Electricity through the Eighteenth Century

Though humans would not fully understand the nature of electricity until the nineteenth century, the properties of electricity were detected much sooner. One of the earliest written sources to comment on electricity comes from Thales of Miletus, a Greek mathematician and philosopher. Around 600 BCE, Thales recognized that amber, when rubbed with cloth, would attract very small, light objects like feathers. Thales had discovered how to charge amber with static electricity; indeed, the word “electron” is derived from the Greek word for “amber” [electron].

Thales’s discovery was the most significant advance in the understanding of electricity for many hundreds of years. People from around the world made note of naturally occurring electrical phenomena—lightning storms and electric eels, for example—but few made significant contributions to better understanding electricity. The scientific effort to understand electricity resumed in the early seventeenth century with the personal doctor of Queen Elizabeth I of England, William Gilbert, who experimented with a wide range of materials to determine which of them

would generate an electrical charge when rubbed. He also made many observations regarding the impact of fluids and climate on the capacity of certain materials to generate charges. This knowledge helped pave the way for the development of electrostatic machines—hand-cranked devices that used friction to generate short bursts of electricity. Such devices attracted a great deal of attention and curiosity, and were used on more than one occasion by wealthy pranksters to deliver small shocks to unsuspecting guests.

In 1746, Dutch scientist Pieter van Musschenbroek invented the Leyden Jar—a water-filled glass container, wrapped inside and out with wires, and connected to an electrostatic machine. The Leyden Jar represented a major advance forward in the science of electricity because it was capable of retaining an electric charge for several days. Though a relatively primitive device, the Leyden Jar was a major advance forward in attempting to solve one of the most fundamental challenges involved in harnessing electricity for useful applications—storage.

Around the time van Musschenbroek was developing the Leyden Jar, another major figure was making his own contributions to the study of electricity: Benjamin Franklin. Franklin is perhaps the most famous North American associated with the early study of electricity because of his famous (and ill-advised) kite experiment. There was significant debate among scientists regarding the nature of lightning (whether it was the same as other forms of electricity, or something distinct). Franklin sought with the experiment to capture an electrical charge from the storm, which he theorized would travel down the wet kite string into a Leyden Jar (while he would hold a dry kite string and remain safe). According to his own account, Franklin’s experiment was a success, as the jar captured a modest charge. Fortunately for Franklin, the kite did not sustain a direct hit—others who followed in Franklin’s footsteps and conducted their own version of this dangerous experiment were not so lucky! Franklin used his insights into the nature

of lightning to develop one of his most important inventions, the lightning rod, which was designed to protect buildings from the threat of lightning strikes.

By the turn of the nineteenth century, tremendous advances had been made in the understanding of electricity. Scientists had developed a means of generating it on a small scale though electrostatic machines, and had also invented a means to store the charge for future use. Despite these advances, there were still significant limitations on the practical application of electricity. Leyden Jars, for example, could store electricity for only a few days and could release the stored power in only a short burst rather than in a steady current. Electrostatic machines were useful for studying electricity and entertaining people, but they could not generate sufficient electricity for useful applications. The major breakthroughs that paved the way for the large-scale, industrial use of electricity came with the discovery of electromagnetism.