Abstract
DB. J. D. COCKROFT gave the twenty-seventh Annual Kelvin Lecture to the Institution of Electrical Engineers on April 23. He chose as his subject the transmutation of matter by high energy particles and radiations. In 1919, Rutherford's discovery that the central nuclei of atoms could be penetrated and permanently changed by a bombardment of very high speed atomic projectiles, such as those given off by radioactive bodies, proved that the ordinary elements are not immutable. It took some years before the importance of his experimental results was fully recognised. He observed that nitrogen gas, penetrated by helium nuclei, ejected hydrogen nuclei. It has been shown since that boron, fluorine, sodium, magnesium, aluminium, phosphorus and sulphur can be similarly transmuted. In the case of nuclear transmutations, it seems that the loss of mass is precisely equal to the increase in the kinetic energy that has taken place. This gives a striking proof of the modern physical law that mass and energy are equivalent. In 1932, Chadwick discovered the neutron, a new type of atomic particle which has no electric charge. It does not therefore interact with other electrons and produces no ionisation when passing through a gas. It is of outstanding importance because of its power to produce transmutations. There is little hope that this process can be used on
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Transmutation of Matter. Nature 137, 772 (1936). https://doi.org/10.1038/137772b0
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DOI: https://doi.org/10.1038/137772b0