Helen Hogg - Astronomer and Faculty Stephen Leacock - Humorist and Graduate Elsie MacGill - Engineer and Graduate
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University of Toronto
U of T Great Past

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What team of physicists first produced liquid helium in Canada in 1923?

Answer The University of Toronto team was led by Professor John McLennan and helped establish U of T's reputation for expertise in low temperature physics.

On March 15, 1827, King's College - the precursor to the University of Toronto - was granted its royal charter by King George IV. Throughout 2002, U of T celebrated 175 years of Great Minds. As part of the celebration, the U of T website featured excerpts from The University of Toronto: A History, written by Martin Friedland, University Professor and Professor Emeritus of Law at U of T.

Physics was responsible for the most doctorates in the University
between the wars; they were supervised principally by John
McLennan and, after he left in 1932, by E.F. Burton.
There was a great amount of research productivity in the department, and McGill's pre-eminence in physics under Ernest Rutherford passed to Toronto.

The initial query was: 'What's new'. It was unwise to have nothing to discuss since this
was regarded as evidence of lack of endeavour"

Elizabeth Allin, one of McLennan's Ph.D. graduates - three of McLennan's women graduate students received doctorates - described his morning visits to see what progress had been made. "Each morning," she wrote, "McLennan, accompanied by the head of the workshop, the glassblower, and often a junior staff member, visited the site of the experiment of each of his graduate students, to enquire what, if any, progress had been made, what difficulties had been encountered and how it was proposed to overcome these. The initial query was: 'What's new'. It was unwise to have nothing to discuss since this was regarded as evidence of lack of endeavour"' She obviously made good progress because she joined the department in 1930 and remained there until her retirement in 1970.

McLennan had a number of areas of research. One was spectroscopy, that is, the study of the spectra of atoms and molecules, on which he started work in 1910. One of the students who worked with him in this area was Harry Welsh, who received his PhD in 1936. Welsh himself would supervise about 65 PhD students, including Boris Stoicheff, who received his PhD in 1950 and at the time of writing continues to work on lasers in the physics department. A number of Stoicheff's own graduate students have positions in Toronto and across North America in physics, electrical engineering, and chemistry. Another area of research for which Toronto became well known was "low temperature physics," which facilitates the study of atoms and other particles. Helium was important in achieving low temperatures.

At the end of the Great War, McLennan had access to large quantities of helium gas, which he was producing for balloons and similar lighter-than-air vehicles. If liquid helium could be produced, it would be possible to create the desired low temperatures. In 1923, liquid helium was successfully produced by McLennan's team. He and his students could now study matter under conditions approaching absolute zero.

John McLennan's offical pass for British Admiralty work
John McLennan's official pass for work with the British Admiralty in 1918. McLennan and others from the physics department were particularly active in aiding the war effort.

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