Alessandro Volta and the Invention of the Voltaic Pile

Introduction: Early History of Electricity

Some evidence suggests the use of primitive batteries in Iraq and Egypt as far back as 200 BC for electroplating and precious metal gilding (Rubin, 2011). Extant records suggest that magnetism and electricity first stirred curiosity around 600 BC, one early observer being the Greek philosopher Thales of Miletus (HBCI, 2010). He observed that when amber was rubbed, it would attract light objects, and he already knew that lodestone could attract iron. The terms "electricity" and "magnetism" were, in fact, drawn from the Greek language — "electricity" from the word for amber, and "magnet" from Magnesia, a place where lodestone could be found. Thales associated the concepts of these two phenomena at that time, and he and other early thinkers believed that magnets were "living rocks" with souls (Rubin, 2011; HBCI, 2010).

Benjamin Franklin's remarkable invention, the condenser — which he called a "battery" — was the evolutionary link between the brief sparks he observed emanating from the Leyden jar and the voltaic cell (HBCI, 2010). He posited the existence of a basic charge, an assumption that developed directly into the concept of electrons moving through conductors. He organized and unified scattered existing knowledge to form a foundation for subsequent advances. In 1749, he suggested the equivalence of lightning and electricity and reported this concept a year later to Peter Collinson of the Royal Society. Three years after that, in 1752, Franklin conducted his legendary kite experiment, eventually connecting his work with Volta's major and lasting contribution to science. The discovery of electricity captivated people of the eighteenth century; his kite experiment drew electricity from lightning and inspired widespread fascination (Corrosion Doctors, 2011).

Leyden jars were invented in 1746 and were used to store, charge, and produce electricity. Physicians soon took advantage of this capability, using electric shocks to treat illnesses. A need for continuous electrical current soon arose, however, and this became available only with the invention of the first electric pile by Alessandro Volta. That pile became the forerunner of the modern battery (Corrosion Doctors, 2011).

Life and Background of Alessandro Volta

Alessandro Giuseppe Antonio Anastasio Volta was born on February 18, 1745, in the town of Como in Lombardy, Italy (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011). Although part of the aristocracy, his family was not considered wealthy. His father died when Volta was only seven, leaving him and his education in the care of church-going relatives who logically aimed at an ecclesiastical career for him. Yet he took a different path, developing a passion for science. From his teenage years, he communicated his scientific ideas to French physicist Jean-Antoine Nollet and to well-known Italian men of science. His interest was clearly electricity. His first published treatise, entitled De vi attractive ignis electrici, appeared in 1769. Another work was published two years later on a new type of electrostatic generator he had created. These early works gained him recognition and an academic teaching appointment at the Liceo of Como in 1774.

The following year, Volta described another invention — the perpetual electrophorus — in a letter to Joseph Priestley. The principle of electrostatic induction was already known at the time, but Volta's electrophorus was the first practical instrument for translating mechanical work into electrostatic charge without the need for constant rubbing. The invention was quickly adopted by laboratories across Europe and brought Volta considerable renown (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011).

Volta was also interested in gases and conducted research in that field (CIRL, 2011). His curiosity was ignited during a visit to Lake Maggiore in 1776, when he observed water bubbles rising as he stirred the mud beneath the surface. He collected some of the gas produced by the bubbles and studied it in his laboratory. That gas became known as methane, the main component of marsh gas. Volta found that it was highly flammable, a discovery that led to another novel apparatus: the pistol, a predecessor of the internal combustion engine. He found that it could produce a controlled explosion in a closed environment and used it to measure the force of gaseous explosions and the amount of oxygen in combustible air samples. The device eventually developed into the eudiometer (CIRL, 2011).

Volta accepted an offer to teach natural philosophy at the University of Pavia in 1779 (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011). At the University of Bologna at roughly the same time, another renowned Italian scientist, Luigi Galvani, was also experimenting with electricity. Galvani worked with dissected frogs and noticed that the dismembered legs of the frogs were animated by certain stimuli — specifically, an electrical storm and the touch of a steel scalpel against a brass hook from which the legs were hanging. He concluded that electricity is naturally present in the tissues of frogs and other animals, and he published these observations on animal electricity in 1791. Some scientists accepted his findings while others rejected them. Volta was among his most prominent opponents, conducting his own experiments to find an alternative explanation for Galvani's results (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011).

At first, Volta accepted Galvani's theory concerning animal electricity as demonstrated by the involuntary movements of Galvani's frogs (Scratch, 2011). But repeated test results pointed elsewhere. Volta discovered that the contractions of the frogs' legs were not caused by something originating within their bodies but by an external electricity — produced by two different metals forming an arc while in contact with the moist tissue of the frogs. He came to see the frogs as functioning merely as a simple and sensitive electroscope. In addition to repeating Galvani's experiments, Volta noticed other effects involving dissimilar metals in contact with moist substances: when two different metals touched the tongue and were then brought into contact with each other, a bitter taste resulted; when two metals touched the eye and were brought into contact, a sensation of light was created. After conducting all these experiments, Volta became convinced that the metals not only served as conductors but also generated electricity when they came into contact with each other (Scratch, 2011).

The Galvani–Volta Dispute and the 1800 Scenario

The year 1800 was a time of notable social, political, and scientific developments (HBCI, 2010). Experiments in electrical science had been few and limited in scope until Galvani and Volta entered the field. As with many scientific discoveries, Galvani's original finding arose largely by accident. His claim about animal electricity provoked sharp criticism, and both sides engaged in heated debate, each accusing the other of error. By the time Volta's argument ultimately prevailed, Galvani could no longer benefit from the resolution — he had died in 1798. It was in that same period that electricity was poised to break new ground. Volta invented his pile, which would become one of the most significant scientific discoveries of the era and earn him widespread recognition and distinction (HBCI, 2010).

Although his invention brought him considerable honor and fame, Volta preferred to live quietly (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011). He gradually withdrew from most of his research and teaching, spending his final years in a country house. He died on March 5, 1827, at the age of 82. His portrait has appeared on currency and postage stamps, and his contribution to science was immortalized when his name was assigned to the volt, the unit of electromotive force (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011).

Conclusion: Volta's Lasting Legacy

From Volta's first and crude battery evolved electrochemistry, electromagnetism, and the modern applications of electricity (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011). Even the ultimately disproven principles of Galvani on animal electricity served as the catalyst for the development of electrophysiology and modern biology. From Volta's name came the unit of electromotive force — the volt — while from Galvani's name was coined the term galvanometer, the instrument used for detecting and measuring small electric currents. Together, their rivalry and complementary discoveries left an indelible mark on science and technology that endures to the present day (CIRL, 2011; Rubin, 2011; Scratch, 2011; Corrosion Doctors, 2011).