Alfred Varley noticed a remarkable fall in the resistance of masses of metallic filings under the action of atmospheric electrical discharges. Towards the end of 1875, while experimenting with the telegraph, Thomas Edison noted a phenomenon that he termed "etheric force", announcing it to the press on November 28. He abandoned this research when Elihu Thomson, among others, ridiculed the idea, claiming it was electromagnetic induction. In 1879 the experimenter and inventor David Edward Hughes, working in London, discovered that a bad contact in a Bell telephone he was using in his experiments seemed to be sparking when he worked on a nearby induction balance (an early form of metal detector). He developed an improved detector to pick up this unknown "extra current" based on his new microphone design (similar to later detectors known as coherers or crystal detectors) and developed a way to interrupt his induction balance to produce a series of sparks. By trial and error experiments he eventually found he could pick up these "aerial waves" as he carried his telephone device down the street out to a range of . On February 20, 1880, he demonstrated his experiment to representatives of the Royal Society including Thomas Henry Huxley, Sir George Gabriel Stokes, and William Spottiswoode, then president of the Society. Stokes was convinced the phenomenon Hughes was demonstrating was merely electromagnetic induction, not a type of conduction through the air. Hughes was not a physicist and seems to have accepted Stokes observations and did not pursue the experiments any further. His work may have been mentioned in William Crookes' 1892 Fortnightly Review review of 'Some possibilities of electricity' article as an unnamed individual whose experiment Crookes participate in. Development of radio waves The Branly detector In 1890, Édouard Branly demonstrated what he later called the "radio-conductor," which Lodge in 1893 named the coherer, the first sensitive device for detecting radio waves. Shortly after the experiments of Hertz, Branly discovered that loose metal filings, which in a normal state have a high electrical resistance, lose this resistance in the presence of electric oscillations and become practically conductors of electricity. This Branly showed by placing metal filings in a glass box or tube, and making them part of an ordinary electric circuit. According to the common explanation, when electric waves are set up in the neighborhood of this circuit, electromotive forces are generated in it which appear to