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.