal Navy or professors from universities.
47:28They just didn't understand mechanics. I think they were frightened of it.
47:31It was a system of solving the longitude problem that they couldn't really cope with.
47:35They could understand an astronomical problem, but the very idea of a mechanical timekeeper that was so good,
47:42it was just too good to be true. They couldn't accept it.
47:46As far as the members of the Board of Longitude were concerned, there was no particular vendetta against Harrison.
47:53In some ways, these people were far too boring for that kind of exercise.
47:57But at this stage, they really believed that their solution was best and that these tick-tock clocks simply could not be believed.
48:05Just imagine today that the government introduced an award of, say, a million pounds for someone who could produce a two-litre motor car that could do 1,000 miles per gallon.
48:14We all laugh at the idea. But supposing someone from the remote regions of the country comes down to London with a car and he says to the government,
48:22this car will do 1,000 miles per gallon, where's my million pounds? And they say, oh, come on, what's under the bonnet?
48:29I want my million pounds, then I'll tell you. And so the arguments start.
48:34He's not going to tell you what's under the bonnet because he knows perfectly well someone's going to pinch the idea.
48:39And Harrison was in exactly the same position.
48:44On the instructions of Neville Maskelyne, Harrison's timekeepers were carted away for further tests.
48:51This left Harrison deeply discouraged.
48:54Justice has touched in my reward or an encouragement.
49:09He's been scandalously frustrated.
49:13Mr. Graham said to several gentlemen that I deserved the 20,000 pounds.
49:18Yet the board has turned me into a slave.
49:22Well, they took great care about my watch.
49:25For they also locked it up for some time in a closet at the Admiralty because he had performed two voyages so well.
49:31And so they would keep it as a piece of treasure for fear nobody else would ever be able to make another.
49:37It's a fair sign, indeed, that they did not understand it.
49:41Nay, my timekeeper is beyond the reach of both the latitude and the longitude of these villainous priests of Cambridge and Oxford.
49:56The trouble which these lunar men of occasion be.
50:06Finally, in 1772, Harrison's son wrote a letter to George III, pleading on behalf of his father.
50:15The two Harrisons were soon granted an audience with the King of England.
50:21The monarch must have been moved by the men's story because he whispered to an aide,
50:25These two people have been cruelly wronged.
50:28And then, turning to face father and son, he cried out for all to hear,
50:34By God, Harrison, I shall see you righted.
50:37I think it was very difficult for Harrison.
50:52And I think after all those years of willing struggle to have finally succeeded and met many unfair demands
51:05To push the project through extra trials and repeat replica performances.
51:12To get the money grudgingly, but never the full trumpet fanfare.
51:21Yes, you did it. Well done.
51:24Must have left him feeling terribly bitter and disappointed.
51:29Because it was always the principle of the thing with him.
51:34And so, 43 years after a young John Harrison first travelled to London,
51:43A reluctant Parliament, at the insistence of the King, awarded him the full £20,000.
51:50I can boldly say that no timekeeper, whether in the pendulum way or that of the balance,
51:56Can never be able to go any truer or better than mine.
52:01And now, at sea, the longitude may be had with great certainty and exactness.
52:08I have indeed had a long deal of labour.
52:13But I thank God I've got it through.
52:17In 1995, the first truly worldwide navigation system was realised.
52:27GPS, the Global Positioning System, now provides navigators their latitude and longitude within a few feet anywhere on Earth.
52:40As 24 satellites orbit 10,000 miles overhead, their atomic clocks are monitored for almost perfect accuracy.
53:01Perceding on 29.
53:13Today, just as it was 300 years ago, the secret of knowing where you are is knowing what time it is.
53:22Finding your way at sea was the greatest challenge of the 1700s.
53:35What is our challenge today?
53:38Hear from leaders on the frontiers of science.
53:52To order this show for $19.95, plus shipping and handling, call 1-800-255-9424.
54:06And to learn more about how science can solve the mysteries of our world, ask about our many other NOVA videos.
54:14NOVA is a production of WGBH Boston.