The Making of the Atomic Bomb

sometimes sickening insecurity, the stiff scar of his colonial birth.

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.”)

“Magnetization of iron by high-frequency discharges” was skilled observation and brave dissent. With 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.

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. Thomson 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. Marconi only caught up with him in September.

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 fiancde 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.”

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 protdgd Peter Kapitza, for example, when Ka-pitza was offered consulting work in industry, “You cannot serve God and Mammon at the same time.” The 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. “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. Yet 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.

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 Rontgen discovered X rays radiating from the fluorescing glass wall of a cathode-ray tube. Rontgen 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 ?100,00 °Company on its promotion, but no more.”

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 Rontgen 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.” The tone is chastened and not nearly convinced, as if a ghostly, parental J. J. Thomson were speaking through Rutherford to his fianc6e. 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.

It seems probable that J. J. Thomson sat eager young Ernest Rutherford down in the darkly paneled rooms of the Gothic Revival Cavendish Laboratory that Clerk Maxwell had founded, at the university where Newton wrote his great Principia, and kindly told him he could not serve God and Mammon at the same time. It seems probable that the news that the distinguished director of the Cavendish had written the Olympian Lord Kelvin about the commercial ambitions of a brash New Zealander chagrined Rutherford to the bone and that he went away from the encounter feeling grotesquely like a parvenu. He would never make the same mistake again, even if it meant strapping his laboratories for funds, even if it meant driving away the best of his protdges, as eventually it did. Even if it meant that energy from his cherished atom could be nothing more than moonshine. But if Rutherford gave up commercial wealth for holy science, he won the atom in exchange. He found its constituent parts and named them. With string and sealing wax he made the atom real.

The sealing wax was blood red and it was the Bank of England's most visible contribution to science. British experimenters used Bank of England sealing wax to make glass tubes airtight. Rutherford's earliest work on the atom, like J. J. Thomson's work with cathode rays, grew out of nineteenth-century examination of the fascinating effects produced by evacuating the air from a glass tube that had metal plates sealed into its ends and then connecting the metal plates to a battery or an induction coil. Thus charged with electricity, the emptiness inside the sealed tube glowed. The glow emerged from the negative plate — the cathode — and disappeared into the positive plate — the anode. If you made the anode into a cylinder and sealed the cylinder into the middle of the tube you could project a beam of glow — of cathode rays — through the cylinder and on into the end of the tube opposite the cathode. If the beam was energetic enough to hit the glass it would make the glass fluoresce. The cathode-ray tube, suitably modified, its all-glass end flattened and covered with phosphors to increase the fluorescence, is the television tube of today.

In the spring of 1897 Thomson demonstrated that the beam of glowing matter in a cathode-ray tube was not made up of light waves, as (he wrote drily) “the almost unanimous opinion of German physicists” held. Rather,