Humans have long known that rubbing substances together can produce static electricity. The ancient Greeks rubbed together balls of amber on spindles to generate sparks. Electrical effects puzzled early scientists, but they lacked a means of generating electricity in order to study it.
Then, in the mid 1600s, German physicist Otto von Guericke came up with a very early version of a machine that did just that: the electrostatic generator. A version of the machine dating from 1785 is pictured here. It generates a high voltage charge at very low current.