At which Canadian university did Rutherford and Soddy study thorium radioactivity?

Rutherford and Soddy studied thorium radioactivity at McGill University in Montreal, Canada.

Rutherford joined McGill in 1898 as the Macdonald Professor of Physics. From 1900 to 1903, he worked with Frederick Soddy, a young chemist who later won the 1921 Nobel Prize in Chemistry. Their collaboration helped establish that radioactivity involved changes within atoms rather than merely an unusual chemical reaction.

Thorium was central to their investigation because it produced a radioactive emanation that could temporarily coat nearby objects. After ruling out ordinary chemical explanations, Soddy proposed that the emanation was an inert gas. They called it thoron; it was later identified as radon-220.

A common mix-up is confusing McGill with Rutherford’s earlier university training in New Zealand or with Manchester, where he later conducted his famous gold-foil work with Hans Geiger and Ernest Marsden. McGill was the Canadian institution where Rutherford and Soddy’s thorium research took place.