Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time - Dava Sobel (2005)

Chapter 12. A Tale of Two Portraits

How sour sweet music is

When time is broke and no proportion kept!

So is it in the music of men’s lives.

I wasted time, and now doth time waste me;

For now hath time made me his numbering clock;

My thoughts are minutes.


Two compelling likenesses of John Harrison, both made during his lifetime, survive into ours. The first is a formal portrait in oils by Thomas King, completed sometime between October 1765 and May 1766. The other is an engraving by Peter Joseph Tassaert, from 1767, obviously taken from the painting, which it copies in almost every detail. In all details, really, except one—and this one difference tells a story of degradation and despair.

The painting now hangs in the gallery at the Old Royal Observatory. It shows Harrison as a man to be reckoned with. Dressed in a chocolate brown frock coat and britches, he sits surrounded by his inventions, including H-3 at his right and the precision gridiron-pendulum regulator, which he built to rate his other timepieces, behind him. Even seated he assumes an erect bearing and a look of self-satisfied, but not smug, accomplishment. He wears a gentleman’s white wig and has the clearest, smoothest skin imaginable. (The story of Harrison’s becoming fascinated with watch-works in childhood, while recuperating from an illness, holds that he suffered a severe case of smallpox at the time. We must conclude, however, that the tale is tall, or that he experienced a miraculous recovery, or that the artist has painted out the scars.)

His blue eyes, though a bit rheumy at seventy-plus years of age, direct a level gaze. Only the eyebrows, raised at the center, and the lines between them, betray the man’s cautious craftsmanship, his nagging concerns. He holds his left arm akimbo, hand on hip. His right forearm rests on a table, and in his fingers is . . . the Jefferys pocket watch!

Where is H-4? It was long finished by this time, and always the apple of his eye. Surely Harrison would have insisted on having it pose with him. Indeed, it does pose with him in the Tassaert engraving. Strange how the mezzotint departs from the oil at the point of Harrison’s right wrist. His hand is empty in this image, upturned and vaguely gesturing toward the Watch, now lying on the table, a bit foreshortened by perspective, atop some drawings of itself. Admittedly, the timekeeper looks too large for Harrison to cradle comfortably in his palm, as he could do with the Jefferys watch, which was only half the size of H-4.

The reason H-4 is missing from the oil portrait is that Harrison didn’t have it in his possession at the sittings. It was fudged in later, when Harrison’s growing fame as “the man who found Longitude” occasioned the creation of the engraving. The intervening events stressed Harrison to the limits of his forbearance.

After the fractious second trial of the Watch in the summer of 1764, the Board of Longitude allowed months to pass without saying a word. The commissioners were waiting for the mathematicians to compare their computations of H-4’s performance with the astronomers’ observations of the longitude of Portsmouth and Barbados, all of which had to be factored into the judging. When they heard the final report, the commissioners conceded that they were “unanimously of opinion that the said timekeeper has kept its time with sufficient correctness.” They could hardly say otherwise: The Watch proved to tell the longitude within ten miles—three times more accurately than the terms of the Longitude Act demanded! But this stupendous success gained Harrison only a small victory. The Watch and its maker still had lots of explaining to do.

That autumn, the board offered to hand over half the reward money, on the condition that Harrison hand over to them all the sea clocks, plus a full disclosure of the magnificent clockwork inside H-4. If Harrison expected to receive the full amount of the £20,000 prize, then he would also have to supervise production of not one but two duplicate copies of H-4—as proof that its design and performance could be duplicated.

Adding to the tension of these developments, Nathaniel Bliss broke the long tradition of longevity associated with the title of astronomer royal. John Flamsteed had served in that capacity for forty years, Edmond Halley and James Bradley had each enjoyed a tenure of more than twenty, but Bliss passed away after just two years at the post. The name of the new astronomer royal—and ex officio member of the Board of Longitude—announced in January 1765, was, as Harrison no doubt predicted, his nemesis, Nevil Maskelyne.

The thirty-two-year-old Maskelyne took office as fifth astronomer royal on a Friday. The very next morning, Saturday, February 9, even before the ceremony of kissing the king’s hand, he attended the scheduled meeting of the Board of Longitude as its newest commissioner. He listened while the thorny matter of Harrison’s payment was further debated. He added his approval to the proposed monetary awards for Leonhard Euler and the widow of Tobias Mayer. Then Maskelyne attended to his own agenda.

He read aloud a long memorandum extolling the lunar distance method. A chorus of four captains from the East India Company, whom he’d brought with him, parroted these sentiments exactly. They had all used the procedure, many times, they said, just as it was outlined by Maskelyne in The British Mariner’s Guide, and they always managed to compute their longitude in a matter of a mere four hours. They agreed with Maskelyne that the tables ought to be published and widely distributed, and then “this Method might be easily & generally practiced by Seamen.”

This marked the beginning of a new groundswell in activity directed at institutionalizing the lunar distance method. Harrison’s chronometer may have been quick, but it was still a quirk, while the heavens were universally available to all.

The year of 1765 brought Harrison further woes, in the form of a new longitude act from Parliament. This one—officially called Act 5 George III—put caveats and conditions on the original act of 1714, and included stipulations that applied specifically to Harrison. It even named him in the opening language and described the current status of his contrariety with the board.

Harrison’s mood deteriorated. He stormed out of more than one board meeting, and was heard swearing that he would not comply with the outrageous demands foisted on him “so long as he had a drop of English blood in his body.”

Lord Egmont, the chairman of the board, gave Harrison his comeuppance: “Sir . . . you are the strangest and most obstinate creature that I have ever met with, and, would you do what we want you to do, and which is in your power, I will give you my word to give you the money, if you will but do it[!]”

Eventually, Harrison knuckled under. He turned in his drawings. He provided a written description. He promised to bare all before a committee of experts chosen by the board.

Later that summer, on August 14, 1765, this illustrious party arrived at Harrison’s house in Red Lion Square for a watchmakers’ tribunal. Present were two of the Cambridge math professors Harrison referred to derisively as “Priests” or “Parsons,” the Reverend John Michell and the Reverend William Ludlam. Three reputable watchmakers attended: Thomas Mudge, a man keenly interested in making marine timekeepers himself, William Mathews, and Larcum Kendall, formerly apprentice to John Jefferys. The sixth committee man was the widely respected scientific instrument maker John Bird, who had fitted the Royal Observatory with mural quadrants and transit instruments for mapping the stars, and outfitted many scientific expeditions with unique devices.

Nevil Maskelyne came along, too.

Over the course of the next six days, Harrison dismantled the Watch piece by piece, explained—under oath—the function of each part, described how the various innovations worked together to keep virtually perfect time, and answered all the questions put to him. When it was over, the judges signed a certificate saying that they believed Harrison had indeed told them everything he knew.

As the coup de grâce, the board insisted that Harrison now reassemble the Watch and surrender it, locked in its box, to be sequestered (held for ransom, really) in a storeroom at the Admiralty. At the same time, he had to commence building the two replicas— without the Watch to serve as a guiding pattern, and stripped even of his original diagrams and description, which Maskelyne had delivered to the print shop so they could be copied, engraved, published in book form, and sold to the public at large.

What a time to sit for a portrait. Yet it was at this juncture that Mr. King painted Mr. Harrison. A look of calm may have come over him late that fall, when he at last received the £10,000 he had been promised by the board.

At the beginning of the New Year, 1766, Harrison heard for the second time from Ferdinand Berthoud, who arrived from Paris with high hopes of accomplishing what he had failed to do on his last trip in 1763: learn the details of H-4’s construction. Harrison felt little inclined to confide in Berthoud. Why should he divulge his secrets to anyone who couldn’t make him do so? Parliament had been willing to pay £10,000 to hear from Harrison what Berthoud seemed to expect for peanuts. On behalf of the French government, Berthoud offered £500 for a private tour of H-4. Harrison refused.

Berthoud, however, before coming to London, had been in correspondence, watchmaker to watchmaker, with Thomas Mudge. Now that Berthoud was in town, he dropped in at Mudge’s shop in Fleet Street. Apparently, no one had told Mudge—or any of the other expert witnesses—that Harrison’s disclosure was supposed to be kept confidential. In the course of dining with the visiting horologist, Mudge waxed loquacious on the subject of H-4. He had held it in his hands and been privy to the discovery of its most intimate details, all of which he shared with Berthoud. He even drew sketches.

As it turned out, Berthoud and the other continental clockmakers did not steal Harrison’s designs in the construction of their own marine timekeepers. Yet Harrison had cause to cringe at the casual manner in which his case was opened and aired.

The Board of Longitude slapped Mudge’s wrist. The commissioners were not overly upset by his indiscretion, and besides, they had a few other matters to oversee, in addition to the Harrison affair. Notable among these was the petition from the Reverend Mr. Maskelyne, who wanted to begin annual publication of the nautical ephemerides for seamen interested in finding longitude by lunars. By incorporating a wealth of prefigured data, he would reduce the number of arithmetical calculations the individual navigator had to make, and thereby dramatically shorten the time required to arrive at a position—from four hours to about thirty minutes. The astronomer royal declared himself more than willing to undertake responsibility for the work. All he needed from the board, as official publisher, was the funding to pay salaries for a pair of human computers who could hash out the mathematics, plus the printer’s fees.

Maskelyne produced the first volume of the Nautical Almanac and Astronomical Ephemeris in 1766, and went on supervising it until his dying day. Even after his death, in 1811, seamen continued relying on his work for an additional few years, since the 1811 edition contained predictions straight through to 1815. Then others took over the legacy, continuing the publication of the lunar tables until 1907, and of the Almanac itself up to the present time.

The Almanac represents Maskelyne’s enduring contribution to navigation—and the perfect task for him, too, as it embodied an abundance of excruciating detail: He included twelve full pages of data for each month, abbreviated and in fine print, with the moon’s position calculated every three hours vis-à-vis the sun or the ten guide stars. Everyone agreed, the Almanac and its companion volume, the Tables Requisite, provided the surest way for mariners to fix their positions at sea.

In April of 1766, after Harrison’s portrait was completed, the board dealt him another blow that might well have changed his mien.

In order to put to rest all lingering doubts that H-4’s accuracy might be chalked up to chance or luck, the board decided to subject the timekeeper to a new sort of trial, even more rigorous than the two voyages. To this end, the timekeeper was to be moved from the Admiralty to the Royal Observatory, where, for a period of ten months, it would undergo daily tests performed, in his official capacity, by the astronomer royal, Nevil Maskelyne. Also the large longitude machines (the three sea clocks) were to be consigned to Greenwich, and have their going rates compared with that of the big regulator clock at the Observatory.

Imagine Harrison’s reaction when he learned that his treasure, H-4, having languished many months in a lonely tower at the Admiralty, had been delivered into the hands of his archenemy. Within days of this shock, he heard a knock at his door, and opened it to find Maskelyne, unannounced, carrying a warrant for the arrest of the sea clocks.

“Mr. John Harrison,” this missive begins, “We the . . . Commissioners appointed by the Acts of Parliament for the discovery of the Longitude at Sea, do hereby require you to deliver up to the Rev. Nevil Maskelyne, Astronomer Royal at Greenwich, the three several Machines or Timekeepers, now remaining in your hands, which are become the property of the public.”

Cornered, Harrison led Maskelyne into the room where he kept the clocks, which had been his close companions for thirty years. They were all running, each in its own characteristic way, like a gathering of old friends in animated conversation. Little did they care that time had rendered them obsolete. They chattered on among themselves, oblivious to the world at large, lovingly cared for in this cozy place.

Before parting with his sea clocks, Harrison wanted Maskelyne to grant him one concession—to sign a written statement that the timekeepers were in perfect order when he found them under Harrison’s roof. Maskelyne argued, then acceded that they were by all appearances in perfect order, and affixed his signature. Anger escalated on both sides, so that when Maskelyne asked Harrison how to transport the timekeepers (i.e., should they be moved as is, or partly dismantled), Harrison sulked and intimated that any advice he gave would surely be used against him in the event of some mishap. At length he offered that H-3 might go as it was, but that H-1 and H-2 needed to be taken apart a bit. He could not watch this ignominy, however, and went upstairs to be alone in his private room. From there, he heard the crash on the ground floor. Maskelyne’s workers, while carrying H-1 outside to the waiting cart, dropped it. By accident, of course.

Although H-4 had traveled on a boat, accompanied by Larcum Kendall, down the Thames to Greenwich for its trial, the three large sea clocks rumbled and bumped their way there through the streets of London in an unsprung cart. We need not imagine Harrison’s response. The enamel paste medallion portrait of him in profile by James Tassie, which dates from about 1770, depicts the aging watchmaker’s thin lips decidedly downturned.