Stubblefield coil as a galvanic capacitor to power an Adams motor. No battery.
Galvanic pair here is a steel bolt and copper tube with a cotton layer between.
It runs as long as a cotton stays wet; if placed in the ground it can run till cotton gone, months, years.
Secondary coil lights a LED 'cause the primary field collapses.
But a real genius of Natan Stubblefield is a wireless power transmission through the ground.