XVIII Century

Benjamin Franklin

(January 17, 1706 – April 17, 1790) was an American polymath and one of the Founding Fathers of the United States. As a scientist, he was a major figure in the American Enlightenment and the history of physics for his discoveries and theories regarding electricity. As an inventor, he is known for the lightning rod, bifocals, and the Franklin stove, among other inventions. 

The usage of “battery” to describe a group of electrical devices dates to Benjamin Franklin, who in 1748 described multiple Leyden jars by analogy to a battery of cannon (Benjamin Franklin borrowed the term “battery” from the military, which refers to weapons functioning together).

Franklin started exploring the phenomenon of electricity in 1746 when he saw some of Archibald Spencer’s lectures using static electricity for illustrations. Franklin proposed that “vitreous” and “resinous” electricity were not different types of “electrical fluid” (as electricity was called then), but the same “fluid” under different pressures. (The same proposal was made independently that same year by William Watson). Franklin was the first to label them as positive and negative respectively, and he was the first to discover the principle of conservation of charge. In 1748, he constructed a multiple plate capacitor, that he called an “electrical battery” (not to be confused with Volta’s pile) by placing eleven panes of glass sandwiched between lead plates, suspended with silk cords and connected by wires.

In recognition of his work with electricity, he received honorary degrees from Harvard and Yale universities (his first). The CGS unit of electric charge has been named after him: one franklin (Fr) is equal to one statcoulomb.

Franklin briefly investigated electrotherapy, including the use of the electric bath. This work led to the field becoming widely known.

Franklin published a proposal for an experiment to prove that lightning is electricity by flying a kite in a storm that appeared capable of becoming a lightning storm. On May 10, 1752, Thomas-François Dalibard of France conducted Franklin’s experiment using a 12 m. iron rod instead of a kite, and he extracted electrical sparks from a cloud.


Johan Carl Wilcke

(6 September, 1732 – 18 April, 1796) was a Swedish physicist. He spent the years from 1751 travelling abroad and received the magister degree from the University of Rostock in 1757, after having published the dissertation De electricitatibus contrariis. He became a titular professor in 1770, and permanent secretary of the Royal Swedish Academy of Sciences in 1784.

His two areas of significant research were electricity and caloric theory. In 1762 he invented an electrostatic generator that was a first version of the electrophorus, a device named and popularized in 1775 by Alessandro Volta. In 1772 he calculated the latent heat of ice. In 1781, he coined the concept and term of “specific heat”, in analogy with the term “specific gravity”.


Joseph Priestley

(13 March, 1733 – 6 February, 1804) was an 18th-century English Separatist theologian, natural philosopher, chemist, innovative grammarian, multi-subject educator, and liberal political theorist who published over 150 works. He has historically been credited with the discovery of oxygen, having isolated it in its gaseous state, although Carl Wilhelm Scheele and Antoine Lavoisier also have strong claims to the discovery.

During his lifetime, Priestley’s considerable scientific reputation rested on his invention of carbonated water, his writings on electricity, and his discovery of several “airs” (gases).

Between 1767 and 1770, he presented five papers to the Royal Society; the first four papers explored coronal discharges and other phenomena related to electrical discharge, while the fifth reported on the conductivity of charcoals from different sources. His subsequent experimental work focused on chemistry and pneumatics.


Charles-Augustin de Coulomb

(14 June, 1736 – 23 August, 1806) was a French military engineer and physicist. He is best known as the eponymous discoverer of what is now called Coulomb’s law, the description of the electrostatic force of attraction and repulsion, though he also did important work on friction. The SI unit of electric charge, the coulomb, was named in his honor in 1908.

In 1784, his memoir Theoretical research and experimentation on torsion and the elasticity of metal wire appeared. This memoir contained the results of Coulomb’s experiments on the torsional force for metal wires, specifically within a torsion balance. His general result is: “the moment of the torque is, for wires of the same metal, proportional to the torsional angle, the fourth power of the diameter and the inverse of the length of the wire”.

In 1785, Coulomb presented his first three reports on Electricity and Magnetism:

  • Premier Mémoire sur l’Électricité et le Magnétisme. In this publication, Coulomb describes “How to construct and use an electric balance (torsion balance) based on the property of the metal wires of having a reaction torsion force proportional to the torsion angle.” Coulomb also experimentally determined the law that explains how “two bodies electrified of the same kind of Electricity exert on each other.” On page 574 he states: “It follows therefore from these three tests, that the repulsive force that the two balls — [which were] electrified with the same kind of electricity — exert on each other, follows the inverse proportion of the square of the distance“.
  • Second Mémoire sur l’Électricité et le Magnétisme. In this publication, Coulomb carries out the “determination according to which laws both the Magnetic and the Electric fluids act, either by repulsion or by attraction.” On page 579, he states that the attractive force between two oppositely charged spheres is proportional to the product of the quantities of charge on the spheres and is inversely proportional to the square of the distance between the spheres.
  • Troisième Mémoire sur l’Électricité et le Magnétisme. “On the quantity of Electricity that an isolated body loses in a certain time period, either by contact with less humid air or in the supports more or less idio-electric.”


Luigi Galvani

(9 September, 1737 – 4 December, 1798) was an Italian physician, physicist, biologist and philosopher, who discovered animal electricity. He is recognized as the pioneer of bioelectromagnetics. In 1780, he discovered that the muscles of dead frogs’ legs twitched when struck by an electrical spark. This was one of the first forays into the study of bioelectricity, a field that still studies the electrical patterns and signals from tissues such as the nerves and muscles.

The beginning of Galvani’s experiments with bioelectricity has a popular legend which says that the Galvani was slowly skinning a frog at a table where he and his wife had been conducting experiments with static electricity by rubbing frog skin. Galvani’s assistant touched an exposed sciatic nerve of the frog with a metal scalpel that had picked up a charge. At that moment, they saw sparks and the dead frog’s leg kicked as if in life. The observation made the Galvanis the first investigators to appreciate the relationship between electricity and animation—or life. This finding provided the basis for the new understanding that the impetus behind muscle movement was electrical energy carried by a liquid (ions), and not air or fluid as in earlier balloonist theories.

Galvani coined the term animal electricity to describe the force that activated the muscles of his specimens. Along with contemporaries, he regarded their activation as being generated by an electrical fluid that is carried to the muscles by the nerves. The phenomenon was dubbed galvanism, after Galvani and his wife, on the suggestion of his peer and sometime intellectual adversary Alessandro Volta. The Galvanis are properly credited with the discovery of bioelectricity. Today, the study of galvanic effects in biology is called electrophysiology, the term galvanism being used only in historical contexts.


Alessandro Volta

Alessandro Giuseppe Antonio Anastasio Volta (18 February, 1745 – 5 March, 1827) was an Italian physicist, chemist, and pioneer of electricity and power who is credited as the inventor of the electric battery and the discoverer of methane.

In 1774, he became a professor of physics at the Royal School in Como. A year later, he improved and popularised the electrophorus, a device that produced static electricity. His promotion of it was so extensive that he is often credited with its invention, even though a machine operating on the same principle was described in 1762 by the Swedish experimenter Johan Wilcke.

He invented the Voltaic pile in 1799, and reported the results of his experiments in 1800 in a two-part letter to the President of the Royal Society. With this invention Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings. Volta’s invention sparked a great amount of scientific excitement and led others to conduct similar experiments which eventually led to the development of the field of electrochemistry.

Volta also drew admiration from Napoleon Bonaparte for his invention, and was invited to the Institute of France to demonstrate his invention to the members of the Institute. Volta enjoyed a certain amount of closeness with the emperor throughout his life and he was conferred numerous honours by him. Volta held the chair of experimental physics at the University of Pavia for nearly 40 years and was widely idolized by his students.

Despite his professional success, Volta tended to be a person inclined towards domestic life and this was more apparent in his later years. At this time he tended to live secluded from public life and more for the sake of his family until his eventual death in 1827 from a series of illnesses which began in 1823. The SI unit of electric potential is named in his honour as the volt.


Tiberius Cavallo

also Tiberio Cavallo (30 March, 1749 – 21 December, 1809) was an Italian physicist and natural philosopher. His interests included electricity, the development of scientific instruments, the nature of “airs”, and ballooning. He became both a Member of the Royal Academy of Sciences in Naples, and a Fellow of the Royal Society of London in 1779. 

He made several improvements in scientific instruments. Cavallo is often cited as the inventor of Cavallo’s multiplier. He also developed a “pocket electrometer” that he used to amplify small electric charges to make them observable and measurable with an electroscope. Parts of the instrument were protected from drafts by a glass enclosure.

He was interested in the physical properties of “airs” or gases, and carried out experiments on “inflammable air” (hydrogen gas). In his Treatise on the Nature and Properties of Air (1781) he makes “a judicious examination of contemporary work”, discussing both the phlogiston theory of Joseph Priestley and the contrasting views of Antoine Lavoisier. In June 1782, a paper of Cavallo’s was read at the Royal Society, describing the first attempt to lift a hydrogen-filled balloon into the air.


William Nicholson

(13 December, 1753 – 21 May, 1815) was a renowned English chemist and writer on “natural philosophy” and chemistry, as well as a translator, journalist, publisher, scientist, inventor, patent agent and civil engineer.

Nicholson communicated to the Royal Society in 1789 two papers on electrical subjects. In the same year he reviewed the controversy which had arisen over Richard Kirwan’s essay on phlogiston, and published a translation of the adverse commentaries by the French academicians (Lavoisier, Monge, Berthollet, and Guyton de Morveau) as ‘An Essay on Phlogiston, to which are added Notes.’ In 1797 he founded, published, and wrote part of the Journal of Natural Philosophy, Chemistry and the Arts, generally known as Nicholson’s Journal, the earliest monthly scientific work of its kind in Great Britain.

In May 1800 he with Anthony Carlisle discovered electrolysis, the decomposition of water into hydrogen and oxygen by voltaic current. The two were then appointed to a chemical investigation committee of the new Royal Institution.


Abraham Bennet

(20 December, 1749 – 9 May, 1799) was an English clergyman and physicist, the inventor of the gold-leaf electroscope and developer of an improved magnetometer. Though he was cited by Alessandro Volta as a key influence on his own work, Bennet’s work was curtailed by the political turbulence of his time.

Bennet had broad interests in natural philosophy and was associated with, though not a member of, the Lunar Society and the Derby Philosophical Society. He was particularly close to Erasmus Darwin. Darwin suggested that Bennet make electrical measurements as part of an investigation into electricity and weather. Bennet then worked assiduously to establish his expertise in electricity, achieving a reputation sufficient to take part in a meeting with Tiberius Cavallo, William Nicholson and Volta in London in 1782.


Anthony Carlisle

(15 February, 1768 – 2 November, 1840) was an English surgeon. In 1793 he was appointed Surgeon at Westminster Hospital in 1793, remaining there for 47 years. He also studied art at the Royal Academy.

In 1800, he and William Nicholson discovered electrolysis by passing a voltaic current through water, decomposing it into its constituent elements of hydrogen and oxygen.

He was elected a Fellow of the Royal Society in 1804. He was Professor of Anatomy of the Society from 1808 to 1824. In 1815, he was appointed to the Council of the College of Surgeons and for many years was a curator of their Hunterian Museum. He served as president of the society, by then the Royal College of Surgeons, in 1828 and 1839.


Giuseppe Zamboni

(June 1, 1776 – July 25, 1846) was an Italian Roman Catholic priest and physicist who invented the Zamboni pile, an early electric battery similar to the voltaic pile.

He was born in either Venice (or, depending on the source, Verona), in June 1776. Shortly after completing his studies in the seminary at Verona, Abate Zamboni was appointed to the chair of physics in the lyceum of that city.

Zamboni is known for an improved version of the dry pile (an electric battery which does not use an electrolyte) which he invented in 1812. It consists of a number of paper discs coated with zinc foil on one side and manganese dioxide on the other; the moisture of the paper serves as a conductor.

By pressing a large number of such discs together in a glass tube, an electromotive force can be obtained that is sufficient to deflect the leaves of an ordinary electroscope. By bringing the terminal knobs of the pile near each other and suspending a light brass ball between them, Zamboni devised what was called an electrostatic clock. The device is so named because the ball oscillating between the knobs looks like a pendulum.

In the Oxford Electric Bell experiment at the Clarendon Laboratory at Oxford University, the terminals of what is believed to be such a pile are fitted with bells that have been continuously ringing since the device was set up in 1840. Note that the Zamboni pile is not a hypothetical perpetual motion device, as all action will eventually cease when the zinc is completely oxidized or the manganese exhausted


John Frederic Daniell

(12 March, 1790 – 13 March, 1845) was an English chemist and physicist. In 1831 he became the first professor of chemistry at the newly founded King’s College London.

His name is best known for his invention of the Daniell cell, an element of an electric battery much better than voltaic cells, becoming an industry standard and seeing widespread adoption as a power source for electrical telegraph networks. It consisted of a copper pot filled with a copper sulfate solution, in which was immersed an unglazed earthenware container filled with sulfuric acid and a zinc electrode.

These wet cells used liquid electrolytes, which were prone to leakage and spillage if not handled correctly. Many used glass jars to hold their components, which made them fragile and potentially dangerous.


Michael Faraday

(22 September, 1791 – 25 August, 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic induction, diamagnetism and electrolysis.

Although Faraday received little formal education, he was one of the most influential scientists in history. It was by his research on the magnetic field around a conductor carrying a direct current that Faraday established the basis for the concept of the electromagnetic field in physics. Faraday also established that magnetism could affect rays of light and that there was an underlying relationship between the two phenomena. He similarly discovered the principles of electromagnetic induction and diamagnetism, and the laws of electrolysis. His inventions of electromagnetic rotary devices formed the foundation of electric motor technology, and it was largely due to his efforts that electricity became practical for use in technology.

As a chemist, Faraday discovered benzene, investigated the clathrate hydrate of chlorine, invented an early form of the Bunsen burner and the system of oxidation numbers, and popularised terminology such as “anode“, “cathode“, “electrode” and “ion“. Faraday ultimately became the first and foremost Fullerian Professor of Chemistry at the Royal Institution, a lifetime position.

The SI unit of capacitance is named in his honour: the farad.


William Cruickshank

(died 1810 or 1811) was a Scottish military surgeon and chemist, and professor of chemistry at the Royal Military Academy, Woolwich.

William Cruickshank was awarded a diploma by the Royal College of Surgeons of England on 5 October 1780. In March 1788 he became assistant to Adair Crawford at the Royal Military Academy, Woolwich. He identified carbon monoxide as a compound containing carbon and oxygen in 1800. Circa 1800, Cruickshank invented the Trough battery, an improvement on Alessandro Volta’s voltaic pile. The plates were arranged horizontally in a trough, rather than vertically in a column.

Shortly learning of Alessandro Volta discovery of the voltaic pile in 1800, Cruickshank conducted a number of experiments involving electrolysis. He connected wires of silver to the poles of a battery and placed in a solution of distilled water, and then in a variety of other solutions observing the results. When the wires placed in the solutions of lead acetate, copper sulfate and silver nitrate, deposits of pure lead, copper and silver formed, respectively, on one wire. From these experiments he observed that “where metallic solutions are employed instead of water, the same wire which separates the hydrogen revives the metallic calx, and deposits it at the extremity of the wire in its pure metallic state.” This process of extraction of pure metals from metallic solutions is known today as electrowinning. It is used in the refining of copper and other metals.


Johann Christian Poggendorff

(29 December, 1796 – 24 January, 1877), was a German physicist born in Hamburg. By far the greater and more important part of his work is related to electricity and magnetism. Poggendorff is known for his electrostatic motor which is analogous to Wilhelm Holtz’s electrostatic machine. In 1841 he described the use of the potentiometer for measurement of electrical potentials without current draw.

Poggendorff overcame the problems of gravity cells with separating the electrolyte and the depolariser using a porous earthenware pot in 1842. In the Poggendorff cell, sometimes called Grenet Cell due to the works of Eugene Grenet around 1859, the electrolyte is dilute sulphuric acid and the depolarizer is chromic acid. The two acids are physically mixed together, eliminating the porous pot. The positive electrode (cathode) is two carbon plates, with a zinc plate (negative or anode) positioned between them. Because of the tendency of the acid mixture to react with the zinc, a mechanism is provided to raise the zinc electrode clear of the acids.

The cell provides 1.9 volts. It proved popular with experimenters for many years due to its relatively high voltage; greater ability to produce a consistent current and lack of any fumes, but the relative fragility of its thin glass enclosure and the necessity of having to raise the zinc plate when the cell is not in use eventually saw it fall out of favour. The cell was also known as the ‘chromic acid cell’, but principally as the ‘bichromate cell’. This latter name came from the practice of producing the chromic acid by adding sulphuric acid to potassium dichromate, even though the cell itself contains no dichromate.

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Sources : Wikipedia and others