Richard Rhodes - The Making of the Atomic Bomb

It was a hard and healthy childhood. Rutherford capped it by winning scholarships, first to modest Nelson College in nearby Nelson, South Island, then to the University of New Zealand, where he earned an M.A. with double firsts in mathematics and physical science at twenty-two. He was sturdy, enthusiastic and smart, qualities he would need to carry him from rural New Zealand to the leadership of British science. Another, more subtle quality, a braiding of country-boy acuity with a profound frontier innocence, was crucial to his unmatched lifetime record of physical discovery. As his protégé James Chadwick said, Rutherford’s ultimate distinction was “his genius to be astonished.” He preserved that quality against every assault of success and despite a well-hidden but sometimes sickening insecurity, the stiff scar of his colonial birth. 111, 112

His genius found its first occasion at the University of New Zealand, where Rutherford in 1893 stayed on to earn a B.Sc. Heinrich Hertz’s 1887 discovery of “electric waves”—radio, we call the phenomenon now—had impressed Rutherford wonderfully, as it did young people everywhere in the world. To study the waves he set up a Hertzian oscillator—electrically charged metal knobs spaced to make sparks jump between metal plates—in a dank basement cloakroom. He was looking for a problem for his first independent work of research.

He located it in a general agreement among scientists, pointedly including Hertz himself, that high-frequency alternating current, the sort of current a Hertzian oscillator produced when the spark radiation surged rapidly back and forth between the metal plates, would not magnetize iron. Rutherford suspected otherwise and ingeniously proved he was right. The work earned him an 1851 Exhibition scholarship to Cambridge. He was spading up potatoes in the family garden when the cable came. His mother called the news down the row; he laughed and jettisoned his spade, shouting triumph for son and mother both: “That’s the last potato I’ll dig!” (Thirty-six years later, when he was created Baron Rutherford of Nelson, he sent his mother a cable in her turn: “Now Lord Rutherford, more your honour than mine.” 113, 114)

“Magnetization of iron by high-frequency discharges” was skilled observation and brave dissent. 115With deeper originality, Rutherford noticed a subtle converse reaction while magnetizing iron needles with high-frequency current: needles already saturated with magnetism became partly demagnetized when a high-frequency current passed by. His genius to be astonished was at work. He quickly realized that he could use radio waves, picked up by a suitable antenna and fed into a coil of wire, to induce a high-frequency current into a packet of magnetized needles. Then the needles would be partly demagnetized and if he set a compass beside them it would swing to show the change.

By the time he arrived on borrowed funds at Cambridge in September 1895 to take up work at the Cavendish under its renowned director, J. J. Thomson, Rutherford had elaborated his observation into a device for detecting radio waves at a distance—in effect, the first crude radio receiver. Guglielmo Marconi was still laboring to perfect his version of a receiver at his father’s estate in Italy; for a few months the young New Zealander held the world record in detecting radio transmissions at a distance. 116

Rutherford’s experiments delighted the distinguished British scientists who learned of them from J. J. Thomson. They quickly adopted Rutherford, even seating him one evening at the Fellows’ high table at King’s in the place of honor next to the provost, which made him feel, he said, “like an ass in a lion’s skin” and which shaded certain snobs on the Cavendish staff green with envy. 117Thomson generously arranged for a nervous but exultant Rutherford to read his third scientific paper, “A magnetic detector of electrical waves and some of its applications,” at the June 18, 1896, meeting of the Royal Society of London, the foremost scientific organization in the world. 118Marconi only caught up with him in September. 119

Rutherford was poor. He was engaged to Mary Newton, the daughter of his University of New Zealand landlady, but the couple had postponed marriage until his fortunes improved. Working to improve them, he wrote his fiancée in the midst of his midwinter research: “The reason I am so keen on the subject [of radio detection] is because of its practical importance…. If my next week’s experiments come out as well as I anticipate, I see a chance of making cash rapidly in the future.” 120

There is mystery here, mystery that carries forward all the way to “moonshine.” Rutherford was known in later years as a hard man with a research budget, unwilling to accept grants from industry or private donors, unwilling even to ask, convinced that string and sealing wax would carry the day. He was actively hostile to the commercialization of scientific research, telling his Russian protégé Peter Kapitza, for example, when Kapitza was offered consulting work in industry, “You cannot serve God and Mammon at the same time.” 121The mystery bears on what C. P. Snow, who knew him, calls the “one curious exception” to Rutherford’s “infallible” intuition, adding that “no scientist has made fewer mistakes.” The exception was Rutherford’s refusal to admit the possibility of usable energy from the atom, the very refusal that irritated Leo Szilard in 1933. 122“I believe that he was fearful that his beloved nuclear domain was about to be invaded by infidels who wished to blow it to pieces by exploiting it commercially,” another protege, Mark Oliphant, speculates. 123Yet Rutherford himself was eager to exploit radio commercially in January 1896. Whence the dramatic and lifelong change?

The record is ambiguous but suggestive. The English scientific tradition was historically genteel. It generally disdained research patents and any other legal and commercial restraints that threatened the open dissemination of scientific results. In practice that guard of scientific liberty could molder into clubbish distaste for “vulgar commercialism.” Ernest Marsden, a Rutherford-trained physicist and an insightful biographer, heard that “in his early days at Cambridge there were some few who said that Rutherford was not a cultured man.” One component of that canard may have been contempt for his eagerness to make a profit from radio. 124

It seems that J. J. Thomson intervened. A grand new work had abruptly offered itself. On November 8, 1895, one month after Rutherford arrived at Cambridge, the German physicist Wilhelm Röntgen discovered X rays radiating from the fluorescing glass wall of a cathode-ray tube. Röntgen reported his discovery in December and stunned the world. The strange radiation was a new growing point for science and Thomson began studying it almost immediately. At the same time he also continued his experiments with cathode rays, experiments that would culminate in 1897 in his identification of what he called the “negative corpuscle”—the electron, the first atomic particle to be identified. He must have needed help. He would also have understood the extraordinary opportunity for original research that radiation offered a young man of Rutherford’s skill at experiment.

To settle the issue Thomson wrote the grand old man of British science, Lord Kelvin, then seventy-two, asking his opinion of the commercial possibilities of radio—“before tempting Rutherford to turn to the new subject,” Marsden says. Kelvin after all, vulgar commercialism or not, had developed the transoceanic telegraph cable. “The reply of the great man was that [radio] might justify a captial expenditure of a £100,000 Company on its promotion, but no more.” 125

By April 24 Rutherford has seen the light. He writes Mary Newton: “I hope to make both ends meet somehow, but I must expect to dub out my first year…. My scientific work at present is progressing slowly. I am working with the Professor this term on Röntgen Rays. I am a little full up of my old subject and am glad of a change. I expect it will be a good thing for me to work with the Professor for a time. I have done one research to show I can work by myself.” 126The tone is chastened and not nearly convinced, as if a ghostly, parental J. J. Thomson were speaking through Rutherford to his fiancée. He has not yet appeared before the Royal Society, where he was hardly “a little full up” of his subject. But the turnabout is accomplished. Hereafter Rutherford’s healthy ambition will go to scientific honors, not commercial success.