Invention of the Leyden Jar
The Leyden jar, invented independently in the mid-18th century, is a pioneering electrical device that allowed for the accumulation and storage of electrical charge. Its invention came amidst a surge of interest in electricity, sparked by earlier experiments from scientists like Otto von Guericke and Sir Isaac Newton. The first to create the Leyden jar were Ewald Georg von Kleist and Pieter van Musschenbroek, who discovered that a simple setup involving a glass container and conductive materials could effectively store electric charge. This device greatly popularized electricity, leading to a surge in public demonstrations and experiments, often accompanied by dramatic displays of sparks and, at times, unfortunate accidents involving live animals.
Jean-Antoine Nollet contributed to the Leyden jar's fame through spectacular demonstrations, captivating audiences, including royalty, with its capabilities. The invention also catalyzed further scientific research, with notable contributions from figures like Benjamin Franklin, who explored the nature of electric charge using the jar. Beyond entertainment, the Leyden jar laid the groundwork for electrotherapy, with applications emerging in medical practices. Its legacy continues today, as it represents the first condenser and a precursor to modern capacitors, which play a critical role in various electronic devices and systems. Overall, the Leyden jar not only marked a significant milestone in the study of electricity but also influenced its practical applications across different fields.
Invention of the Leyden Jar
Date October, 1745, and January, 1746
Experimenting independently in different countries, Ewald Georg von Kleist and Pieter van Musschenbroek invented the Leyden jar, the first device that could accumulate and store large amounts of electric energy. Later called a condenser or capacitor, the Leyden jar could conserve an electric charge for future use or experimentation.
Locale Camin, Pomerania (now in Germany); Leiden, the Netherlands
Key Figures
Ewald Georg von Kleist (1700-1748), German scientist and clericPieter van Musschenbroek (1692-1761), Dutch physicist, mathematician, and professorJean-Antoine Nollet (1700-1770), French abbot and physicistWilliam Watson (1715-1787), English physician, apothecary, and scientistBenjamin Franklin (1706-1790), American statesman and inventor
Summary of Event
Significant experimentation with electricity began after 1660, when Otto von Guericke of Magdeburg, Germany, invented the first electrical machine, which generated electricity by friction. In 1675, using an improved machine with a glass globe, Sir Isaac Newton studied sparking, attraction, and repulsion. In 1729, Stephen Gray established the important principle that electricity could travel or be transmitted, and he was the first to differentiate between materials that were insulators or nonconductors (such as silk filaments) and conductors (such as metal or water).
By the early 1740’s, amateurs and philosophers, as well as scientists, were performing electrical experiments and demonstrations, often for entertainment. For instance, a popular pastime was igniting combustibles such as gunpowder and alcohol by sparks from an electrical friction machine. However, experimenters still needed a way to accumulate and store electricity. The solution was the Leyden jar, invented independently by Ewald Georg von Kleist in October, 1745, and by Pieter van Musschenbroek in January, 1746.
Von Kleist was a German scientist and cleric who had become interested in electricity while studying at the University of Leyden in the 1720’s. Later, he learned about the experiments of University of Leipzig professor Georg Mathias Bose, who experimented with electrical flares and sparks from water in an electrified glass vessel. Von Kleist began experimenting with his own electric generator with the goal of creating stronger flares or sparks.
In October, 1745, von Kleist accidentally invented the first condenser. He had set up a medicine bottle (a nonconductor) filled with fluid (a conductor), and inserted a nail in the cork stopper. One end of a metal wire was connected to his electrical machine’s prime conductor, and the other end was placed inside the jar of fluid. While holding the jar in one hand, von Kleist connected the nail to the electric generator and electrified the nail. Touching the nail with the other hand, he received a severe shock, and the charged nail also produced sparks when it touched another object. It was then obvious to von Kleist that the nail and the jar had temporarily stored electricity. In November, he wrote letters about his invention to other scientists, but none of them could successfully replicate von Kleist’s experiment before the news broke about van Musschenbroek’s similar experiment in January, 1746.
Van Musschenbroek was a Dutch professor, medical doctor, mathematician, and scientific instrument maker, who, in 1729, was the first person to use the term “physics” to name what had previously called natural philosophy. Independently of von Kleist, van Musschenbroek, along with Jean Allamand of the University of Leyden and an assistant, Andreas Cunaeus, conducted the same experiment as von Kleist. However, unlike von Kleist, van Musschenbroek realized that the hand holding the jar served as a conductor and that the bottle’s exterior had to be grounded (held by a person standing on the ground) when electrifying the nail or wire.
In January, 1746, van Musschenbroek announced his invention, and in April, 1746, his discovery was presented to the Académie des Sciences (Academy of Sciences) in Paris. Van Musschenbroek was able not only to develop a working model of the condenser but also to explain the device sufficiently to allow other scientists to repeat his experiement. He was therefore credited with its invention, and the device came to be known as a Leyden jar, since it was invented at the University of Leyden.
The news of the Leyden jar spread rapidly, first in Europe and then throughout the world. Electricity became more popular than ever. Even nonscientists became “electricians,” performing various kinds of sensational new demonstrations. Frequently, exhibitions resulted in animals and birds being killed by electrical shock. Longer and more powerful sparks became possible with Leyden jars built into frictional static-generating machines. Some of the most elaborate and memorable demonstrations were experiments by Jean-Antoine Nollet, a French physicist, member of the Académie des Sciences, and abbot of the Grand Convent of the Carthusians in Paris. It was Nollet who coined the term “Leyden jar.” Moreover, in 1745, Nollet developed a theory that electricity could travel long distances quickly, based on attraction and repulsion in a continuous flow of electrical matter between charged bodies.
Combining scientific research with spectacular effects, Nollet helped popularize electrical phenomena. At Versailles in 1746, for instance, Nollet impressed King Louis XV by sending a discharge or current from a Leyden jar through a long chain of 180 royal guards connected by pieces of wire. The discharge caused all of the soldiers to leap into the air simultaneously when the circuit was completed. Louis XV was so entertained that he requested a second demonstration be performed in Paris. Consequently, Nollet repeated the procedure with a single row of 700 monks holding hands. When the Leyden jar was discharged, all the monks jumped simultaneously into the air.
The Leyden jar also stimulated serious scientific research. Within a year of its invention, the English apothecary, scientist, and physician William Watson created an improved Leyden jar coated with metal foil on both the inside and outside. The metal foil on the outside served the purpose of the hand holding the jar in the earlier experiments. Watson attempted to devise an accurate test for measuring the velocity of electricity. In 1747, he laid out a wire circuit 12,276 feet long across the River Thames at Westminster Bridge. He then discharged an electric spark from a Leyden jar through the wire. Transmission occurred immediately, so Watson determined that the velocity of electricity was instantaneous.
In the United States, Benjamin Franklin conducted experiments using the Leyden jar. He proved that the electrical charge was stored in the glass rather than the water, as had generally been thought, and that the basis of the jar’s electrostatic activity was the insulating material around the conductor. After wrapping both the inside and outside of a glass jar with lead foil and electrifying the jar, Franklin removed the wrappings and discovered that each sheet had been charged. As a result, the device was called a “condenser.” In 1752, Franklin collected electrical charge in a Leyden jar during his famous experiment flying a kite in a lightning storm.
Significance
With the invention of the Leyden jar, scientists finally had a device that could generate and store large quantities of electrical charge for later use. Thus, the invention was crucial for future advancements in electrical research. The Leyden jar further popularized electricity, as even nobility and royalty were drawn to the dramatic demonstrations it made possible.
The Leyden jar also marked a turning point in the field of electrotherapy, or the therapeutic use of electricity. Since about 400 b.c.e., electrical shocks from torpedo fish had been used to treat pain, gout, and other illnesses. Christian Gottlieb Kratzenstein (1723-1795) was possibly the first physician to use the Leyden jar to treat diseases. By 1752, there were forty published medical applications of electricity, and by 1789 there were seventy published uses. There were reports of successful treatment of disorders such as paralysis, epilepsy, angina pectoris, kidney stones, and sciatica. Beginning in the late 1760’s, hospitals began installing electric shock machines. However, interest in electrotherapy declined toward the end of the nineteenth century.
Most significantly, the Leyden jar was the first condenser and the forerunner of modern capacitors, devices that contain two conductors separated by an insulator. In the twenty-first century, capacitors come in all sizes, including microscopic ones that are part of integrated electric circuits. The devices store electricity and are used in electric power systems, radios, televisions, computers, and various kinds of electronic equipment.
Bibliography
Bernal, J. D. A History of Classical Physics from Antiquity to the Quantum. New York: Barnes & Noble Books, 1997. Includes sections on Benjamin Franklin’s Leyden jar experiments and a discussion and illustration of van Musschenbroek’s experiment. Illustrations and index.
Ford, R. A. Homemade Lightning: Creative Experiments in Electricity. New York: McGraw-Hill, 2002. A chapter on the Leyden jar condenser describes the early jars and includes instructions for creating Leyden jars. Illustrated, with an appendix, a bibliography, and an index.
Heilbron, J. L. Electricity in the Seventeenth and Eighteenth Centuries: A Study in Early Modern Physics. Mineola, N.Y.: Dover, 1999. This significant and scholarly work provides detailed chapters on the invention of the Leyden jar and Benjamin Franklin’s experiments. Illustrated. Index and extensive bibliography.
Schiffer, Michael B. Draw the Lightning Down: Benjamin Franklin and Electrical Technology in the Age of Enlightenment. Berkeley: University of California Press, 2003. This story of Franklin and eighteenth century electrical technology discusses the Leyden jar extensively. Illustrated. Bibliography and index.
Whittaker, E. T. A History of the Theories of Aether and Electricity. New York: Tomash, 1987. This general history includes sections about the work of van Musschenbroek and Watson. Illustrated. Bibliography and index.