of his receiving the Nobel Prize and in it he describes his part, both in the
evolution of the conception of isotopes, and also how he and others contri
buted to the fitting of the radio-elements into the periodic law. In this paper
full justice is done to the work and ideas of Stromholm and Svedberg, of
Russell, of Hevesy and of Fajans. In 1911 Soddy had written ‘The loss of a
helium atom or a particle appears to cause the change of the radio element
not into the next family but into the next but one . . .’ This was known as
‘The a-ray generalization’. I believe A. S. Russell first made the suggestion
that when a /3 ray is emitted the atom changes in chemical nature so as to
pass into the family in the periodic table next higher in number.
With the characterization of the chemical properties, particularly of those
radio elements subsequent to the emanation the full chemical behaviour of
the three series of radio elements was made clear. Soddy was most clear that
on the theoretical side the names of Fajans, Hevesy and Russell are associated
in the advance which resulted in the formulation of the displacement law. It
can now be stated in the following terms—Each a ray expelled causes a shift
of two places in the direction of diminishing mass and diminishing valence,
and each /3 ray expelled causes a shift of one place in the opposite direction.
At the same time when it was originally formulated it was not possible to
connect in the actinium series with the uranium series. That was made
possible by the independent work of Soddy and Cranston (35)
Roy.
Soc. 1918) and H ahn and Meitner (
P
h
ys.
1918) which showed that action
was produced by an
a ray change from ‘ekatantalium’—an element occupy
ing the place between uranium and thorium and, therefore, isotopic with
uranium-X2.
An important piece of research work was carried out arising from the
general conception of isotopes in collaboration with H. Hyman (32). The
displacement law led to the conclusion that isotopes of lead were the end
products of both the uranium and thorium disintegration series, and if lead
should be the end of the thorium series it should have an atomic weight of 208
where the disintegration of uranium would give lead of 206:—the accepted
value of common lead being 207*2. In Soddy’s work he commenced with
30 kilos of Ceylon thorite and the atomic weight was determined to be 207 • 7.
The isotope work vastly enhanced his reputation in the scientific world and
the word ‘isotopes’ has come to be closely associated with his name through
out the whole scientific world. It was not his first attempt to bring in a new
word into scientific use. Rutherford and he had suggested that the word
‘metabolon’ should be used for an element possessing the properties of
radioactive disintegration, but the word never found favour in the minds of
scientists—it seemed just as easy to say ‘radioactive elements’ and even its
parents ceased to use it after a few papers of the 1903 vintage.
Carrying on the process of imaginative insight into what the disintegration
theory had achieved, Soddy’s thoughts went on to examine some of the things
that radioactivity in the fullness of time might achieve. It is, therefore, worth
while recording a paper on ‘The internal energy of elements’ (47), read in
Frederick Soddy
209
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210
March 1906 to the Glasgow Local Section of the Institution of Electrical
Engineers: ‘We cannot regard the existence of this large internal energy as a
peculiar property of the element radium. . . .Y e t uranium since it produces
radium with evolution of energy must possess all the internal energy of
radium and more . . .’ ‘But there is no saying now that we are assured we are
on the right track, how or when a discovery may not be made which will
unlock this great store of energy bound up in the structure of the elem ent. . . ’
‘We are starting the twentieth century with the prize in full view . . /
He was a long way ahead of experimental achievement, but no one can
deny that there was vision in his appreciation of the then situation and its
potentialities.
Soddy’s translation to the Professorship of Chemistry in Aberdeen and the
outbreak of the First World War in 1914 were interruptions to his outlook—
in fact so serious* that apart from the collaboration with Cranston on the
parent of actinium, no new experimental work on radioactivity came from
him that should be recorded in this memoir.
During the 1914-1918 war he was active in various forms of chemical work
which was immediately necessary for national purposes. Organic preparations
were carried out in the University laboratory and semi-technical work on the
extraction of ethylene from coal gas was carried out in the Aberdeen Gas
Works. By the courtesy of Mrs Muriel Howorth, to whom all his papers have
been left by his will, I have seen the reports of his work for the Marine Sub-
Committee of the Board of Inventions and Research under whose auspices
he did work on steam raising by addition of water to strong or anhydrous
caustic soda. It is worth while stressing, therefore, that he was active in
technical work arising from the war situation, but none of it needs to be
recorded here in detail.
Biographical Memoirs
O
x f o r d
a n d
his
soc ial
o u t l o o k
I had almost written ‘Oxford and fermenting causes’ since from 1918
onwards his mind was more and more occupied with ideas analysis and
suggestions as to what was wrong with the world at large, or ‘why so far the
progress of science has proved as much a curse as a blessing to humanity’.
His own words are—‘My main conclusion . . . was that it was entirely due
to the fictitious money system which arose contemporaneously with the birth
of the scientific civilization and that now was being purposefully and
consciously used to frustrate it and to preserve the earlier civilizations founded
on slavery.’
At the end of the war he was appointed Lees Professor at Oxford in which
appointment he remained for some 17 years. Although he did an amount
of work in the laboratory he did not publish any papers based on experi
mental chemistry. On that aspect of science he had shot his bolt. He spent
a great deal of time on teaching aspects of his appointment, such as plans for
the reconstruction of the laboratory. At this time, too, much thought was
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