between Rutherford and Soddy was a happy one. Rutherford was essentially
an experimental physicist with a knowledge of chemistry that would not be
regarded as fundamental. Soddy was a chemist and always had a good grasp
of atomic conceptions. Although the two men were both outstandingly strong
personalities and thus might easily have found it difficult to get on with one
another, the fact that their approach to their own experimental work was
from different directions made for ready and complementary discussion.
Certainly their period of collaboration left Soddy with an appreciation of
Rutherford as a great experimental physicist. The partnership in Montreal was
a happy one, both from the point of view of the participants and of science.
Re-reading the Rutherford and Soddy papers today (2), (3), (4), (5),
and remembering all the time that these papers—essentially four of them—
are the foundations of one of the biggest revolutions in scientific thought, I
cannot help but be impressed with their matter of fact and unsensational
tone. The setting out of what we know as the disintegration theory is not
done with much if any headlining. Their ideas are based on two basic facts—
the experimental curves for growth and decay as measured in an electroscope
and the repeated assertion that the phenomena were atomic or sub-atomic
and not molecular. It is difficult at this distance of time to visualize the
immediate effect of these papers on the scientific world of that day. Up to
then the ideas of possible explanation of radioactivity rested on a form of
continuity of emission of energy analogous in some way to the wave theory
of light. Continuity seemed to be the basic ideas of the Curies. The older
generation of British scientists had ideas about the capacity of the radioactive
elements to absorb energy from their surroundings and then to re-emit it.
Harold Hartley, who by that time was very interested in the impact of the
new scientific idea, describes the effect of the Rutherford and Soddy papers
as that of a wave which swept over the scientific world and carried away
most if not all of the previous vague alternatives. Certainly by the end of
1903 all the great names such as Lodge, Thomson, Crookes, with the signal
exception of Kelvin, had acknowledged the strength of the disintegration
theory. In most respects this is all very satisfactory, but I think it is unfortu
nate that nowhere that I am aware of does either Rutherford or Soddy give
an account of the mental process by which they arrived at their conception
which has so fully stood the test of time. In such conversations as I had with
Soddy on the subject I could not get any closer in a definite way beyond a
very specific statement that the conception was in very truth a joint effort.
Kelvin remained for a year longer an unbeliever—until in fact the Cambridge
Meeting of the British Association in 1904, when he acknowledged that the
phenomena were atomic. But in the last year of his life (Kelvin 1907) he was
writing a paper in an attempt to explain the radioactivity of radium.
Here it may be appropriate to record an incident that has come to my
knowledge from the Kelvin side—from Mrs H. N. Beilby who is a grand
niece of Lord Kelvin and who was frequently in the Kelvin household in the
early years of the century. After Soddy’s arrival in Glasgow, Lord and
Frederick Soddy
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Lady Kelvin seriously discussed whether it would be desirable and wise for
them to invite this young scientific revolutionary for a weekend at Largs, and
they then decided to do so. The effect was most fortunate. The discussions
which took place then did not, so far as I am aware, change in any way the
views held by either side, but they did have a most happy result in that both
Lord Kelvin and Soddy found their respect for each other on a much higher
level than hitherto.
Soddy left Montreal with the objective of working with Sir William
Ramsay in London and this piece of collaboration was entirely successful,
namely the proof that helium was a product of radium emanation dis
integration. This piece of work (8), published in 1903 in the Proceedings o f
the
Royal
S
o
ciety, did much to remove any lingering doubts that any one had on
the basic correctness of the Rutherford and Soddy disintegration conception.
There is one period to which reference should be made because I feel it is
characteristic of Soddy’s vitality. While he was in London in the spring of
1904 he accepted the position of Lecturer in Physical Chemistry in Glasgow
University, but before he took up the appointment he set out on a lecture
tour in Western Australia. The arrangement was for a course of Extension
Lectures under the auspices of London University, and dealt with electrical
matters before settling down to the new and, to the then, very exciting
subject of radioactivity. This tour took Soddy into mining townships in
Western Australia, such as Kalgoorlie and Coolgardie as well as Perth and
Fremantle. As he left Western Australia en route for Glasgow via New Zea
land and the United States, he called in at Adelaide and made the acquain
tance of W. H. Bragg. I have Sir Lawrence Bragg’s authority for saying that
the impression he created in Adelaide was most favourable.
Although the work was carried out in Glasgow it is perhaps appropriate
in this place to refer to his other great contribution to the establishment of the
disintegration theory, namely the proof of the growth of radium from
uranium. Available for this purpose was 50 kilos of uranyl nitrate given to
him by Sir George Beilby. There is a long series of papers (11) on this subject
in which he was assisted by T. D. MacKenzie and Miss A. F. R. Hitchins;
the first paper of the series is dated June 1905 and the last November 1931.
He found that the rate of growth of radium was slow at first but developed
later at increased speed. He correctly deduced the presence before radium
of a relatively stable radio element. Both the helium work in London and the
radium work in Glasgow are important contributions to the development of
the disintegration theory.
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Biographical Memoirs
G
l a s g o w
a n d
isoto pes
The research work which was initiated after arrival in Glasgow in the
main came from the extension of ideas inherent in the disintegration theory
and some has been mentioned under that heading. With his growing reputa
tion as a scientist it is natural that a number of research students should
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