In 1866, Mahlon Loomis - an American dentist - conducted a wirelessly telegraph experiment to demonstrate the concept. He used two kites to fly in the air. On the first kite string, he installed an electric meter. The second kite string was fitted with an electromagnetic coil. The results of the experiment revealed that the magnetic field of the second coil had been deflected by the meter on the first kite string. This was the first time that an airborne signal had been transmitted. In the air, a rope was being flown. A few years later, the German physicist Heinrich Rudolph Hertz demonstrated that radio waves could be transmitted through space like light and heat.