Simplify the following text for a Grade 7 native English-speaking person.
Original: The idea for the Leyden jar was discovered by both German scientist and jurist Ewald Georg von Kleist , and by two Dutchmen â `` Musschenbroek and Cunaeus . It was in 1744 when von Kleist lined a glass jar with silver foil , and charged the foil with a friction machine .
Simplified: Ewald Georg von Kleist developed this system in Germany in 1744 .