Thunderstruck Read Online Free PDF

than that deployed by Lodge, and he experimented with different sizes and combinations of filings. At last he got a response, but the process proved fickle. The coherer “would act at thirty feet from the transmitter,” Marconi wrote, but “at other times it would not act even when brought as close as three or four feet.”
    It was maddening. He grew thinner, paler, but kept at it. “I did not lose courage,” he wrote. But according to Degna, “he did lose his youth” and took on a taciturnity that, by her account, would forever color his demeanor.
    He wanted distance. He knew that if his telegraphy without wires was ever to become a viable means of communication, he would need to be able to send signals hundreds of miles. Yet here in his attic laboratory he sometimes could not detect waves even an arm’s length from the spark. Moreover, established theory held that transmitting over truly long distances, over the horizon, simply was not possible. The true scholar-physicists, like Lodge, had concluded that waves must travel in the same manner as light, meaning that even if signals could be propelled for hundreds of miles, they would continue in a straight line at the speed of light and abandon the curving surface of the earth.
    Another man might have decided the physicists were right—that long-range communication was impossible. But Marconi saw no limits. He fell back on trial and error, at a level of intensity that verged on obsession. It set a pattern for how he would pursue his quest over the next decade. Theoreticians devised equations to explain phenomena; Marconi cut wire, coiled it, snaked it, built apparatus, and flushed it with power to see what would happen, a seemingly mindless process but one governed by the certainty that he was correct. He became convinced, for example, that the composition of the metal filings in the coherer was crucial to its performance. He bought or scavenged metals of all kinds and used a chisel to scrape loose filings of differing sizes, then picked through the filings to achieve uniformity. He tried nickel, copper, silver, iron, brass, and zinc, in different amounts and combinations. He inserted each new mixture into a fragile glass tube, added a plug of silver at each end, then sealed the apparatus and placed it within his receiving circuit.
    He tested each mixture repeatedly. No instrument existed to monitor the strength or character of the signals he launched into space. Instead, he gauged performance by instinct and accident. He did this for days and weeks on end. He tried as many as four hundred variations before settling on what he believed to be the best possible combination for his coherer: a fine dust that was 95 percent nickel and 5 percent silver, with a trace of mercury.
    At first he tried to use his transmitter to ring a bell at the far side of his laboratory. Sometimes it worked, sometimes not. He blamed the Branly-style coherer, calling it “far too erratic and unreliable” to be practical. Between each use he had to tap it with his finger to return the filings to their nonconducting state. He tried shrinking the size of the tube. He emptied thermometers, heated the glass, and shaped it. He moved the silver plugs within the tube closer and closer together to reduce the expanse of filings through which current would have to flow, until the entire coherer was about an inch and a half long and the width of a tenpenny nail. He once stated that it took him a thousand hours to build a single coherer. As a future colleague would put it, he possessed “the power of continuous work.”
    Marconi’s obsession with distance deepened. He moved the bell to the next room and discovered how readily the waves passed through obstacles. As he worked, a fear grew within him, almost a terror, that one day he would awaken to discover that someone else had achieved his goal first. He understood that as research into electromagnetic waves advanced, some other scientist or inventor or