Known as a microwave distance-measuring device, the Tellurometer was invented by Durban’s Dr Trevor Lloyd Wadley in 1959. The Tellurometer emits an electronic wave, a remote station absorbs and re-sends the wave back in a more complex form, and the distance the waves travelled is measured. It is mostly used to survey rough terrain, especially between mountain tops.
In 1958, the New York Times reported that through the use of the Tellurometer it had suddenly become possible for two men to measure the island of Manhattan in three-and-a-half hours, whereas previously it would have taken four men five days with traditional surveying methods.
Over 20 000 Tellurometers were produced in Cape Town and distributed worldwide under the patent for the Tellurometer held by the South African Council for Scientific and Industrial Research (CSIR). Eventually production was taken over by Plessey, South Africa.