the other side to the ground. This device was used in meteorological work to detect the approach of thunderstorms. He was, therefore, the first to use an antenna in connection with the real wireless telegraph. Having thus increased the working range of the receiver, it only remained to connect an antenna to the transmitter; this was done by Marconi in 1896. Since that time improvements have been made in the transmitting and receiving devices, and the distances of communication have been increased from a few hundred feet to several thousand miles.
The development of very sensitive detectors has had much to do with the progress of wireless telegraphy. The Fessenden electrolytic detector is, probably, the most efficient type.
Nikola Tesla has rendered important service in the development of high-frequency apparatus, and is now experimenting with a system to transmit power without the use of wires.
