Selected Scientific Works of Hans Christian Ørsted
(The book includes, for example, Ørsted's account of his r...)
The book includes, for example, Ørsted's account of his revolutionary experiments in electromagnetism. In 1820, he discovered that a compass needle deflects from the magnetic north when an electric current is switched on or off in a nearby wire. This showed that electricity and magnetism were related phenomena, a finding that laid the foundation for the theory of electromagnetism and for research that later created such technologies as radio, television, and fiber optics. The unit of magnetic field strength was named the Ørsted in his honor.
Selections here also show the extraordinary breadth of Ørsted's interests, which range through a long and prolific career from the study of plant alkaloids and the compression of fluids to the nature of light and the "natural science" of beauty. The writings are taken from scientific papers, Ørsted's correspondence, and reports of the Royal Danish Academy of Sciences and Letters. The book will not only draw long overdue attention to Ørsted's own work but will also shed new light on the nature of the scientific study in the nineteenth century.
Hans Christian Ørsted, Ørsted also spelled Oersted, was a Danish physicist and chemist. He discovered that electric current in a wire can deflect a magnetized compass needle, a phenomenon the importance of which was rapidly recognized and which inspired the development of electromagnetic theory.
Background
Hans Christian Ørsted was born on August 14, 1777, in Rudkøbing, Denmark on the island of Langeland. He was the elder son of an apothecary, Søren Christian Ørsted, and his wife, the former Karen Hermansen. The demands of his father’s business and his mother’s superintendence of a large family forced his parents to place Hans Christian and his younger brother, Anders Sandøe, with a German wigmaker and his wife while they were still young boys. Anders would later become Denmark’s Prime Minister. At age 12, Oersted started helping in his father’s pharmacy and became interested in chemistry.
Education
Hans Christian Ørsted received his education from some friendly townspeople, but what was lacking in the way of competent teachers was amply supplemented by Oersted's extraordinary thirst for knowledge. He and his younger brother Anders were educated through a combination of homeschooling and private tutors – a German wigmaker taught the brothers to speak fluent German. In 1793, he went to Copenhagen and matriculated in science at the university in the fall of that year. The completion of his training in pharmacy came in 1796. Two years later he received his doctorate for a dissertation in which a new and competent theory of alkalies was proposed.
Hans Christian Ørsted began his teaching career at the University of Copenhagen as a lecturer in pharmacy. In 1801 he went abroad and sought out some of the best philosophic and scientific minds in Germany, the Netherlands, and France, where he spent the winter of 1802/1803. One of the things he immediately realized was the excitement created everywhere by Alessandro Volta's development of the electric battery 2 years earlier. Ørsted's attention to this advance was evidence of his ambition to occupy eventually the chair of physics at his university. In 1803 his application was rejected. Clearly he was more of a chemist or pharmacist than a physicist. But he kept experimenting and publishing, not only in chemistry but also in physics. His ingenious analysis of Chladni's acoustic figures finally secured for him the position of professor extraordinarius (associate) of physics in 1806.
Three years later Ørsted published the first volume, dealing with mechanics, of a longer work planned to cover all areas of natural philosophy (physics). During 1812 and 1813 Ørsted visited Germany and France. While in Berlin he published in German his Views of the Chemical Laws of Nature Obtained through the More Recent Discoveries. It came out the next year in French translation under the revealing title Researches on the Identity of Chemical and Electrical Forces. Ørsted spoke in his Researches about the identity of magnetism and electricity with such assurance that he seemed predisposed to be the discoverer of electromagnetism. In the eighth chapter, he noted the close analogies between the properties of magnetic and electric fields, their equally universal presence in nature, and certain reciprocal actions between them such as the loss of magnetism in steel due to rise in temperature and the simultaneous increase of the metal's electrical conductivity. Ørsted was also aware of the fact that lightning often resulted in the magnetization of pieces of iron, even to the point of altering the polarity of compass needles.
Ørsted spent years in search of an elusive goal as he systematically vitiated his work by expecting the magnetic effect to be in the direction of the flow of the current. During those years of search, Ørsted blossomed into a most sought-after lecturer both within and outside the university. In recognition of his consummate versatility in scientific matters, he was appointed the leader of a geological survey party charged with the exploration of the island of Bornholm.
In the spring of 1820, Ørsted was giving a series of lectures on the interaction between electricity and magnetism before an advanced group of students. The responsiveness of the audience proved to be stimulating, and he was prompted to demonstrate the experimental evidence in support of one of his conjectures. It concerned the possible action of electric discharge on a magnetic needle placed near the circuit. As he expected a discharge through incandescence to be most effective, he inserted in the circuit a very thin platinum wire right above the magnetic compass. He resumed the experiments in July, carefully repeating all the steps in the presence of a group of colleagues and students.
On July 21, 1820, Ørsted dispatched to scientists, universities, and learned societies throughout Europe the account of his findings in a four-page essay written in Latin, Experimenta circa effectum conflictus electrici in acum magneticam (Experiments about the Effects of an Electrical Conflict [Current] on the Magnetic Needle). In the essay, Ørsted noted the dependence of the extent of the needle's motion on the strength of the battery, on the direction of the current in the wire, and on the needle's position with respect to the wire. He found that no effect was noticeable when the wire was perpendicular to the plane of the magnetic meridian. From the dip of the needle, he concluded that the magnetic effect existed in closed circles and not in spirals around the wire. He also found that neither metal plates nor wood nor stoneware would, when interposed between the wire and the needle, screen the effect.
In his account of his discovery given in 1821, Ørsted merely cared to correct the belief that the magnetic needle was in its actual position accidentally. It was only 10 years after the event that he emphasized, in the third person, in an article prepared for the Edinburgh Encyclopedia that "In composing the lecture, in which he was to treat of the analogy between magnetism and electricity, he conjectured, that if it were possible to produce any magnetical effect by electricity, this could not be in the direction of the current, since this had been so often tried in vain, but that it must be produced by a lateral action." In the same article Ørsted also expressed his surprise over the fact that he failed to resume his experiments for 3 months and that those present were not impressed at all as the needle made the historic movement. One of the witnesses later claimed it was by chance that the compass needle was almost under the wire in the desired position.
Ørsted was 43 when he made his great discovery. For the rest of his life, he held the position of a leader in science. He had a major role in the establishment of the Royal Polytechnic Institute in 1829, of which he became the first director.
The impact of Ørsted's discovery on the scientific world was enormous. According to Ørsted's own count, more than a hundred scientists published their comments and researches on electromagnetism during the first 7 years following its discovery. He was showered with honors and awards. The Royal Society of London gave him the Copley Medal, and the French Academy awarded him a prize of 3, 000 gold francs. But his greatest satisfaction was undoubtedly the spectacular growth of a new branch of physics, electromagnetism, which was to have a revolutionary impact on modern culture.
Formally Protestant, Hans Christian Ørsted was one of the important Agnostic thinkers highly influenced by Kant.
Politics
Hans Christian Ørsted wasn't known to be directly involved in politics despite belonging to politically active circles and being a brother of the Danish Prime Minister.
Views
There is a unity in Hans Christian Ørsted’s scientific work that is rarely found in the results of someone whose researches ranged from the forces of chemical affinity, electromagnetism, and the compressibility of fluids and gases to the new phenomenon of diamagnetism. This unity was drawn from Ørsted’s philosophy, inspired by his reading of Kant. Most Kantian scholars today would insist that Ørsted totally misread Kant and came to conclusions to which Kant would have objected. That charge is probably correct; but what is important is that Ørsted, and a number of other philosophers and scientists of the time, misread Kant in the same way. Basically, what Ørsted thought Kant was saying was that science was not merely the discovery of Nature; that is, the scientist did not just record empirical facts and sum them up in mathematical formulas. Rather, the human mind imposed patterns upon perceptions; and the patterns were scientific laws. That those patterns were not arbitrary was guaranteed by the existence of Reason. Human reason corresponded to the Divine Reason, for man was made in the image of God. And, inasmuch as God had created Nature, it too shared in the Divine Reason. Thus human reason, unaided, could construct the laws of nature by virtue of its congruence with the Divine Reason.
Ørsted’s reading of Kant led him to more than an attitude toward nature. It also gave him what he felt was a firm metaphysical foundation for his beliefs. In a now neglected treatise, Metaphysische Anfangsgründe der Naturwissenschaft (1786), Kant had abandoned some of his agnosticism expressed in the antinomies in the Critique of Pure Reason. More particularly, whereas in the Critique he had argued that it was impossible for reason to decide between an atomistic or a plenist concept of matter, in the Metaphysische Anfangsgründe he came down on the side of the antiatomists. He argued that we experience only force; that force manifests itself in the matter as the force of attraction that defines the limits of a body and the force of repulsion that gives a body the property of impenetrability. These two forces Kant called Grundkräfte (basic forces). Other forces, such as electricity, magnetism, heat, and light, he hinted, were merely modifications of the Grundkräfte under different conditions.
Ørsted read both the Critique of Pure Reason and the Metaphysische Anfangsgründe while still at the university. His doctoral dissertation is a defense of the Metaphysische Anfangsgründe and an attempt to have it accepted in Denmark as a basic philosophical treatise. As early as 1800 it is possible to discern the two elements that were fundamental in Ørsted’s later scientific work: the clear enunciation of the doctrine of forces and the disbelief in atoms. The first was to lead him, through the convertibility of forces, to the discovery of electromagnetism; the second seems to have been the stimulus behind his work on compressibility, for if solid, incompressible atoms existed, there ought to come a point when further compression of a gas or fluid was impossible.
In 1800, however, Ørsted’s ideas were only half-formed. He was far more au courant in philosophy than he was in science. This is why his journey to Germany and France was so crucial. It acquainted him with men who were at the frontiers of science and forced him to bring his philosophical speculations down to earth.
The reentry was a difficult one. The “new” chemistry of Lavoisier and the other French chemists left him unmoved because it turned its back on the very questions, such as elective affinity and the true nature of acids and bases, that fascinated Ørsted. Winterl’s system, on the other hand, was just what he was looking for. Instead of some thirty-odd elements, defined only empirically as the last products of laboratory analysis, Winterl offered two fundamental and opposed substances. Andronia and Thelycke could be viewed as materializations of the Grundkräfte and chemistry could then, it was hoped, be seen as a Kantian science. Similarly, Ritter’s work in electro-chemistry appeared to Ørsted as the development of Kantian thought and all of a piece with his own philosophy of forces. It was only when his philosophical theories and the empirical facts refused to fit together in repeatable experiments that Ørsted’s critical faculties were awakened. It is significant that, at this point, he did not reject his philosophical faith. Instead, he rejected the physical systems of Winterl and Ritter. His first real scientific achievement was to create his own system, based upon his own experiments. The results appeared in German in 1812 and in a French translation in 1813. The title of the latter, Recherches sur l’identité des forces chimiques et électriques, indicates its purpose. From the Grundkräfte, Ørsted hoped to deduce a system of chemistry that would be in accordance with the results of the experiment.
According to Ørsted, the Kantian Grundkräfte of attraction and repulsion manifest themselves in chemistry as combustibles and combusters. These forces are in conflict and when allowed, in combustion, to come to grips with one another, so to speak, produce the light and heat that are so preeminently the effects of combustion. But these two forces do not annihilate one another chemically; instead, they produce a higher synthesis - the acids and bases. Acidity and basicity, in turn, are opposites which unite to form the neutral salts. The supposedly Hegelian triad of thesis-antithesis-synthesis is here clear and is a standard aspect of Naturphilosophie. Although this analysis of fundamental chemical processes did provide a conceptual unity where before there was chaos, it left little impression upon Ørsted’s colleagues. Nor did his final chapters, in which he examined the convertibility of other forces. By 1813 everyone admitted the chemical role of electricity, but Ørsted’s treatment of it seemed to be of little help. What is of interest, at least to historians of science, is his discussion of the possibility of the conversion of electricity into magnetism.
For Ørsted the situation was quite different. The Kantian doctrine of Grundkräfte led directly to the idea of conversion of forces. All that was necessary was to discover the conditions under which such conversions took place. The particular conditions for the conversion of electricity into magnetism were deduced by Ørsted from the nature of electricity. Electricity to him was a conflict of the positive and negative aspects of magnetism, which conflict spread out in wave fashion in space. When the electric conflict was confined in a rather narrow-gauge wire, the result was heat. When the conflict was restricted still further by decreasing the diameter of the wire, the light was produced. So, Ørsted suggested in his treatise on the identity of chemical and electrical forces, the magnetic force should be produced when the electrical conflict is still further confined in a very narrow-gauge wire. In 1813, therefore, he had already predicted the existence of the electromagnetic effect. He was wrong, of course, on the conditions; and this error, together with his increasing teaching duties in the years that followed, prevented him from bringing his prediction to reality. The actual discovery was made in the early spring of 1820 and may best be given in Ørsted’s own words.
Ørsted’s second major area of research involved the compressibility of gases and fluids. It may be, as his biographer Kirstine Meyer implies, that he became interested in this problem by noting inconsistencies in the experiments of previous investigators. There may also, however, be a matter of theoretical importance involved. In all his experiments on compressibility, especially the compressibility of fluids, Ørsted was intent upon proving that the reduction in volume was proportional to the pressure. If this were so, then the law of compressibility would provide a smooth pv curve. The existence of incompressible atoms, occupying space, would force a discontinuity in this curve if and when the point could be reached when the atoms were packed tightly together. Ørsted’s system of forces permitted continual compression, and it seems plausible that his experiments on compressibility were intended to test the atomic hypothesis. The results were inconclusive, but his apparatus and critical acumen in detecting sources of error were of basic importance for later investigations of compressibility.
Ørsted’s last scientific researches were on the phenomena of diamagnetism. He tried to account for diamagnetic substances by assuming reverse polarity and reverse inductive effects in substances that were repelled from, rather than attracted to, a magnetic pole. This work, in the late 1840s, was made obsolete by Faraday’s investigations, which showed that the concept of polarity could not be applied to diamagnetics.
In his last years, Ørsted returned to his first love, philosophy. In a series of articles, published together in The Soul in Nature, he considered the relation between beauty and science. He still saw the hand of God in both. Beauty in art and music was the Divine Reason manifested in the harmonies of sight and sound.
Quotations:
"The agreement of this law with nature will be better seen by the repetition of experiments than by a long explanation."
Membership
Hans Christian Ørsted was a member of the Royal Society, the Royal Swedish Academy of Sciences, the Bavarian Academy of Sciences and Humanities, the American Academy of Arts and Sciences, the Royal Prussian Academy of Sciences (now Berlin-Brandenburg Academy of Sciences), the Royal Society of Edinburgh, the Accademia Nazionale delle Scienze detta dei XL, the Royal Danish Academy of Sciences and Letters.
Royal Society
,
United Kingdom
Royal Swedish Academy of Sciences
,
Sweden
Bavarian Academy of Sciences and Humanities
,
Germany
American Academy of Arts and Sciences
,
United States
Now Berlin-Brandenburg Academy of Sciences
Royal Prussian Academy of Sciences
,
Germany
Royal Society of Edinburgh
,
United Kingdom
Accademia Nazionale delle Scienze detta dei XL
,
Italy
Royal Danish Academy of Sciences and Letters
,
Denmark
Personality
Ørsted had a kindly and sympathetic personality. He had a successful marriage and a large family. In 1819 he befriended a poor fourteen-year-old boy who over the years became virtually another member of the Ørsted family. The boy, Hans Christian Andersen, was to become the great Danish storyteller. Andersen often referred to himself as "little Hans Christian" and to Ørsted as "great Hans Christian."
Interests
music
Philosophers & Thinkers
Immanuel Kant
Writers
Johann Wolfgang Goethe, Victor Hugo, Walter Scott
Artists
Christoffer Wilhelm Eckersberg
Music & Bands
Ludwig van Beethoven
Connections
Ørsted married Inger Birgitte Ballum, the daughter of a pastor, and in the following years, the couple had three sons and four daughters: Karen, Niels Christian, Anna Dorthea Marie, Sophie Wilhelmine, Mathilde Elisabeth, Anders Sandø, and Albert Nicolay.
