Three months later, he tried again. He had decided that he needed a stronger battery, so he custom-made one for the task. It consisted of twenty voltaic batteries linked together to make their power add up. Each was a rectangular copper trough a foot high, a foot long, and two and a half inches wide, holding two copper strips. The strips were bent to hold a copper rod, which in turn held a zinc plate in the adjoining trough. Ørsted filled the troughs with enough water to nearly immerse the zinc plates and added slight amounts of both sulfuric acid and nitric acid. It was, in essence, Volta’s pile turned on its side, making it more stable and capable of holding more fluid chemicals. He connected a wire to either end of the line of troughs—in modern terms to the positive and negative ends of the battery—and then connected the loose ends of the wires to each other. This was a closed electrical circuit, with the electricity running from the battery through the wire. The electricity was created by the chemical reaction between copper and zinc through the medium of the sulfuric and nitric acids. Simply put, electrons were flowing, making energy run through the wires. And there was so much of it that the wires themselves glowed with its heat.
Next, Ørsted suspended the conductive wire horizontally above the magnetized needle of a compass, in parallel with the needle. The closer the wire was to the needle, the farther west the needle pulled away from its usual north-facing position. If he put the conductive wire underneath the needle, the needle pulled east. No matter what type of conductive metal Ørsted tried for the wire, the compass needle moved. Even placing glass, metal, wood, water, resin, earthenware or stone—or combinations of these—between the wire and the needle did not prevent the needle from moving. This was indisputable proof: There was some sort of previously unrecognized physical connection between electricity and magnetism.
In all, Ørsted did sixty careful versions of the experiment. He was so concerned about how others would react to his findings that he conducted his work in front of eminent scientific witnesses who could vouch for his methodology. (“At this point does he know how important this experiment is?” I asked. “You bet!” said Jackson, nodding.) On July 21, 1820, Ørsted self-published his results in a sparely written four-page pamphlet—including the names and pedigrees of the witnesses—sent it by stagecoach to all the leading scientific lights and societies of Europe, and awaited the fallout.
The compass Ørsted used in the experiments is on display at the Danish Museum of Science and Technology in Elsinore, whose castle is famous for being the setting of Shakespeare’s play about Hamlet, the melancholy Danish prince. The museum is in an unheated industrial barn reminiscent of an airplane hangar. (“They do not have so much there, and what they do have is not displayed well,” Jackson had warned.) You get there by train and then bus, traveling north from Copenhagen through dark and forested northern European landscapes that bring to mind the gothic feel of “Little Red Riding Hood.”
The compass itself is an elegant brass affair, covered by a glass dome, nestled on a carefully curved, highly polished dark wood base. You can see how it would have looked impressive to a class of students or an admiring group of Danish scientists. A replica of the elaborate battery Ørsted created for the experiments stands nearby on its own imposing wooden table. Two rows of ten copper galvanic troughs stand on its black-covered surface, dusted with the white detritus of chemical reactions. Affixed to the front end on either side are wooden spindles attached by wires to the ends of the pile. The wires attach to another set of spindles on the table and, finally, to each other, suspended overtop a compass. It’s a huge and unwieldy apparatus, tucked into a drafty corner of the rather desultory museum.
Nearby, encased in a room made of glass, a display from Ørsted’s laboratory and home gives a peek into his life. A box of glass and metal materials the British physicist Michael Faraday gave to him. Rotating globes on high wooden stands. An elaborate candelabra he built and placed on his desk so he could work by candlelight. Photographs of his family. Shelves of his books, including two Bibles—one ancient, its brown leather creased with wear, and another, more stately in red and gold—along with his much-read copy of Sir Walter Scott’s The Lord of the Isles. A copy of the poem Hans Christian Andersen composed to commemorate Ørsted’s death.
Nestled in its own cubicle along one side of the display is a copy of the paper Ørsted published about his subversive findings. He wrote it in Latin, the formal language of science at that time, and entitled it Experimenta circa effectum conflictus Electrici in Acum magneticam (Experiments on the Effect of the Electric Conflict on the Magnetic Needle). Carefully typeset, in rather large print for the day, the paper looks magisterial.
It caused an immediate splash, Jackson told me, rustling around on his bookshelf for a copy of one of Ørsted’s works to give me. Triumphant, he pulled it off the shelf: a softbound, inch-thick volume, in both Danish and English, its glossy white cover adorned with the image of a middle-aged Ørsted, medals on his chest, hands folded over his stomach, looking prosperous and content. Called Theory of Force, it was his previously unpublished textbook in dynamical chemistry, unknown until a single proof from 1812 was discovered in an antiquarian bookstore in London in 1997. Jackson and Jelved tackled the translation a few years later and it came out in 2003. I had been planning to visit its publisher, the Royal Danish Academy of Sciences and Letters, at its neoclassical headquarters in downtown Copenhagen the next day to see if I could buy a copy. Jackson held it out, insistent: I must have this one.
The splash from Ørsted’s 1820 experiment and paper was not just immediate. It was revolutionary. The unforeseen, unimagined, and inexplicable finding was that the magnetic force appeared to be circular. Above the magnet, the conducting wire forced the needle to the west. Below, to the east. That implied that the force was moving in a circle. Before Ørsted’s experiment, the only forces that had been proven in science had worked in straight lines, explained Faraday’s biographer, L. Pearce Williams. It “threatened to upset the whole structure of Newtonian science.”
Within three months, Ampère had worked out a mathematical description, which still stands, of how electric currents give rise to magnetic fields, and then wrote to Faraday to ask him what he thought of it. (“Ampère was a very arrogant character,” Jackson said.) Faraday couldn’t read math and demurred.
Jackson told me that when grilled by a rather chauvinistic friend the following February about why it was a Dane who made the discovery rather than the French with all their magnetic history, expertise, and equipment, Ampère wrote back blaming Coulomb. Coulomb had assured them there couldn’t be a link and so, said Ampère, they didn’t look. (“Never believe received wisdom!” Jackson advised with a dramatic shrug.)
Within a few months, Ørsted’s paper had been translated and published from London to Paris to Geneva to Leipzig to Rome. Humphry Davy, the chemist who was president of the Royal Society in London, made sure Ørsted got the Copley Medal that year. Scientists all over the continent were reproducing Ørsted’s experiments and some were conducting public demonstrations to convince the skeptical. By 1822, Ørsted had commenced what Jackson called a “triumphal procession” through Europe, meeting with scientists and discussing his grand finding. The same year, his insistence that chemistry be its own branch of science bore fruit. He was allowed to set up a chemistry lab that was untethered to the medical faculty and establish the position of full-time chemistry professor, a Danish first.
On a black-topped table in his office, Jackson had laid out his own apparatus to show me the experiment that gave Ørsted his place in history. He had a small compass in a clear plastic casing that could double as a tiny ruler, red string knotted at the top on the chance that you might need to hang it from your belt loop. Next to it was an unadorned black plastic case with two simple metal terminals inside, a plus and a minus, containing an AA battery. A black-plastic-coated wire came out the negative end and a red-plastic-coated wire out the positive. The whole contrapti
on could easily fit in a trouser pocket. Jackson put the bare ends of each wire together—where they were stripped of their insulating colored plastic coatings—to make a circuit of electrical current and held them a few centimeters above the compass running in the same direction as the needle. The needle moved from due north to about 25 degrees northwest. No matter how often he connected the wires to make the current run, the needle still moved. The moving electrical charge was creating a magnetic field that the compass was responding to.
“That,” he said, “is Ørsted.”
No string of monumental copper troughs or glowing metal wires or diluted acids. Just a single everyday battery that today you can pick up at a corner store. And yet, as the science historian Gerald Holton put it, the finding “opened up physics itself to a succession of unifying theories and discoveries without which the modern state of our science would be unthinkable.”
It was Faraday who figured out the next piece of the puzzle: Not only does a moving electrical charge make a magnetic field, but a moving magnet creates an electrical field. It is the basis for every electric power generator in use today. Jackson was set up to show me the nuts and bolts of that seminal scientific moment too. He held a foot-long plastic tube parallel to his body and inserted a strong magnet in its top end. The magnet swiftly fell out the bottom into his hand, just as you would expect. Then he replaced the plastic tube with one made of aluminum and repeated the experiment. This time, the magnet passed through the tube far more slowly than you would expect.
“And that,” said Jackson, “is Faraday.”
What was happening? Jackson explained: As the magnet moved, it created an electric current in the metal tube. That current created its own magnetic field, the equivalent to that of a magnet facing the opposite way. The opposite magnetic poles were resisting each other, and that’s why it took the magnet longer to exit the tube.
But although Ørsted’s finding was immediately accepted, his understanding of why it was happening was roundly rejected. Ørsted’s Kantian interpretation, which he described as an electrical “conflict” between forces, made little sense to any of the eminent French and British researchers who tried to understand it. In fact, Ørsted seems to have had trouble describing what he meant and went back to the theme time and time again over the years, adding precious little more clarity. He spent three hours during a trip to Paris in 1823 trying to explain his ideas to Ampère and other French scientists. It was unsatisfactory. (“Ampère despised what he regarded as German speculative philosophy,” Jackson commented.) Ørsted remarked in a letter home to his wife that the French didn’t seem sympathetic to the idea of combining philosophy and science. In London, Faraday frankly admitted he didn’t understand Ørsted’s explanation, just as he had not understood Ampère’s math.
By the end of his life in 1851, Ørsted’s abiding faith in Kantian natural philosophy had fallen out of step with the science of the day. No longer did scientists so roundly hew to the Romantic fashion of seeing God’s design in nature. A more modernist and more empirical understanding was slowly emerging, paving the way for the findings of the late nineteenth and early twentieth centuries, including the discovery of atomic structure. Ørsted’s magnum opus, The Soul in Nature, a floridly written philosophical dialogue that he tried to have published in English in 1848, was repellent to the few British scientists who read it. The English naturalist Charles Darwin, who in the next decade published his theories of evolution and natural selection, said he found it “dreadful.” He spoke for all Britain. Ørsted, once at the forefront of scientific thought, was sidelined, most of his work spurned, if it was thought of at all.
CHAPTER 14
the bookbinder’s apprentice
The Royal Institution, where Michael Faraday lived and conducted his experiments, is in Mayfair, the upscale neighborhood of London that British aristocrats favor when they are in town, much of it owned by the Duke of Westminster, one of the wealthiest people in the world. To get there, you might take the short stroll from Buckingham Palace up through the narcissus-dotted expanses of Green Park, one of the royal parks, before ambling past the Ritz Hotel on Piccadilly. From there, you head up Albemarle Street, named after the famously dissipated duke who owned the mansion that stood on that patch of London until he sold it to developers in the late seventeenth century to square his debts. Once on Albemarle itself you go past the art galleries featuring plush antique Persian rugs, past the flagship store of the American fashion designer Alexander Wang and the discreet shop of the British designer Amanda Wakeley, who dresses the Duchess of Cambridge, and onward in front of the luxury jeweler Boodles until you arrive at number 21.
Michael Faraday first found his way there in the spring of 1812, just as Ørsted, over in Copenhagen, was preparing his ill-fated textbook on dynamical chemistry. Faraday was twenty and not at all part of the establishment that the area catered to. In fact, he was almost as far from an establishment figure as it was possible to be: a journeyman bookbinder with little formal education, destined by birth to be a tradesman. But he was fascinated by science and had taught himself some basics, primarily by reading books in the shop where he apprenticed as a binder. One of his most cherished was Conversations on Chemistry, by Jane Marcet. It was part of a series of illustrated introductory science books aimed at the popular audience, featuring conversations between the teacher, Mrs. B, and her two students, Emily and Caroline. This was not the scientific canon taught at universities.
The Royal Institution was a few years younger than Faraday was, set up in 1799 to put the “applied” into science for the sake of the expanding empire. There was agriculture to foster, mines and shipping to make safe with the latest scientific knowledge. As part of the impulse to democratize science and raise money, the institution put on lectures for the paying public. Faraday was there to hear one of them.
The lecturer was Humphry Davy, the Royal Institution’s star attraction. Not only was he an engaging speaker, but his good looks had garnered him a substantial following among London’s women, including Marcet, whose book on chemistry that Faraday so admired was based on Davy’s talks. Davy’s performances were so sought after that Albemarle was made into London’s first one-way street in a bid to cope with the heavy traffic his appearances spawned. But the spring lectures of 1812 were to be his final appearances. The son of a Cornish woodcarver, he had determinedly and very successfully worked his way up the social ladder. He had been knighted that year and had come into money by marrying the exceedingly wealthy Edinburgh widow Jane Apreece a few days after he could bestow the title “Lady” on her. He was set to retire from the rigors of the public stage.
Faraday had acquired tickets to Davy’s talks by chance, one of the most legendary bits of serendipity in the history of science. Tucked away behind a clock in the theater’s gallery, he drank in the ideas and made careful notes. In the months following, he wrote up detailed accounts of Davy’s lectures, adorned them with finely drawn illustrations, bound them, and, shortly before Christmas, got up the courage to send them to Davy. He had already served as Davy’s copyist assistant for a few days after Davy had injured his eyes in a laboratory explosion. On Christmas Eve, Davy, clearly chuffed, wrote back an appreciative note. By March 1813, one of Davy’s laboratory assistants had been sacked for being involved in a brawl and Faraday had taken his place at the Royal Institution, taking a pay cut from his journeyman’s job to do so. He spent the following decades altering the course of science. Davy, who chemically isolated a string of elements, including sodium, in his chemistry lab, and who was not known for self-effacement, nevertheless once quipped that his biggest discovery was Faraday.
Few know Faraday’s precise and brilliant trajectory through the scientific world better than Frank James, the Royal Institution’s head of collections and professor of the history of science. James landed a job at the Royal Institution almost straight out of his PhD program at Imperial College London. And despite the fact th
at only half of one chapter of his doctoral thesis was on Faraday, he told me with a self-deprecating bow of the head shortly after we met, he became the editor of Faraday’s 5,053 letters. It took twenty-five years and six door-stopping volumes to get through them all. Along the way James has produced many other books, essays, journal articles, and public lectures on Faraday and has pored over the bound notebooks Faraday made explaining the experiments he conducted throughout his working life. James has become so identified in the public mind with Faraday that a specially commissioned oil painting of him dressed in Victorian garb and sitting in Faraday’s original magnetic laboratory now hangs in the Faraday museum in the basement of the Royal Institution.
I had written to James, asking to meet with him so he could help me understand how Faraday helped put together the concepts of magnetism and electricity in the wake of Ørsted’s experiment. So, despite nursing a heavy cold that day, he was treating me to a morning latte at the institution’s luxe café while we chatted. The building, which has been designated a historical site partly because of the work Faraday did within its walls, went through a budget-draining renovation in the first decade of this millennium, and the café now overlooks a glittering glass-and-steel elevator that pumps up and down through the open-concept heart of the building. Above us was a ring of shining offices. Below, enticingly, was the archive with Faraday’s notebooks and the Faraday museum, whose refurbishment James oversaw. It includes the actual laboratory where Faraday did his magnetic experiments, which had been a servants’ hall until Faraday took over on the quiet in the 1820s.
The Spinning Magnet Page 12
