The Day the Universe Changed - James Burke [141]
Herschel’s telescope. When he discovered the planet Uranus in 1781, Herschel was a musician struggling to finance his obsession with astronomy. Uranus brought him scientific honours and the patronage of George III.
Sound was recorded and played back for the first time in 1877 by Edison. By 1888, listening to music and recordings of celebrities on the Edison phonograph had become a popular form of family entertainment.
Six years before Maxwell’s final definitive paper linking electromagnetism and light in a common theory of wave propagation, the first transatlantic cable had been laid. Its use revealed to the least scientifically minded that when it was noon in London it was only six in the morning in Newfoundland. It also persuaded the public still further that science was concerned only with application.
This view was enhanced as never before by Thomas Edison, ‘the inventor of inventing’. This immensely prolific man, who reckoned to produce a minor invention every ten days and a major one every six months, unveiled device after device that captured the public imagination. The phonograph, the stock ticker, the electric pen, the kinetoscope, the duplex repeating telegraph, and over a thousand other patents poured out of his laboratory at Menlo Park, New Jersey, where he set up what was effectively the world’s first invention factory. The innovation that amazed the entire world and which certainly brought the most profound change to every aspect of living was the electric light, which Edison switched on at 3 pm on New Year’s Day 1879. The event was witnessed by three thousand specially invited guests brought there by a train which Edison had hired for the occasion. Almost single-handed, Edison did more than anyone else to widen the gulf of comprehension between science and the public by finally convincing ordinary people that gadgets were science.
Sketches of light bulbs from Edison’s notebook. The incandescent bulb he produced in 1879 burnedfor 45 hours and was the first commercially feasible electric light. .In 1880 he succeeded in producing a bulb that burned for 170 hours.
Edison assiduously cultivated the public image of the tireless inventor in photographs like this one, taken in his Orange, N.J. laboratory in 1888.
Hertz’s experiment. The emitter on the left produces a spark, whose energy is radiated. On the right, a secondary circuit with a gap in it is energised by the radiation enough to build up a charge and produce its own small spark.
Meanwhile, the question of the ether and its function continued to trouble the scientists. If Maxwell had been right and if light and other radiation took time to travel, would time differences be discovered between earth and the visible stars? It all depended on whether or not the ether existed. In 1885, Heinrich Hertz, working in Karlsruhe, found the answer. He had decided to try to create electromagnetic waves in the open air in order to see if their propagation took place at a finite rate and if they behaved like light.
Hertz set up two polished metal balls close to each other and produced a spark by sending alternate surges of current into the balls. Would this spark in turn produce waves of energy moving through space at the speed of light? The coil producing the current was attached to two solid brass cylinders 1 inch by 10 inches, with 1½ inch diameter solid balls on their ends. Behind the balls, which were ⅛ inch apart, stood a concave zinc sheet, acting as a mirror. If electromagnetism behaved like light it would be reflected forward to a series of secondary, open circuits 15 yards away.
Although the results were hard to see, the secondary circuits