Origin and use of the term metalloid antimony and tellurium, was recorded merely on a 'sometimes' basis. Use of the term metalloid subsequently underwent a period of great flux up to 1940. Consensus as to its application to intermediate or borderline elements did not occur until the ensuing years, between 1940 and 1960. In 1947, Pauling included a reference to metalloids in his classic and influential textbook, "General chemistry: An introduction to descriptive chemistry and modern chemical theory." He described them as 'elements with intermediate properties ... occupy[ing] a diagonal region [on the periodic table], which includes boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.' In 1959
Crystal detector voltage of around 0.2V from a battery to make it more sensitive. Although the zincite-chalcopyrite "Perikon" was the most widely used crystal-to-crystal detector, other crystal pairs were also used. Zincite was also used with carbon, galena, and tellurium. Silicon was used with arsenic, antimony and tellurium crystals. During the first three decades of radio, from 1888 to 1918, called the "wireless telegraphy" or "spark" era, primitive radio transmitters called spark gap transmitters were used, which generated radio waves by an electric spark. These transmitters were unable to produce the continuous sinusoidal waves which are used to transmit audio (sound) in