State of Wonder: Providence’s Pendulum Mania

by Anne-Marie Kommers ‘18

Pitch: In 1851, French scientist Jean Bernard Léon Foucault used an enormous pendulum to demonstrate physically, for the first time, that the earth rotates on its axis. His dramatic public experiment swept first Europe and then America in a wave of “pendulum mania,” inspiring dozens of copycat demonstrations throughout the world including one on Brown University’s

College Hill. Thanks to Professors Alexis Caswell and William A. Norton, Providence citizens experienced the same sense of awe and wonder that the Parisian scientists did when they watched the earth turn, a wonder that occurs once in a long while when scientists make discoveries that remind us of the scale and mystery of the universe.

To gaze at the night sky, with its millions of stars and occasionally visible planets and comets, is to gaze at something familiar but distant, fascinating but unknown. Though we are surrounded by billions more people than ever before, we realize that in a larger sense we are alone, rotating slowly in a vast galaxy of beautiful but unfeeling objects in space. We feel a sense of awe: what Berkeley psychologists Paul Piff and Dacher Keltner call “that often-positive feeling of being in the presence of something vast that transcends our understanding of the world.”

Historically, stars and planets were described in biblical terms. The space outside of the earth was called the “Heavens” or the “Firmament.” The sun, moon, stars, and other “luminous bodies” were called the “Heavenly Bodies,” and all of these bodies together were called “the

Heavens.” There was a kind of religious or spiritual aspect attached to the very names of the objects in the sky. To understand astronomy was to understand God.

1 So when French scientists opened a letter and read, “You are invited to see the Earth turn,” they were intrigued.

This was the message that Jean Bernard Léon Foucault sent out to his fellow scientists in

Paris on February 2, 1851. It was a bold declaration for a sickly man who suffered from extreme shyness. Foucault’s colleague Joseph Bertrand wrote that Foucault was a genius who was

“enthusiastic about science but not about study,” and who as a consequence lacked a scientific degree. Despite his shyness, despite his frailty (he tried to go to medical school but fainted at the sight of blood), and despite his lack of formal training, Bertrand claimed that Foucault

“displayed a quiet authority and frankness which irritated many leading scientists.”

Nevertheless, on February 3 nearly every member of the Parisian scientific community huddled inside the Meridian Room of the Paris Observatory. The great domed windows let in plenty of sunlight onto the stone floor, and in the pinnacle of this light, surrounded by a sea of skeptical scientists, stood Foucault.

Foucault had hung an iron ball from the roof by a wire over 200 feet long. He placed a circular rail with a ridge of coarse sand under the pendulum so that the pin attached to the ball would scrape the sand and leave a mark with each vibration. Then he lifted the ball to the side with a cotton cord and left it suspended in the air. Painfully aware of all the eyes boring into him,

Foucault lit a flame and burned the cord. Silence reigned as the flame crept up the cotton.

And then all at once, the pendulum was set free.

There was something eerie about the pendulum’s motion. It swung slowly back and forth, like a trapeze artist on stage. The experiment was deeply theatrical in a way that is unusual for most scientific demonstrations. Each time the pendulum swung back down toward the sand, it made a soft pfft as the pin grazed the sand and left a mark. It slowly dawned on all the scientists in attendance that the pendulum’s markings deviated towards the right, cutting the sand in a

2 different place with each swing. The pendulum appeared to be moving as the Earth beneath it lay still. But, being scientific men, everyone in the room knew the truth of what they were seeing: it was not the pendulum but the Earth on which they stood, the solid stone floor beneath their feet, that was moving.

There must have been considerable awe in the room. Scientists had long known that the

Earth rotates on its axis due to their mathematical calculations, but to know abstractly that the

Earth turns and to see its rotation before your eyes are two different things. Yet the scientists snubbed Foucault’s demonstration because he lacked a scientific degree. Perhaps they were annoyed that a young amateur had shown them up; there may also have been a toxic climate at the time of French “snobisme.” Although the word “snob” originated in English, it was only when it passed into French in the 1800s that it gained its modern meaning, that of a person with exaggerated respect for high social position or wealth. The Parisian scientists had an idea in their stove pipe-capped heads of what a great scientist should be, and a timid, uneducated man who fainted at the sight of blood was not it.

A month after Foucault’s demonstration in the Meridian Room, a larger and decidedly more boisterous crowd of everyday Parisians flocked to the Paris Panthéon. Women clad in ruffled hoop skirts mingled with the men, many of them in noticeably more modest attire in comparison to the scientists. The building in which they stood was a far cry from the winding streets and narrow apartments of everyday Parisian life: the Panthéon was a monster of a building with marble floors, intricate carvings of famous learned men of antiquity, Greco-Roman columns and, most importantly, a large dome. It was from this dome that Foucault hung his pendulum.

The crowd stood, transfixed. The pendulum was so big. Despite the jungle of people, despite the din of gossip and exclamations of wonder, there is little doubt that everyone in the

3 room could clearly see the pendulum swinging back and forth in its hypnotic motion. People could stay as long as they wanted to, gazing at the large pendulum as it grazed the sand with tiny scratches. For days, crowds of onlookers flocked to the Panthéon to witness the experiment.

Once the news reached America about Foucault’s pendulum, many readers wrote to newspapers asking for explanations. A correspondent to the National Intelligencer known as

“A.Z.” claimed to have “more zeal for science than capacity for imbibing it,” and he complained that “the more I read the less I understand.”

Adding to the confusion were reporters who, in their haste to bring the breathtaking news to the public, published erroneous accounts of how the pendulum worked. The most damaging of these accounts came from the London Globe on April 5, 1851. The report claimed that the pendulum completed a full rotation every 24 hours, something that was only possible at the earth’s poles and not at the lower latitude of Paris. Most American newspapers, including the

Providence Journal, introduced the Pendulum Experiment to their readers through a reprint of the Globe’s article.

Even after the Globe’s errors were corrected, people were confused. Almost no one understood why the pendulum swung at different rates at different latitudes. And it didn’t make sense to many people that a pendulum could swing independent of the Earth’s rotation if it was tied to a rod attached to the ground. Moreover, the experiment itself was extremely difficult to perform.

Even seasoned scientists had trouble reproducing Foucault’s pendulum. In 1851, George

B. Airy was an expert at the top of his field, the “astronomer royal” of Great Britain. And yet in his private correspondence, Airy admitted that he had been unsuccessful at replicating the

Pendulum Experiment, which he called a “fraud.” The idea that the pendulum’s rotation depended on latitude, he wrote, was simply a “mathematical curiosity” with no application to the

4 real world. Still, because of the experiment’s acceptance among the wider scientific community,

Airy kept his opinions private and was highly embarrassed when his opinions were leaked by popular journals. Perhaps galvanized by the snickers of his fellow scientists, Airy tried the experiment once again. This time he was successful and presented his results to the Royal

Astronomical Society.

To be clear, almost no one doubted the fact that the Earth turns on its axis. The Earth’s rotation had been almost universally accepted for hundreds of years by the time 1851 came around, and there was an entire chapter on it in the astronomy textbook in use at Brown

University at the time. Instead, people took issue with the notion that a pendulum attached to the

Earth could demonstrate physically that the Earth turns.

One article published in the magazine Punch outright ridiculed the Pendulum

Experiment. It was reprinted in several newspapers, including the Providence Journal. A man named “Swiggins” wrote that it was self-evident that the earth was turning because he could see it happening before his very eyes. But he didn’t care about “latitude or longitude or a vibratory pendulum… That is all rubbish. All I know is, I see the ceiling of this coffee-room going round: I perceive this distinctly with the naked eye – only my sight has been sharpened by a slight stimulant. I write after my sixth go of brandy-and-water, whereof witness my hand.”

In Providence, a reader known only as “F.” wrote to the Editor of the Providence

Journal. Professing “not to be an adept in the sciences,” F. declared that he did not understand the experiments enough to “fully understand and believe them.” How could Foucault’s pendulum, he reasoned, take thirty-five hours to turn when the Earth completed a full revolution every twenty-four hours? “Are not philosophers a little too fast in their calculations?” he asked.

“Let us have the facts. If not, then better try it, and learn from the facts, instead of theorizing on the basis of an experiment of two or three hours.”

5 The goading tirades continued, slowly finding their ways up College Hill.

F. wrote to the Editor again denouncing the “dearth of intelligence” surrounding the

Pendulum Experiment. In reference to several columns that had attempted to explain the

Pendulum Experiment, F. accused the Providence Journal of “containing not a word of the why and the wherefore” and of containing too many “sines, cosines, tangents, A, B, C’s, &c.”

A man named “Filopanti” responded a week later to F.’s commentary. As a native of

Italy, the country of the Renaissance and the Catholic Church, Filopanti suggested that doubters like “Mr. F.” were more pathetic modern versions of the oppressive Catholic forces that had denounced Galileo’s astronomic observations. “Fortunately, for us, the times are very considerably changed since then,” Filopanti wrote. “The worst which may befall M. Foucault, now a day, is something like the half anonymous witticism of Mr. F. Doubtless, this will be much easier for the ingenious Frenchman to bear than were the dungeons and the torture of the

Inquisition for the father of experimental philosophy.”

Looking down on the controversy in Providence from the heights of Brown University’s

College Hill were two of the men most qualified to demonstrate Foucault’s Pendulum

Experiment: Professors William A. Norton and Alexis Caswell.

Although they worked together to demonstrate the Pendulum Experiment, in many ways

Norton and Caswell were like oil and water. Norton was slightly overweight, his hair was wispy and thin, and his eyes, though kindly, had a tired look to them. From an early age he proved to be extremely intelligent, and the West Point Military Academy offered him a professorship position almost immediately after he graduated. By the time Norton came to Brown as a professor of natural philosophy and civil engineering in 1850, he had already published a highly lauded textbook, “An Elementary Treatise on Astronomy.” It was the textbook in use in Professor

Caswell’s class when Norton arrived on campus.

6 Caswell, for his part, was playful. He had an alert look to him, his eyes piercing and his posture erect. He seemed like someone who would keep you on your toes. Like Norton and most other men of his time, he had a full head of hair, a mustache, and sideburns, but Caswell’s hair looked bushier and healthier than Norton’s. He excelled at math and science, but he also participated in wrestling and other sports. At various times throughout his life, he was the

President of Brown University, the President of Rhode Island Hospital, the Vice President for the

American Association for the Advancement of Science, and the President of the National

Exchange Bank and American Screw Company. He also spent his entire adult life as a Baptist minister. Norton liked to focus on his chosen field, spending hours reading and writing scientific papers on cutting-edge experiments; Caswell preferred to go out into the world, to lead things and get his hands dirty by interacting with other people.

Still, the two men shared an unquenchable thirst for knowledge that may have brought them together. Caswell kept a notebook on which he scribbled passages from great writers such as Homer and Milton, notes on Christian morality and architecture and swimming, and lists of books he planned to read. Norton, for his part, spent his life exploring the most recent scientific discoveries and sharing this knowledge with his students, most of whom regarded him as their favorite professor.

It is unclear whether Norton and Caswell specifically accepted F.’s challenge to demonstrate the pendulum’s movement or simply bowed to popular demand. Perhaps it was a mix of the two. Whatever the reason, sometime in the summer of 1851 the two men arranged for a public demonstration in the Providence railroad depot.

The Providence Union Station was a rather grand edifice for such a small city. Voted one of the twenty best buildings in the United States by American Architect, the Union Station had

7 red-brick Romanesque architecture with an octagonal building on one side and two tall towers on the other. It was from one of these towers that Norton and Caswell hung their pendulum.

On the first day of the experiment, a crowd of Providence citizens gathered inside the

Union Station. The men were on a break from their jobs at the seaports; the women, some with babies or small children in tow, were taking a break from the grocery shopping and housework.

Outside, lines of horse-drawn carriages sat in a neat row along the side of the road, and much of the city’s crooked streets and seaports bustled with the daily activity of Providence’s shipping industry. The Union Station provided a dark and hot respite from the urban rush, emphasis on the hot. Norton and Caswell had closed all openings in the tower to avoid interference from the wind outside. No ocean breeze wafted in to relieve the midday summer’s heat. The women could not pull down their necklines because it was not yet nighttime, and at most the men could furtively loosen the ties beneath their waistcoats.

Norton and Caswell seemed unfazed by the heat. They were busy hanging a 97 foot long wire with a nearly spherical ball of lead at its end from the ceiling. Once this was accomplished, as Norton later reported, they divested the weight “of any tendency to rotatory movement” and then drew it to the side to attach it to an “upright” by a cotton-threaded loop. One of the men lit a match, and the cotton thread began to sizzle as the flame crept up its side.

In absolute silence, the pendulum began to swing at a sloth-like pace of 5 seconds per oscillation. Norton and Caswell were immersed in their work, sparing barely a glance for the crowd of observers and recording observations and angles of oscillation into their notebooks. But the crowd, most of them without high school degrees, were watching the swinging lead ball and ignoring the two scientists.

For hours, Providence citizens directed their gaze toward “the heavens where the mystery of absolute immobility was celebrated,” wrote Umberto Eco over a century later in his novel

8 Foucault’s Pendulum. “The Pendulum told me that, as everything moved – earth, solar system, nebulae and black holes, all the children of the great cosmic expansion – one single point stood still: a pivot, bolt, or hook around which the universe could move. And I was now taking part in that supreme experience. I, too, moved with the all, but I could see the One, the Rock, the

Guarantee, the luminous mist that is not body, that has no shape, weight, quantity, or quality, that does not see or hear, that cannot be sensed, that is in no place, in no time, and is not soul, intelligence, imagination, opinion, number, order, or measure. Neither darkness nor light, neither error nor truth.”

There is a story by Isaac Asimov called Nightfall, in which the stars are only visible to humans on Earth every thousand years. Everyone stops what they are doing to gaze up at the sky in awe. In real life, of course, humans take this nightly beauty for granted. But sometimes a new discovery, some new planet or scientific accomplishment, makes us give the sky a second glance. Foucault’s Pendulum was one such discovery. Or, in the words, of American astronaut

Kathy Sullivan, the spectators at the Pendulum Experiment felt that they were “seeing, woven together, the power and scale of the entire world.” It was the same feeling people would have when they watched the Moon landing on their television sets, when they saw the pictures of the surface of Mars or detected the distant bump of two black holes colliding in space.

Norton reported that he and Caswell conducted 23 experiments with the pendulum, during which time Providence citizens could wander in and out of the Union Station whenever they wanted to watch the Earth turn. Once the pendulum was taken down, it was not stored away and forgotten. Norton and Caswell hung it in the octagonal rotunda of the college library for all

Brown University students to enjoy.

Norton left Brown for good in 1852. He was offered a teaching position at Yale, and several of his most loyal Brown students transferred schools to follow him. Caswell remained as

9 a professor, and years later he would become the President of the University. But even after both men had left, another professor took up the torch of keeping “pendulum mania” alive on Brown’s campus: Professor Winslow Upton. In Brown Daily Herald articles throughout the 1890s and early 1900s, there are numerous references to Professor Upton’s annual Pendulum demonstrations. An 1893 article read, “In the library yesterday morning Professor Upton gave a practical illustration of Foucault’s Pendulum Experiment, which actually shows the earth’s rotation to the eye.” Two years later the Herald reported that “Prof. Upton entertained his astronomy class with the pendulum experiment, by which it is shown that the earth rotates upon its axis.” And in 1900, “For the benefit of Prof. Upton’s class in general astronomy, the very interesting experiment with a pendulum, which shows the earth’s rotation, was performed… in the library.”

Eventually, Brown professor Charles Smiley decided to film the experiment to save the bother of having to recreate it each year. His efforts quickly backfired; the first showing brought forth the suggestion that the movie might have been faked. It was decided that live annual performances of the Pendulum Experiment would continue.

It is unclear precisely when the demonstrations ended. Perhaps people stopped seeing

Foucault’s Pendulum as remarkable and unusual, and they no longer felt the need to see the

Earth’s rotation performed before their eyes. The experiment that had sparked “pendulum mania” throughout Europe and the United States had, with time and repetition, become bland and ordinary. Humanity would have to wait until the 1960s Moon landing for another astronomical phenomenon to grip it so firmly by the lapels.

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