Once past Africa’s northern coast, Halley thought he’d left the reputedly fiercest marauders behind him. Yet as the sails of the Gloucester, Falmouth, Dunkirk, and Lynn frigates blended into the seascape, the realization set in. As much as Admiral Benbow might have applauded Halley’s quest, his fleet could ensure the Paramore safe passage only to Madeira. Naval duties and vibrant trade winds were calling his armada to the West Indies. A mere two and a half weeks after leaving the English Channel, Halley and his crew were adrift alone. It was four days before Christmas 1698.

Halley had much to ponder during the long hours at sea that would unfold before him. His attention was divided between captaining and plotting his experiments. Of course, his second in command was there to back him up—or so he hoped.

He had little or no idea what threats were coming up from the horizon. A good captain exuded confidence even when surviving seamen’s journals prompted paranoia. At the time of Halley’s venture, treacherous weather was blamed for about half of all shipwrecks.

After that a vessel’s lack of seaworthiness and a captain and his crew’s ineptitude were tied for the second leading cause of lost ships. Even with its obvious shortcomings, Halley’s pink was in better shape than many a floating mausoleum out there pressed into service beyond its years. Earlier in his voyage, Halley informed the secretary to the Admiralty in London, Josiah Burchett, that “the Pink proves an excellent Sea boat in bad Weather.” Other captains were more harshly tasked. The Lindsey, for example, was destined to be lost returning from Jamaica that very year. “She was old and crazy and not fit to go to sea.”

Damage from shipwrecks was not tallied at the time of Halley’s mission. Anecdotal evidence suggests all hands were saved in a majority of wrecks, maybe as much as 75 percent of the time. Many ships sank slowly or grounded near shore, enabling the escape of all on board.

Much of Halley’s and the world’s interest in magnetism was spurred by the drive to improve navigation. As commerce routes grew, in large part due to the burgeoning slave trade, fewer and fewer transatlantic voyages traced straight lines of latitude on paths that ran strictly east-west or west-east. Halley believed his ideas about Earth’s magnetism, first documented six years prior in 1692, might help solve the nagging problem of how to determine longitude at sea on such courses. Its frequent misjudgment was blamed for many a disaster on the waves. The sheer number of lost ships, crew and cargo, and associated horrors warranted a search for better navigation techniques. And with the queen’s blessing, Halley hoped to improve the odds of survival of even the most incompetent of captains. The Royal Society called on the maritime community to submit its sea observations and take more readings at sea when possible.

IN THE EARLY DAYS OF OCEAN NAVIGATIONS, the key measurement was declination or magnetic variation. These essentially interchangeable terms refer to the angle between true north and the direction to which a compass needle points. Thus, keeping the compass in working order was all important. In the absence of more scientific methods, cap-

tains would punish sailors for having garlic or onion breath. Early seafarers believed the odor was pungent enough to demagnetize a ship’s compass.

While Italian Christopher Columbus is often popularly credited with discovering the existence of magnetic variation, the Chinese knew of the phenomenon in the 12th century. It’s clear that Portuguese captains had also been aware of it for two generations. They navigated using the Pole Star to follow lines of latitude and noticed the needle “north-easted and north-wested” from time to time. The first description of an azimuth compass, which best detected the variation, was actually published in 1514 by Joao de Losboa in his Livro de Marinharia.

Soon enough, Portuguese philosophers reasoned that a “true meridian” of no variation may exist. That is, the magnetic variation from true north was zero along this special meridian. Many pilots believed such a meridian ran through the Azores and Canaries. Famed chief pilot of the Portuguese India fleet John de Castro would disavow them of such notions. On a voyage to India begun in 1538, he recorded 43 values for variation—many of which wavered by five or six degrees east. He employed what was known as a “shadow instrument,” a device developed by Pedro Nunez, the mathematical adviser to the king of Portugal, essentially the forerunner of the azimuth compass. It was a round metal plate with a graduated edge that was connected to a magnetic needle and hung in gimbals, with the plate set on the meridian and used in tandem with the astrolabe to measure altitudes of the Sun. Castro, accompanied by Nunez’s brother, Dr. Lois Nunez, demonstrated that the variation did not follow a set pattern, as philosophers had predicted: There was no “true” meridian.

The potential value of knowing how the needle wandered or the amount of declination was widely recognized in the early 17th century. Good navigators knew that determining one’s true bearings was critical for staying on a prescribed course, especially one that traversed the Atlantic on a diagonal trajectory.

But the puzzle was more complicated than such enterprising pi-

lots first realized. As early as 1633, Henry Gellibrand, chair of astronomy at London’s Gresham College, demonstrated that the city’s magnetic declination had shifted. Other observations revealed that similar variations occurred around the globe without any obvious pattern. Within two years, Gellibrand had recognized that “the variation is accompanied with a variation,” that is, magnetic declination changes with time or experiences a secular variation. In other words, declination not only varied from place to place, but the lines of magnetic variation gradually moved at minimum from year to year—in fact, as much as a few minutes of an arc, analyses would reveal.

Halley was not the first Englishman to believe that magnetic variation could be used to find longitude. As soon as Gellibrand revealed secular change, a navigation teacher named Henry Bond, driven by substantial personal debt, began an investigation of declination. Bond boldy wrote a book, titled The Longitude Found, in which he claimed exactly that. He surmised that the variation would be zero in London but would gradually climb to the west. As this was true, Bond’s ideas were given some credibility. In 1674, King Charles II established a committee of six, which included Robert Hooke and John Flamsteed, to explore Bond’s method. Its creation was prompted by Le Sieur de St. Pierre, a Frenchman and alleged imposter, who lay claim to an impracticable rival method, based on lunar and stellar distances, and sought reward from Charles. Although the committee’s members knew Bond’s work itself was near rubbish, they sanctioned it on March 3, 1675, and recommended Bond be remunerated in order to dispatch St. Pierre. On the basis of the commission’s full report, Charles immediately founded the Greenwich Observatory to make the lunar-distance method usable and placed Flamsteed in charge. (Some 150 years would pass before enough data were collected to do so.)

Over time many seafarers came to associate changes in magnetic declination with various destinations. For example, some sea captains preferred using changes in magnetic declination over conventional sounding as markers of location. William Dampier, a

contemporary of Halley’s who captained a Royal Navy ship a year after him, noted in one of his journals that 50 to 60 leagues off the Cape of Good Hope, declination was superior to soundings.

Astute sea captains knew they needed to be constantly compensating for such changes in the Earth’s magnetic field. If a navigator made an incorrect allowance for local magnetic declination, a ship could quickly and unknowingly sail off course. Both under- and over-estimations of the local differences between magnetic and geographic north could cause a pilot to mistake a ship’s true position. Exactly how mariners adjusted their compasses on the basis of magnetic readings is unclear to historians of science. Yet the compass remained invaluable. In the 1670s, English astrologer Henry Coley summed up the compass’s use well: “Although it pretend[s] uncertainty, yet it proveth to be one of the greatest helps the seaman have.”

At the time the Paramore sailed, a central question remained unanswered: How could magnetism vary if the Earth was a permanent magnet, Halley and others wondered?

HALLEY PLANNED TO SAIL to St. Helena, an isolated volcanic island in the middle of the South Atlantic, a no-man’s-land for Atlantic voyagers, on the first leg of his mission. He’d sail past Madeira, the Canary Islands, and Cape Verde on the way. This southernmost province in the British kingdom had only in recent decades come under control of the English East India Company through a charter from King Charles II. Since its discovery 200 years earlier by Portugal, it had become established as a welcome pitstop on the sail to and from the East Indies. In 1672, when Charles declared war on Holland, the Dutch wrestled the strategic jewel away from the English and held it for a brief time. Fortressed by jagged cliffs, the little paradise, about a three-month sail from London, was familiar to Halley. Some 20 years earlier he had first made a name for himself there in the world of science and letters. Though under 50 square miles in size, the island offered good conditions for viewing the southern constellations—or so Halley believed when he selected the location.

A mere two and a half months into the Paramore’s journey, Halley’s log had grown thick with observations of all sorts. On the way to St. Helena, he wrote that the pink “[passed] through a Streak of Water in appearance turbid. But when in it we took up some Water, and it was full of Small transparent globules, but less than white peas interspersed with very small blackish Specks. These globules were so numerous as to make the Sea of a yellow muddy Colour. Their Substance appeared like that of our Squid … and there were two or three sorts of them.” The yellow hue was an armada of jellyfish—an undocumented species at the time—according to one Halley chronicler named Dalrymple.

Halley had been recording his observations daily since sailing out of the Thames from Deptford. These included variations of the compass, wind, course, mileage, latitude and longitude from London, biological phenomena, and more. Despite the challenges of his ship and the open waters, he religiously took his research measurements no matter the conditions.

Halley intended to measure the magnetic variation over the vast test bed of the Atlantic and beyond in order to develop his hypothesis on the origin of Earth’s magnetic field and understand how it changes. He hoped the results might solve the longitude problem once and for all. If the phenomenon proved to follow a regular pattern, he reasoned, it would be suitable for determining longitude at any point at sea.

Whenever the skies and seas cooperated and Halley was allowed a clear, steady glimpse of the celestial clockworks, he determined his position and calculated true north, conveniently lodged under that beacon for mariners, the North Star. True north was the direction toward the geographic North Pole, where the lines of longitude on a globe converge.

Halley used the two steering compasses couched within his ship to maintain his course. Comprised of little more than an iron wire attached to a marked card and encased in water-tight glass, the devices hung inside a square wooden box or binnacle on gimbals to

keep them level against the ship’s motion. Navigators have long exploited the compass needle’s tendency to seek the north. The devices are built so that their magnetic needles can rotate freely in the horizontal plane. But as one approaches the magnetic poles, the needle veers more and more from the horizontal. At the north geomagnetic pole, the needle points down, while it points up at the south geomagnetic pole.

To measure magnetic declination, Halley relied on two bearing or observational compasses. At periodic intervals he eyed their quivering needles and recorded as best he could the movement away from magnetic north. Just how much it was off kilter from true north depended on where the ship was when he took the reading. (Since his school days Halley had been well aware that the horizontal angle between the direction of true north and magnetic north varied depending on geographical location.)

Compasses had a privileged position on most ships but especially on the Paramore. Halley’s top officers, especially Harrison, were no strangers to the inner workings and importance of the compass. In his book on longitude, Harrison wrote: “Suffer no great guns or other iron too near your compasses.” He had included the old mariner’s maxim to help describe the problem of compass deviation, wherein the needle improperly deflects due to nearby iron.

UNDERSTANDING OF THE EARTH’S MAGNETISM had evolved gradually. Halley’s contribution would fold into a history involving many countries across centuries. Although the compass likely developed independently in many regions, including China, Arabia, and Greece, the Chinese were the first to write about the compass for navigation in 250 B.C. It was described in the works of Hanfucious. Historians of science believe the Chinese were using the compass for navigation at least by the 14th century.

The first compasses were made of magnetized magnetite. The black, dense iron compound was called lodestone for “leading stone.” The word “magnet” most likely derived from a place in ancient

Macedonia called Magnesia, where lodestone deposits abounded. Ancient Greeks also knew of the mysterious properties of lodestone.

The whole notion of a north magnetic pole originated with European navigators’ need to understand the compass’s directional properties. The compass had been exported from China to Europe by the 12th century, although it wasn’t used there—as in China—for navigation until centuries later. Oddly enough, the Chinese viewed the compass as a southward-pointing device. This change in orientation would be key to devising theories about the nature of magnetic poles.

Incredibly, the sea compass technology remained quite primitive throughout the 17th century. Standard compass needles, commonly made of hard steel wire, did not retain their magnetism for long. The craftsmanship was often rudimentary. For example, the needles were frequently improperly attached to the card, skewing their readings. Still, valiant explorers of the 15th, 16th, and 17th centuries somehow successfully reached their destinations.

When four of Admiral Sir Clowdisley Shovell’s fleet were lost on the rocks west of Scilly in October 1707, reducing England’s military might by a couple thousand able men overnight, the Navy investigated the state of its compasses on its ships. Only 3 out of 145 ported aboard ships functioned properly! The majority of the compasses were floated in wooden bowls. Despite the fact that brass bowls had been found to be superior, they were expensive and only issued to flagships or ships voyaging abroad like Halley’s.

Distances at sea were measured by throwing a log overboard and then observing how much time passed before the stationary log played out the distance on a line of a certain length that was demarcated with knots. The practice was developed in the 16th century, and to this day, as in Halley’s time, the speed a ship travels is measured in knots, which along with other vital data is recorded in a “logbook.”

Dead reckoning navigation employed both the compass and the log to determine a ship’s position. The compass indicated the direc-

tion and the log gave the speed through the water, but the inefficiencies of these instruments often yielded erratic headings.

Halley typically used several methods to determine magnetic variation. They all hinged on the notion that the position of a celestial object at a given time would give the direction of geographic north. Then he could compare the readings with the compass needle’s position. The difference was the declination. The simplest was a double-amplitude observation. He would compare the local meridian, which is half the angle between the Sun or a given star’s rise and set, to the needle’s orientation. Yet on many a day at sea, taking a single measure of the amplitude of the arch of the horizon was more practical. It required one observation, say at sunset, but more calculation. Essentially, Halley took the difference between the Sun’s true orientation and magnetic direction on the horizon relative to east or west as pointed out by the ship’s compass. He typically then allowed for refraction on the horizon and then compared the result with the Sun’s computed azimuth from geographical north.

Sometimes, however, Halley found a third method for measuring the variation more reliable. For this approach he used one of the two portable azimuth compasses, which he himself brought aboard the ship. Like the amplitude compass, they could be set up virtually anywhere on deck atop a tripod or stool. With them, the idea was to take a precise magnetic bearing of the Sun or another object to compare with its true bearing. Since the Sun can’t be viewed directly, its orientation was determined by the shadow cast through a slit in the device. Halley then used spherical trigonometry to calculate the true orientation of the point on the horizon at which the Sun sets and rises given the latitude and solar declination. The variation could then be found by simple subtraction: It was half the difference between these two amplitudes. At sunset and sunrise, Halley would take two readings of the angle between the magnetic needle and the Sun. At these times the Sun rests on the horizon, making the angles between it and the needle easier to observe. The variation could then be applied to the position of the Paramore at midnight or basically any time of day.

If the Sun’s altitude and time of the observation were also known, the azimuth of the Sun at that moment could be calculated directly instead of taken from tables carried aboard the ship. The method required that the local time aboard the ship be known and that the observer was a relatively skilled mathematician.

At the time of Halley’s voyage, the azimuth compass had not yet been accepted over the amplitude measurements as a better method to take local magnetic declination, however. Most navigators weren’t yet knowledgeable enough in spherical trigonometry. Halley would take azimuth readings as backup: “Finding it scarce possible to get an amplitude in this cloud and foggy climate, I am forced to take the Sun’s azimuth when it is low,” he once noted in his log.

Halley’s self-taught contemporary, Dampier, an ex-buccaneer and admittedly not a scientist, explained how variation all out stumped him from time to time:

The first real improvement in the azimuth compass was more than a century away.

Halley’s first mate, Harrison, independently measured the variation as well, probably hoping his data would vindicate some of his assertions about a geomagnetic scheme for longitude, which had been summarily dismissed by the Royal Society before the voyage. The fact that his book Idea Longitudinis came out in 1696, four years after Halley first posited his hypothesis on magnetism, didn’t help his

book’s acceptance. Halley and others had reported to the Admiralty that Harrison’s book was more of a synopsis of ideas already out there and that it contained nothing novel. But some of his ideas for navigational practice were noteworthy. For one thing, Harrison had advocated that mariners take multiple readings: “Trust not to one observation, when you can have the medium of 5 or 6 or more, nor to one amplitude when you may have the mean of 3 or 4 azimuths,” he wrote.

Both men shared the belief that longitude could be determined but with a painstaking amount of time and research. Harrison expressed it well in his Idea Longitudinus: “Some Blockheads are apt to say, the Longitude cannot be found; no, no it cannot Accidentally … but by Care, Diligence and Industry; it may be found, without which it cannot be understood.”

WHAT ENGLISH SAILORS FEARED most, even above wrecking at sea, was capture or worse at the hands of pirates or Barbary corsairs. The threat probably lingered with Halley’s crew even then. During wartime, French and Dutch privateers often collected crew as bounty as well. Historically, the corsairs, based in the North and West African regions of Algiers, Tunis, Tripoli, Morocco, and most commonly Sallee, were the most dreaded raiders. They enslaved their prey. Some of the wealthier captives were returned for ransom, but the average detainee faced a life of servitude.

Moslem raids on Christian ships had declined sharply from their peak 60 to 80 years earlier when 350 English subjects a year were captured by Barbary corsairs, scholars estimate. When Halley set sail, protective treaties with many of the marauding nations such as Algiers had been signed, but they were unenforceable. Random hijacks at sea continued. Moreover, not all African countries participated in even partial truces with England. Roving pirates from Morocco and Sallee continued to seize English ships though in much smaller numbers. By the 1690s, a dozen or so of such pillaging ships still roamed the sea in a given year—down from hundreds in the corsairs’ heyday.

Meanwhile, the threat from European pirates known as buccaneers still loomed large. They had emerged in the pirating gambit in the 1660s and gradually expanded their territory from the Caribbean to the Indian Ocean.

French privateers, though considered more benign than buccaneers or corsairs, were also to be respected. Between 1695 and 1713, they captured roughly 10,000 ships, a majority—perhaps 400 a year—of them English.

Torture of captives was prevalent. “It is, and ever was usual and common amongst privateers of all nations upon taking of their enemies, where they suspect any hidden treasure to be aboard, to use some torture or other,” Halley’s contemporary privateer Bartholomew Biggs said in a deposition in 1706 before the High Court of the Admiralty. Sticking burning matches between the bound fingers of a captive was the most common method of torture, he said, revealing practices from his 50-year career. Other techniques included crunching fingers in carpentry vices or “woolding”—supposedly the preferred practice of buccaneers—whereby the raiders slowly tightened a rope around a hostage’s head sometimes to the point where his eyes popped out.

In most raids torture wasn’t necessary. Sheer might or mere intimidation sufficed. And sometimes the greatest loot was food and water, priceless commodities miles from land. As we shall see, ample threat also existed from those humans closest to oneself aboard ship.

HALLEY WAS 20 WHEN HE FIRST visited St. Helena, traveling aboard the sailing vessel Unity, owned by the powerful East India Company. At the time, the island was the only territory in the Southern Hemisphere in England’s possession. It is actually the summit of a composite volcano eroded by the elements and time. While the island itself is unappreciable in size, the base of the volcano is massive, extending to a depth of 12,600 feet. Overall, modern volcanologists put its volume at 20 times that of Mt. Etna, Europe’s largest volcano.

Halley ended his schooling as a commoner at Oxford University to undertake his premiere adventure with his friend and assistant

known only as Mr. James Clark. The trip served as Halley’s primary schooling in life at sea. Aboard Unity he first learned the daily rigors of seamanship and glimpsed firsthand the obligations of a sea master, his first mate, and his crew.

As an Oxford undergraduate at Queen’s College, Halley probably engaged in all the traditional coursework to continue his studies in Latin, Greek, likely Hebrew, and mathematics, which then included the spectrum of advanced work in geometry, algebra, navigation, and astronomy. Spherical trigonometry, which would come in especially handy in his later work, was also de rigueur. His dons included the Reverend John Wallis, Savilian Professor of Geometry and a founding Royal Society fellow, and his student Edward Bernard, who became Savilian Professor of Astronomy in 1673 after Wren. Scholars are unsure which of Halley’s tutors would have had the most influence over his work.

Halley was most passionate about astronomy, for he claimed it had grabbed “hold of him early and would not let him go.” Even before entering Oxford, he had earned a reputation as a shrewd star watcher. As a prominent London book and map seller named Joseph Moxon commented, according to John Aubrey’s writings, “If a star were misplaced in the globe he would presently find it.” By this time Halley was also possessed by geomagnetism. His first known scientific observation, while still a 16-year-old pupil at St. Paul’s School in London, was of Earth’s magnetic field. In 1672, about a year before college, he measured the declination of the magnetic compass. (A decade later he published the observation in the Royal Society’s flagship journal Philosophical Transactions.) He would devote his life to the pursuit of his wide-ranging passion to understand the physical relationships between Earth, the sea, sky, and beyond.

Not content just to read about the work of others in an Oxford classroom, Halley struck up a correspondence with England’s top astronomer, John Flamsteed. Later, the two collaborated on numerous observations. Flamsteed was impressed with Halley’s imagination, ambition, and powers of observation and in this period could only be proud and not jealous of his protégé.

During Halley’s time at Oxford, Flamsteed had undertaken cataloging all the stars of the Northern Hemisphere. By employing the latest observational techniques, he achieved a degree of precision 40 times greater than that of Tycho Brahe, the celebrated 16th-century Danish astronomer who, before the invention of the telescope, logged more than 1,000 stars and revolutionized gazing accuracy in his era. Though equipped with the best instruments money could buy, the wealthy Tycho had no telescopes or reliable clocks. He relied on the motion of heavenly bodies for reference. Flamsteed’s new positions were accurate within 10 seconds of an arc. Instead of relying on open sights, Flamsteed, like Halley and others, used instruments with telescopic sights that were attached to the frames of angle-measuring instruments, such as the sextant or quadrant. Invented by Middleton amateur astronomer William Gascoigne, the sights extended the length of the radius of the instrument, on average about six feet. Although equipped with the latest built-in telescopic sighting technology, Flamsteed, who paid for most of his instruments out of his own pocket, observed from Greenwich, where most of the Southern Hemisphere is not visible. Cassini and Hevelius were also documenting northern stars in parallel efforts. Not intimidated in the slightest by the old guard, Halley saw an opportunity to contribute.

With the support of Flamsteed and many others such as Hooke, Wren, and his leading patron Sir Jonas Moore, Halley boldly hatched a plan to observe the southern stars himself. For Halley, though he had been excelling in his studies at Oxford, this side survey trip was a risky undertaking to tackle before receiving his degree. Halley’s father, “respected as a Gentleman of considerable Estate, and plentifully happy in all the Goods of Fortune,” according to a leaflet circulated at the time of his death, agreed to finance the expedition at a handsome level. He gave Halley an annual allowance triple that of Flamsteed’s salary as astronomer royal, or roughly 300 pounds, which is equivalent to about 157,200 pounds today. Before leaving, Halley garnered permission not only from the British government and King Charles II but also from the mighty East India Company, which had controlled St. Helena since 1651 and was his best possible transport

to the island. (Boyle may have supported the venture as not only a dynamic Royal Society fellow but also a director of the East India Company.)

Halley and Clark arrived on the isle in February 1677 and immediately set up shop on Diana Peak, a mountain in the center of the island that soars some 800 meters above sea level. Halley’s observatory was about 100 yards above sea level on the mountain’s northern slopes. From his fern-covered perch, Halley had a breathtaking view of the whole island, from its majestic volcanic crags to its thickly forested briars to its rare sandy bays. Some 150 years later, Napoleon’s tomb would be among the sites visible from Diana’s slopes.

A sextant and a quadrant, specifically built for the expedition, made up the core of Halley’s observatory. His customized brass and steel sextant, essentially a metal frame extending 60 degrees from one side to the other connected by a curved scale, had a 5.5-foot radius and a built-in telescope mounted on one side of the frame to afford improved viewing accuracy. The device was used to measure the angle or celestial arc between two neighboring bodies. To determine the angular distance between two stars and thus their apparent positions, for instance, an observer fixed one side of the frame of the sextant on a given star and moved the other sight to line up with a second star.

Halley’s quadrant, a device that measures the altitude of the Sun from the horizon, was standard, the common 2-foot radius variety. He also brought along a 24-foot telescope that his father had given him when he embarked on his academic career and a pendulum clock. Halley, of course, used the quadrant to maintain the correct time, a calculation critical for determining a star’s position. Amid his travails he most curiously realized that the length of the pendulum on his clock required shortening to keep correct time on St. Helena, even though it worked perfectly back in London. He was baffled as to why. His future friend Isaac Newton would one-day follow-up this line of inquiry. The pendulum length needed to be changed because Earth is not perfectly spherical: It has a bulge at its equatorial region, within which St. Helena is located.

The far-flung island boasted less than 500 inhabitants at the time, nearly half of them imported slaves from the East Indies, Madagascar, and elsewhere. The rest of its denizens were mainly English farmers lured there by the company for the promise of 10 acres and a cow—20 acres and two cows if a man were married or betrothed. Finally, both Portuguese and Dutch settlers who first introduced slaves to the island filled out the population rolls. Since its discovery, voyagers to the Indies gladly watered there, especially on return voyages. About the time of Halley’s visit, passing ships began to be required to pay a toll: one Madagascaran slave. For a visitor the cost of living was very high, but Halley’s allowance was three times the annual compensation of the island’s ruling governor.

During Halley’s stint on St. Helena, the British monarchy replaced the governor, Richard Field, on the basis of reports of his “ill living” at the sizable company plantation. Among other things, he failed to treat the young astronomers with “all respect and kindness” as ordered. Apparently he lacked the political chops to successfully balance the whims of the East India Company’s desire for profits and the needs of the islanders. The company feared his insolent demeanor might jeopardize the island’s prospects. Yet Field’s lack of graciousness as a host did not impact Halley’s work much.

Although the island was often shrouded in clouds and mist, Halley and Clark plotted more than 340 stars over the course of the next year. Cleverly, Halley took pains to ensure the longevity of his masterly observations. He surveyed some northern stars from St. Helena and the distance between various stars, so newer, more accurate observations of northern stars would not render his catalog obsolete. His expertly compiled chart could simply be recalibrated when necessary from the relative distances.

When the sky clouded over as it often would, Halley would spend time gazing closer to Earth where wild partridges and turkey hens roamed and a host of exotic flora and fauna thrived. The small island never bored him. He noted a curious plant that “bore perfect plants with a root on the extremities of its leaves and those sometimes will

have others or grandchild plants.” He described a polypus called a cuttfish by locals. The fish could walk on dry land like a long-legged spider. But when pursued, it could dash into the water and propel itself by a motion like respiration, emitting a dark russet-colored ink that turned the clear blue waters opaque. If that were not enough to elude a predator, “he will stick so fast to the rocks by means of several acetabula on his points or legs that he will be torn in pieces before he will let go of his hold.” Islanders there also kept flounders for sale year-round in sea pens in the salt marshes, he reported. But the fish couldn’t breed there because the muddy bottom destroyed their spawn. Such observations he’d later report to the Royal Society in its journal books—some he entered in his own hand when he assumed the job of clerk.

In November of that year Halley also made an important first observation in the heavens: a full transit of Mercury across the face of the Sun. Halley knew such an astronomical event could be used to measure the distance to the Sun. “I can say in truth,” he said, “that if one can find the true position of [Mercury’s] path with the Ecliptic, without difficulty my observations will provide the parallax of the Sun.” Halley knew that from the parallax—the angular displacement—the distance of a celestial body could be determined. That is, if the relative position of the Sun’s apparent path in the sky, or the ecliptic, is also known with respect to another body like Mercury, then the distance to the body can be calculated. Although Halley planned to observe the positions of the other planets, the weather did not cooperate with such ambitions. He mentioned his observation of Mercury’s transit and celestial anomalies in a letter to Sir Jonas Moore, his lead patron who also helped found the Royal Observatory at Greenwich and personally financed many of its first instruments. Moore, surveyor general of the ordnance, worked from an office in the Tower of London and served as a communications agent to the Royal Society for Halley, Flamsteed, and others. In the Moore letter, Halley also noted that the Southern Hemisphere lacked a pole star like the North Star.

On returning to London in May 1678, Halley immediately sought to publish his astronomical findings and set his career in motion. He published a catalog of star positions, entitled the Catalogue of Southern Stars, and a celestial planisphere, or star chart. They were the first ever compiled from telescopic observations. He dedicated a constellation to Charles II, naming it Rober Carolinum or Charles’s Oak. The work secured his M.A. from Oxford at age 22. Charles conferred the degree of master of arts per literas regius and “without performing any previous or subsequent exercises for the same” in November.

For the great minds of this period, self-directed study was not that unusual. Isaac Newton had gained most of his science education through independent study at Cambridge. John Wallis, a Cambridge student from 1632 through 1640, learned mathematics, “not as a formal study, but as a pleasing diversion, at spare hours; as books of Arithmetic or others mathematical fell occasionally … [his] way.” Halley also followed in the footsteps of the likes of Jeremiah Horrocks, an up-and-coming astronomer at Cambridge in Wallis’s day, and Wren at Oxford, who both contributed to the body of knowledge of modern science by publishing papers while still engaged in university studies.

Halley’s southern star charts also conveyed prestige by securing him election as a fellow of the Royal Society and launching his reputation in the community as a man of scientific competence and verve. Astronomers and navigators alike made wide use of his charts. For Halley’s efforts, Flamsteed paid him a high compliment, dubbing him the “Southern Tycho,” after Tycho Brahe, who first cataloged the northern stars from Hveen, an island off the coast of Sweden.

AS HALLEY VEERED OFF the western coast of Africa near Cape Verde in early January 1699 still heading to St. Helena, the Paramore sighted two ships in the distance. After some time, they were identified as English merchant ships.

Halley awaited a proper salute. None came. Before Halley could change heading, a thunderous crash erupted toward the rear of the

hull. Off the port side, puffs of smoke emanated from the two frigates that were closing range. Great and small shots hurled toward the ship, crashing into the nearby sea.

The Paramore was outmanned and outgunned. Halley knew his pink didn’t have a prayer of outrunning a merchant ship built for speed and that the odds of winning a fight were slim. He moved windward of the attackers, bracing the pink’s headsails to the mast in surrender, still flying the Union colors. Likely somewhat agitated, he sent the dinghy over to inquire why a sister ship was firing on the research vessel.

The captain of the lead ship, the New Exchange, doubting the authenticity of its flag, had taken the Paramore for a pirate vessel and claimed to be “obliged to do what they did in their own defense.” In fact, two masters aboard claimed that the Paramore was the very ship that had recently hijacked their former charges and released them of their commands. Perhaps relieved at the irony of the incident, Halley apparently accepted the misidentification at face value. That his pink emerged unscathed probably assuaged any urge for retribution. After all, pirates to deceive their victims commonly flew false flags of other countries, among other tactics. Moreover, nary a captain had seen a vessel like the Paramore charged with a scientific mission before. Halley quickly shrugged off the episode as other worries encroached on his sea laboratory. He set a course on January 6 for Trinidada (modern Trinidade) off the coast of Brazil.

THE ONLY UNIVERSAL LAW of the sea, according to lore, was that strange, inexplicable things happen. In the lingua franca of turn-of-the-century sailing, there was no such thing, no matter how benign the surface waters, as a safe harbor. Squalls emerged from dead calms, sailors deserted, mates disappeared overboard, captains ran amuck, entire crews became cannibals or mutinied for no apparent reason. The science of Halley’s day was no match for such phenomena. Rather than the laws of physics, ordinary sailors often looked to the supernatural for an explanation, so much so that some 17th-century captains of-

ten hid their precious compasses from common sailors, wary their reactions might be unpredictable.

Superstitions abounded among many a mate. Some, like Halley’s contemporary seaman Edward Barlow, a merchant captain who kept extensive journals, believed the wind to be the breath of God or that vengeful witches conjured wicked storms and uncooperative winds. Others swore ghosts of deceased sailors haunted their ships. Still others were plagued by mythical portents of death and disaster and lived in fear of great sea monsters like the “Pongo, a terrible monster, half tiger and half shark,” as one historian tells. Most sea superstitions were more mundane, however. Sailors commonly linked the behavior of birds, fish, and other marine mammals, such as flocking of flamingoes or herding of porpoises about the ship, to weather patterns, as William Dampier described in captivating accounts of his voyages published at the turn of the 18th century, including A New Voyage Round the World, Voyages and Descriptions, and A Voyage to New Holland.

Sailors also turned to natural events like the appearance of shooting stars, comets, or rings around the Sun or Moon as harbingers of impending danger. For example, they believed the strange electrical discharge that sometimes appears near the top of the masts after a violent storm at sea—called St. Elmo’s Fire—was a divine signal of sorts or even the embodiment of spirits. Per chance, some of these methods worked from time to time. The notion of using sea and sky phenomena to better manage a voyage was more in keeping with Halley’s thinking than outlandish tales of Tinkerbell and other sea fairies guiding the way. If the Paramore’s captain had witnessed such odd phenomena, he surely would have reported and investigated them; for although Halley had taken leave from his position as clerk of the Royal Society, which he’d held for 13 years, a large part of his job entailed documenting the discourse on perplexing issues.

AS THE Paramore PRESSED on to the slave and sugarcane island of Trinidad, the ship’s water supply was running low and occasional

clouds of mosquitoes plagued the crew. Maintaining a steady reserve of fresh water was a chronic challenge for sea captains on long voyages. Although they had refilled all the water casks on the Isle of May, their progress since then had been slower than expected due to feeble winds. In fact, some days they traveled less than 20 miles. Caution called for rationing, and Halley limited each man to three pints of water a day.

Halley’s pink was holding its own. The crew knew her faults well enough so they might seem mere quirks. When wind was slightly off the beam or somewhat forward of her, she could barely hold a forward tack due to her especially poor lateral resistance. When off the wind, she would easily clock a respectable speed and cover an easy 80 miles a day in good weather. However, in temperate breezes with her considerable forward resistance, she moved at a slower clip than a comparable merchant vessel. She wasn’t all that large compared to the average seagoing vessel, but sizable enough that many tasks such as weighing anchor and getting under sail were major undertakings that involved all crew members.

Like most sea masters, Halley likely took the arduous daily work—the physical strenuousness and long hours—of sailors for granted, making little mention of it in his journal or ship’s log. Halley sensed early on that his officers might not be up to the challenge of properly disciplining the crew. In a letter to the secretary of the Admiralty, Josiah Burchett, on leaving the English Channel, he expressed apprehension over “the weakness of his officers.”

Sailors worked long hours with few chances for uninterrupted sleep. Typically, crews were divided into two watches, staggered at four-hour intervals, to keep the ship on point 24 hours a day. Shorter two-hour watches called “dog watches” were interspersed usually in the evening from 4 to 8 p.m. to rotate the watches throughout the day, so they didn’t fall at the same time every day. In this way, men usually alternated between 10- and 14-hour days, though necessity often mandated longer workdays.

As captain, Halley probably wouldn’t have routinely stood watch.

He would have left that chore to Lieutenant Harrison and to his boatswain. Yet as captain Halley was likely on duty around the clock. (His carpenter and cook probably didn’t stand watch either.)

Maintenance of wooden ships like the Paramore was especially labor intensive, and when the crew wasn’t actively engaged in sailing duties, there were lots of other things to do. Rigging, blocks, and cables required regular overhaul. Sails needed constant upkeep. Every piece of timber needed proper care to prevent waterlog. Ships’ carpenters often enlisted help, scraping and repairing planks and sealing timber with caulk, tar, grease, and paint.

Most ships of the day chronically leaked, and the Paramore was no exception. Sailors were also charged with pumping out water that was taken on. Aboard the Paramore the task was perpetual.

Despite the arduous days, there is no evidence that Halley was an especially difficult taskmaster or that he abused his men in any way. To the contrary, Halley had taken efforts to ensure the health and success of his crew more than most captains. Of course, the paternalistic discipline aboard, especially that of the Royal Navy, was inherently strict. And its severity only increased during the Restoration period, scholars tell. The use of a whip at its peak to punish a court-martialed offender “rarely exceeded a hundred lashes,” according to J. D. Davies. By any standard, England’s naval code was harsh.

ONE MID-FEBRUARY MORNING some time after 2 a.m., Halley awoke to observe the helmsman suspiciously steering off course. The westerly heading would mean the ship would miss his target: Fernando de Loronho, a nearer island than Trinidad, where Halley hoped to replenish the ship’s ever-dwindling water supply.

The boatswain protested that his error was accidental. The crew contended that the candle in the binnacle, encasing the steering compasses, had gone out and could not be relit. But Halley knew better.

When confronted, his boatswain immediately set the ship back on course. Had the Paramore continued on this rogue path, it would have collided with a sunken rock waiting off the island’s southwest-

ern coast. If Halley suspected Harrison had something to do with his botswain’s behavior, he took no immediate action. He did not let doubts about his crew show. But he became more vigilant now, perhaps paying as much attention to his crew as to his daily measurements.

When morning broke, the pink reached Fernando de Noronha and dropped anchor off the more benign leeward shores. Turtledoves cooed and land crabs scurried in abundance, as Halley described in his journal. The atoll was devoid of any hallmarks of human trespass such as feral goats and pigs. Much to Halley’s chagrin, the stopover was a bust: no fresh water was to be found—only an abundant supply of wood. Halley instead used the break to do routine maintenance on the ship’s hull, shrouds, and mast. He also sketched a map of the island in his log. Very likely the crew had definite thoughts about their leader’s decision to linger there, more grist for Harrison’s mill.

Halley was not as fluent in the colorful banter of sailors as was Harrison, a shortcoming he frankly acknowledged. A mixture of necessity and chaos had forged a sea vernacular comprised of mainly one-syllable words. For example, “by” meant sailing by the wind or on a bowline; “bear down” referred to sailing downwind rapidly toward a landmark; the “bitter end” was the loose, unsecured end of a line, often an anchor cable; and “pipe down” was the botswain’s call for all hands to go below. Seamen could easily converse in this terse tongue at the peak of a storm or while under attack.

Although Halley spoke like a proper Englishman, his crew’s disrespect was undeserved. He hadn’t made any gross navigational gaffes in commanding his ship. In fact, Halley had actually shown up Harrison on several occasions with his piloting acumen and geographical knowledge. Exactly how the Paramore was steered into the doldrums remains an open question, of course. Perhaps it was purely bad luck or their squabbling over course plotting that took a toll.

Meanwhile, Halley’s displeasure with his crew was mounting as winter came to the Southern Hemisphere—probably more so than most captains, given the stakes. His officers’ resentment overshad-

owed any veneration they displayed for science. Yet in Halley’s mind the outlook for the mission remained bright.

DANGEROUSLY LOW ON WATER, the Paramore pushed on for the northeastern coast of Brazil. They made landfall on February 26, one week later, and anchored off shore at Paraiba. On their arrival, the Portuguese governor of the region Dom Manuel Soares Albergaria sent his deputies to greet Halley. A sergeant major and an interpreter invited him to refill his empty water casks the next day from the Paraiba River. He also stocked up on tobacco and sugar. Afterward, Halley dined with the governor and impressed him with expensive gifts. Albergaria was “very obliging and civil,” Halley reported to the Admiralty. But the Portuguese officials “were very willing to find pretenses to seize us and tempted us several times with a sort of wood they call Poo de Brasile which is an excellent dye, but prohibited to all foreigners under pain of confiscation of ship and goods.” Keen to their ploys to entrap them by enticing them to purchase the contraband wood, Halley refused all trade with them. Once Halley had replenished his water provisions, he was ready to shove off as soon as possible.

During his sojourn at Paraiba, Halley measured longitude astronomically by observing the end of the Moon’s eclipse as well as the magnetic variation using his compasses. He had hoped to survey the estuary, too, but the Portuguese officials, still untrusting, denied his request.

Departing from the Brazilian coast on March 12, Halley by now had given up on the notion of wintering there. He recorded in his journal soon after that “my Officers showing themselves uneasy and refractory, I this day [March 16] chose to bear away for Barbados in order to exchange them if I found a Flagg [a flagship] there.” Whether due to his unruly crew, mistimed winds, or winter’s onset in the South Atlantic, Halley’s meandering return to St. Helena would be postponed. For the time being, he abandoned his plan to venture farther south, much to the pleasure of his impatient crew. He advised the Admiralty that instead he’d “adjust the Longitude of most of the Plan-

tations [in the West Indies] and see what may be discovered in relation to the Variation of the Needle in the Northern Hemisphere.”

Things had been relatively quiet. Then, while approaching Barbados, the final straw came from his top lieutenant. Harrison defied a direct order from Halley. He “pretended that we ought to go to Wind-ward of the Island, and about the North end of it, whereas the Road is at the most Southerly part almost. He persisted in this Course, which was contrary to my orders given overnight, and to all sense and reason, till I came upon Deck, when he was so far from excusing, that he pretended to justify it; not without reflecting [offensive] language.”

In front of other officers and deckhands, Harrison said Halley was “not only incapable to take charge of the Pink, but even a Longboat.” As James Burney noted in his 1815 account of Halley’s Atlantic voyage: “Respect for science, however, did not operate sufficiently strong on the Officers of Dr. [Halley’s] or rather Captain Halley’s ship, to prevent their taking offense at being put under the command of a man who had risen without going through the regular course of service with the Royal Navy.”

Enough was enough. Halley’s lenience expired. In a letter to Secretary Burchett, Halley complained, “For a long time [Harrison] made it his business to represent me, to the whole ship’s company, as a person wholly unqualified for the command their Lordships have given me, and declaring he was sent on board here because their Lordships knew my insufficiency.” From then on, Halley stifled any further mutinous acts. He placed Harrison under arrest and restricted him to his cabin that night and took charge of the ship. He reiterated his orders and made sure the crew complied. Under Halley’s stern authority, the Paramore reached Barbados with surety.

Halley would later note the irony of Harrison’s selection for the mission: “My dislike of my Warrant Officers made me Petition their Lordships that my Mate might have the Commission of Lieutenant, thereby the better to keep them in obedience, but with a quite contrary effect it has only served to animate him to attempt upon

my Authority, and in order there to side with the said officers against me.”

By this point, Halley had relinquished any intent of wintering in Brazil and pushing southward in the spring. He had lost all patience with his crew’s antics. He had no success finding a flag officer, possibly Admiral Benbow, to reprimand Lieutenant Harrison in Barbados, Martinique, Antigua, or St. Christopher.

With Harrison secured in his cabin, a frustrated Halley aborted the mission and set sail to return to London. Reaching the homeport in July 1699, likely full of personal disappointment, Halley pledged to pursue an official court-martial against not only his lieutenant but also several crew members. He needed to salvage his bungled mission. After arriving in Plymouth in the English Channel, Halley complained bitterly of his personal ordeal with Lieutenant Harrison in another letter dated June 23 to Secretary Burchett:

Halley was confident the Admiralty would find that the behavior of his crew had been intolerable. After all, he had proven himself a worthy captain, returning to London without losing a single life, a rarity in those days. He requested a new crop of officers with the hope that he might proceed once again with his mission. But first, there was his case against Harrison and his officers to settle.