Ernest Rutherford and Frederick Soddy

McGill University, Montréal, Québec

On November 30, 2009, as part of its Historic Sites initiative, APS presented a pair of plaques (one English, one French) to McGill University in Montréal to honor the achievements of Ernest Rutherford and Frederick Soddy. The English plaque read: "At this location, Ernest Rutherford and Frederick Soddy, during 1901-03, correctly explained radioactivity as emission of particles from the nucleus and established the laws of the spontaneous transmutation of the elements." Representing APS were the Chair of the Historic Sites Committee, John Rigden, and Associate Executive Officer Alan Chodos, a McGill alumnus.

Radioactivity involves atoms of one element being transformed into atoms of another through particle decay. Radioactivity was discovered by Henri Becquerel in France in 1896, and had been studied, by various scientists, including Rutherford (while still in England), and Pierre and Marie Curie in Paris, but its essential properties were unknown. Rutherford and Soddy, who were laboring at McGill in Physics and Chemistry, respectively, came together in the early 1900s as research allies and "concluded that it was a phenomenon involving atomic [not molecular] disintegration with the formation of new kinds of matter." They called this the "disintegration theory of radioactivity," and it "was supported by a large amount of experimental evidence, [and] a number of new radioactive substances were discovered." 1

The foundations for the collaboration between Rutherford and Soddy began in the United Kingdom. In the late 1800s, Rutherford, a native of New Zealand, received a scholarship to study at Trinity College, Cambridge, at the Cavendish Laboratory under J.J. Thomson, who was considered a significant expert on electromagnetic radiation. He quickly jumped into a number of projects with his advisor. He invented an electromagnetic wave detector and, in concert with Thomson, examined the behavior of ions in gases which had been exposed to X-rays. The duo also analyzed the movement of ions in relation to the strength of an electric field and the photoelectric effect. In 1898, Rutherford announced the existence of alpha and beta rays in uranium radiation, as well as some of their properties. 2 That same year, he joined McGill University, which "boasted one of the best-equipped laboratories in the Western Hemisphere," 3 as the Macdonald Professor of Physics.

While Rutherford was analyzing ions in Cambridge, Soddy was studying under scholarship at Merton College, Oxford. He graduated from the College in 1898 in chemistry, remained two more years to conduct further research, and in 1900 joined McGill as a Demonstrator in the Chemistry Department.

According to John Campbell, author of the book Rutherford – Scientist Supreme and related website, "The first Rutherford-Soddy interaction was in 1901 when they were on opposite sides of a discussion held by the McGill Physical Society. Rutherford pointed out there were objects smaller than atoms, JJ Thomson's electron. Soddy defended the integrity of the chemical atom. Rutherford was already on the way to transmutation, having reported and studied the radioactive emanation of thorium, and had reported on the different lifetimes of thorium and radium emanations, and also that the radioactivity ‘induced’ by each element were different too…Following the McGill Physical Society discussion, Rutherford…invited Soddy to join him in working out the chemistry of the emanations." 4

Rutherford had many collaborators during his nine year tenure at McGill, but clearly his most important was Soddy. Although the partnership lasted only 18 months, from October 1901 to March 1903, it culminated in nine crucial papers, including "The cause and nature of radioactivity," published in two parts in 1902. 5 Of course, they both were awarded Nobel Prizes in Chemistry. Soddy received his in 1921 "for his contributions to our knowledge of the chemistry of radioactive substances, and his investigations into the origin and nature of isotopes." Rutherford, who had Honorary Doctorates from 20 universities including McGill, was awarded the Nobel Prize in 1908 "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances." 6

Today, McGill University offers a number of opportunities for visitors to steep themselves in the history of this discovery. The Ernest Rutherford Physics Building houses the Rutherford Museum, which contains the "world's best collection of Rutherford apparatus," 7 as well as many of his most important papers and documents. 

1Nobel Lectures, "Chemistry 1901-1921", Elsevier Publishing Company, Amsterdam (1966).
3Encyclopædia Britannica, "Ernest Rutherford," (website - 2010).
4John Campbell, Ernest Rutherford – Scientist Supreme (website - 2010).
5McGill University-Rutherford Museum, "Ernest Rutherford's Life" (website - 2010).
6Nobel Lectures.