A newly developed instrument shocked (most literally) scientists researching electricity in 1745: the Leyden Jar or Amplifiying Jar. The Prelate Ewald Jürgen von Kleist and the Leyden based physicist Musschenbroek described the initial version of the device and its effect independently. However, Kleist’s findings could initially not be reproduced by his correspondents.
The Leyden Jar is basically a condensator where the glass of the bottle serves as a dielectric. Initially, the hand of the experimenter formed the outer coating, soon after the initial experiments, a metal coating was introduced instead. The inner coating was initially water, soon to be replaced either by metal filings or a metal foil glued to the inside of the glass and connected with the rod inserted into the (wooden) lid of the jar.
Silva, C. C., & Heering, P. (2018). Re-examining the early history of the Leiden jar: Stabilization and variation in transforming a phenomenon into a fact. History of Science, 56(3), 314-342.
Winkler, Johann Heinrich (1746): Die Stärke der Electrischen Kraft des Wassers in gläsernen Gefäßen. Leipzig: Breitkopf.