Early Radio Discoveries
Over the next thirty years different inventors, including Preece and Edison, experimented with various induction schemes. You can read about many of them by clicking here (internal link). The most succesful systems were aboard trains, where a wire atop a passenger car could communicate by induction with telegraph wires strung along the track. A typical plan for that was William W. Smith's idea, contained in U. S. Pat. No. 247,127, which was granted on Sept 13, 1881. Edison, L. J. Phelps, and others came out later with improved systems. In 1888 the principle was successfully employed on 200 miles of the Lehigh Valley Railroad. Now, let's get back to true radio and Maxwell's findings, which lead to intense experimenting.
Maxwells' 1864 conclusions were distributed around the world and created a sensation. But it was not until 1888 that Professor Heinrich Hertz of Bonn, Germany, could reliably produce and detect radio waves. Before that many brushed close to detecting radio waves but did not pursue the elusive goal. The most notable were Edison and David Edward Hughes, who became the first person to take a call on a mobile telephone.
On November 22, 1875, while working on acoustical telegraphy, a science close to telephony, Thomas Alva Edison noticed unusual looking electro-magnetic sparks. Generated from a so called vibrator magnet, Edison had seen similar sparks from other eclectric equipment before and had always thought they were due to induction. Further testing ruled out induction and pointed to a new, unknown force. Although unsure of what he was observing, Edison leapt to amazing, accurate conclusions. This etheric force as he now named it, might replace wires and cables as a way to communicate. Under deadline to complete other inventions Edison did not pursue this mysterious force, although in later years he returned to consider it. Edison's vibrating magnet had in fact set up crude, oscillating electromagnetic waves, although these were too weak to detect at much distance. [Josephson]
An on-line Edison bioghrapy which touches on this subject is here. It is a 376K(!) file: http://www.bookrags.com/books/ehlai/PART32.htm (external link)