Leyden jars, Museum Boerhave, Leyden
The Leyden jar was the original capacitor.
Around 1650, Otto von Guericke built a crude friction generator - a sulphur ball that rotated at high speed on a shaft. When Guericke held his hand against the ball and turned the shaft quickly, a static electric charge built up. In 1745, another German, Ewald Georg von Kleist, found a method of storing this charge. He lined a glass jar with silver foil, and charged the foil with a friction machine. Kleist was convinced that a substantial charge could be collected when he received a significant shock from the device.
In 1746, Pieter van Musschenbroek of Leyden, Netherlands, independently made the same discovery. The device is known as a "Leyden jar" because Musschenbroek made the storage jar known to the scientific world.