English: Drawing (left) showing a dissectible Leyden jar. A Leyden jar, the first form of capacitor, was an antique electrical device that stored static electricity. This disassemblable version, Invented by American statesman and scientist Benjamin Franklin, was used during the 19th century to demonstrate the erroneous theory that the electric charge in a Leyden jar was stored in its glass dielectric, not on the metal plates. The assembled jar was first charged with electricity. When it was disassembled, the pieces could be handled and were found to be uncharged. However, when it was reassembled, a large spark could still be obtained from the jar. This was supposed to show that the electric charge was inside the glass. However, it was later shown that this was a special effect due to charge transferred to the glass by corona discharge when the jar was disassembled. Leyden jars, like other capacitors, store their charge on their metal plates.