The next hour and a quarter was wide-eyed with what doctors of the day called “excitement of the nerves.” Pulses pounding, with cold sweat dripping from their brows and chins, the ship’s two scientists stayed their post and ensured no lens, gear, or eyepiece met with the same fate as bones and skulls of the fighting men above.
Then, just as suddenly as the engagement began, the French booms from beyond stopped. Groans and wails from the Seahorse’s injured continued unabated. But from behind a closed cabin door, the sounds of the able-bodied had turned from those animating a warship in battle to those driving a frigate under sail.
Captain Smith had more than a score of maimed and wounded men, many beyond saving. “Monsieur” may have broken off the battle, but this was still war. The Seahorse gave chase as best she could. But French hulls, known to be sleeker than those of the lumbering English fleet, gave L’Grand a natural advantage that “monsieur” used to his benefit.
Soon a battered English frigate turned around and sailed back north whence she’d originated.
PLYMOUTH, ENGLAND
Monday, February 2, 1761
The post coach from London via Bath didn’t run on Sundays.8 So the letter that arrived at Mason’s temporary lodgings in this dockyard city had one day longer to steep in its rich juices. It was dated Saturday, January 31.
“Resolved unanimously,” it began. “That the Council are extremely surprised at [Mason and Dixon’s] declining to pursue their Voyage to Bencoolen and which they have solemnly undertaken; and have actually received several sums of money upon account of their expenses, and in earnest of performing their contract.”
Dogs—even cattle and poultry—openly foraged for food in Plymouth’s filthy streets.9 The farmyard chorus of moos and clucks provided all the sonic accompaniment that Mason, not lacking in a good sense of humor, could have wanted as he read through the Royal Society’s haughty post.
The society’s governing council, including a new member from the colonies named Benjamin Franklin, clearly had not appreciated Mason’s argument that withdrawal, under the circumstances, was necessary. Three weeks had now passed since the Seahorse had limped back to port. Some of the nation’s finest shipwrights were repairing the battle damage.
On January 12, Mason had posted notice to his paymasters at the Royal Society in London about the unfortunate turn of events in the channel. “The stands for our instruments are tore very much,” he reported. “But the clock, quadrant, telescopes, etc. are not damaged that I can find.”10 He asked what the society would have them do next. They soon learned the society’s wish, as Mason paraphrased their new orders, to “do every thing in our power to answer the intention of our expedition.”11 Stay the course, in other words. Mason and Dixon were to wait in Plymouth and sail on the Seahorse once she was seaworthy again.
And so the Royal Society’s representatives bided their time as each passing day made the mission to Bencoolen more likely to miss the transit altogether. The society should probably, considering the lengthy voyage, have initiated the expedition two or three months before it actually did. But now another precious month would pass before Mason and Dixon could log even their first bona fide nautical mile beyond English coastal waters.
The duo had been writing letters to both Royal Society officials and the Astronomer Royal begging to be reassigned to a closer destination, one they knew their ship could reach with time enough to construct an observatory worthy of their task. The eastern Mediterranean coastal city of Scanderoon (Iskenderun in present-day Turkey), they said, “will make a third point upon the Earth’s disk of very great advantage to those of St. Helena [where a second Royal Society transit voyage had also been posted] and Greenwich.”12 Moreover, Mason informed his boss in Greenwich that his calculations suggested Scanderoon or another location in the eastern Black Sea could give them a leg up against competition from across the English Channel. One of these alternate locations, Mason wrote, “will answer beyond those of the French in Siberia.”13
The two men undoubtedly were aware of the additional fact that, especially in a time of open war in the Atlantic, sailing through the Mediterranean rather than around Cape Horn drastically reduced the risk of shipwreck by storm or of another rendezvous with the enemy.14
And now, receiving the January 31 letter from the council, Mason had the final answer he’d been seeking. Not only did the council reproach Mason and Dixon for daring to suggest workable alternatives, the august body saw their action as something approaching mutiny. The Royal Society threatened legal action if the two continued with any more innovative thinking.
“That in case they shall persist in their refusal,” the letter concluded, “or voluntarily frustrate the end and disappoint the Intention of their Voyage, or take any steps to thwart it, they may assure themselves of being treated by the Council with the most inflexible Resentment, and prosecuted with the utmost Severity of Law.”
The next day, Mason and Dixon sent a short, apologetic post back to the council. “We shall to our best endeavours make good the trust they have pleas’d to confide in us,” they said—adding, in a postscript, “We hope to sail this evening.”15
TABLE BAY, CAPE TOWN (PRESENT-DAY SOUTH AFRICA)
April–May 1761
Two weeks on the open ocean for someone as prone to seasickness as Charles Mason might make a nonconfrontational man pine for the English Channel—even if it meant another gunboat fight. But more than two months at sea, steadily southward past the Azores and riding the trades west toward Brazil and back east again, provided daily affirmation of Samuel Johnson’s quip, “Being in a ship is being in a jail—with the chance of being drowned.”
Poorly ventilated and pungent with every foul odor human bodies can unleash, a frigate at sea berthing 160 men in its close quarters gave Mason and Dixon ample excuse to take the fresh air on deck. They certainly exercised such opportunities when working with the ship’s master to fix Seahorse’s latitude (via measurement of stars and the sun against the horizon) and its longitude (via lunars) along the way. Hours spent measuring stars and planets and calculating the ship’s position probably constituted the best moments of the day that the two mathematicians spent on an otherwise wearisome passage.
As winter turned to spring—and, descending into the Southern Hemisphere, toward cooler weather again—the prospects looked progressively worse for anything approaching a further 6,000-mile voyage to Sumatra. The Dutch East India Company port of Kaapstad (Cape Town) represented the last hope for setting up their temporary observatory in anything resembling civilization.
An English ship dropping anchor in late April in Cape Town’s Table Bay16 already told company officials plenty. The stormy quaade mousson (Southern Hemisphere winter) was fast approaching. Either the visitors were stocking up for a hellish passage into the Indian Ocean, or they were somewhere they hadn’t planned to be.
An exchange of salutatory cannon fire between fort and ship opened the dialogue. The last time Mason and Dixon’s ears had rung with such thunder, of course, an enemy threatened to take away their phenomenal career-making opportunity. This gunfire, on the other hand, represented the opening salvo in a backup plan that might give the Venus transit back to them.
Dutch officers boarded Seahorse to learn of the circumstances that brought her to their shores. Captain Grant, prideful mariner that he was, couldn’t tell the Dutch officials that Seahorse had been bested by a French warship. Instead, he explained that circumstances outside their control had forced Seahorse’s hand.
As luck would have it, Cape Town’s governor was no stranger to scientific expeditions. Ryk Tulbagh,17 who’d overseen an era of reform during the ten years he’d reigned, had in 1751 welcomed the French astronomer Nicolas Louis de la Caille for a two-year sojourn that included compiling the world’s most detailed sky map of the Southern Hemisphere. Tulbagh also counted famous natural philosophers among his personal friends, including Swedish botanist Carl Linnaeus. The legendary Swede had once written to Tul
bagh that, even if he could switch places with Alexander the Great, he’d still rather be governor of the Cape. “The Beneficent Creator,” Linnaeus wrote, “has enriched [Cape Town] with his choicest wonders.”18
To his credit, Tulbagh welcomed the scientific expedition with open arms, unheralded and unannounced though it was. And so Tulbagh’s star-shaped Castle of Good Hope, close by the city’s main dock, became the first unnatural wonder to greet the visitors as they offloaded their gear.
A second spectacle awakened the senses upon passing the stone fortress. As one contemporary put it, the bulk of the city was located “a good musket shot to the west of the castle.”19 And walking toward Cape Town’s sea of thatched roofs and the company’s sumptuous garden beyond, a brutish contradiction came into view that visitors from afar had fresh eyes to see.
While admirers like Linnaeus praised Cape Town as “paradise on earth,” it was also a city built, maintained, and run on an often unspeakably brutal institution of slavery. Gibbets around the town’s periphery exhibited condemned slaves’ maimed corpses and body parts.20 Mutiny onboard a ship might lead to executions, but the punishment of swift death looked merciful compared to the drawn-out and horrific ends revealed by these vulture-chewed charnel remnants.
From the porters who carried the expedition’s gear to the servants in Tulbagh’s entourage to the manpower that kept the bulk of this company town moving, the city’s slaves also served as living mementos of conquered cultures to the north and east. Tribesmen from mainland southern Africa and Madagascar, as well as Indians, Ceylonese, and Indonesians, all made up the city’s shackled population. Many slaves eked out their miserable lives in an overcrowded lodge near the castle, where the inhumane conditions (in some years the mortality rate was 20 percent) would have been unacceptable even in the Dutch East India Company’s zoo farther inland.21
The zoo comprised a small portion of a forty-three-acre rectangular garden that practically defined the city. Sailors the world round may not have visited or even known of the Compagnies Garten. But if they sailed the Cape regularly, they had certainly feasted on its output. Mutton, beef, fruit, vegetables, bread, wine, and fresh water all flowed like manna—ensuring visitors like Mason and Dixon could scarcely want for good food and drink during their stay. And just east of Cape Town’s cornucopia lay the company stables, beyond which city officials allowed Mason and Dixon to set up.22
As the rainy season approached, the men turned toward their final pretransit duty—constructing the observatory. The first two and a half weeks of Mason’s meticulous Cape Town observer’s log recorded just one night of stargazing. Had the duo wanted to calibrate their instruments, the skies didn’t permit. It was cloudy, Mason notes, “nearly all the time.” Mornings especially, he said, “are very subject to thick fogs, which lie till 9 or 10 o’clock. But I hope our intentions will not be finally disappointed.”
Mason wrote back to his paymasters at the Royal Society on May 6 that Tulbagh had “supply’d us with necessaries for building an observatory, but the Dutch are so slow and so few speak English that I was very doubtful of getting it completed in time.”23 So instead, Mason and Dixon hired the Seahorse’s six carpenters—men trained to patch leaky hulls and masts shot through with cannon fire—to build their tiny wooden shrine to the stars. The expedition’s account books note a hefty cash outlay of £12, 6 shillings, 6 pence ($3,000 in today’s money) going toward timber, a rare and expensive commodity on the Cape. The carpenters clearly knew how essential their services had become, and they charged accordingly. Their ten days of labor cost another £12, along with a hefty sum of £13, 16 shillings ($3,400) covering the costs of “victualing.”24
By May 18, the well-fed men had completed the twelve-foot-wide structure and set the observers’ expensive pendulum clock onto boards sunk four feet in the ground. The whole structure was less than nine feet tall, with three feet occupied by a conical roof. The roof rotated with a sliding aperture that enabled both telescope and quadrants to be pointed through the hole. Heedless visitors to the cramped space found ample opportunity to stub their toes and slam their head on the low door.
CAPE TOWN
June 5, 1761
For five weeks, Mason glared at the skies. Clouds and rain cursed the explorers practically every day and every night when they tried in vain to point their telescopes at the planets and stars. The observatory was now fully ready, but the finest instruments in the world meant nothing if the weather refused to cooperate.
At dawn the next morning, June 6, the sun would rise with the Venus transit under way. Cape Town provided a window seat for only the second half of the planet’s progress across the solar disk. The three hours immediately after sunrise would see Venus’s ink spot shadow crawl up the rest of the sun’s face and then disappear from the top edge, like a dog tick climbing and then falling from a lamp. This celestial spectacle—in conjunction with other transit measurements elsewhere on the globe—could still give the Royal Society the numbers it needed to triangulate the sun’s distance.25
On the other hand, the society would hardly look kindly on a Venus transit mission to Bencoolen that never reached Bencoolen and then, even from its makeshift secondary observatory in Cape Town, returned home with nothing but tales from afar. If the skies on the morning of June 6 were like the cloudy skies every other morning during their Cape Town stay, these Royal Society hired hands could probably expect more love letters from the governing council like the one they’d sent to Mason on January 31.
But on the night of June 5, their fate took a turn. The clouds began to dissipate. Mason and Dixon, for only the second night of their entire Cape Town stay, were now free to do their job.
To the east, the star Antares—brightest star in the constellation Scorpio—rose above the jagged peaks of the Stellenbosch Mountains.26 The occasional whinny from the Dutch East India Company stables broke the studied silence of the most serious night in these men’s lives. Mason trained his scope on Antares over the course of the night for thirty-two separate measurements of its height above the eastern, and later the western, horizon. At Mason’s each recording of the star’s altitude, Dixon read off the clock down to the half second. Clouds obscured four of the thirty-two measurements, however, as if reminding the astronomers how close to precipice they remained.
With the night chill and the seasonal offshore Cape winds buffeting the round-topped shanty, the observers took turns rotating their tiny dome to the other star they monitored throughout the night: Altair. Known to sky watchers as one of the three vertices in the “summer triangle,” this late-rising star—whose progress through the sky Dixon closely monitored—glimmered to the north over Table Bay.
Dixon completed his final measurement of Altair in the northwestern sky as the first fingers of dawn colored the bay’s anchored ships in shades of marzipan. Mason and Dixon rotated their observatory roof toward the east. And so at 5:45 AM on this morning of sweaty palms and adrenaline, they cast their fate with a turgid atmosphere.
The sun should have risen, Venus’s transit already under way, glazing the top of Tygerberg Hill with the day’s first hint of sunlight. But Mason logged in his journal, “The sun ascended in a thick haze and immediately entered a dark cloud.” The skies had turned sour again.
JAMESTOWN, ST. HELENA ISLAND
February 1762
When he met them after their respective Venus transit experiences, Nevil Maskelyne had had little interest in hearing Mason and Dixon’s stories of bad weather.
After spending another three months in Cape Town, the two explorers had arrived in October in the coastal town of the British-occupied island of St. Helena—one of the remotest islands on the planet, 1,100 miles west of the nearest African coastline and 1,900 miles northwest of the Cape. They’d come to assist Maskelyne, a fellow Royal Society explorer.
The twenty-nine-year-old Anglican curate had been holed up on this seven-mile-wide shard of volcanic rock for more than a year. Maskelyne’s assistant, the
navigator Robert Waddington, had left his boss behind soon after June 6. (The Royal Society had hired Waddington only to help with transit observations.) In fact, Waddington enjoyed a more productive time returning to England than he did during his St. Helena stay. Sailing home, Maskelyne’s assistant so impressed the ship’s captain with his lunar navigational skills that the captain refused any payment for Waddington’s passage.
On the other hand, at dawn on June 6, Maskelyne and Waddington experienced much the same nervous anticipation that Mason and Dixon had known. Clouds flirted with the sun, occasionally blurring it or hiding it altogether. But Maskelyne and Waddington had also snuck in some measurements of an immersed Venus’s varying distances from the sun’s edge. Yet all was trivia unless the St. Helena observers could secure one crucial number: the exact time (down to the second) when Venus’s silhouette touched the inside of the sun’s edge. (In 1761 only the latter half of the Venus transit was visible in the south Atlantic. So lacking any ability to measure the complete duration of the transit, a different method of computing the sun’s distance became necessary: one that compared from different observing stations on the globe the exact time of a single moment in the transit—in this case the instant when Venus first began exiting the sun’s disk.)
The Day the World Discovered the Sun Page 4