Ewald Georg von Kleist
Ewald Georg von Kleist was an influential German jurist, Lutheran cleric, and physicist born in 1700 in Farther Pomerania, a region nestled between modern-day Poland and Germany. He attended prestigious universities, including Leipzig and Leiden, where he became fascinated with electricity, inspired by the experiments of professors like Georg Matthias Bose. Von Kleist's significant contribution to the field of electricity came in the 1740s when he independently discovered a method to create a primitive capacitor, known later as the "Leiden jar"—though it was named after his Dutch contemporary Pieter van Musschenbroek, who made a similar discovery shortly afterward. His experiments demonstrated the ability to store electrical charges, which could ignite flammable substances and deliver strong electrical shocks.
Though he initially faced challenges in gaining recognition, von Kleist's work laid the groundwork for advancements in electrical science, leading to the development of the capacitor—a crucial component in modern electronics. His discoveries not only captivated the scientific community but also had practical applications that extended into medicine and other fields. After serving as dean of a cathedral chapter and later as president of the royal court of justice, von Kleist passed away in 1748, but his legacy in the field of electricity endures, influencing the technologies we rely on today.
Ewald Georg von Kleist
German physicist
- Born: June 10, 1700
- Birthplace: Vietzow, Farther Pomerania, Prussia (now in Germany)
- Died: December 11, 1748
- Place of death: Köslin, Pomerania, Prussia (now Koszalin, Poland)
Von Kleist developed the Leiden jar, an early device that stored electricity by accumulating electricity generated by a primitive friction machine in a glass container. This device is the ancestor of the capacitor, which is used in modern electrical and electronic equipment.
Primary field: Physics
Primary invention: Leiden jar (precursor of the capacitor)
Early Life
Ewald Georg von Kleist (A-vawlt GAY-ohrk fahn klist), a German jurist, Lutheran cleric, and physicist, was born in 1700 in Farther Pomerania, a region in north-central Europe on the Baltic Sea between what is now Poland and Germany. Little is known of his early life beyond the fact that he was born into an upper-class family; his father was a Prussian district manager. Von Kleist enjoyed a reasonably comfortable childhood and youth and was well educated.
In the 1720’s, he attended first the University of Leipzig in Germany and then the University of Leiden in the Netherlands, where he studied jurisprudence. His interest in science was stimulated by the experiments of one of the professors in Leipzig, Georg Matthias Bose. Bose, intrigued by electricity, as were many other upper-class Europeans, explored the phenomenon of igniting flammables with sparks generated by electrical friction machines. Much of Europe had become enthralled by the diversions produced with gadgets and the party jokes that used static electricity. However, those more serious-minded individuals saw the potential of electricity to accomplish more worthwhile benefits than mere entertainment and were interested in finding ways to harness its power for practical uses. Von Kleist was one of those who, after observing the demonstrations, developed an interest in serious experimentation. He was particularly interested in those demonstrations in which alcohol, gunpowder, and turpentine were ignited by electrical sparks.
When he completed his education at the University of Leiden, he returned home to Pomerania and became a dean (bishop) of a cathedral chapter of Camin, where he remained from 1722 to 1745. His curiosity about electricity continued, and his aim was to find a way to conserve or accumulate an electrical charge so that it could be used later.
Life’s Work
By the 1740’s, electricity as a means of entertainment and a scientific phenomenon had captured the interest of large segments of European society. Professor Bose at the University of Leipzig continued conducting experiments that generated considerable interest in electricity’s potential. Frederick the Great, king of Prussia, opened the Berlin Academy of Sciences in 1744, where experiments in electricity were conducted. About the time von Kleist was experimenting with capturing electrical charges and attempting to increase their power, a Dutch professor at the University of Leiden named Pieter van Musschenbroek was working on a project with the same goal. Both men would independently arrive at the same discovery. Musschenbroek made his in January, 1746, but von Kleist had made his discovery two months earlier.
Working with knowledge of the experiments of contemporaries such as Bose and Johann Krueger, von Kleist began his attempts to increase the strength and reliability of the electrical flare. His discovery was probably an accident. According to his account of the experiment, he inserted an iron nail into the cork sealing the opening of a handheld glass jar. The jar contained a liquid, variously supposed to be alcohol, mercury, or water. Von Kleist connected the nail to his friction machine to electrify it. He found that the electrical charge could be retained for several hours. Even more astonishing, the charge retained by the jar could be strong enough to ignite wine or other spirits as successfully as the friction machine had done. Von Kleist also received a severe shock when, while holding the glass jar in one hand, he touched the nail with his other hand. He noted that he got a shock only when both hands were on the jar. (This was an example of closed circuitry, a concept unknown at the time.) When his hands touched only the nail, no shock was felt. The shock was strong enough to numb his arm and shoulder. When he touched the nail in the jar to another object, the jar discharged the stored electricity and produced a spark. The device’s spark lasted long enough to make a noticeable light in the room.
When he was finally satisfied with the results of his experiment, he wrote to several professors and Berlin Academy members describing the experiment and its effects. They tried to replicate his experiment, but most of them were unsuccessful. Those few who managed to perform the experiment successfully shared the news among themselves but apparently did not widely disseminate the discovery. On the other hand, news of the same discovery by the more famous Musschenbroek quickly reached several countries. Therefore, Musschenbroek’s discovery of the Leiden jar and his more thorough investigation of the jar’s potential was more widely known for many years. Nevertheless, von Kleist was eventually recognized as the discoverer of this primitive capacitor.
Though the device von Kleist discovered was once called the “Kleistian jar” in his honor, a French scientist, Abbé Nollet, coined the term “Leiden jar,” named for Musschenbroek’s hometown and the Dutch university where he taught. After its discovery, the Leiden jar was used to put on spectacular demonstrations for spectators. One demonstration that created a particular stir was prepared for the king of France: A regiment of soldiers was lined up, linked together with pieces of wire. Then an electrical charge was sent them, causing them to simultaneously leap into the air, to the amazement of onlookers.
After von Kleist’s career as dean of a cathedral chapter at Camin ended in 1745, he went on to become president of the royal court of justice in Köslin. He died there in 1748.
Impact
The Leiden jar was significant to eighteenth century scientists as well as to those who recognized its potential beyond entertainment. By 1752, numerous publications had proclaimed the many uses for the jar in several fields, especially medicine. By 1789, as many as seventy applications in medicine alone had been ascribed to the jar.
Over time, as scientists learned about the concepts of charge, current, and capacitance, the jar became increasingly important for research. It made possible the production of electrical charges that had greater power than any previously produced. As its power was demonstrated to ever more philosophers and scientists, its advantages beyond entertainment were brought to the attention of leaders of different countries, who proceeded to support more research.
Eventually, experimenters used the jar to develop the capacitor, a device with the ability to store unused electrons and ultimately deliver electric power over great distances. The capacitor is an integral element of today’s radios, televisions, and other electronic devices. The jar itself is still used today in laboratories for experiments and demonstrations.
Bibliography
Graves, Daniel. Scientists of Faith: Forty-eight Biographies of Historic Scientists and Their Christian Faith. Grand Rapids, Mich.: Kregel, 1996. Includes biographies of such scientists as von Kleist, Roger Bacon, Robert Boyle, Michael Faraday, and James Clerk Maxwell.
Gribbin, John. The Scientists: A History of Science Told Through the Lives of Its Greatest Inventors. New York: Random House, 2003. The chapter devoted to eighteenth century science and the study of electricity discusses the discovery and early uses of the Leiden jar.
Hankins, Thomas L. Science and the Enlightenment. New York: Cambridge University Press, 1985. A general history of eighteenth century science, with a relatively full discussion of the Leiden jar and information about von Kleist.
Porter, Roy, ed. The Cambridge History of Science. Vol. 4, The Eighteenth Century. New York: Cambridge University Press, 2003. Contains essays on the individual sciences and scientific instruments and their makers. One essay on electricity discusses the Leiden jar and electricity experiments performed by Musschenbroek.
Sennett, Richard. The Craftsman. New Haven, Conn.: Yale University Press, 2008. A sociological account exploring craftsmanship, from ancient Rome to the modern world. A chapter is devoted to the Leiden jar.
Shectman, Jonathan. Groundbreaking Scientific Experiments, Inventions, and Discoveries of the Eighteenth Century. Westport, Conn.: Greenwood Press, 2003. The introduction gives an overview of the eighteenth century interest in science; several essays discuss scientific discoveries, applications, and investigations to provide background on the impact of scientific advances, such as the Leiden jar, on social and political history.