Karen Garvin
The modern world runs on electricity. From lighting and heat, to computers and cell phones, almost all technology relies on a steady supply of electrical current for power. Yet despite people being aware of electricity for more than two millennia it has only been within the last 200 years that the study of electricity was formalized, leading to the development of a complete system of electrical power distribution and the invention of numerous electrically powered appliances and machines.
The Greek philosopher Thales of Miletus (circa 626–623 BCE) was one of the first to investigate the phenomenon of electricity. He observed that rubbing a lump of amber with fabric would cause small objects, such as feathers, to cling to it.[1] There was little progress in understanding this strange effect until the English physician and philosopher William Gilbert (1544–1603) began experimenting with various materials to see whether they were magnetic or displayed an electric effect, which he thought was due to “electrical effluvia” that behaved much like flowing water.[2]
Gilbert’s legacy of experimentation was taken up by other natural philosophers, and gradually there emerged a small body of knowledge about electricity. The English dyer and astronomer Stephen Gray (1666–1736) worked out how to transmit electricity over a distance but was hampered by the small amounts of electricity he could generate, and so his efforts led nowhere.[3]
There was no way to store electricity until the Leyden jar was developed in the mid-eighteenth century. It was independently discovered by the German cleric Ewald Georg von Kleist (1700–1748) and Dutch mathematician Pieter van Musschenbroek (1692–1761), who generally gets the credit for the invention.[4] This device was a glass jar partially coated with a thin metal foil on both the inside and outside. A metal rod was inserted through the jar’s cork, making contact with both the inner and outer foil plates.[5] The Leyden jar was capable of delivering a very high voltage of around 10,000 volts (fig. 1).[6]
Figure 1. Illustrations of a Leyden jar being discharged. One method produces a quick discharge (and possible shock to the user), while the second method produces a slow trickle of current. From Adolphe Ganot and Edmund Atkinson, Elementary Treatise on Physics, Experimental and Applied (New York: W. Wood and Co., 1868). Public domain; book held by the Library of Congress, https://www.loc.gov/item/17008559/.
In 1800, Alessandro Volta (1745–1827) developed the first chemical storage battery, called a “pile,” which consisted of a stack of alternating copper and zinc discs separated by pasteboard.[7] Instead of delivering a high-voltage spark like a Leyden jar, the battery produced a steady electrical current.[8] The English scientists William Nicholson (1753–1815) and Anthony Carlisle (1768–1840) used electricity to separate chemical compounds into elements; this process was named electrolysis and it soon led to other