The Investigations and Inventions of Volta
Volta: Science and Culture in the Age of Enlightenment. Giuliano Pancaldi. xx + 381 pp. Princeton University Press, 2003. $35.
Many people today who use batteries, and the terms volt and voltage, without a second thought might be surprised to learn that it was Alessandro Volta (1745-1827), a self-taught citizen of a northern Italian province of the Austrian empire, who invented the voltaic battery in 1799. He did so while trying to reproduce the behavior of the torpedo fish, or electric ray (whose two electric organs above the pectoral fin on either side of the head give an electric shock), and thus he named his creation the artificial electrical organ.
Volta had an interesting life: At age 18 he refused to attend university and started a correspondence with two leading authorities on electricity, Giambattista Beccaria and Jean-Antoine Nollet, writing that he had a "genius" (passion) for electricity. He rapidly acquired legions of correspondents, and his enthusiastic membership in the cosmopolitan intellectual community of the day is testified to by thousands of pages (published in five thick volumes) and by innumerable journeys and visits to his colleagues and friends all over the Europe of the Enlightenment.
He wrote his first book (in Latin) in 1769, at the age of 24, and kept writing intensively and extensively during his whole life (his collected works amount to another eight volumes). But instruments, rather than theory, made him famous: He invented the electrophorus (a simple electrostatic generator with an insulating cake of resin and a metal plate, the first such device not based on continuous friction and rotation), the electrical pistol (a scientific device born from an attempt at building a new weapon: a glass container in the form of a pistol sealed with a tap, in which a spark fires a mixture of hydrogen and oxygen), the eudiometer (a device for measuring the oxygen content of air by mixing it with a known volume of hydrogen and igniting the mixture), and then the condenser (which makes even very faint electric charges detectable), the electrometer (for measuring electrical tension), the condenser-electrometer and, most famously of all, the battery.
Volta clarified the concept of electrical tension (or, in modern parlance, voltage); formulated the mathematical relation between quantity of charge, tension and capacity; introduced the concepts of contact "potential" and of electromotive force; and came very close to formulating quantitatively the relations between tension, resistance and current. He committed himself not only to electricity but also to meteorology, pneumatics and thermology. He identified methane, gave Antoine-Laurent Lavoisier and Pierre Simon de Laplace hints on what they interpreted as the synthesis of water, and determined the dependence of the density and pressure of steam on temperature and the coefficient of expansion of air.
Volta achieved almost-immediate and lasting institutional recognition. He was appointed physics teacher in Como in 1775, and university professor in experimental physics in 1778 at the old (founded in 1361) and famous Pavia University. There a new lecture theater was built for him by a major architect, and he was allowed (once) to spend "without limits" for the instruments of his physical cabinet. He received important international prizes. He was an active witness of important political events: the reforms of the enlightened Austrians, the French Revolution and the liberation-domination of Northern Italy (1796-1814), and the Austrian restoration.
Volta boldly committed himself to scientific debates and controversies (the long-lasting debate with Luigi Galvani over the nature of "animal electricity" is only the most famous) but also managed to enjoy life socially and emotionally, certainly encouraged by an attraction to women that was reciprocated. Before marrying a family acquaintance at age 50 (and having three children), he had, during the first years of his works on his theory of contact electricity, a "scandalous" relationship with an opera singer—at the time not the best match for a university professor. (The scandal largely consisted in his passionate request to the Austrian emperor for permission to marry, which was denied as a result of his own family's adverse lobbying.)
Volta's fame was such that a number of celebrations in the two centuries since the invention of the battery now have their own history. A "temple" built in Como in 1927, the reconstruction of his scientific cabinet in Pavia in 1999, and about 1,500 books and papers about him are testaments to a lasting interest in his work.
In this detailed and ambitious book, Volta's life and the fascinating and complicated patterns that led to the battery are beautifully described by Giuliano Pancaldi, a historian of science at the University of Bologna (the university of Luigi Galvani, Volta's competitor). Two basic narrative tensions can be discerned.
The first contrasts Volta's Catholic background and traditional education with his early and lasting adherence to the cosmopolitan Republic of Letters, a loose network of lay natural philosophers (later to be called "scientists") sharing the quantifying spirit of the Enlightenment and the related interest in useful knowledge. This tension is illustrated through iconology: A fresco painted in 1876 by Nicolò Barabino (a portion of which is reproduced in color on the cover of the book) shows Volta presenting his battery to a large group of timeless natural philosophers (from Christopher Columbus to Joseph Michel Montgolfier). The battery is close to other technological tools. The scene is illuminated by a young woman (Science) at whose feet a dark figure (Obscurantism) lies defeated. It is this "light" of the Enlightenment that, according to Pancaldi, allows the young Volta to abandon the Aristotelian teachings of the Jesuits and the role models of his family, who were part of the relatively wealthy minor nobility and deeply committed to the Catholic Church. Despite the fact that most of his closest relatives belonged to various religious orders (one brother was a Dominican and a local representative of the Inquisition), Volta shows in a juvenile poem his interest in a materialistic natural philosophy, an interest that expanded through a huge correspondence with a great number of European and Italian researchers and through numerous travels in various European countries.
Pancaldi studied 74 Italian scholars in the age of Volta (most born between 1715 and 1765) and found that despite the wide circulation of Enlightenment literature and some vigorous reforms, the persistence of a courtly mentality slowed down the improvement of higher education and scientific research in the Italian states. More important for Volta was the European connection: Among many others, he met Joseph Priestley, Jean-Hyacinthe Magellan, Joseph Banks, Jean Senebier, Benjamin Franklin, Horace Bénédict de Saussure, Martinus van Marum, Georg Christoph Lichtenberg and Giuseppe Luigi Lagrange. The relevant countries were Britain, Switzerland, Holland, the German states and France, the relevant capitals London and Paris. In Paris, Volta had difficult relations with Pierre Simon de Laplace, Lavoisier and, later, Charles Augustin Coulomb. However, his instruments enjoyed wide acceptance everywhere. Volta had a continuous and reciprocated predilection for the Royal Society of London: In 1794 he became the first foreigner to receive the Copley medal, for his contact theory, and in 1800 he announced his discovery of the battery to the Society.
The success of the battery was enormous, despite differing interpretations in different research schools. Volta, who traveled without serious problems from the Enlightened Austrian regime to the Enlightened French (1796) and later (1814) back again to a much less enlightened Austrian regime, received in 1801 a gold medal and a pension from Napoleon.
Volta's role as hero in the industrial era prompts Pancaldi to criticize the use of past science to serve local interests, local pride and local ambitions, as occurred when two residents of Como, a fascist and a silk industrialist, organized the 1927 celebrations there, using Volta to call attention to the town. One of the events was an international congress of 61 physicists, which permitted 12 Nobel Prize winners, plus three winners-to-be, to listen to Niels Bohr's first enunciation of the complementarity principle—but only after four full days of their meeting had been devoted to themes linked with the heritage of Volta's work and classical physics, rather than the hot issues of the day.
The second narrative tension that runs through the book is between theory and experiment, or rather instrument, in Volta's exceptionally productive career. This is illustrated with an anonymous painting made after 1805, which represents Volta with one of his books close to his heart and a couple of his inventions standing a bit farther away, closer to the viewer. For Pancaldi, this setting is an indication of Volta's lasting but unsuccessful desire to be considered a theoretician, while his instruments, standing by themselves, independent of the theory that led to their existence, are closer to the public who gave them widespread and admiring acceptance.
Pancaldi tells us in detail the intriguing and difficult stories of the births of the electrophorus, the condenser, the electrometer and the battery. He believes that
Volta's best qualities as an investigator were the result of adjustment between his aspirations as a natural philosopher and the more modest role of inventor of intriguing machines that sections of the community of electricians came to assign him.
That is, Volta's early microscopic theories of 1769 had to be modified into successful midrange concepts: tension, capacity and "actuation" ("a special version of the notion of electrical atmospheres . . . in some way corresponding to the concept of electrical induction"). In turn,
The battery was . . . the result of an investigative process in which Volta's contact theory interacted with a variety of other factors. . . . In that process, there was no single or privileged path leading Volta from the contact theory (the core of his natural philosophy in the late 1790s) to the battery.
Pancaldi does not aim at a general and complete scientific biography of Volta. Only some of his inventions are discussed (not the eudiometer or the electrical pistol), and almost no room is dedicated to Volta's nonelectrical studies. Pancaldi does not seem to believe in a stable research program that would explain the exceptional fertility of Volta's multidisciplinary researches, which were largely based on analogies. But at the same time Pancaldi's contextual analysis does not take into full account either the reforms that shaped Pavia University at Volta's time and granted him a chair, or the relations with his colleagues in Pavia. Nor does Pancaldi deal with Volta's scientific inheritance (for example, the theory of the electrophorus and the battery acquired a relevant place in the works of two pioneers of energy conservation: Julius Robert von Mayer and Hermann von Helmholtz, respectively) and philosophical influence (on Naturphilosophie, for instance). In his history of Volta's "heroic" role in the 19th and 20th centuries, Pancaldi does not mention the national attempt to save Volta's manuscripts, the rescuing of his instruments after a fire in the exposition hall in Como where they were on display in 1899, the publication of the national edition of his collected works, or the building in Como of the amazing "Voltaic Temple."
But no book on Volta can be complete, and the one Pancaldi has written, the first biography in English, is excellent. Every chapter has an interesting and original thesis, shows detailed and painstaking knowledge of manuscripts and adds to our knowledge of Volta and his time. Pancaldi is at his best when he tells the story of the battery and when he adds to the historiography of science in the age of Enlightenment his vision of diversity and contingency. That vision is a good antidote to the "normative" view of critics and supporters of the Enlightenment, who both see the enterprise of science and technology at that time as having been "strictly rational, ordered, and purposeful" but who differ in their evaluation of that enterprise: For the supporters, it is "a model to be imitated in all other human endeavors," whereas for the critics it is a deceitful attempt "to repress diversity and control society."
Fabio Bevilacqua is professor of the history of science at the University of Pavia in Italy. Recently he has coedited a number of digital and printed publications about Volta's primary and secondary sources.
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