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Saturday, March 5, 2011

Ernest Rutherford – the New Zealander who first described the nub of things on March 7th 1911


Tomorrow will mark the centennial of Ernest Rutherford’s presentation to the Manchester Literary and Philosophical Society in which the 39-year-old Professor of physics at Manchester University outlined his revolutionary new interpretation of the structure of the atom and the nature of its nucleus.

The UK Independent has already published a formal tribute in the form of an article by Manjit Kumar and I have rounded off this post by repeating it. But there are openings for more personal reflections from a New Zealand perspective.

After all Rutherford is our most distinguished son. He received a Nobel Prize in 1908, was knighted in 1914, decorated with the Order of Merit in 1925, and created Lord Rutherford of Nelson in 1931. As if that wasn’t enough, he also has an element – rutherfordium – named in his honour.

So I have drawn together some material on his family history and upbringing that goes some way to explaining how his extraordinary gifts arose and were fostered. It also complements my earlier post of 16th February: ‘Andrew Baird (1869-1944) - planting Scotland's far-famed tree in Southland, New Zealand', in exploring the contribution that has been made to New Zealand society by Scottish settlers.

Ernest Rutherford was the fourth of the 12 children of James Rutherford and Martha Thompson who had been married in 1866 in the Nelson district of the South Island of New Zealand. He was born in Spring Grove on 30th August, 1871. James was a Scot from Dundee and Martha was an English girl from Hornchurch, Essex.

Arguably, the mixture of sturdy and staunch Scots with staid status-seekers from the semi-feudal society of rural southern England has defined the New Zealand character. Thoroughly admirable in most respects, with a practical, collaborative and acquisitive turn of mind, their weaknesses are perhaps an immunity to irony and a tendency to regard humour as either unnecessary or unseemly.

Well, leaving my own possibly ungenerous footnotes aside, let’s explore Rutherford’s family.


Rutherford is very much a Border Scottish surname, focussing on Roxburgh but Ernest’s antecedents must have made an earlier migration to Dundee at some point prior to 1800. His grandfather George Rutherford married Barbara Adie on the 18th November, 1836. Both George (b 1805) and his wife (b 1807-8) had been born in Dundee.

The Marriage Records show that George was the son of John Rutherford and Jean McCurroch. Barbara was the daughter of Moses Adie who was recorded as a Cow Feeder (i.e. dairying crofter). George was recorded as a Wright (i.e. joiner or carpenter). McCurroch is a Highland (Banffshire) surname and Adie is widespread across the Grampians.

George and Barbara Rutherford travelled to New Zealand on the ‘Phoebe’, leaving London on 16th November 1842 and arriving on the 29th March 1843 in one of the earliest landings of New Zealand Society settlers in the Nelson area. George had been engaged to come to New Zealand to erect a sawmill for Captain Thoms at Motueka. At this time Ernest’s father James was five years old.

The ‘Phoebe’ was a small ship of 471 tons, captained by William Dale. The Rutherfords are recorded as follows in the manifest:

George 34 Wheelwright & Joiner
Barbara 31
Andrew 10
George 7
James 5
John 2

On their voyage out from Britain, the Rutherfords would have had occasion to get to know the Surgeon of the ‘Phoebe’ John Danforth Greenwood. Greenwood’s wife Sarah later established a considerable reputation among the early settlers as an artist, letter-writer and teacher.

The Greenwood family had settled in France prior to their New Zealand adventure and Danforth invested heavily in New Zealand Company sections in Wellington, Nelson and Motueka. Arriving at Nelson on 29 March 1843, the Greenwoods found that their balloted town section was a swamp.

While Sarah and her younger children stayed in Nelson, the three eldest boys went with Danforth to clear and drain 50 acres and build a log house at Motueka, where they would have also been neighbours of the Rutherfords. In early letters Sarah reported her progress in house cleaning and cookery and enclosed her first drawings of Nelson. Later she wrote of moving into the new house (which lacked a staircase, chimney and kitchen stove), of eating home-grown potatoes and eggs and selling their first milk and butter.

As recorded in Sarah’s biography, the directors of the New Zealand Company had hoped that prospective settlers would be 'enlightened capitalists', with a concern for political and civil rights, Christian religion and education.

Like many of their countrymen, the Greenwoods had little capital but brought integrity, energy, an active social conscience and a civilising culture to their new country. For example, Sarah Greenwood made her parlour available for church services and played the piano for worship and social gatherings.

These qualities and her unwavering insistence on 'exact fidelity' in her art would have found resonance with Ernest Rutherford’s family.


Rutherford’s mother Martha (nee Thompson) was the daughter of Charles Edwin Thompson (b 1819) and Caroline Shuttleworth who were married in Islington the later part of 1840. In the 1841 English Census Charles and Caroline are recorded as still being childless, and as living in Butts Green, Hornchurch, Essex, where Charles worked as a machinist.

It is likely that Charles Edwin was the son of the Charles Thompson (b 1796) who was recorded as a Clerk in the 1841 Census - living in Hornchurch, with his wife Ann and six younger children.

The Thompson Family is recorded in the 1851 English Census living at 11 High Street, Hornchurch, Essex, with the head Charles E. Thompson being recorded as a 32 year old Agricultural Machine Maker, wife his wife Caroline (nee Shuttleworth) also 32, and four children, including 8 year old Martha. Caroline’s sister Louisa Shuttleworth (18) was also living with the family.

It seems that Charles was a well-regarded employee of the Fairkytes Foundry in Hornchurch which manufactured agricultural implements. As his career progressed, he was given accounting responsibilities and was said to have been a brilliant mathematician.

Unfortunately, Martha’s father Charles died in 1853 when she was 10 years old. Three years later, she emigrated from Hornchurch, with her mother Caroline and 3 siblings, in the company of her Shuttleworth grandparents and Shuttleworth relatives - arriving in Auckland from London on 28th December 1856 on the ship ‘Bank of England’.

The arrival of the Bank of England, captained by W. Maxton, was recorded with the following notes:

‘At 5 a.m. she made her appearance round the North Head. The water was as smooth as grass and with scarcely an air stirring, the ship drifted slowly to her anchorage, which she fetched about 7 a.m.

‘The ‘Bank of England’ had sailed from Gravesend on the 6th September and from the Downs on the following day, crossing the equator in 31 degrees W on the thirty-first day. She had a very fair run to Van Diemen’s Land, passing without sighting, to the Southward of that island and from which her passage has occupied a period of 18 days.

‘On Christmas Day, at 2 a.m., the crew sighted the Three Kings, experiencing light northerly and north-easterly winds on the coast. A very melancholy accident occurred in 1 degree N. lat., 30 degrees W. longitude. The ship was then going about 7 knots through the water, when William Hawkins, a miner and native of Falmouth, unhappily fell overboard.

‘The ship was immediately hove all aback and, as the poor fellow was swimming light, and strong, there was every prospect of saving him. All at once he gave a piercing shriek and disappeared, having been taken, as is supposed, by a shark. Hawkins had a wife and child on board; the child died about a month since.

‘The ‘Bank of England’ brings 76 passengers and a general cargo of merchandise.

The Shuttleworths and Thompsons then made their way to New Plymouth where they settled initially. They were evacuated to Nelson in 1860 during the Taranaki Land War and had it not been for the war, Ernest’s parents James and Martha would never have met.


James Rutherford and Martha Thompson were married in 1866. James became a wheelwright and engineer, and later a flax-miller. According to family tradition, he maintained that the family had migrated "to raise a little flax and a lot of children". In line with this aphorism, they had, in fairly rapid succession, twelve children, of whom Ernest, afterwards Lord Rutherford, was the fourth.

Ern as he was known led the life typical of a child growing up in rural New Zealand. The family always maintained a small farm to provide basic foodstuffs and augment its income. This meant that all the children shared tasks such as milking and harvesting but the countryside gave ample opportunities for swimming and the use of the catapults and kites that they made.

As a boy Ernest was surrounded by hard-working people with technical skills. At the same time, the family as a whole was regarded as consisting of gifted individuals. Ernest later claimed his inventiveness was honed on the challenges of helping out on his parents' farm, where the motto was ‘We don't have the money, so we have to think’.

And his teacher mother, who believed ‘all knowledge is power’, made sure her children had a good education. Under the influence of their parents it seems that they were a singularly united and happy family.

According to the NZ Dictionary of National Biography:

‘Rutherford's father was a man of great character, of fine, quiet disposition, straight and honourable. His mother was a truly remarkable woman of high education, very musical, a good organiser, thrifty, and hard working. So Ernest Rutherford and his siblings received a good education because of parents who appreciated education: his father because he hadn't had much and his mother because she had.

‘She had a true appreciation of the value of education and had a practical ambition for her children. For instance, she exercised them in the evenings by spelling bees and arithmetical exercises. In common with many of the early pioneers, the parents, even in adversity, denied themselves to give their family a good education.

‘Ernest Rutherford attended the local primary school at Foxhill, and his school record is still available there showing how, at one stage, he passed through two standards in one year. His teacher was Harry Ladley, evidently an inspiring master. It is not improbable that under Ladley, Rutherford's attention was first drawn to the studies in science which he was afterwards to make his life work.

‘There has been preserved by his mother, his first science text book inscribed in his name, at the early age of ten. It was a small text book on physics by Balfour Stewart, Professor of Natural Philosophy at the University of Manchester, and it is an interesting coincidence that Rutherford was destined afterwards to fill so worthily the same Chair.

‘In the preface to this book, the author stated: “The book has been written, not so much to give information, as to endeavour to discipline the mind by bringing it into immediate contact with Nature herself, for which purpose a series of simple experiments are described, leading up to the chief truths of each science, so that the power of observation in the pupils may be awakened and strengthened.”

‘Later Ernest attended the Havelock primary school where he came under the influence of an enthusiastic teacher, particularly of boys—Mr. Jacob H. Reynolds who, not content with the ordinary syllabus, taught some of his pupils Latin for an hour each morning before school.

‘Here, at the age of 15, Ernest won an Education Board Scholarship, value £52/10/per annum, for two years, obtaining the astonishing total of 580 marks out of a possible 600. Thus he went to Nelson College, and such was his grounding that he was immediately placed in the fifth form and soon justified this classification.

‘It is interesting to realise the energy and ability which James Rutherford put into his flax-milling operations. He harnessed water power to drive his mill. He experimented and developed a method of soaking the fibre after stripping and subsequently a special scraper to remove the vegetable matter so as to minimise the labour and time of paddocking.

‘He looked ahead and planted specially selected native varieties. Nevertheless, he relied most on ready-grown swamp flax, and such was the success of his operations that the flax he produced was reckoned amongst the best in the Dominion, and he was later able to retire to New Plymouth, all his children having married and settled in different parts of the country.

‘Naturally, Ernest always took a part in the family work. Even at Foxhill, he had his share of wood-chopping and earned money in the holidays picking hops. At Havelock he milked his share of the cows each morning, tended the vegetable garden, ran messages to the flax-mill at Ropaka. While on holiday from Nelson College at Pungarehu, he worked in the flax-bleaching paddocks.

‘On one occasion he painted the house; on another, built a tennis-court. During another holiday he built a battery of Grove cells; but this is anticipating. The main thing is that he was not only a diligent and brilliant student, but he took part to the full in the every-day duties of a family engaged in country occupations.

‘He won four scholarships and his crowning achievement was to win a University Entrance Scholarship in 1889 which took him to Canterbury College, where he commenced his University Course the following year, specialising in mathematics and physics. Compared with the numbers of students in these days, the classes were small and the teaching and student relationships were of a much more personal nature.

‘He was fortunate in his Professors, C. H. H. Cook, who gave him a thorough training in mathematics, and A. W. Bickerton, an original and somewhat unorthodox teacher of physics and chemistry. It is perhaps a coincidence that Bickerton had almost an obsession in regard to his theories of the effects of the impact of stars, and that Rutherford, many years later, drew such important and revolutionary conclusions from his own experiments on the impact of what he showed to be miniature stars, i.e., the nuclei of swift moving atoms of matter.

‘Bickerton, and his later disciple, Gifford, held the idea that in stellar encounters a third body would be produced. Rutherford later showed experimentally that such third bodies were produced by atomic impacts resulting in disintegration of one of the atoms concerned.

‘In 1893, Rutherford accomplished what had been done only once previously in the history of the University. He gained a double first-class honours in mathematics and physics. He had already turned his attention to physical research in spite of the paucity of equipment available.

‘In 1887, Professor Heinrich Hertz, of the University of Bonn, had experimentally proved the existence of electric waves, the possibility of which had previously been mathematically foretold by Clerk Maxwell. This discovery was revolutionary and already the best scientific minds of Europe had devoted their whole energy to the study.

‘Nevertheless, with home-made equipment and electric batteries, Rutherford attacked the problem of finding a suitable detector of these radiations so that their nature could be studied. He submitted his investigations as a thesis for the 1851 Exhibition Science Scholarship and also published them in the Proceedings of the New Zealand Institute. The selectors for this Scholarship are always faced with the difficult task of comparing students from various branches of science and, in this case, they actually selected J. C. Maclaurin of Auckland for the Scholarship.

‘Maclaurin was a brilliant chemist who afterwards became the New Zealand Dominion Analyst, and did outstanding work in the development of the cyanide process for separation of gold. At the time, however, Maclaurin was not able to take up the Scholarship which was accordingly awarded to Rutherford, and this enabled him to proceed to a British University and start on a scientific career.

‘He wisely chose to study under Professor J. J. Thomson at Cambridge, and entered Trinity College in 1895. At first he continued his investigations of electric waves, and was the first to signal over any considerable distance. Using his own detector he managed to signal over the space of half a mile, full of intervening streets and houses in Cambridge, but he did not continue these studies, his ideas being taken up and developed by Marconi. His search for scientific truth was uncontaminated by any worldly motive, and he did not concern himself with the economic application of his results.’

Rutherford became Professor of Physics at Manchester University in 1907. During the First World War, he worked on acoustic methods of detecting submarines. He was a promoter and mentor to young scientists, both male and female – and unsuccessfully tried to persuade the United States government to use young scientists for research rather than in the trenches in WWI. He also campaigned for women to share men's privileges at Cambridge University, and spoke up for the freedom of the British Broadcasting Corporation from government censorship.

On his final trip to New Zealand in 1925, Rutherford was received as a national hero and gave talks to packed halls around the country. His call for government to support education and research helped drive the establishment of the Department of Scientific and Industrial Research (DSIR) the following year.


[by Manjit Kumar, UK Independent, 3 March 2011]

Did the nuclear age begin in 1942, when Chicago Pile-1, a reactor built in a squash court, went "critical" by achieving self-sustaining chain reaction?

Or was it on 16 July 1945 in the Jemez mountains in New Mexico, when "The Gadget", the first atomic bomb, was successfully tested and Robert Oppenheimer quoted the Bhagavad Gita? Maybe it was June 1954, when the Russian Obninsk nuclear station first generated electricity for the grid.

In reality, it was during a meeting of the Manchester Literary and Philosophical Society that the nuclear age was announced, on Tuesday, 7 March 1911, by Professor Ernest Rutherford, the 39-year-old head of physics at Manchester University. Rutherford was born in 1871, in Spring Grove, New Zealand.

Descended from Scottish emigrants, it was from this scattered rural community on the north coast of the South Island that Rutherford's aptitude for science and maths led in 1895 to a coveted place at Cambridge. There, under the direction of JJ Thomson, Rutherford established a reputation as a fine experimentalist with a study of X-rays.

Though surrounded at Cambridge by all the excitement generated by Thomson's discovery of the electron in 1897, Rutherford opted to investigate radioactivity and soon found that there were two distinct types of radiation emitted from uranium, which he called alpha and beta, before a third was discovered, called gamma rays.

Aged just 27, in 1898, he was appointed professor of physics at McGill University in Montreal, Canada. Among his successes over the next nine years the most important was the discovery, with his collaborator Frederick Soddy, that radioactivity was the transformation of one element into another due to the emission of an alpha or beta particle.

Rutherford regarded "all science as either physics or stamp collecting" but saw the funny side when he received the 1908 Nobel prize for (philatelic) chemistry for this seminal work. By then he was in Manchester.

"Youthful, energetic, boisterous, he suggested anything but the scientist," was how Chaim Weizmann, then a chemist but later the first president of Israel, remembered Rutherford in Manchester.

"He talked readily and vigorously on any subject under the sun, often without knowing anything about it.

"Going down to the refectory for lunch, I would hear the loud, friendly voice rolling up the corridor."

At the time Rutherford was busy using the alpha particle to probe and unlock the secrets of the atom. But what exactly is an alpha particle? It was a question that Rutherford and his German colleague Hans Geiger answered. It was a helium ion; that is, a helium atom that had been stripped of its two electrons. Rutherford had noticed, while still in Montreal, that some alpha particles passing through thin sheets of metal were slightly deflected, causing fuzziness on a photographic plate. It was something he asked Geiger to investigate.

As instructed by Rutherford he fired beams of alpha particles at some gold foil and by the tiny flashes of light when they struck a zinc sulphide screen discovered that a few "were deflected through quite an appreciable angle".

Soon afterwards Rutherford assigned a research project to a promising undergraduate called Ernest Marsden: "Why not let him see if any alpha particles can be scattered through a large angle?"

Marsden found some alpha particles bouncing straight back after hitting the gold foil and Rutherford was shocked:

"It was almost as incredible as if you had fired a 15-inch shell at a piece of tissue paper and it came back and hit you."

Marsden and Geiger made comparative measurements using different metals and they discovered exactly the same large angle scattering. In June 1909 they published their extraordinary results, but with Rutherford unable to offer any kind of explanation they attracted little interest.

After decades of intense arguments, by 1910 the reality of atoms was established beyond reasonable doubt. The most widely-accepted atomic model was Thomson's so-called "plum pudding". Its ingredients consisted of a ball of diffuse "positive electricity" in which negatively charged electrons were embedded like plums in a pudding.

But Rutherford knew that the atom of his old mentor couldn't explain alpha particle scattering. The probability that the accumulated effect of a number of tiny ricochets off electrons in Thomson's atom resulted in even one alpha particle being scattered backwards was almost zero.

By December 1910, Rutherford believed that given the mass and energy of an alpha particle the large deflections must be the result of a single collision with an atom. It led him "to devise an atom superior to J.J's" he said at time.

Rutherford's atom consisted of a tiny central core containing virtually all the atomic mass, which he later called the nucleus, but it occupied only a minute volume "like a fly in a cathedral".

Most alpha particles would pass straight through Rutherford's atom in any "collision", since they were too far from the tiny nucleus at its heart to suffer any deflection. But if an alpha particle approached the nucleus head-on, the repulsive force between the two would cause it to recoil straight back like a ball bouncing off a brick wall.

Rutherford said that such direct hits were "like trying to shoot a gnat in the Albert Hall at night". Rutherford's model allowed him to make definite predictions using a simple formula he had derived about the fraction of scattered alpha particles to be found at any angle of deflection.

Experimental checks performed by Geiger and Marsden confirmed the predictions, but few physicists beyond Manchester gave any serious attention to the nuclear atom.

Although Rutherford did not explicitly suggest a planetary model of the atom, there were those who knew that's exactly what it was. For most that settled the matter, Rutherford's atom was fatally flawed.

A model of the atom with electrons moving around the nucleus, like planets orbiting the sun, would collapse. Any object moving in a circle undergoes acceleration, if it happens to be a charged particle, like an electron, as it accelerates it continuously losses energy in the form of radiation.

An electron in orbit around the nucleus would spiral into it. Rutherford's atom was unstable and the existence of the material world was compelling evidence against it.

Enter Niels Bohr.

Arriving in Manchester in March 1912 to learn about radioactivity, it wasn't before long the 27-year-old Dane began thinking about how to prevent Rutherford's nuclear atom from collapsing. His solution employed the quantum – the idea that energy comes in packets. Bohr argued that electrons inside an atom could only move in certain orbits in which they did not radiate energy and therefore couldn't spiral into the nucleus.

Bohr said that each orbit had a certain energy associated with it, so all the allowed orbits were in effect a series of energy levels, like the rungs of a ladder. For an electron to move between levels, the famous quantum leap, required it to absorb or emit a quantum of energy that was equivalent to the difference in energy between the two levels.

"It is difficult to underestimate the scientific importance of the discovery of the nucleus," says Sean Freeman, professor of nuclear physics at Manchester University.

"Rutherford's insight, imagination and attention to detail enabled him to make revolutionary discoveries using rather rudimentary technology by modern standards. He was a true pioneer."

One of his most important achievements was made in his spare time while Rutherford was developing methods for detecting submarines during the First World War – he split the atom. Arriving late for a committee meeting one day, Rutherford didn't apologise, but announced: "I have been engaged in experiments which suggest that the atom can be artificially disintegrated.

"If it is true, it is of far greater importance than a war!"

It was 1919 before he published the results that showed the nucleus contained positively charged particles he called protons by knocking them out of nitrogen nuclei using alpha particles – thereby effectively splitting the nucleus and hence the atom.

It was the last work he did at Manchester before moving to Cambridge to take over from Thomson as head of the Cavendish Laboratory.

It was there that in 1932 his colleagues James Cockcroft and Ernest Walton "split the atom" using the world's first particle accelerator. Also at the Cavendish, James Chadwick used Rutherford's suggestion that there was probably another constituent to heavier nuclei to discover the neutron. The particle plays the central role in establishing a nuclear chain reaction. The three men were among the 11 former students and colleagues of Rutherford who would win the Nobel prize.

Another of those 11 was Niels Bohr, who said that Rutherford never spoke more angrily to him than he did one evening at a Royal Society dinner.

He had overheard Bohr refer to him by his title (Rutherford was awarded a peerage in 1931) and angrily asked the Dane loudly: "Do you Lord me?"

Rutherford never cared for the honours and was indifferent to academic or social standing. What mattered most to him were the results of experiments.

"I was brought up to look at the atom as a nice hard fellow, red or grey in colour, according to taste," he once said. It was a model he replaced with an atom that began the nuclear age.

1 comment:

  1. Why did Rutherford design this experiment? and why did he choose to use gold foil?