Tall and charismatic, twenty-seven-year-old Bohr was a gifted sportsman who had played top-level soccer in his native Denmark alongside his brother, Harald, who had gone on to represent their country at the 1908 Olympic Games. Bohr became not only a favourite of Rutherford but also of the professor’s wife, Mary, who adopted the Dane as a surrogate son. If anyone challenged Rutherford about the incongruity of his closeness to a theoretician, the former Nelson College rugby forward would opine, ‘no, no, Bohr’s different – he’s a football player’.14
Bohr applied the quantum theories that had been initially developed in 1900 by German Max Planck to solve the quandary of Rutherford’s atomic model. The basis of Planck’s assertions, which would revolutionise the understanding of energy forces, was that light and other electromagnetic waves were emitted in discrete packets of energy that he dubbed quanta. In 1912, Bohr essentially showed that when electrons came into direct contact with energy forms such as light or radioactive heat, they would absorb that energy and jump into an altogether new orbit path, which would prevent them from collapsing into the atom’s nucleus. A quantum leap, as it would later be called.
Consequently, by 1913, the world would know the end product of years of detective work as the Rutherford–Bohr atomic model.
* * *
By this time, Rutherford was without peer in experimental physics. While his laboratory time at Manchester was largely devoted to counting alpha particle scintillations and further testing his ideas on atomic structure, he also maintained a hectic schedule of scientific lectures, international conferences and exclusive social events. These included the 1912 function at Windsor Castle to celebrate the Royal Society’s 250th anniversary, where he was introduced to King George V and Queen Mary. The following year, at the 1913 meeting of the British Association for the Advancement of Science held in Birmingham, he helped organise for Marie Curie to travel to Britain to receive an honorary degree from Birmingham University. She responded to the gesture by noting, in a rare media interaction, that Rutherford was ‘the one man living who promises to confer some inestimable boon on mankind as a result of the discovery of radium’.15
When the 1914 New Year Honours list was published, the forty-two-year-old son of a New Zealand flax farmer and his schoolteacher wife was confirmed as Sir Ernest Rutherford. He responded to the cascade of well-wishers with typical humility, writing to his former McGill research student Otto Hahn that he did not place great significance upon ‘such forms of decoration for they have obvious disadvantages in the case of a scientific man like myself’.16
He gained greater pleasure in documenting thirteen-year-old Eileen’s excitement at the succession of telegrams that greeted the news – though she voiced adolescent concern that neither her father nor ‘Lady Rutherford’ (as Mary had become) carried sufficient ‘swank’ to justify such recognition. Upon seeing her father clad in the outfit he would wear to Buckingham Palace to be knighted, complete with ceremonial sword dangling at his side, she teased that he resembled a ‘somewhat superior footman’. Accordingly, Rutherford self-mockingly advised her that ‘henceforth, young lady, you may address me as “Sir Ernest”’.
If Rutherford was not especially impressed by his new societal status, he could appreciate the benefits it afforded. Later that year, he was prominent among 300 or so delegates who sailed en masse to Australia for a series of British Association for the Advancement of Science meetings. This event had been organised primarily to meet an overwhelming curiosity among members to study the continent’s egg-laying monotreme, the platypus.
As Ernest and Mary prepared to sail for the southern hemisphere in mid-1914, he expressed his distress over the assassination of Archduke Franz Ferdinand in Sarajevo. ‘The Hapsburghs [sic] have a very tragic family history,’ he noted.17
That tragedy was about to be visited upon the world in the form of brutality that not even the prescient professor could have foreseen. It was while the flotilla of luminaries made their way from Perth to Adelaide, where the first four-day congress was scheduled to begin on 8 August, that Britain declared war on Germany.
* * *
The news broken by the headmaster to Mark Oliphant’s high school class had a more profound impact on Britain’s science fraternity as they disembarked at Port Adelaide. The RMS Orvieto, on which many of the association members had travelled, was immediately requisitioned for war duties, and carried the first wave of Australian troops to the distant battlefront.
Rutherford, however, continued with his lecture commitments as planned, and also went ahead with the New Zealand visit he and Mary had appended to the journey. In Christchurch, Rutherford was afforded a civic reception and delivered a lecture at Canterbury College entitled ‘Evolution of the Elements’. It was the same topic on which he had made his first presentation to the college’s scientific society before leaving for Cambridge almost twenty years earlier. He and Mary also returned to their families for the first time since he had earned his Nobel Prize and knighthood. They then undertook a leisurely return to England via Canada, arriving home in Manchester soon after New Year 1915.
However, other members of the British Association delegation had made a beeline for Britain as soon as war was declared, to fulfil their patriotic duty. Among them was Henry Moseley, another of Rutherford’s Manchester ‘boys’, who was considered among the most brilliantly gifted. Moseley, known to all as Harry, had gained kudos at an early age for establishing the sequence of atomic numbers that re-ordered Dmitri Mendeleev’s 1869 table of elements. Like Soddy, Marsden and later Oliphant, Moseley had become a revered member of Rutherford’s student coterie because of his rare scientific insight, and appetite for hard work.
Moseley had enlisted as a signalling officer with the 38th Brigade, which made landfall at Gallipoli on 6 August 1915. He was unaware of Rutherford’s entreaties to officials to find the young man means to contribute to the war effort through scientific work, and thereby have him recalled from active service. In the course of telephoning through an order four days after deploying on the Gallipoli Peninsula, Moseley was shot through the head by a sniper and died aged twenty-seven. As per his will, his earthly wealth was then bequeathed to the Royal Society to be used for the furthering of scientific research. Rutherford wrote a moving obituary for Nature magazine.
It is a national tragedy that our military organisation at the start was so inelastic as to be unable, with a few exceptions, to utilise the offers of services of our scientific men except as combatants in the firing line. Our regret for the untimely death of Moseley is all the more poignant because we recognise that his services would have been far more useful to this country in numerous fields of scientific enquiry rendered necessary by the war than by the exposure to the chances of a Turkish bullet.18
Like almost everyone who lived through the hardships and horrors of the First World War, Rutherford came to harbour myriad personal reasons to abhor modern warfare and its increasingly sophisticated weaponry. His uncle – Martha Rutherford’s brother, Archie Thompson – sailed from the southern dominions to answer the call but did not survive the Gallipoli campaign. Rutherford’s future son-in-law and Cavendish colleague, Ralph Fowler, was severely wounded on the same stretch of peninsula and would spend the rest of his life tortured by serious lung ailments. The youngest son of William Bragg, Rutherford’s early inspiration and lifelong friend, died at Gallipoli after both his legs were blown off by an artillery shell.
Rutherford, too, made a concerted contribution to the war effort – though in keeping with his views, it came not through military service but scientific expertise. The improvements he helped bring to the field of underwater warfare, many of which were trialled in the water tank he had built in his basement workroom at Manchester University, yielded the technology that became recognised as sonar.
Often, however, scientific input into areas of military expertise was conceitedly opposed by the uniformed class. Rutherford repeatedly butted heads with infuriatingly intractable militar
y men whom he saw as suspicious and resentful of civilian scientists. On one occasion, he was sent to Hawkcraig base near the mouth of Scotland’s Firth of Forth to investigate the use of underwater microphones in submarines – only to be abruptly told he would not be granted access to any of the navy’s fleet because they were all required for active duty.
It was understandable, therefore, that he returned to his laboratory whenever possible to exercise his preference for sub-atomic matter over matters submarine. Near the end of the conflict, he missed most of a meeting held by the Anti-Submarine Committee, of which he was a key member. As he explained in a message sent to unimpressed delegates, he needed to complete a round of experiments in his laboratory, where he believed he had created history by successfully splitting the atomic nucleus. ‘If this were true,’ his apology offered, ‘its ultimate importance is far greater than that of the war.’19
Rutherford also enjoyed poking private fun at bumptious individuals who exuded self-importance but no self-awareness. ‘He’s like the Euclidian Point,’ he said of a man who fitted that assessment, drawing deeply on his pipe for dramatic effect. ‘He has position without magnitude.’20
* * *
Rutherford’s Manchester colleague Ernest Marsden, who had been integral to the gold foil experiments, was another to choose a direct role in the war effort. Marsden had already accepted the position of Professor of Physics at New Zealand’s Victoria University when war erupted, having been recommended for the job by Rutherford. But soon after arriving in Wellington to take up his new role, he signed up with the New Zealand Expeditionary Force, and his contribution as a signals engineer in Europe earned him a Military Cross.
It was while Marsden was undergoing military training that Rutherford inquired whether his former student would object to him revisiting some of the research work begun by Marsden at Manchester before the outbreak of fighting. On receiving his former student’s blessing, Rutherford ran his own series of tests using alpha particles to bombard atoms of hydrogen. He was intrigued by Marsden’s reports that some of the emanations had slammed into the scintillation screen with far greater force than that used to originally propel the alpha bullets.
At war’s end, before he sailed home to New Zealand, Marsden made a farewell visit to Manchester University, where Rutherford hurried him to the laboratory to take a look at what his continuation of the earlier experiments had revealed.
Marsden saw that Rutherford had replaced his original glass apparatus with an elegant brass cylinder that was less susceptible to radioactive contamination. He explained how he had filled it with dry air, then with water, then oxygen and finally carbon dioxide as he searched for a source of the powerful hydrogen atoms that were being detected.
None of these substances produced startling results on the scintillation screen when hit with a barrage of alpha particles. But when the chamber was filled with pure nitrogen, the screen lit up like the Western Front in miniature.
Rutherford then explained to Marsden how he had used magnetic fields to verify that the particles hitting the screen were positively charged hydrogen atoms that had been ‘chipped off’ the nitrogen nuclei. The process had effectively changed atoms of nitrogen into altogether different elements: hydrogen and oxygen.
It was the same form of transmutation through natural radioactivity that Rutherford had witnessed in his laboratory at McGill. Only this time it had been manufactured artificially in his darkened Manchester basement.
As he sat with colleagues waiting for their eyes to adjust to the blackness ahead of the never-before-witnessed spectacle, Rutherford warned with a laugh: ‘you know, we might go up through the roof’.21
* * *
Rutherford was in France, on Admiralty business related to submarine research, in November 1918 as the war entered its final days. He noted the contrast between the high spirits of Parisians and the sombre sight of rows of captured German heavy artillery lined up along the Place de la Concorde. ‘It is a very exciting time to live in but people here are very quiet and refrain from celebrations till our main enemy goes under,’22 he wrote to his mother, as the world awaited Germany’s surrender.
It would take until the following year for the findings of the investigations he had revealed to Marsden to be published, carrying the deliberately unremarkable title ‘Collision of Alpha Particles with Light Atoms’. However, the paper clearly proclaimed Rutherford’s stunning conclusion that the atoms liberated by the collision between alpha particles and nitrogen ‘are not nitrogen atoms but probably atoms of hydrogen . . . if this be the case, we must conclude that the nitrogen atom is disintegrated’.23
Newspapers quickly distilled these findings to a blunt announcement. Tiny fragments chipped off by collision they might have been, but for the first time, a human had knowingly instigated the splitting of an atom. While this made for an arresting headline and a high point of scientific inquiry, the deeper implications of what the potential destruction of the atom might ultimately yield for the planet and its inhabitants were not immediately obvious – even to Rutherford.
He simply concluded that, such was the force at which those fractured hydrogen atoms were expelled upon the scintillation screen, the source of that energy must have been the nitrogen nucleus itself (complete with the binding energy that held particles together). Thus he offered the first experimental proof of one of physics’ most familiar hypotheses: Einstein’s theory of special relativity, which includes the famous equation ‘E = mc2’.
More than a decade earlier, this theory had predicted the quotient at which mass might be transformed into energy, if such a means of disintegrating matter were somehow discovered. In Einstein’s equation, ‘c’ represents the speed of light, a dauntingly huge number even before it is multiplied by itself. If the equation rang true, then the level of energy that might be liberated by splitting the atoms of heavy elements – those with the greatest atomic mass (Einstein’s ‘m’) – was almost beyond comprehension. The heaviest naturally occurring element, as per Moseley’s revised periodic table, was uranium, with an atomic number of ninety-two. The atomic mass – the collective sum of masses of the protons, neutrons and electrons contained in a single atom – of naturally occurring uranium’s most common isotope is 238.
Until such time as Rutherford showed that the atom was not an indivisible entity, Einstein’s premise had existed on paper alone. Now the urgent aim of experimental physicists worldwide would be to devise more and more powerful means of exploding matter’s building blocks.
Rutherford would lead that charge, albeit within a different – if familiar – environment. At the height of his post-war fame, he was approached and appointed as Cavendish Professor of Physics at Cambridge University, taking over from his sixty-two-year-old mentor, J.J. Thomson.
To probe the inner-most secrets of the universe, Rutherford would build a team of the sharpest, most energetic minds that science had ever seen concentrated within a single laboratory.
6
A BENEVOLENT LORD
Cambridge, 1919 to 1927
Rutherford’s return to Cambridge as Cavendish Professor in 1919 brought him a sense of muted triumph. While the laboratory had maintained its reputation as a centre of excellence in experimental physics under J.J. Thomson’s continued stewardship, like most British and European institutions it bore significant scars from the Great War. Research had effectively ground to a halt as a bulk of the students and many staff rallied to the patriotic cause. A large experimental room had been reassigned to billet serving soldiers, and the technical workshops had turned out gauges for use in armaments, rather than vacuum tubes and precision instruments.
Rutherford had also wrestled with the notion of abandoning Manchester, where so many experimental triumphs had taken place, and where the Rutherford home had become a hub of social activity for physics department staff and students. Rutherford confided as much to his mother, after his appointment was confirmed in April 1919.
It was a difficult qu
estion to decide whether to leave Manchester as they have been very good to me. But I felt it probably best for me to come here, for after all it is the chief physics chair in the country and has turned out most of the physics professors of the last 20 years.
It will of course be a wrench pulling up my roots again and starting afresh to make new friends, but fortunately I know a good few people there already and will not be a stranger in Trinity College. The latter will no doubt offer me a Fellowship which will give me the rights of the College to dine there when I please.1
The other factor that dulled Rutherford’s excitement at inheriting the most prestigious post in global physics was the potential it carried to damage his relationship with Thomson, who was effectively being shunted aside. As he was considering the approach made to him by Cambridge, Rutherford wrote to his greatly admired former instructor: ‘If I decided to stand for the post, I feel that no advantages of the post could possibly compensate for any disturbance to our long continued friendship or for any possible friction, whether open or latent, that might possibly arise . . .’2
Rutherford’s angst was greatly smoothed by the reassuring response of Thomson: ‘If you do, you will find that I shall leave you an absolutely free hand in the management of the Laboratory . . .’3
That was not how it panned out in practicality, however; Thomson would request that a number of his previous privileges be retained to allow him to continue research work in the manner he had enjoyed.
* * *
In preparation for their move from Manchester, Mary Rutherford and seventeen-year-old Eileen travelled to their new home town so Eileen could sit a senior school entrance exam. As they strolled across the grassed Backs, they ventured upon an abandoned house on Queen’s Road that was being rapidly colonised by its voracious garden. Emboldened by the obvious neglect, the women broke in, and Mary felt an immediate affinity with the place.
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