perimentally demonstrated that electric waves exist in free ether until 1888, when this great discovery was made by Professor Hertz.
The apparatus used by Professor Hertz, to generate the high-frequency oscillations, was, naturally, a simplified form of the generating apparatus of to-day, but without any antenna or ground connections. For a detector he employed a loop of wire with the ends nearly touching one another. When the generator, or “oscillator,” was set in operation, and the loop of wire was held near it, minute electric sparks were seen to pass between the ends of the wire constituting the loop, and the existence of the free ether waves was thus proved.
So great a discovery naturally set scientists, the world over, to experimenting, and in 1890 Dr. Branly discovered that loose metal filings, which normally have a high resistance, become fairly good conductors of electricity in the presence of electric oscillations. Dr. Branly demonstrated this by placing the filings between metal plugs in a glass tube, the device (which he called a Radio-Conductor) being connected in circuit with a battery and electric indicator. Professor Lodge called the Branly device a Coherer, and as it was found to be more sensitive than the Hertz detector, Professor Lodge combined the Hertz oscillator with the coherer in 1894, this forming the first complete wireless set.
In 1895 Count Popoff attached a vertical wire to one side of the coherer of the Lodge receiver, and connected