Or, for that matter, lightning?
Couple of previous threads from the FAQ to add to any answers here:
Answered by /u/Ragleur: https://www.reddit.com/r/AskHistorians/comments/24v121/how_was_static_electricity_rationalized_before
Answered by /u/sn34kypete:
https://www.reddit.com/r/AskHistorians/comments/2fg7di/before_the_discovery_of_electricity_what_did