he waves, they soon became known as Hertzian waves. 6 Newnes Guide to Radio and Communications Technology With the existence of the electromagnetic wave firmly established it did not take long before people started to think of using them for communicating. However, to be able to achieve this it was necessary to be able to have a much better way of detecting them. This came in the form of the coherer. A Frenchman named Edouard Branly initially designed it in 1890. He discovered that the resistance of a glass tube filled with metal filings fell from a very high resistance to a few hundred ohms when the filings cohered or clung together when an electrical discharge took place nearby. A small tap on the glass could reset it quite easily. After its initial discovery the coherer was greatly improved and popularized by an English scientist named Sir Oliver Lodge. Such were his improvements that in 1894 he was able to detect signals from a transmitter a few hundred yards away. It was around this time that a young Italian named Marconi started to experiment with Hertzian waves. His drive, intuition and business sense enabled this new science to progress much faster than it would otherwise have done. Marconi was born in Bologna in northern Italy in 1874, receiving a private education during his early years. Despite his parents' expecta- tions he failed to gain a place at Bologna University. Fortunately he had a growing interest in science and a family friend who was a lecturer at the university encouraged him. Marconi was allowed to sit through his lectures and through this he discovered about the new Hertzian waves. Marconi quickly became interested and soon started to perform many experiments in the attic of his parents' house. Early in the summer of 1895 he managed to transmit a signal a distance of a few yards. By the end of the summer he had succeeded in receiving a signal over 2 km away from the transmitter. Even at this early stage Marconi was able to see the commercial possibilities. Accordingly he approached the I