Brooks and Rutherford Emanate

The more physics you have the less engineering you need. (Ernest Rutherford)

Portrait of Ernest Rutherford by R.G. Matthews, 1907

Portrait of Ernest Rutherford by R.G. Matthews, 1907

Physics at McGill was born in 1891 when the tobacco manufacturer, William Macdonald, dedicated funding for a new Physics Building and for the creation of the Macdonald Chair in Physics. In 1893 the Macdonald Physics Building opened and the M.Sc. program was established.

This was almost three decades before Ernest Rutherford split the core of the atom in 1919 and declared that he had “broken the machine and touched the ghost of matter”. The nucleus of Rutherford’s experiments into ‘transmutation of matter’ had started in a basement lab of the Macdonald Physics building in 1898. His instruments and apparatus, concocted with the help of laboratory assistants out of wire, wax and glass apparatus which they blew themselves, are today preserved and exhibited at the Rutherford Physics Museum.

Harriet Brooks, 1898. Photo by Wm. Notman & Son.

Harriet Brooks (1876 – 1933) graduation photo, 1898. Photo by Wm. Notman & Son. Courtesy of the McCord Museum of Canadian History, Montreal.

Rutherford was attracted to McGill because of its new Physics Building constructed without iron or steel and reputed to be one of the finest, and best equipped, science buildings in the world. Planners accounted for the sensitive experiments in the new field of radioactivity and ensured the structure was made entirely of wood and masonry. Copper, bronze and brass were used for the nails and fixtures, while ceramics was used for the radiators to keep magnetic interference at a minimum.  In 1901 his student Harriet Brooks, the first Canadian woman nuclear physicist, graduated with her Masters degree and went to work with J.J. Thomson at the Cavendish Laboratory in Cambridge England. Even though Madame Curie had coined the original term radioactivity in 1898 to describe the ‘radio-actif’ emissions or rays released by unstable atomic nuclei, this field of experimental work was still considered novel. Harriet Brooks does not even use the term ‘radiation’ in 1902 when she writes to Rutherford to tell him that she has taken the first measurement of the half-life of the thorium “emanation” (radon-220).

In 1903 Harriet returned to McGill to work as a research assistant with Rutherford. At McGill she discovered an “emanation” from thorium that was quite different from the alpha- and beta-rays commonly observed by researchers such as Rutherford and Thomson. Brooks speculated that the emanation from thorium could be deviated by a current of air and, using a diffusion method, she concluded that it was a radioactive gas with a molecular weight significantly lower than the molecular weight of the parent-element, thorium. This new idea from Brooks was central to the whole development of nuclear physics and chemistry and led to Rutherford and Frederick Soddy’s hypothesis that radioactivity results from the disintegration of atoms.  In 1908 Rutherford was awarded the Nobel Prize in Chemistry. Soddy won the Nobel in 1921.

Born in Exeter, Ontario in 1876, Brooks entered McGill in 1894. Women had been welcome at the university for less than a decade, and when she received a Masters degree in Electromagnetism in 1901 she was the first Canadian woman to reach this level of academic achievement.

In 1906, she worked with Marie Curie in Paris. Few if any other scientists have worked with three Nobel laureates: Thomson, Rutherford and Curie.

Rutherford credits Brooks’s discoveries in his Bakerian Lecture in 1904 and in her obituary he noted that ‘next to Mme Curie she was the most pre-eminent woman physicist in the department of radioactivity’.

In 1904 Harriet Brooks moved to Barnard College, New York City as tutor in Physics, and two years later became engaged to be married to a physicist from Columbia. The Dean of the college insisted that Brooks must resign, saying ‘the good of the College and the dignity of the woman’s place in the home demand that your marriage shall be a resignation’. This was common practice at the time and Brooks eventually broke the engagement and left Barnard. In her resignation letter to the Dean she indignantly comments on the injustice: ‘I think it is a duty I owe to my profession and to my sex to show that a woman has a right to the practice of her profession and cannot be condemned to abandon it merely because she marries. I cannot conceive how women’s colleges, inviting and encouraging women to enter professions can be justly founded or maintained denying such a principle.’ (Quotation from Margaret W. Rossiter’s book Women Scientists in America: Struggles and Strategies to 1940. Baltimore: Johns Hopkins University Press [1982].)

Leaving Barnard College for the Curie Institute in 1906, she worked with André Debierne (1874–1949) on the recoil of radioactive atoms using the radium decay series.  She was the first person to realize that one element can change into another. She was also among the early discoverers of radon and the first researcher to attempt to determine its atomic mass.

A year later, in 1907 she chose to marry and returned to live the rest of her life in Montreal, dying at age 56, of a ‘blood disorder’.

Read more about Harriet Brooks at:

Rutherford, McGill, and the golden age of physics

Don’t let me catch anyone talking about the Universe in my department. (Rutherford, while he was the Director of the Cavendish laboratory at Cambridge from 1919 until his death in 1937.)

Harriet Brooks’s graduate supervisor, Ernest Rutherford, pioneered the orbital theory of the atom and was the first person to artificially disintegrate an element.  Sometimes called the ‘Father of nuclear physics’, his gold foil experiments at the University of Manchester helped describe the nuclear structure of the atom.  Particles named and characterized by him include the alpha particle, beta particle and proton.

Even the neutron, discovered by James Chadwick, owes its name to Rutherford. According to Robert Jungk, the author of the Brighter than a Thousand Suns, the personal history of the atomic scientists published in 1956, it was no accident that the discovery of the neutron occurred in Rutherford’s laboratory at Cambridge. In 1932 no other physics-research establishment in the world possessed such excellent measuring instruments as the Cavendish laboratory, including a new amplifier which had just been invented. Encouraged by Rutherford, Chadwick conceptualized the possible existence of the neutron after hearing the announcement by the Germans Bothe and Becker that they had observed a very strong, inexplicable ‘radiation’ (in the original manuscript they use the words “gamma rays”) on bombarding beryllium with alpha particles . Rutherford speculated that the nature of this radiation was due to the difference found between the atomic number of an atom and its atomic mass. He thought it could be explained by the existence of a neutrally charged particle within the atomic nucleus. Rutherford’s theory of neutrons was proved in 1932 by Chadwick, who in 1935 was awarded the Nobel Prize in Physics.

Rutherford in his lab at McGill, circa 1905.

Rutherford in his lab at McGill, circa 1905.

Before running his “stable” in Cambridge, Rutherford was Chair of Physics at the University of Manchester from 1907 to 1919 but it was his work into the disintegration of the elements, and the chemistry of radioactive substances at McGill that started everything. He was lured to Montreal in 1898 by the appointment as Macdonald Professor of Experimental Physics. At this time the Physics Department (strictly speaking, the Physics Laboratory) comprised two professors, and a small number of junior instructors and research students. There was a fairly heavy teaching load, mainly to students of engineering, medicine, chemistry and other disciplines rather than physics. Rutherford was offered what was essentially a research post, and, according to Jean Barrette, the Curator of the Rutherford Physics Museum, this kind of offer at the age of 26 would have been nearly impossible in England. The annual salary of $2,500 was also considered one of the highest in the university if not in the country.

At McGill Rutherford began using ionization as a tool for studying radioactivity. Almost immediately he discovered the heterogeneous nature of the “Becquerel rays”; he called the non-penetrating component alpha rays and the more penetrating, beta rays. The gamma rays were discovered in 1900 by Paul Villard in Paris. Rutherford’s research at McGill covered every aspect of radioactivity, including the nature and properties of the ‘emanation’ (radon) produced by radium and thorium, the heating and ionization properties of the radiations, the charge and nature of the alpha and gamma rays, excited radioactivity, and elucidation of the three natural radioactive series (uranium-radium, actinium and thorium). During his nine years at McGill, Rutherford published 69 papers, either alone or with a second author. The latter group included graduate students, demonstrators and professors at McGill and (after 1903) graduate students and post-doctoral scientists from several countries outside Canada. These collaborators published some 30 independent papers on various aspects of radioactivity, mostly on topics suggested by Rutherford and under his general guidance.

Rutherford died in 1937 after an unsuccessful operation on a ruptured artery. With him disappeared a desire to understand the nature of the world of atoms just because they were there. As he told journalists in 1932, after the great successes of his team at Cambridge: “We are not searching for a new source of power or the production of rare or costly elements. Our reasons lie deeper and are bound up with the urge and fascination of a search into one of the deepest secrets of nature.”

The chemical element rutherfordium (element 104) was named for him in 1997.

Information taken from the Website of the Rutherford Physics Museum:

More quotes from Rutherford taken from the Secret Science Spot: Macdonald Physics, McGill Faculty of Science publication (2009), and from

If you can’t explain your research to the cleaning lady, it’s not worth doing.

Never say, ‘I tried it once and it did not work.’

We haven’t got the money, so we’ve got to think!

Article by Ingrid Birker, with files from the Secret Science Spot: Macdonald Physics, by Michael Woloschuk and Ingrid Birker, 2009.

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