Benjamin Franklin (plus and minus)
The Leyden Jar very quickly became a global sensation. Ben Franklin referred to it as Musschenbroek’s “wonderful bottle” in a letter to a friend on July 28 1747, and over the next couple of years tried to describe the phenomenon with limited vocabulary that sounds curious these days. “Electrical fire”, “electrical atmosphere”, and “substance” are some of the words he uses to describe the mechanism. But among his most important dialectic (and dielectric?) contribution is the introduction of “positive” and “negative”. Just like Musschenbroek’s literal thinking of “fluids” had led him to use a jar, Franklin chose to imagine a summation and subtraction (of the number of strokes in the Hauksbee) where a balance is necessary. He tries to look for analogies in other systems (such as vacuum and pressure), where a balance is always what nature seeks. But what baffles him the most is the fact that this balance only happens when “communication from without” is made. “So wonderful are these two states of Electricity, the plus and minus, combined and balanced in this miraculous bottle!” Through these analogies and other observations, Franklin dares to make a connection between the observations and effects of electricity and water in a Lyden jar and the forces of nature that for millennia had fascinated and tormented humans: lightning. In an undated letter, likely 1749, he hypothesized on the formation of rain as a consequence of electricity (not quite correct, but ok). He proceeds to describe the formation of lightning; speaking of its dangers, such as why we shouldn’t seek shelter under a tree in a thunderstorm, or curiosities, such as how lightning melts the metal coins in people’s pockets but not necessarily burns their clothes. The age of Enlightenment gave courage to our questions, and Franklin was pointing the way to a connection between the divine and the earthly
Source: Experiments and observations on electricity. Franklin, Benjamin; Collinson, Peter. Printed and sold by E. Cave, at St. John's Gate, 1751
Public Domain
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Full disclosure, I may occasionally borrow a sentence from Will Durant's Story of Civilization. I absolutely love that collection!