Journal of Radioanalytical Chemistry Vol. 1 (1965) 97--102
G E O R G E HEVESY
F. SZABADVARY
Institute for General and Analytical Chemistry of the Technical University,
Budapest (Hungary)
(Received July 19, 1967)
As the starting of a special journal devoted to radioanalysis had come up, the idea
arose that George Heresy should be asked to write some lines in the first issue. But
he had died earlier than the journal started, after having been ill for some time.
So now we only have the sad duty of commemorating this great pioneer of radioanalysis.
There have been only few people in our century to contribute to analytical chemistry as much as Hevesy did, although he wrote to the author of this paper in
one of his letters in 1961 that " I am not an analytical chemist, so I do not feel
myself called to make expert statements".
It is rather rare that a many-sided field of good prospects is linked so much with
the name of only one person, as radioanalysis is with the name of Hevesy. It is
even more seldom that a great achievement like Hevesy's work in this field is only
a part of his scientific life-work, since Heresy made outstanding contributions
also in other fields of science. His activity goes far beyond the bounds of analytical
chemistry. There is hardly any field of natural science which does not use radioisotope indication methods.
George Hevesy was born in Budapest, on the 1st August, 1885, of a wealthy
family. He finished his secondary school studies in the Piarist G r a m m a r School
in Budapest. He began his academic studies at the University of Budapest, then
zontinued in Berlin and Freiburg. He took his doctor's degree in physics and
chemistry in 1908. His doctorate thesis dealt with the interactions between sodium
and molten sodium hydroxide. His scientific career started in Zurich, when he
was appointed assistant lecturer to the department led by professor Richard
Lorenz. He attended the demonstration lectures of the honorary lecturer, the
young Albert Einstein. As Hevesy mentioned in his reminiscences I he had
shown Einstein round their laboratories, and Einstein was surprised to see a hydrogen electrode. He had thought such an electrode to be only a theoretical concept.
When Lorenz left for Frankfurt and Hevesy wanted to go with him, Professor
Wilst/itter, winner of the Nobel Prize, dean of the Faculty, and head of the Chemical Department, declared: " I n G e r m a n y the assistant belongs to the professor, in
Switzerland to the laboratory, you stay here." In spite of this, Hevesy soon left
Zurich. He was interested in catalytic processes, and therefore he went to Haber,
1"
J. RadioanaL Chem. 1 (1968) 97--102
98
F. S Z A B A D V A R Y : G E O R G E HEVESY
discoverer of ammonia synthesis, to the Technical University of Karlsruhe. To
Hevesy's disappointment, instead of catalytic studies, Haber required his work to
investigate whether the oxidation of molten zinc was accompanied by the emission
of electrons. As it turned out that no one in the Institute had any experience in the
measurement of radiation, in 1911 Hevesy was sent to Manchester, to the institute
of Rutherford, to learn the technique of measurement.
The young man met a new world. Here a completely new physics, nuclear physics was being born, which then gave several surprises to our century.
At that time the first period of discoveries was already over. The nature of the
types of radioactive radiation had been determined, radium discovered, the decomposition and transformation of some elements described, and several decomposition products of natural radioactive elements identified and separated. Rutherford announced his idea of the atom considered similar to the solar system, Soddy
stated his displacement rule. It appeared that chemically very similar elements of
different atomic weights may occupy the same place in the periodic system. Soddy
termed these isotopes.
Rutherford's laboratory was well supplied with the by-products of uraniulnprocessing in Joachimsthal, where radium was produced according to the prescription given by the Curies. The laboratory had amongst other things plenty of a
material containing radioactive r a d i u m D , which is known nowadays to be one of
the radioactive isotopes of lead. Radium D was accompanied by great amounts
of natural lead, which absorbed the radiation.
The ideas were not quite clarified. It is shown by the fact that Rutherford spoke
to young Hevesy like this: " I f you are worth your salt, you separate radium D
from all that nuisance of lead." Hevesy set to work at once, and did not think how
difficult his work was going to be. He worked for a year, but could not separate
radium D by any chemical method. It turned out that isotopes could not be separated ;n this way. It occurred to him that radium D might be used for tracing lead,
and so lead could be followed by virtue of the radiation of RaD. He went to Vienna,
into the Radium Institute where a young assistant, Paneth, had also made fruitless efforts to isolate the same substance, and where there was plenty of uraniumbase material.
Their first common paper entitled "Solubility of lead sulphide and lead c h r o mate" appeared in 1913[2 This paper is regarded as the basis of all methods using
radioactive isotopes for tracing, whether applied in biology, metallurgy, medicine,
or in analytical chemistry. The introduction of the paper giving the essence of the
method is cited below:
"Das vierte Zerfallsprodukt der Radiumemanation, das RaD zeigt bekanntlich alle chemischen Reaktionen des Bleis; vermengt man das RaD mit B|ei oder Bleisalzen, so l/isst sich
ersteres vom Blei durch keine chemische oder physikalische Methode trennen, und wenn
einmal die vollst~indige Vermischung der beiden Stoffe stattgefunden hat, bleibt dasselbe
Konzentrationsverh/iltnis auch fiir beliebig kleine Mengen Blei, die man der L6sung entnimmt,
bestehen. Da RaD infolge seiner Aktivit~t in unvergleichlich viel geringerer Menge bestimmt
werden kann als Blei, so kann es zum qualitativen und quantitativen Nachweis des Bleis,
dem es zugefiigt wurde, dienen; das RaD wird zum Indikator des Bleis."
J. Radioanal. Chem. 1 (1968) 9 7 - - 1 0 2
F. S Z A B A D V A R Y : G E O R G E HEVESY
99
This paper was rewarded by the Nobel Prize in Chemistry 30 years later, in 1943.
The comprehensible reason for the late acknowledgement of the discovery is that
the work was ahead of its time. At that time, when only natural radioactive isotopes were available, the method had only a narrow field of application. Its importance suddenly increased as the isotopes of nearly all elements became available. Most methods discovered by Hevesy may be characterized as being ahead of
their time. He applied the tracer method in different fields, where it proved to be
indispensable.
The electrochemical behaviour of lead and bismuth was studied similarly to the
solubility of lead salts not much later, and the concept of isotopes interpreted
in detail, 3 which essentially promoted the elucidation of ideas in this field. Hevesy
later studied the exchange of lead ions between the solid and liquid p h a s e s / R a d i o activity made perceptible that the atoms were in continuous motion, migration,
and exchange, not only in the liquid but also in the solid phase.
After finishing his successful experiments and getting acquainted with Madame
Curie in Paris, Hevesy returned to England.
Many scientists who later became well known for their achievements in nuclear
sciences (e.g., Hahn, Geiger, Bohr) worked in Rutherford's Institute. Hevesy
formed a close friendship with Bohr. A young Englishman, Moseley, worked also
there at the time, who began to study X-rays, and succeeded in finding a relationship between the frequency of the K lines and atomic numbers of elements. Hevesy
helped with the work of Moseley concerning rare earth metals. Here he learned
the X-ray diffraction technique which he successfully used in his researches later,
and which he also improved.
After a visit to his country, Hevesy was travelling back to England through
Holland to continue the above-mentioned experiments, when the First World
War broke out, in which Moseley was soon killed. Hevesy joined the A u s t r i a n Hungarian regiment, where he did technical service. He continued his experiments
also during the war. He equipped a small laboratory where he investigated the
difference between the ionic and colloidal state of thorium. After the war he worked at the Veterinary College, and later at the University of Budapest. He investigated, together with J. Grdh, the self-diffusion of lead atoms in solid lead, by means
of RaD melted into it previously. '~ This can be considered to be the first application of the tracer method of metallurgy. Together with Zechmeister he established that radioactivity was equally divided between salts crystallized from the
mixture of inactive lead chloride and labelled lead nitrate; when a solution
of a labelled lead salt was mixed with that of an organic lead compound, the
activity was retained in the original salt. 6 Arrhenius greeted this experiment as a
significant and striking proof of his ionic theory that was half a century old at
the time.
In 1920 Hevesy left Budapest for Copenhagen, to join the institute of Niels
Bohr. His activity in Copenhagen was amazingly many-sided, and very successful.
He worked with Br6nsted, professor of chemistry of the University, on the separation of natural isotopes by physical methods. They succeeded in separating isoJ. Radioanal. Chem. 1 (1968) 97--102
100
F. SZABADVARY: GEORGE HEVESY
topes of chlorine and mercury, the latter by a hundred successive distillations in
vacuum. 7
The periodic system was nearly complete at the time, only four elements being
unknown. Moseley's discovery made possible the determination of atomic numbers experimentally. By means of the new method vigorous work was started after
the war to find the elements which were still unknown. One of them was that with
atomic number n. Since its place was just after the rare earths, it was searched
for in such ores.
In 1921, on the basis of Bohr's atomic theory, a table was made of the electron
configuration of elements. Tn the light of this, the periodic system obtained a deeper explanation. Bohr made known his still unpublished conception to Hevesy.
It followed from the new theory that the nnd electron of the nnd element in the
periodic system was on a new orbital, so it had to be similar to zirconium, and not
to the rare earths.
Hevesy and Coster therefore studied the X-ray spectra of zirconium-containing
ores, and found the lines of the new element. They separated it from the ore as the
fluoride. They called the new metal (which was very similar to zirconium) hafnium,
after the Latin name of Copenhagen. H
Hevesy made also other very important experiments at that time. In 1923 he
attempted to follow the absorption of lead in plants by means of radioactive lead,n
this being the first application of the radioactive tracer technique to biology. This
was followed by the use of radioactive tracers in living animals. Compounds of
bismuth were important in curing syphilis. Hevesy and his co-workers investigated
the distribution of bismuth in animals, for example rabbits by means of radio
active bismuth. lO
The application of radioactive indication to biology was limited as long as only
natural radioactive isotopes were available, which are not very important in life,
such as uranium, thorium, actinium, lead and bismuth. The importance of the
method suddenly increased when after the discovery of artificial radioactivity the
radioactive isotopes of a number of common elements could also be produced.
The importance of the above-mentioned pioneering work became obvious only
at that time. Hevesy was one of the first researchers to use artificial radioactive
isotopes. He and his colleague Chiewitz were the first to prepare phosphorus-32
and to investigate the metabolism of phosphorus in ratsY During the next decades
Hevesy published several papers on biochemical and biological investigations
made by means of phosphorus-32, heavy water, calcium-45, carbon- 14, with Krogh,
Hahn, Parnass, Aten and others, as co-workers. The tracer technique was used to
investigate the distribution of phosphorus and other elements in the human organism, the formation, regeneration and detection of erythrocytes, amino acids,
and desoxyribonucleic acids, and to study several other important problems.
They were the first to use the tracer method for studying cancerous tumours.
George Hevesy became a professor of the University of Freiburg in 1926.
With excellent intuition he again started working in a field which later proved to
be very important, especially in analytical chemistry: he did pioneering work in
J. Radioanal. Chern. 1 (1968) 97-102
F. SZABADVARY: G E O R G E HEVESY
101
discovering X-ray fluorescence analysis. Hevesy and Alexander studied the phenomenon in the thirties and published their paper in 1932.12 The spreading of the
method was promoted by the perfection of instruments for measuring radiation
and by the introduction of scintillation crystals.
There followed two discoveries in the field of radioanalysis. The first of them
was the isotope dilution method. Hevesy and Hobbie reported the first analysis
by this method in 1931. They determined the lead content of various rocks by the
isotope dilution method using electrogravimetry. 13
After Nazism had come into power in Germany, Heresy soon left Freiburg and
went to Denmark into Bohr's institute, where he elaborated the method of activation analysis. He analysed rare earths, and he came to the thought that the
method of preparation of artificial radionuelides discovered by Joliot Curie and
his wife in 1932 was also suitable for the determination of very small amounts
of various elements. Hevesy and Levi determined europium and dysprosium by
this m~thod. 14 They characterized this very useful analytical method as follows~
"The usual chemical methods of analysis fail, as is well known, for most of the rare earth
elements and have to be replaced by spectroscopic, X-ray and magnetic methods. The latter
methods can now be supplemented by the application of neutrons to analytical problems,
by making use both of artificial radioactivity and of the great absorbing power of some of
the rare earth elements for slow neutrons. Qualitative analysis with the aid of artificial radioactivity is based on the determination of periods of decay...
We used the method of artificial radioactivity to determine the dysprosium content of
yttrium preparations. The procedure was the following: we mixed 0.1 ; 1% etc. of dysprosium
with neodymium oxide, the latter being chosen because it is one of the cheapest rare earth
elements, and determined the intensity obtained. The yttrium sample to be investigated was
then actived under exactly the same conditions and a comparison of the dysprosium activities
obtained gave 1% as the dysprosium content of the yttrium sample... This method of
analysis.., gives a direct means of identification of the nuclei involved; this distinguishes
it from all other analytical methods, chemical, spectroscopic, X-ray and magnetic, which are
based on the investigation of the electronic properties of the atom in question."
Hevesy was in Copenhagen as the Second World War broke out, and also during the time of the German occupation. Bohr was worried about the Nobel-medal
of Max yon Laue. The German physicist entrusted it to Bohr for safeguarding,
since keeping gold was forbidden in Germany. Bohr was afraid that the medal in
which Laue's name was engraved would be found. He was relieved of his fears by
Heresy who dissolved the medal in acid. 1 After the war the medal was done again
for Laue.
Bohr was warned in 1942 that he and his institute were under observation. Bohr
escaped to Sweden, then to England and later to the United States. Hevesy could
also get to Sweden and settled down there. He worked in the Institute for Organic
Chemistry of the University of Stockholm. He continued his research work until
his old age. He followed the progress in science with interest till his death. He died
on the 6th July 1966, in a clinic in Freiburg where his grave illness had been treated.
His unequalled versatility and ingeniousness are proved by his nearly 400 papers
on physics, chemistry, biochemistry, biology and botany.
J. Radioanal. Chem. 1 (1968) 97--102
102
F. SZABADV~RY: GEORGE HEVESY
H e m a d e a g r e a t i m p r e s s i o n on his c o ll e ag u es: H. Levi, his c o - w o r k e r in disc o v e r i n g activation analysis w r o t e the f o l l o w i n g :
"Hevesy's inexhaustible stream of new ideas, his dynamic personality, his incredible
memory for everything ever done or read, and his apparently effortless endurance of long
working hours - - he never could sleep more than a few hours a night - - brought about his
ever-presence at all odd hours of the day in different laboratories scattered all over the city of
Copenhagen. In spite of his pride in his four children and although his family requested his
presence and attention, he would often forget to come home for special occasions, for example
when he invited guests. One of the favourite stories from that period tells how Hevesy rushed
from his office, leaving behind one of his galoshes. He mounted his bicycle and shouted to one
of his young assistants: 'You are lucky, young man, you have your rabbits, I must go home
to my family'. ' ' ~
G e o r g e Hevesy received m u c h r e c o g n i t i o n d u r i n g his life. Besides the N o b e l
Prize he received F a r a d a y , C o p l e y and B o h r Med al s, F e r m i Prize, and the second
~"Atoms f o r P e a c e " A w a r d . A n d there are few p e o p l e to deserve the latter as m u c h
as he did. His life-work did only g o o d to m a n k i n d and never caused destruction.
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r. RadioanaL Chem. 1 (1968) 97--102