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 Napoleon, who understood Voltas contributions, was frustrated by the greater honors given Voltaire. He was reported by Victor Hugo to personally have modified a memorial to Voltaire at the library of the National Institute at Paris which read Au Grand Voltaire to Au Grand Volta.


2000 AD - Two Hundredth Anniversary of Voltas Invention
His was a lifelong dedication to better understanding of electrical science

by Donald Georgi


Two centuries have passed since Volta wrote his historic letter on March 20th, 1800 to Sir Joseph Banks, President of the Royal Society of London, describing two forms of an electric battery. But in popular sources of today, his discovery of the principles leading to the battery is an almost forgotten event. In listening to others explain Galvanic effects, one again might be mislead to forget Volta, and in perusing the popular press, todays teenager might infer that the first battery was a Lithium-ion cell invented in Japan.

 In 1801, in audience with Napoleon as first consul, (above) Volta demonstrated his column-shaped piles. Napoleon recognized the contributions, made him an associate member of the Institut de France and raised Volta to a Count and Senator of the Kingdom of Italy. Volta, representing Como, first met Napoleon in paying tribute to the conqueror in Milan in May 1796. In later years when Volta wanted to retire, Napoleon refused his request, stating that a soldier should die on the field of honor.

Why then is this Italian, his life, his times and his contributions so hidden that we may almost be unaware that the unit of one of the most fundamental electrical parameters, electrical potential, has been named the Volt in honor of his battery invention?
Without being able to answer todays oversight of Volta, we can look at the details of his life and see that his early decision to choose science put him in the right place. With his disciplined hands-on enjoyment of investigations and experiments along with a critical eye to rigor, reason, connectivity and repeatability, he was gifted with the innate tools to unearth the battery. So intent was Volta to understand the principles of electricity, that he used his own body as a sensory instrument to formulate more intricate descriptions of what he was observing. With only the electrometer to characterize his experimentation combined with the added experiences he sensed from stimulating his sense of touch, taste, vision and hearing, he was able to connect observations to build an understanding of principles. He was on unknown ground when he performed such measurements, which could have been dangerous. Had he chosen too high a potential when passing current between his ears or eyes, he could have instantly ended his career as the professor of experimental physics at Pavias University.

On the surface, one might think that discovering the principles to create a battery was an end in itself, but by bringing it to the attention of the scientific world, Volta also provided the first continuous current source, which would be the foundations for communications, lighting, medical therapies and electromechanical power.

In reviewing the understanding of electricity in Voltas time, one would find only concepts of magnetism and static electricity. The Chinese are thought to have discovered magnetism by 300 AD., but observations of magnetism and static electricity produced by friction on amber did not reach any scientific level until Dr. William Gilbert (1540-1603) experimentally separated the amber effect from magnetism, establishing electricity as a science. He proposed that the earths magnetic field emanated from the earth, acting as a giant lodestone. In 1603 Dr. Gilbert , a court physician to Queen Elizabeth, published a book entitled On the Magnet, which established truths through experimentation - a fundamental building block upon which Volta would build his lifes work. Gilbert also identified electrical attraction, which differed from magnetic attraction, and invented an electroscope named the versorium ( a pivoted needle) to be able to demonstrate the presence of charge. Small electroscope improvements were made which encompassed light insulator balls suspended by silk threads that separated in the presence of an electrical charge.

 

Volta ceaselessly created variations on the electroscope which became important tools in analyzing Galvanis muscle-nerve conduction phenomenon which lead to Voltas battery. Above, one of his measuring devices is a condensator with a moving armature. As a laboratory instrument, it allowed quantitative investigation of distance and charge upon electromotive force.


In 1660 Otto von Guericke constructed the first electrical machine, which generated electricity by the friction of a sulphur globe and demonstrated electrical attraction and sparks.

Experimenters soon found that the electrical charge could be transported by a thread, and in the mid- 1700s, E.G. von Kleist invented the Leyden jar, the first capacitor that would store the charge generated by friction either by hand or by machine. Ben Franklin was to further electrical thinking by proposing a single electrical fluid rather than two (plus and minus) fluids. He became a fellow of the Royal Society in 1756. He is attributed with being the first to use the term electric battery to describe a collection of Leyden jars connected in series. Thus, Volta, in describing the results of his experiments, used the then known term electric battery which meant a string of capacitors. However, he extended the terminology to his newly discovered electrochemical batteries to have an inexhaustible charge.

When Alessandro arrived into the world on February 18th, 1745, electrical knowledge was primitive, tools were equally sparse, and his early life was not easy. At age four he was not able to speak, and his father died when he was 7. Raised by his mother and uncle, he fended off family attempts to push him into a life in the church and as an attorney. After seminary school at 18, Volta obeyed his genius to study electricity independently.

At this juncture he had three innate gifts which would carry him though to a monumental life of scientific contributions. First, he had an insatiable curiosity to understand the reasons behind phenomenon. The second gift was his ability to develop a scientific approach founded on the contributions of Gilbert, and third, he had a surprising talent for communicating with people everywhere in the scientific world of the time. When beginning his work, he first wrote letters to Nollet and Beccaria, the electrical authorities of the times, but Beccaria chastised his frivolity and recommended further readings and doing experiments. By age 20, Volta had experimental results and was able to dialogue with the experts and wrestle with the concepts on how they could be applied to his initial observations and data.

By 1769 he published his first work on electrical attraction. During this period, he was to formulate a concept based on observation, which would be instrumental in his quest for the later understanding of Galvanis work and lead to his discovery of the battery. His published concept stated that only mixed bodies are electric. With growing recognition, he was appointed regent of the State Gymnasium in Como in 1774.

His investigations with static electricity led to his 1775 invention of the electrophorus, an insulating disk which could be charged in order to capacitively charge a second conducting disk. Thinking he had invented a perpetual motion machine, he informed Joseph Priestly in 1775 of his elettroforo propetuo. Unfortunately, it was not a perpetual motion machine because it required that work be done to pull the charged disk from the alternately charged insulator. The novelty of the electrophorus was the repeated charging of the removed disk without having to first recharge the base insulating disk. The device was worth much argumentative dialog and added immensely to Voltas renown, which in 1775 garnered him the professorship of experimental physics at the Gymnasium without the usual examinations.

Diverting his focus temporarily, Volta observed methane in swamps and described ways to use the gas for lanterns and an electric pistol. There was some connectivity to his electrostatic work because an electric spark could be used to ignite the pistol gas.


   
   

Volta continued to gain recognition with his communications skills. This recognition afforded him a trip to Switzerland and Alsac in 1777. Soon afterward, he was appointed to the professorship of physics at the University of Pavia.

Although lesser scientists belittled Voltas mathematical skills, he properly interpreted his experimental results to mathematically define fundamentals which included describing the relationship of charge with Voltage and capacitance (Q = CT, where T is the tension of the charge as measured with an electrometer). He understood the need for universally accepted guidelines and recommended a standard for the fundamental unit of tension (Voltage) using a standard, charged metal disk on a balance at a standard distance above a conducting surface which is then counterbalanced by a standard weight. The unit is equal to about 13,350 Volts. Using this standard, he was able to correctly determine that the attractive force of charged bodies is proportional to (T/d) squared.

Since electricity included lightning, and lightning was in the air, the study of meteorology and gasses became part of Voltas realm. He used his connectivity to build improvements to Saussures improved electrometer to sense even smaller charge and named it the condensator. Visiting with Lavosier and Laplace in France in 1782, the team worked on electrification in the change of state of water vapor, but they came up with erroneous results. Volta independently experimented with the sparking of gas and air over water. He wrote of his work to Lavosier, resulting in the Frenchmen obtaining water over mercury from the sparking. Lavosier and Laplace thought they had synthesized water, but Volta correctly believed they had analyzed gasses using his still accepted phlogiston chemistry. In 1784 he carried out experiments on partial pressures and sent the results in a letter to Lichtenberg. However, the general law of partial pressures is ascribed to Dalton, not Volta.

Unfortunately, Volta lost his colleague Lavoisier to the French Revolutionists who did not like the tax collecting private company, Ferme Generale. Lavoisier, the founder of modern chemistry and a stockholder in the company, was executed by the Revolutionists in 1794.

By 1790 Volta had all the tools in his possession for the unexpected grand challenge. This event was not to be an evolutionary happening, but rather a quantum type of jump based on the observations of his neighbor, Dr. Luigi Galvani, Professor at the University of Bologna. Galvani discovered that frog legs convulsed when a knife touched the crural or sciatic nerve by a person who was drawing a spark from an electrical machine. Galvani pursued the effects with Leyden jar discharges and atmospheric lightning. Twitching was even observed when two dissimilar metals connected the frogs main nerve and the leg nerve.

Galvani described his observations and a theory of animal electricity in the
Proceedings of the Bologna Academy of Sciences in 1791. His implied source of the stimulation was the animal tissue. One of 12 pamphleted copies was sent to Volta, who acknowledged Galvanis observations in a paper to the Royal Society to which he had been elected in 1791.

Volta, the disciplined experimentalist, began to reproduce Galvanis work. As a reference, he repeated an experiment of Johann Sulzer, who in 1752 had reported that placing two touching pieces of metal (zinc and copper) on the tongue produced an unpleasant sensation. Opening the metal connection stopped the sensation. Volta decided to extend the experimentation and connected the metals to his eye where he sensed light flashes. He also connected coins to tinfoil, and then connected them to his tongue, producing a sour taste sensation. One day when placing one piece of metal to his forehead and a connecting it electrically to a different metal on his palate, a bright flash was sensed in his mind! He became convinced that the dissimilar metal conductors, not the animal tissues, were the source of the electricity. Volta wrote to Galvanis nephew, Giovanni Aldine in 1793, stating that the electricity came not from the animal power, but from the contact between the metal and unobserved impurities in the metal.

Building more proof, Volta tested carbon conductors with a metal conductor and got similar results. His metallic electricity was beginning to take form. To develop rigorous fundamentals, he classified different combinations of metals as to their electromotive force (coined by Volta) and identified that those metals, farther apart in the stimulation list would produce greater results. This concept formed the basis of the standard oxidation potentials in aqueous solution. To complete the work, he had to improve electroscope sensitivity, so he improved a condensing electoscope which he had invented in 1782. With rigorous methodology, Voltas next goal was to multiply the potential. With the defined electromotive force of dissimilar metal pairs and series voltage addition, he first piled metal disks, one on top of each other, with no success. The resulting potential would only reflect the potential of the extreme disks in the pile. By 1796 he realized that the series pairs had to produce additive EMFs and discovered the crucial remedy, which was to add a moist conductor in the separated space between the metals to produce generating pairs. The results of the work were published in 1797.


Combining all his experiences of the potential differences and the need for separation by conducting fluid, Volta methodically built batteries in two versions - the pile and string of cups. As his battery experimentation progressed, Volta also discovered that there was a direction to the current (opposite electron flow) and that bucking potentials subtracted from the net effect. He found that ...body fluids in general are a better conductor than water. Many say that Volta was lucky that the metals of his time contained enough impurities to produce the cell. The copper of Voltas time was laden with multiple salts obtained in roasting copper sulfide ores in wood fires. The anode of tin or zinc is easily oxidized, but the cathode of silver or copper cannot provide sufficient ions. Pure metals and pure table salt electrolyte would not produce a working cell. George Gorin of Oklahoma State University suggested that an impurity such as ammonium chloride may have produced hydrogen ions.
Despite any shortcomings or less than perfect explanations of chemically produced continuous current sources, Voltas detailed letter to Sir Joseph Banks was the opening of the floodgate for electrical science. Now sources could provide continuous current and have varying levels of potential. Nicholson and Carlisle used the battery to electrolyze water on April 30, 1800. In 1807 Sir Humphry Davy used the battery to investigate electrolytic decomposition of compounds and substances, and in 1810 he used charcoal electrodes to produce the first electric light. In 1820 Hans Oersted discovered that an electric current deflected a compass. Within months, Ampere formulated the laws of forces acting on current carrying wires. William Sturgeon created an electromagnet. In 1827 Georg Simon Ohm formulated the laws of resistance. Four years later, in 1831, Michael Faraday discovered electromagnetic induction, the critical concept needed to produce the rotating machine which could mechanically produce continuous currents.
Since 1800, the world has been an exploding technological theater with both good and bad uses applied to the battery. Respected by his colleagues, loved by his students, and criticized by those who had produced less real results in life, Volta would both be amazed and expectant by what we have done in the short 200 years since his announcement. Is the battery but a stepping stone to the wondrous and unimaginable things which may add to our health, peace and happiness tomorrow?
BD