Wireless by Conduction
On October 18, 1842, Morse laid wires between Governor's Island and Castle Garden, New York, a distance of about a mile. [For a complete description click here] Part of that circuit was under water, indeed, Morse wanted to show that an underwater cable could transmit signals as well as a copper wire suspended on poles. But before he could complete this demonstration a passing ship pulled up his cable, ending, it seemed, his experiment. Undaunted, Morse proceeded without the cable, passing his telegraph signals through the water itself. This is wireless by conduction.
Over the next thirty years most inventors and developers concentrated on wireline telegraphy, that is, conventional telegraphy carried over wires suspended on poles. Few tinkered exclusively with wireless since basic radio theory had not yet been worked out and trial and error experimenting produced no consistent results. Telegraphy did produce a good understanding of wireless by induction (internal link), however, since wires ran parallel to each other and often induced rogue currents into other lines. University research and some field work did continue, though, with many people making contributions.