Etheric force is a term Thomas Edison coined to describe a phenomenon later understood as high frequency electromagnetic waves—effectively, radio.
Edison, with this small amount of evidence, announced that it was "a true unknown force",[2] since he believed that the spark transmitted electricity without carrying any charge.
He was also interested in finding new forces as a means for providing scientific explanations for spiritualist, occult and other allegedly supernatural phenomena following his disenchantment with Helena Blavatsky's Theosophy.
Edison's apparatus consisted of a spark gap vibrating at a high frequency powered by batteries and connected to tin foil sheet about 12 by 8 inches, effectively acting as an antenna.
[4] Thomas Edison announced the discovery, which he called etheric force, to the press and reports began to appear in Newark newspapers from November 29, 1875.