Experiments with the electric machine were largely aided by the discovery of the Leyden Jar. Resonance was noticed early on in experiments with the Leyden jar, invented in 1746. He is credited with the invention of the first capacitor in 1746&colon; the Leyden jar. Powerful transoceanic transmitters often had huge Leyden jar capacitor banks filling rooms "(see pictures above)". The original capacitor was the Leyden jar developed in the 18th century. A typical Leyden jar of one pint size has a capacitance of about 1 nF. At a young age he built a Leyden jar to play pranks on his friends. Franklin designed a "dissectible" Leyden jar "(right)", which was widely used in demonstrations.