From Wikipedia

Empire of the Air

 In the late 19th century it was clear to various scientists and experimenters that wireless communication was possible. Various theoretical and experimental innovations led to the development of radio and the communication system we know today. Some early work was done by local effects and experiments of electromagnetic induction. Many understood that there was nothing similar to the "ethereal telegraphy" and telegraphy by induction; the phenomena being wholly distinct. Wireless telegraphy was beginning to take hold and the practice of transmitting messages without wires was being developed. Many people worked on developing the devices and improvements.