That matter is congealed energy which can be released is knowledge not attained by a single scientific breakthrough.... That knowledge was gained only after a long chain of achievements in the late nineteenth century and the first half of the twentieth century by scientific and technical experts working in Europe, England, Canada, and the United States.

It had been assumed since the time of the ancient Greeks that “atoms” were indivisible. Then, in 1895, Wilhelm Rontgen, a German physicist, discovered x-rays. The next year, French physicist, Henri Becquerel, discovered that certain substances were changing spontaneously, a process Madame Marie Curie called “radioactivity.”
 

1. Queen Victoria called Sir William Macdonald of Montreal “the greatest philanthropist in the British Empire.” His generous donations to McGill University created the Macdonald Laboratories of Chemistry, Physics, and Engineering. One of the most profound changes in all recorded history in man’s understanding of his physical environment took place in the Macdonald Laboratories during the years 1901-02. Here Ernest Rutherford and Frederick Soddy postulated “a new world,” indeed “a whole new universe,” one in which “energy latent in the atom must be enormous compared with that rendered free in ordinary chemical change.” [Photo, courtesy Macdonald Stewart Foundation, via Vicki Stewart]

The following year, 1897, J.J. Thomson, Professor of Physics at the University of Cambridge, discovered the “electron.” The revolutionary discovery of this tiny particle, much smaller in mass than hydrogen, the lightest atom, attracted the attention of many gifted students, including Ernest Rutherford, who worked with Thomson from 1895 until he was made a Professor of Physics at McGill University in Montreal in 1898.
 

In 1898, Ernest Rutherford left the Cavendish Laboratory at Cambridge University to become a professor of physics at Montreal’s McGill University. The year after he left McGill, in 1908, he was awarded the Nobel Prize for Chemistry. Much of his groundwork for the development of nuclear physics, in particular his nuclear theory of atomic structure, was achieved at McGill. His leadership internationally inspired two generations of physicists. His influence on scientific thought may be compared to that of Faraday and Newton. [Photo, courtesy NAC/C-18230]

Before Rutherford arrived at McGill, a new physics laboratory had been built and scientific positions established through the financial support of Montreal businessman William Christopher Macdonald. Money he provided made possible the remarkable collaboration between Rutherford and Frederick Soddy, a young Oxford graduate.

Rutherford’s discovery at McGill of the “alpha” particle in 1899 was a key event in the early development of atomic science. Frederick Soddy, a demonstrator in chemistry at McGill, initially challenged some of Rutherford’s ideas. Soon Rutherford invited Soddy to collaborate with him in his various scientific endeavours. Together, Rutherford, the physicist and Soddy, the chemist, made dramatic improvements in human understanding of the nature of matter. Together they established the early foundations for the development of atomic science.
 

British-born and Oxford-trained, Frederick Soddy collaborated with Rutherford at McGill University, 1900-1902. His work there on the disintegration of radioactive elements made him one of the very first to conclude (1912) that certain elements might exist in forms that differ in atomic weight while being indistinguishable and inseparable chemically. These elements he named isotopes. His laboratory experiments eventually earned him the 1921 Nobel Prize in Chemistry. [Photo, courtesy McGill University Archives/PR 000755]

In 1904 Rutherford concluded, based on his work with Soddy, that an enormous store of latent power was resident in the atoms of radioactive elements – power derived from the internal energy of atoms. He believed that, if it were possible to control, at will, the rate of disintegration of radioactive elements, an enormous amount of energy could be obtained from a small quantity of matter.

The year after Rutherford published these conclusions, the German-born physicist, Albert Einstein, set out his equation E=mc2. In essence it postulates that material is congealed energy. The implications of Rutherford’s findings and Einstein’s ideas were amazing. If, for example, the energy congealed in a handful of snow could be released in a completely controlled manner, it would be sufficient to heat an apartment house for a year.
 

Born at Ingersoll, Ontario, in 1867, John C. McLennan was greatly stimulated by the intellectual environment at Cambridge University where, as a graduate student, he came under the influence of J.J. Thomson, Cavendish professor or physics and future Nobel Laureate (1908). Upon return to the University of Torotno, McLennan gained international recognition for his research in radioactivity and spectroscopy, attracting such budding science students to his alma mater as Eli Burton and A.J. Dempster. [Photo, courtesy NAC/C-37785]

Rutherford and Einstein did not expect that it would be possible to find the means to release such energy during their lifetime. But many scientists were captivated by their ideas. Among them was Otto Hahn, who had earned a doctorate from the University of Marburg in 1901. After working with Rutherford at McGill for several months, in 1905 Hahn returned to Germany to take up a position in the University of Berlin.

Just as Rutherford was leaving Cambridge to go to McGill, John C. McLennan was arriving to work with J.J. Thomson. After he completed his research with Thomson, McLennan returned to the University of Toronto becoming, in 1906, chairman of the physics department. Under his direction until 1932, the department gained international recognition for its advanced research in spectroscopy and low-temperature physics.

One scholar who studied with McLennan at the University of Toronto was Arthur J. Dempster, whose father had founded Dempster’s Bakery in Toronto. Dempster graduated Gold Medalist in mathematics and physics from the University of Toronto and received, in 1916, his doctorate from the University of Chicago. There, in 1935, he discovered a previously unknown isotope of uranium – Uranium 235 or U235 as it is popularly known.
 

Arthur J. Dempster, circa 1935, takes a reading on the mass spectometer at the University of Chicago. As an undergraduate at the University of Toronto, Dempster has studied under spectroscopist John McLennan and, before the outbreak of World War I, had studied under Nobel Laureate Wilhelm Wein, at Wurzburg, Germany. Completing his Ph.D. in physics at the University of Chicago, summa cum alude, 1916, Dempster, as an atomic scientist, discovered Uranium 235 in 1935.  [Photo, courtesy Arthur & Elizabeth Dempster, Cambridge, Massachusetts]

At that time many scientists regarded U235 as “much too rare to matter” since it is present only as one part in 140 of natural uranium. Later, however, in 1941, when American scientists concluded that there were only two possible ways to make an atomic bomb, and one of these involved the use of U235, uranium became a vital wartime necessity.

In August 1929, Gilbert LaBine flew along the eastern shore of Great Bear Lake in Canada’s Northwest Territories, sensing here was a place of great mineral potential. Soon the Canadian prospector discovered pitchblende, a primary mineral ore of uranium, on the shore of that lake and began mining it. He then established a refinery at Port Hope, Ontario, to extract radium from the pitchblende for use in cancer therapy.

Late in 1938, Otto Hahn and his associates in Berlin completed experiments that led, in early 1939, to an understanding of a new phenomenon – nuclear fission. In this process, a uranium atom, in absorbing a neutron, splits into two parts of comparable size and releases a vast amount of energy. But fission itself would not have made possible the practical release of the power of the atom. A chain reaction was necessary.
 

Gilbert LaBine, born in 1890 at Westmeath, Ontario, was a successful prospector and mining promoter in the Northwest Territories. At age 40, as viewed here, on site, he discovered a valuable desposit of silver mixed with pitchblende on the shores of Great Bear Lake in Canada's Northwest Territories; this ushered Canada directly into the nuclear age. The demand for pitchblende, of which both uranium and radium are extracts, was so great that the Canadian government eventually nationalized LaBine's mining compnay, Eldorado Mining & Refining, to ensure that all by-products of the mine would be properly developed and monitored. [Photo, courtesy NAC/PA-14877]

This new knowledge stimulated great interest in the military potential of uranium. At that time there were only two known deposits of large quantities of uranium. One was in Africa. The other was Gilbert LaBine’s mine on Great Bear Lake.

Adequate supplies of uranium became critically important for the success of the Manhattan Project, the American scientific and military operation launched in the early 1940s to produce atomic bombs. LaBine’s company was quietly acquired by the government of Canada in 1942 to ensure supplies of uranium were available to carry forward that project successfully. Walter Zinn and Louis Slotin were two Canadians who played key roles in the Manhattan Project.

Born in 1906 in Kitchener, Ontario, Walter Zinn, a Queen’s University graduate in 1927, received his doctorate in 1934 from Columbia University. While Zinn was completing his doctorate, major scientific advances were being made by several of Rutherford’s younger associates at the University of Cambridge.
 

After graduating from the University of London in 1936 with a Ph.D. in biochemistry, Dr. Louis Slotin played a major role in the development of the first atom smasher in the midwest at the University of Chicago. There, under the west stands of Stagg Field, University of Chicago, scientists working under Enrico Fermi achieved man’s first self-sustaining nuclear reaction. By 1944, Dr. Slotin was at the Los Alamos, New Mexico Laboratory where the first atomic bomb was produced. [Photo, courtesy Jewish Historical Society of Western Canada]

In 1932, James Chadwick discovered a hitherto unknown subatomic particle that had a mass about that of protons but no electrical charge. It was called the neutron. Having no electrical charge, it was highly effective in penetrating the heaviest nuclei since it was unaffected by their powerful electrical defences. Chadwick’s discovery gave nuclear scientists a most useful device for effecting atomic disintegration.

That same year, John Cockcroft and Ernest Walton split the nucleus of the lithium atom by bombarding it with protons through the use of a new particle accelerator they had developed a voltage-doubling system for producing high voltages. For the first time in a laboratory, they induced an artificial nuclear reaction. This confirmed Einstein’s theory that matter is congealed energy.
 

Walter Zinn, born in Berlin (now Kitchener), Ontario, in 1907, graduated from Queen’s University and received his Ph.D. in nuclear physics from Columbia University in 1934. Recruited by Enrico Fermi to work on the Manhattan Project, Zinn released the world’s first self-sustaining nuclear reaction by withdrawing a control rod from the world’s first nuclear reactor in 1942 at the University of Chicago. This view depicts “Wally” Zinn as a Queen’s University senior in 1927. [Photo, courtesy Queen’s University Archives]

The scientific achievements of Chadwick, Cockcroft, and Walton helped Walter Zinn to realize that he was working on the leading edge of atomic science research. He devoted five years to neutron investigations and became a key member of the nuclear physics research group at Columbia University led by Enrico Fermi, Leo Szilard, Harold Urey, and other gifted scientists. These men played key roles in the Manhattan Project.

When the Columbia nuclear physics research group moved to the University of Chicago early in World War II, Zinn supervised all phases of the construction of the first experimental nuclear reactor, or “atomic pile” as it was then called. On December 2, 1942 he pulled out the emergency control rod from the reactor that released the world’s first self-sustaining nuclear reaction and reinserted it to terminate the chain reaction after 28 minutes of operation. Later Zinn designed the first experimental fast breeder reactor and also provided key scientific advice in the design of the first United States nuclear-powered submarine.

Another Canadian, Louis Slotin, who had received his Bachelor’s and Master’s degrees in science from the University of Winnipeg early in the 1930s, followed by a doctorate from the University of London, also played a key role in the Manhattan Project. He was the chief armourer of the first atomic bomb detonated in the New Mexico desert early on July 16, 1945. Although eager to embark on peacetime work at the University of Chicago, he continued his dangerous critical assembly work until his successor could take over. Slotin died tragically as a result of a radiation accident late in May 1946.

Before becoming involved in the Manhattan Project, Slotin had sought a position with the National Research Council, Canada’s national laboratory in Ottawa. Had he gone to the National Research Council (NRC), he would have met Dr. George C. Laurence, a pioneering participant in Canada’s program for nuclear power development. Laurence, who joined the Council in 1930, was a key Canadian member of the international group of scientists engaged in nuclear research who worked in a special World War II laboratory in Montreal. Its creation and operation under the Council subsequently led to the establishment of Atomic Energy of Canada Limited.

In 1939, the discovery and explanation of nuclear fission seized the attention of scientists at the National Research Council. It became evident that a substantial increase in the rate of the production of nuclear fissions might be accomplished with greater ease if the neutrons were moving slowly. This was a matter of great interest to George Laurence.
 

Another Canadian who studied under Ernest Rutherford was George Craig Laurence. Born in 1905 at Charlottetown, P.E.I., Laurence was a nuclear physicist who believed that Canada should be involved in developing atomic power for peaceful purposes. In 1942, as the first person in the world to set up a small (ten ton) uranium oxide and carbon pile (nuclear reactor), he attracted the attention of Britain’s nuclear scientists, especially John Crockcroft. [Photo, courtesy Atomic Energy of Canada Limited]

About the same time as Laurence was studying neutron multiplication at the Research Council in Ottawa, two European scientists, Hans von Halban and Lew Kowarski, working at the Collège de France in Paris, were involved in experiments that suggested that a large release of nuclear fissions might be possible through the use of heavy water (deuterium oxide), an isotope of hydrogen with a mass double that of ordinary hydrogen.

When France was invaded in the spring of 1940, Halban and Kowarski took their precious quantity of heavy water with them when they fled to England. There they met with John Cockcroft at the Cavendish Laboratory in Cambridge. Not long afterwards, Cockcroft was in Ottawa and learned of the work in which George Laurence was engaged. On his return to England, Cockcroft arranged for a grant to be sent by Britain’s Imperial Chemical Industries to support nuclear research in Canada.

As World War II continued, Britain’s nuclear experts concluded that it would be desirable to move their experiments to North America where they would not be bombed by German aircraft and would be close to American scientists engaged in similar work. In August 1942, the British government proposed that an Anglo-Canadian joint nuclear research group be established and that the scientists then working in the University of Cambridge on slow-neutron research should move to Canada as a group.

Canada’s Minister of Munitions and Supply, the Hon. C.D. Howe, and Dr. C.J. Mackenzie, president of the National Research Council, agreed with the proposal, both realizing that to conduct such research in Canada would be most helpful in the creation of a brand-new industry with great potential.

The scientists from Cambridge arrived in Canada toward the end of 1942 and were housed in an old residence in downtown Montreal owned by McGill University. Early in 1943, the Cambridge Group augmented by Canadians moved into more adequate accommodation in a new building of the University of Montreal. The group grew quickly to over 300, about one-half of whom were Canadians. By 1944, John Cockcroft had returned to Canada to assume overall responsibility for the newly established Montreal Laboratory, as a separate unit under the president of the NRC, Dr. C.J. Mackenzie. He in turn was responsible to both C.D. Howe and Malcolm MacDonald, the British High Commissioner to Canada.
 

Sir John Cockcroft’s pioneering in the use of particle accelerators in the study of the atomic nucleus at the Cavendish Laboratories of Cambridge University in 1932 earned him the 1951 Nobel Prize in Physics. Between these years, he led Canada into the nuclear age by building over a two-year period (1943-45), an experimental nuclear reactor at Chalk River, northwest of Ottawa, where solid foundations were established for Canada’s peacetime role in harnessing nuclear energy. Viewed here, extreme right, circa 1945, John Crockcroft stands with, left to right, C.G. Laurence, C.J. Mackenzie, and C.D. Howe. Laurence, at the time, was a member of the Chalk River atomic research team that was building the first nuclear reactor outside the United States; C.J. Mackenzie, a former student of Howe’s at Dalhousie University, was head of the National Research Council of Canada; C.D. Howe, as Minister of Munitions and Supply during World War II, established a nuclear research program that evolved, after the war, into the CANDU reactor program and the construction of Canada’s first nuclear reactor at Chalk River. [Photo, courtesy Atomic Energy of Canada Limited]

Under Cockcroft’s direction, morale in the laboratory was high. Cockcroft was known and trusted by the British, the Americans, and Canadians. Within less than three months, a site was chosen on the upper Ottawa River for the construction of an experimental nuclear reactor. During the two years in which Cockcroft was the director of the nuclear laboratory, first in Montreal and later in Chalk River, solid foundations were established for Canada’s nuclear industry.

In his 1988 history of the Atomic Energy of Canada Limited, Professor Robert Bothwell has written that Cockcroft’s achievement was obvious in that the Chalk River Laboratory “existed at all. That it worked was even more to his credit. It had been no easy feat to transform a dispirited team into a functional, large-scale scientific enterprise. Cockcroft expected great things from Chalk River.” Years later Cockcroft told the writer of this article of his great appreciation of what had happened there after he left.

When World War II ended, Canada had all the resources necessary to become a powerful nuclear weapons state. It had the uranium, its scientists knew how to release the power of the atom, and its engineers and technical experts knew how to build and operate the equipment to do it. But Canada consciously decided that it would not be a nuclear weapons state.

On July 21, 1949, the Hon. C.D. Howe announced, on behalf of the Government of Canada, that it had chosen to explore only the peaceful applications of nuclear power. Atomic Energy of Canada Limited, which was incorporated in 1952, became the primary agency through which that objective was to be realized.

D. McCormack Smyth