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On 13 May 1897, Marconi, assisted by George Kemp, a Cardiff Post Office engineer, transmitted the first wireless signals over water to Lavernock (near Penarth in Wales) from Flat Holm. This led to speculation that it might be possible to eliminate both wires and therefore transmit telegraph signals through the ground without any wires connecting the stations. He called his invention a "recording telegraph". Caselli called his invention "Pantelegraph". Pantelegraph was successfully tested and approved for a telegraph line between Paris and Lyon. The economic advantage of doing this is greatest on long, busy routes where the cost of the extra step of preparing the tape is outweighed by the cost of providing more telegraph lines. And since conductance is proportional to cross-sectional area, resistive power loss is only reduced proportionally with increasing cross-sectional area, providing a much smaller benefit than the squared reduction provided by multiplying the voltage. These facts made the system impractical on ships, boats, and ordinary islands, which are much smaller than Great Britain or Greenland. The company finally succeeded in 1866 with an improved cable laid by SS Great Eastern, the largest ship of its day, designed by Isambard Kingdom Brunel.

Prominent experimenters along these lines included Samuel F. B. Morse in the United States and James Bowman Lindsay in Great Britain, who in August 1854, was able to demonstrate transmission across a mill dam at a distance of 500 yards (457 metres). Historically, two-pin sockets without earth were used in Britain, but their use is now restricted to sockets specifically designated for shavers and toothbrushes. They thought atmosphere current, connected with a return path using "Earth currents" would allow for wireless telegraphy as well as supply power for the telegraph, doing away with artificial batteries. It doesn’t really matter whether you have AC or DC motors, nowadays either can work with an AC or DC supply. Of course, as many railways use the running rails for signalling circuits as well, special precautions have to be taken to protect them from interference. The first machine to use punched tape was Bain's teleprinter (Bain, 1843), what is electric cable but the system saw only limited use. The late 1880s through to the 1890s saw the discovery and then development of a newly understood phenomenon into a form of wireless telegraphy, called Hertzian wave wireless telegraphy, radiotelegraphy, or (later) simply "radio". Several wireless electrical signaling schemes based on the (sometimes erroneous) idea that electric currents could be conducted long-range through water, ground, and air were investigated for telegraphy before practical radio systems became available.

Left: To make an efficient motor or generator windings have to be packed tight together, minimizing air spaces. A study of these demonstrations of radio, with scientists trying to work out how a phenomenon predicted to have a short range could transmit "over the horizon", led to the discovery of a radio reflecting layer in the Earth's atmosphere in 1902, later called the ionosphere. He would work on the system through 1895 in his lab and then in field tests making improvements to extend its range. Many scientists and inventors experimented with this new phenomenon but the consensus was that these new waves (similar to light) would be just as short range as light, and, therefore, useless for long range communication. Building on the ideas of previous scientists and inventors Marconi re-engineered their apparatus by trial and error attempting to build a radio-based wireless telegraphic system that would function the same as wired telegraphy. Multiple messages can be sequentially recorded on the same run of tape.

1⁄2 in) standard gauge track between the roll ways operate in the same manner. In 1865, a conference in Paris adopted Gerke's code as the International Morse code and was henceforth the international standard. The standard was aligned, where possible, with the proposed IEC standard for domestic plugs and socket-outlets. By the 1927 revision of BS 73 four sizes of two-pin plugs and sockets were standardized: 2 A, 5 A, 15 A and 30 A. This was later superseded by BS 372:1930 part 1 Two-pin Side-entry Wall Plugs And Sockets for Domestic Purposes. Small specialized padlocks are available to fit these holes, allowing "lockout" of hazardous equipment, by physically preventing insertion of locked plugs into a power receptacle. Despite its weaknesses, the tamper-resistant receptacle is superior to protective plastic outlet caps which must be individually installed on each receptacle (and are a choking hazard when removed), and to sliding covers that children easily learn to defeat. For added protection, WR receptacles should be shielded by "Extra-Duty While In-Use" or "Weather-Resistant" covers. The Japanese plug and socket with narrow insulating faces appear and work physically identical to NEMA 1-15, and such non-grounded receptacles are still common in Japan (though grounded 5-15R and 5-20R receptacles are slowly becoming more common).