The Spinning Magnet

by Alanna Mitchell

  The Philadelphia adventure was the second of Franklin’s lightning experiments to succeed. The first, much less hallowed, happened a month earlier in France. Two French researchers set up a metal pole fixed to a church steeple, after Franklin’s instructions, and then waited for a strike. When the lightning struck, their assistants valiantly poked the pole with a brass wire insulated by a glass handle. They drew sparks, just like the sparks in the Leyden jar. It was a risky proposition and other experimenters trying to chase lightning in this way were injured and at least one fatally electrocuted.

  Franklin used the findings from the experiments to lobby for metal lightning rods to be permanently installed in high buildings—especially the towering churches—and linked by a metal cable or wire to the ground. He reasoned, correctly, that such a metal rod would collect the lightning charge and ferry it to the ground, where it would dissipate harmlessly. (The same idea is behind having a “ground” in the modern electrical plug.) It was a bid to protect buildings and people from both a lightning strike and the fire such a strike could cause. It was controversial, especially in France. Lightning, it was said, was the punishment of a miffed God. Diverting the lightning was subverting God’s will.

  Even though electricity couldn’t do much yet, the sheer spectacle of it, and the fact that it was linked to the power of the storm, enthralled people. Leyden jars and spark-making machines flourished, furnishing the diversions of the age. At the British court, dancing was abandoned in favor of “electrical entertainment.” In France, the electrician Jean Nollet, a disciple of du Fay’s, delighted King Louis XV by sending a charge through 180 soldiers, making them leap in near unison. British hosts with questionable taste electrified metal cutlery for the kick of seeing their guests jolted. The British electrician Stephen Gray prompted gasps from onlookers with his “hanging boy” trick, in which he suspended a charity-school child, passed an electric spark through him, and caused feathers to fly toward him. A favorite joke was the electrified painting of the king, primed to jolt any republican who happened to flick fingers at his crown.

  But while all these shocking tricks may have been amusing, the idea that electricity could be routinely made and delivered to homes and businesses, that it could replace the muscle work of humans and horses, that it could shape a different sort of civilization, was unimaginable. Still more remote was the idea that these sparks that filled a jar could be related to magnets or that either could be in any way connected to either the inner workings of atoms or the contortions of the liquid metal in the Earth’s core.

  CHAPTER 13

  the apothecary’s son

  Hans Christian Ørsted didn’t believe in atoms. In fact, he spent a great deal of his life’s work trying to dispute any idea of “atomism,” as it was called. He considered atoms devoid of life. They simply could not be what formed the glories of nature that he saw around him. And not just nature. To him, nature and the human spirit were interwoven. Together, the two were always on the move, interacting, shaping each other. They were a dynamic representation of the mind of God, not tiny bits of dead things.

  Ørsted came to these beliefs through the teachings of the German philosopher Immanuel Kant, whose ideas helped spark Europe’s love affair with Romanticism. Ørsted began to explore Kant’s ideas at university and became hooked. They helped him determine what problems he would work on and shaped his interpretation of his results. For good or for ill, Ørsted was using his experiments to prove some of the ideas that Kant espoused.

  He wasn’t the only scientist of his day to fall under Kant’s spell. Kant, who died in 1804, was one of the last philosophers to have had such a profound effect on scientific thought and practice, Andrew D. Jackson explained to me, relaxing in front of one of the computers in his office at the Niels Bohr International Academy, an independent center of excellence housed at the Institute. His hands were clasped across the front of his navy-blue shirt, eyes dancing with merriment. Jackson helped build this academy into one of the best modern theoretical physics institutes in Europe. (“What we’ve shown is that bright people want to work with other bright people and our job is to let them do what they want and stand on the sidelines and cheer,” he said.) Trained at Princeton University, Jackson got his doctorate in experimental nuclear physics and then taught theoretical physics at the State University of New York at Stony Brook until he moved to Copenhagen in the mid-1990s. He studied shoulder to shoulder with some of the last century’s great physicists, including Kip Thorne and the late Robert Dicke, both renowned for their work on gravitational theory and waves. (“I’ve known them for fifty years,” Jackson said.)

  Like some of those colleagues, and like Ørsted, Jackson was a broad-gauge intellectual. To sit and talk with him for several hours was to go on an elegant, discursive tour with a philosopher-scientist winding through the history of scientific thought, cultural history, and literature, punctuated with pointed asides on many of the major figures in each of the tales. (“Ritter was barking mad,” Jackson confided at one point, referring to Johann Wilhelm Ritter, a German physicist who died in 1810 in his thirties and who was an early influence on Ørsted.) His wide-ranging interests led him to become chairman of the Niels Bohr archives. As a result, he and Karen Jelved translated into Danish the much-traveled stage play Copenhagen by the British playwright Michael Frayn, the account of a meeting in 1941 between Bohr and Heisenberg on the role of atomic weapons in the Second World War.

  But while Jackson was a well-connected polymath, his subject, Ørsted, was a creature peculiar to the Romantic era. At that time, many thought of science not as a discrete branch of learning but as one thread in the broad tapestry of a sound theological education. Ørsted referred to his scientific work as his “literary career” and called it a form of religious worship. His scientific thinking depended not on atoms or particles, but on the Kantian idea that matter relied on two fundamental forces: attraction and repulsion. Attraction brought matter together and repulsion kept matter from collapsing in on itself when it came together. To Kant, everything anyone observed could be traced back to these two Ur-forces. It was spookily reminiscent of our modern understanding of the four fundamental forces of the universe: gravity, strong and weak nuclear interactions, and electromagnetism. In a way, Kant was not so far wrong, Jackson said, shrugging.

  Because Ørsted was such a devout Kantian, he concluded that all the forces observed in nature were derived from these two fundamental push-pull forces. That meant he believed he should be able to find connections and interactions among all the forces he could observe. Not just electricity and magnetism, but also light and heat, motion and air. All facets of nature were somehow bound together; all facets of nature manifested a higher order. It was akin to pantheism, Jackson explained. Since Ørsted believed he knew why they were all related, his goal was to find out how, to develop a unified theory that would explain it all. Because of this overriding philosophy of nature, as well as a belief in experimentation, Ørsted was seen as a progressive, even mildly revolutionary figure in European science at the beginning of the nineteenth century, an important participant in Denmark’s golden age. By the end of his life, as he retained his philosophical beliefs while the world moved on, he was regarded as hopelessly behind the times.

  Ørsted’s interest in science began with chemistry. Modern chemists teach us that chemical reactions are atoms rearranging themselves into new combinations to make new substances, and so it seems odd now to think that an avowed anti-atomist was a chemist. But to Ørsted, chemical reactions were somewhat hazily defined disturbances of the inner equilibrium of the forces, followed by the restoration of equilibrium.

  His passion for chemistry began in the laboratory of his parents’ apothecary shop in the town of Rudkøbing on the island of Langeland—or Long Island—in southern Denmark. Hans Christian was making pharmaceuticals by the time he was eleven, under his father’s tutelage. Jackson and Jelved did a bicycle tour of Langeland in the summ
er of 2015, the first time they had seen where Ørsted was born. Jackson leapt to his keyboard, scrolling through tidy piles of files to find photographs from the trip to show me. There was the apothecary’s shop, which doubled as an inn when Ørsted’s parents ran it. Inside, the brass vessels were still gleaming brightly, still sporting tidy labels, primed to be filled with mysterious concoctions.

  It was such a busy place in the late 1700s that Hans Christian and his younger brother Anders Sandøe were sent down the street during the day to the care of a German wig maker and his Danish wife. Jackson had pictures of their home too—a modest building with a sloping roof, still in decent repair. In those days, the nation’s time was set according to a replica of John Harrison’s famous fourth clock, H4, which had solved the problem of longitude. A man whose job it was to be the nation’s timekeeper would travel all over the country with it and people would set their clocks to “Danish normal time.” That time remained the country’s own until the German Army invaded in 1940, at which time Denmark’s time became Germany’s. As a result, Danes still say they live on borrowed time, Jackson joked.

  A larger-than-life-sized statue of Ørsted stands in Rudkøbing’s immaculate square, hands clasped primly in front of his rather portly figure, frock coat to his knees, vest carefully buttoned. In Ørsted’s day, the town was too small to have a school, and the brothers picked up what education they could from their parents and the wig maker’s family. The boys were multilingual students and voracious learners. What one learned, he taught the other. Despite being out of the Danish mainstream and despite the ad hoc nature of their education, both became top students at the University of Copenhagen.

  Anders Sandøe immersed himself in the law, eventually becoming a Danish prime minister and a famous jurist. Hans Christian devoted himself to chemistry and pharmacy, graduating in 1797. But to his chagrin, chemistry was a degraded discipline at that time. In fact, Kant had deemed it unscientific, just a mechanical process without what he called the dash of intuition or the logic of self-evident truths he demanded in a real science. Part of Ørsted’s mission in life was to have chemistry recognized as a legitimate field of research in its own right, not inferior to either physics or medicine.

  Two feuding Italian experimentalists helped improve chemistry’s standing by discovering what was thought of as “chemical” electricity. The first was the obstetrician Luigi Galvani, whose name lives on in the English verb “to galvanize.” The second was Alessandro Volta, whose name and findings are reproduced in the words “volt,” “voltage,” and “voltaic.”

  Galvani, who died in 1798, trained in Bologna as a surgeon and anatomist. He was fascinated by how the body came to be infused with life. What would animate it? Like others of his era, he suspected the new phenomenon of sparking electricity. Did its sizzle mean that electricity itself was alive? Could it raise creatures, Lazarus-like, from the dead? Researchers of the day began conducting electrical experiments on dead animals and even people, trying to shock them back into the land of the living.

  The novelist Mary Shelley, who was well read in the scientific fixations of her era, captured the fascination with electrical resurrection in her 1818 book Frankenstein, or The Modern Prometheus. The subtitle refers to the Greek myth of the immortal titan who steals fire from the god Zeus and gives it to humanity. Prometheus meets a grisly fate; he is chained to a rock, destined to have his liver eaten out each day by an eagle, only to have it regrow each night. In Shelley’s novel, the crazed Dr. Victor Frankenstein pieces together a towering man from flesh and bone scavenged from slaughterhouses, dissecting rooms, and charnel houses, disturbing “with profane fingers, the tremendous secrets of the human frame.” Finally, “with anxiety that almost amounted to agony,” the doctor “collected the instruments of life” around him in order to “infuse a spark of being into the lifeless thing” that lay at his feet.

  To the contemporary reader, this “spark” would have been understood to come from instruments to harness static electricity. The experiment worked. Frankenstein’s monster came to life: “It breathed hard, and a convulsive motion agitated its limbs.” Although, God-like, Frankenstein manages to create a living being, he loathes his creation. It destroys him and kills most of the people he loves, including his wife on their bridal night. Sick of the bloodshed of others, the monster goes off alone to perish in its turn. The novel, considered one of the first works of science fiction in English, reads as a morality tale. It’s a repudiation of the idea that humans, or their Promethean electricity-fire, can supplant God.

  Galvani’s experiments were not about bringing animals back to life but instead about the mysteries of the body’s nervous system and brain. At that time, researchers suspected that man-made static electricity and lightning were the same, thanks to Benjamin Franklin’s kite experiments. But some animals, including eels and rays, seemed to produce a natural electrical shock. Was that the same thing again? Or was natural, God-made biological electricity a completely different force?

  Galvani experimented on sheep and frogs, alive and dead. One day, he was working on a dissected frog near a machine for making static electricity. The frog was lying on a Franklin square—a foil-wrapped glass sheet that Benjamin Franklin had invented to function like a modified Leyden jar. Galvani mistakenly touched his scalpel to a nerve in the frog’s leg. The leg contorted, twitching in rhythm to sparks emitted by the electricity machine. Galvani tried variations on the experiment, including some that involved affixing frog and sheep limbs by brass hooks to an iron rail. They jerked, but only when two different metals were in use.

  Galvani concluded that he had discovered a new brand of electricity. He called it “animal electricity” and claimed that animals had an electrical fluid flowing from brain to nerves to muscles, the latter of which were de facto Leyden jars built into the body. In fact, what Galvani had made was an electrical current, a flow of electrical charges running through the metals in a circuit as the result of a chemical reaction.

  While Galvani had legions of supporters, some fellow scientists were skeptical. Among them was Volta, a professor of experimental physics at Pavia University, a few kilometers outside Milan. He redid Galvani’s experiments and soon realized that the trick was to have two different types of metals and some sort of moisture. It wasn’t the animal’s native electricity that caused the reaction, but rather the salty fluid in the animal’s body that allowed electricity to flow, he said. He taunted Galvani, saying he didn’t need his dead frogs, only some wet rags. But European scientists were divided, some fervently believing in animal electricity and others just as fervently rejecting the idea.

  By 1800, after a decade of experimentation, and two years after Galvani had died, Volta made his breakthrough. He stacked pieces of zinc and copper on top of one another, separated by discs of cardboard soaked in salty water. Within this pile, a chemical reaction was taking place through the medium of salty water, stealing electrons from the zinc discs and depositing them onto the copper ones. As the electrons moved, they created electricity. It was dubbed “chemical” or “galvanic” electricity.

  Volta had invented the battery. The batteries we use to power modern devices such as flashlights, cell phones, and even cars are the offspring of Volta’s galvanic pile. In fact, the French word for battery is pile, a direct reference to Volta’s stack of metals and briny cardboard. Batteries wear out over time because the chemical reaction becomes exhausted. If they are rechargeable, it means that the chemical reaction inside them can be reversed and the electricity can continue to be produced.

  Volta lost no time writing up his experiments in the French language of the scientific establishment and sending the account to London to be published. A master of self-promotion, he feasted on the finding for the rest of his life, becoming a darling of Napoleon. He was one of the best-known, best-paid physicists in the world. Scientists all over Europe began making voltaic piles and running new experiments.

 
Still, confusion reigned over what, exactly, electricity was. Was galvanic, or chemical, the same as static and lightning? Were there other types, yet undiscovered? Ørsted, the newly minted academic, who in his 1799 doctoral dissertation had tried to argue that Kantian physics should include chemistry, made himself a portable voltaic pile and took it on the road. It was the latest thing, and everybody wanted to have a look at it, Jackson explained. So, in 1801, armed with the pile and a travel grant, Ørsted set out on a years-long international journey, using the novelty of the pile as a way of gaining entry to the best laboratories and drawing rooms in Europe, even scoring a meeting with the German writer Johann Wolfgang von Goethe. It was that trip that scotched his engagement to Sophie Probsthein.

  It was a later version of Volta’s pile that allowed Ørsted to plan his great experiment in 1820 at the University of Copenhagen, where he was a member of the faculty of medicine who liked to teach chemistry. He had been looking for nearly two decades for a link between electricity and magnetism, in keeping with his Kantian principles. In itself, this was both controversial and daring. Mainstream European science had roundly rejected the idea that there could be any connection. No less an eminence than the French physicist Charles-Augustin de Coulomb had declared that electricity and magnetism could not be related and there was no use looking for a link. Coulomb was the one who worked out the math describing the law of electrostatic attraction and repulsion and after whom the standard international unit of electrical charge is named. (“There was precious little mathematics involved,” Jackson remarked.) The French physicist and mathematician André-Marie Ampère, who gave his name to the unit of electrical current (often shortened to “amp”), ridiculed the very idea that electricity and magnetism could be linked.

  Still, Ørsted persisted. In April 1820, he was freshening up a batch of lectures to give to a class of senior students and decided to devote a whole session to the elusive connection between electricity and magnetism. More than that, he would conduct an experiment in class to prove that they were connected. He hoped to do a trial run in private, but the events of the day overtook him and he didn’t get around to it. On his way to the lecture, he hurriedly ditched the idea of doing the live proof, but once in class, overtaken with how splendidly things were going, opted again to run his experiment. He put wires to a voltaic battery and then to each other, creating an electrical current running in a circuit, and then moved it near a compass. The compass needle moved, but only feebly. The electrical current flowing through the wire was creating a magnetic field around the wire and the compass was reacting to that magnetic field. This had never been shown before. The students in the class were unaware that they were witnessing science history. Ørsted was crestfallen that the experiment had shown such unremarkable results.