Answer: Shocking Monks with a Battery
The first scientific, albeit unconventional, measurement of the speed of electricity was conducted in 1764 by French physicist Jean-Antoine Nollet.
In order to test the speed of electrical transmission, he gathered together hundreds of lengths of iron wire, roughly two hundred monks, and a large array of Leyden Jars (an early and primitive type of battery). The monks distributed themselves in a large circle approximately one mile in circumference with each monk holding a length of wire in one hand linking them to the next monk. Without a word of warning, Nollet discharged the contents of the Leyden Jar battery into the last length of wire, sending a large shock through the entire chain of monks.
Nollet was unable to successfully measure the actual speed of electricity with the experiment since all of the monks reacted simultaneously to the electric shock, leaving him to simply note that the transmission speed of electricity was extremely high and appeared to transverse the one mile length of monks almost instantaneously. This experiment planted the seed for the concept of telegraphy—the transmission of data over long lengths of wires using only electrical impulses.
If you’re curious how Nollet was able to find so many monks and convince them to participate in an experiment involving electrical shocks, it’s worth noting that in addition to his role as an early physicist, he was also a former deacon in the Catholic church, calling on his former colleagues to help him with his work.