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IOP History of Physics Newsletter November 2017
Published by the History of Physics Group of the Institute of Physics (UK & Ireland)
ISSN 1756-168X
Contents Editorial Meeting Reports
Chairman’s Report
Rutherford’s chemists - abstracts
‘60 Years on from ZETA’ by Chris Warrick
Letters to the editor Obituary
John W Warren by Stuart Leadstone
Features
Anti-matter or anti-substance? by John W Warren
A Laboratory in the Clouds - Horace-Bénédict de Saussure
by Peter Tyson
On Prof. W.H.Bragg’s December 1914 Letter to the Vice-
Chancellor of the University of Leeds
by Chris Hammond
Book Reviews
Crystal Clear - Autobiographies of Sir Lawrence and Lady Bragg
by Peter Ford Forthcoming Meetings
Committee and contacts
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IOP History of Physics Newsletter November 2017
Editorial
A big ‘Thank you’!
Around 45 people attended the Bristol meeting on the History of Particle
Colliders, in April. It was a joint meeting between the History of Physics
Group, the High Energy Physics Group, and the Particle Accelerators and
Beams Group. With a joint membership of around 2000, that works out at
well under 3% - and that was a good turnout. The Rutherford’s Chemists
meeting held in Glasgow attracted probably a similar percentage - not very
high you might think. But time and travel costs to attend come at a premium
so any means by which the content of our meetings may be promulgated -
reports in our newsletter and in those of the other groups - is a very
worthwhile task.
Better still, though, is the publication of the talks themselves - however, not
only worthwhile but a considerable undertaking for the speakers concerned.
I am very pleased, therefore, to say that the group will be publishing a
special issue next month comprising some of the talks given at both these
meetings.
I am also very pleased to report that the meeting on the history of units held
last year at the National Physical Laboratory, Teddington, is to be
recollected in a book, ‘Precise Dimensions - a History of Units from 1791 to
2018’ published by the IOPP. It includes most of the talks given with the
bonus of two other contributors writing on the mole and the candela.
It seems very appropriate here, to extend my heartfelt thanks to all our
contributors - from the largest articles to the smallest - all are the very
lifeblood of this newsletter and indeed the group as a whole.
Thank you!
Malcolm Cooper
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IOP History of Physics Newsletter November 2017
Chairman’s Report
Four meetings were scheduled for 2017; they have covered a wide range of
areas of physics and have been co-hosted by a number of other
organisations, both other groups of the IOP and those from further afield.
The first, on the History of Particle Colliders, was organised by Vince
Smith and held in Bristol in April; it was a joint meeting between the
History of Physics Group, the High Energy Physics Group, and the Particle
Accelerators and Beams Group, with further sponsorship from the School of
Physics at the University of Bristol. It focussed on the historical and
political aspects of the design, construction and operation of the machines.
The first talk, by Giulia Pancheri of Frascati, discussed the work of the
Austrian Bruno Touschek, who built a 15 MeV betatron with the Norwegian
Rolf Widerøe during World War II, and was responsible for the first
electron-positron storage ring in 1961. Philip Bryant from CERN then
spoke on the CERN Interacting Storage ring and its legacy. In the
afternoon, Peter Kalmus from Queen Mary spoke on The CERN proton-
antiproton collider project, Sir Chris Llewellyn Smith on the genesis of the
Large Hadron Collider, and Brian Foster from Oxford on future energy-
frontier colliders.
The second meeting was held at Birmingham in June, and was a fairly short
joint meeting of the History of Physics, Nuclear Physics, Nuclear Industry
and Plasma Physics Groups of the IOP on Developments in Nuclear Fusion:
60 Years on from ZETA. From the strictly historical point of view, probably
the most interesting talk was the first, given by Chris Warrick, Head of
Communications at UKAEA, on ZETA itself and the subsequent
developments in nuclear fusion. Kate Lancaster from York University gave
a current account of inertial confinement fusion, while David Kingham
from Tokamak Energy and Ian Chapman for the UKAEA gave fascinating
account of the present work on tokamaks in the private and public sectors
respectively.
In July there was a meeting on Rutherford’s Chemists organised in Glasgow
by Neil Todd in conjunction with the Royal Society of Chemistry. During
the meeting it might be suggested that a theme developed that the
reputations of some of ‘Rutherford’s Chemists’ – in particular Frederick
Soddy and William Ramsay, despite their Nobel Prizes - had suffered at the
hands, not so much of Rutherford as of Rutherford’s biographers.
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IOP History of Physics Newsletter November 2017
The first talk, given by Pierre Radvanyi from Orsay, presented a study of
the work of Marie and Pierre Curie, including the discovery of polonium
and radium, and their studies of radioactivity. The rest of the first day was
devoted to accounts of the work of Soddy. Linda Richards from Oregon
State University presented a wide-ranging account of his ideas. This
included a discussion not only of his scientific work, first with Rutherford
and then with Ramsay and later on his own, on radioactivity, in particular
covering the ‘displacement law’ and the identification of isotopes, but also
his later social, political and economic ideas. David Sanderson from
Glasgow presented a general account of Soddy’s work at Glasgow
University between 1904 and 1914, during which much of his work on
radioactivity was performed. Finally, at the evening reception, John
Faithfull of the Hunterian Museum in Glasgow gave a talk on Soddy
artefacts at the museum.
The next day, Finlay Stuart of the Scottish Universities Environmental
Research Centre presented an account of the work of William Ramsay, in
particular his Nobel Prizewinning discovery of the noble gases, and Neil
Todd described the results of his radiological survey and gamma ray
analysis of the laboratory notebooks of Soddy and Ramsay. Then in the
final session, Ted Davis discussed the work of Bertram Boltwood, in
particular his ideas on radio dating, and Dieter Hoffmann from Berlin
described the work of Otto Hahn and also presented Siegfried Niese’s paper
on Georg von Hevesy.
The last meeting of 2017, jointly sponsored with the Medical Physics and
Magnetic Resonance Groups, was scheduled to be held in Nottingham in
September. Unfortunately because of other meetings in magnetic resonance
scheduled for the same day, the meeting was postponed until April 2018. It
will be in memory of Sir Peter Mansfield, winner of the Nobel Prize for
Medicine in 2003 for his invention of Magnetic Resonance Imaging (MRI),
who died earlier this year. It will include talks on the history of Nuclear
Magnetic Resonance (NMR) and MRI in Britain, and also a number of talks
on the recent developments in MRI.
Andrew Whitaker
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IOP History of Physics Newsletter November 2017
Meetings
Rutherford’s Chemists, Glasgow, 15th/16th July, 2017
A two-day meeting, co-sponsored by the Institute of Physics and Royal
Society of Chemistry, to celebrate the centenary of the second scientific
revolution and a unique collaboration between physics and chemistry.
Pierre Radvanyi, Institut de physique nucléaire, Orsay, France.
Marie and Pierre Curie and the discovery of radioactivity
Prompted by the discovery of X rays by W.C. Röntgen, H. Becquerel investigated
whether a very phosphorescent uranium salt did also emit X rays. In these
experiments, in March 1896, Becquerel discovered what he called “uranic rays”. In
the Fall of 1897, Marie Curie Sklodowska wished to prepare a PhD in science at the
Sorbonne university (she would become the first woman in Paris to obtain such a
degree). She decided to investigate if other chemical elements did also emit such
“uranic rays”. Her husband Pierre Curie constructed the necessary apparatus. She
looked also at uranium minerals and found surprisingly that these were more active
than pure uranium. Marie and Pierre continued their searches together. In July 1898
they discovered polonium and in December 1898 radium, using a new physico-
chemical method. The denomination “radio-activity” was introduced for the first
time by Marie Curie. A number of questions were immediately raised by these
discoveries. What were the properties of the rays emitted? Where does their energy
come from? At this point at first E. Rutherford alone, then E. Rutherford and F.
Soddy, joined in the quest to answer these questions. In the following years, Marie
wished to separate pure radium and measure its atomic weight, which she succeeded
in doing in 1910. Pierre devoted himself to its physical properties, and launched the
first medical applications of radioactivity. He died early in a street accident in 1906.
Linda Richards, Oregon State University, Corvallis, USA.
Frederick Soddy - Transmutation in science and society
It is fitting Sir Ernest Rutherford and Frederick Soddy first met in a public debate
over atomic matter, because Soddy was consumed by what mattered most about
atomic energy, for good or ill. While it was Rutherford who received fame for the
two men’s 1901-3 collaboration on disintegration theory, Soddy reached far beyond
chemical and physical science to frame transmutation as a new kind of alchemy for
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IOP History of Physics Newsletter November 2017
mankind. Soddy felt imbued with a special responsibility, having been given a
glimpse of how the atomic and chemical structure of the universe was determined.
Unlike Rutherford, Soddy correctly anticipated (or perhaps he actually inspired?) a
public concern that nuclear forces placed society at the precipice of abundance or
destruction. Soddy began to abandon his nuclear research by 1919 and turned to the
underpinnings of social structure, in the hopes of intervening in the economy in
order to protect human rights and to end war. What mattered most to Soddy about
atomic matter went far beyond chemistry and directed Soddy's trajectory into
economics. Today Soddy is being resurrected as a de-growth economist with his
anti-nuclear war clarion call. Similar in some ways to Linus Pauling’s ideas about
the responsibility of the scientist, Soddy’s life can be a discursive rhetorical tool to
help decipher the relationship between science and society.
David Sanderson, University of Glasgow, Glasgow, UK.
Frederick Soddy - The Glasgow years
Frederick Soddy was born in Eastbourne in 1877 and educated in Eastbourne
College. After a year in Aberyswyth, he studied Chemistry in Merton College,
Oxford graduating with first class honours in 1899. Travelling to Canada he was
appointed demonstrator in Chemistry at McGill University (1900-1903), where,
working in collaboration with Rutherford he developed the transmutation theory of
radioactive decay. In London at UCL with William Ramsay (1903-1904) he showed
that Helium was produced from the radioactive decay or radium. Following a
Commonwealth Universities lecture tour of Australia, he moved to Glasgow as
Lecturer in Inorganic Chemistry and Radioactivity. His time in Glasgow (1904-
1914) was highly productive and happy. He published 24 papers comprising original
research and annual reviews of radioactivity for the Chemical Society. He was an
eloquent lecturer, giving vividly illustrated public lectures on radioactivity, but also
speaking publicly on broader scientific and social questions. During this period the
nature of the radioactive decay series, displacement laws, the re-organisation of the
periodic table of the elements from atomic mass to atomic number, were clarified.
The concept of the isotope, for which Soddy received the 1921 Nobel Prize for
Chemistry was cemented, and the term introduced to the scientific vocabulary in
1913. Soddy returned to Glasgow to lecture to student societies in the early 1950’s,
and his contributions have been commemorated in the University by events in 1953,
1958, 1963, and in the isotope centenary year in 2013. This presentation will look at
some of the Glasgow legacy of Frederick Soddy, including items from the so-called
Soddy Box, and also his work on the atomic weight of lead derived from the decay
of thorium.
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IOP History of Physics Newsletter November 2017
Finlay Stuart, Isotope Geosciences Unit, SUERC, East Kilbride, UK.
Sir William Ramsay: Chemical nobility
William Ramsay was born in Glasgow in 1852, and grew up in the shadow of the
University. Although destined for a career in the church his interest in chemistry,
developed while convalescing with broken leg acquired playing football, led to entry
to University of Glasgow aged 14. After a Ph.D. in organic chemistry at University
of Tubingen with Fittig, he returned to Glasgow University as assistant to the
Professor of Chemistry in 1874. In 1880 he took a Chair in Chemistry at University
College, Bristol. Here he established himself as one of the leading physical chemists
of his generation as well as an expert in the design and use of apparatus for handling
minute volumes of gases. In 1887 he was appointed head of general Chemistry at
University College London, where he worked until his death in 1916. A meeting
with the physicist R.W. Strutt (Lord Rayleigh) at the Royal Society in 1894 proved
pivotal in Ramsay’s career. Within a year he had showed that sequential removal of
N from air produced a progressively denser gas, eventually leading to the isolation
of the inert gas argon, and the recognition that Mendeleev’s Periodic Table needed
an extra column for the inert gases. Subsequent work led to the discovery of helium.
In Summer 1898 his team undertook the mammoth effort of fractional distillation of
120 tons of liquified air, sequentially isolating and identifying the remaining noble
gases; Ne, Kr and Xe. At the turn of the century Rutherford and Soddy discovered
that Th produced minute quantities of a radioactive, inert gas. In 1903 he invited
Soddy to UCL where they refined analysis techniques, then went on to demonstrate
that He is a product of the spontaneous disintegration of radioactive substances -
incontrovertible proof of the transmutation of elements. In late 1910 Ramsay’s
group measured the atomic weight of Rn, completing column 8 of the Periodic
Table.
Neil Todd, University of Exeter, Exeter, UK.
Radioactive contamination in the notebooks of F Soddy and W Ramsay
An account is given of a radiological survey and gamma ray analysis of the
laboratory notebooks of Sir William Ramsay, held at the University College London
archives, and of Frederick Soddy held in the Bodleian Library at Oxford. The
Ramsay notebooks had previously been surveyed and four such notebooks were
identified as being contaminated and held in a box separated from other material.
Within the Soddy papers 46 notebooks were surveyed. The notebooks were initially
scanned for residual radioactivity with a sensitive Geiger counter and the activities
recorded. Selected items from both sets were further analysed by means of a NaI
gamma-ray spectrometer for the purpose of radioisotope identification. Both the
Ramsay and Soddy notebooks show significant contamination from the summer of
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1903 when they were working together at UCL on the production of helium from
radium. Both also show later significant (>100 cps) contamination events, Soddy’s
in 1905 and Ramsay in 1910. Within the Soddy papers documents which were not
used to record experimental laboratory data did not show any contamination, with
one exception (some press cuttings from the Times from 1903). The gamma-ray
analysis indicated that all of the contamination was due to radium (Ra226). In
conjunction with radiological data from buildings and apparatus, these data, as well
as data from other surveys, it is argued, provide an insight into some key events in
the history of science. Of particular interest is the transfer of technology developed
by Ramsay and Soddy for manipulation of radium emanation to the Rutherford
school at Manchester and the propensity for these methods to give rise to radioactive
contamination.
Edward Davis, University of Cambridge, Cambridge, UK.
Bertram Borden Boltwood (1870 – 1927) - Radiometric dating and the age
of the Earth
Extensive correspondence between Boltwood (at Yale) and Rutherford (at
Manchester) started in 1904 and continued for twenty years. The letters reveal much
about the man known to his friends as “Bolty’. He was clearly a very accomplished
radiochemist and, as such, could supply Rutherford with experimental information
and chemical insights that physicists were unable to. In addition, he is revealed as a
kind and generous man, albeit with a wicked sense of humour. Historically he is
known for his discovery of ionium, an element that was later shown to be an isotope
of thorium (Th230). He is also credited with recognising that lead was the stable
endpoint of uranium decay, which led him to suggest an important way of dating
rocks by measuring the amount of lead they contained. Initial estimates for the age
of the Earth based on this idea were on the scale of billions of years, in contrast to
the millions of years proposed earlier by Lord Kelvin. Current values of the Earth’s
age are obtained using an advanced version of this method involving measurements
of the ratios of radiogenic lead isotopes in ocean sediments and basalts. Further
investigation reveals that Boltwood’s contributions to science were considerably
greater than these two achievements alone. I shall endeavour to identify these, as
well as providing insights into his character, which might throw light on why his life
ended so tragically.
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Dieter Hoffmann, Max Planck Institute, Berlin, Germany.
Otto Hahn – From new (radio)Elements to new Energy.
Otto Hahn came in 1905 as a young postdoc to Rutherford in Montreal, after a very
sucessfull year at the institute of William Ramsay. There he had discovered a new
radioactive element, the Radiothorium. This discovery, which were doubt by
Rutherford and in particular by Boltwood, was the entre billet for Rutherfords
laboratory in Monteral and the starting point of a very successful career as a
radiochemist, which lead to the discovery of more radiolements – among them
Radioactinium, which he discovered during his stay in Montreal. These discoveries
not only gave reason of scientific acceptance and for a live long friendship by
Rutherford, but it has also qualified Hahn as an excellent radiochemist. His high
competence in the field enabeld him to carry out decades later the revolutionary
experiments of nuclear fission during the winter 1938/39. Was Hahn one of the
oldest chemists, who has joined Rutherford, so the physicochemist Paul Harteck
belong to the very last one, who came in 1933 as a postdoc from Berlin to
Rutherford. His aim was to learn there nuclear physics, following his conviction,
that „the foreseeable future nuclear physics should open interesting and fundamental
fields for a physical chemist.“
Siegfried Niese, Wilsdruff (Germany), Radiation Protection, Analytics &
Disposal Inc.
Georg de Hevesy – Radioactivity and X-Rays in Manchester
The Nobel laureate Georg de Hevesy (1885-1966) studied physics and chemistry in
Budapest, Berlin, and Freiburg where he defended his PhD thesis on the electrolysis
of sodium hydroxide, followed by three years as assistant in Zurich and Karlsruhe,
because he had planned to contribute to the development of a modern industry in
Hungary. In 1912 he spent one year in Manchester to learn in Rutherford´s institute
something about radioactivity. At the very creative atmosphere he learned new
techniques and ideas, became interest in research work, and found friends like
Moseley and Born. The year in Manchester was fundamental for his long successful
scientific life with important discoveries physics, chemistry, geology, physiology
and medicine. After training in radioactivity by Rutherford ´s assistant Geiger he
determined the solubility of very short-lived actinium-emanation in liquids and the
valences of radio-elements. When Rutherford asked him to separate RaD (210Pb)
from inactive lead, like other chemist before, Hevesy was not successful, and he
concluded that this radioactive element can be used as an indicator for the non-
separable inactive lead in chemical processes, which in 1913 he demonstrated during
a short stay in with Paneth in Vienna. Later he applied the indicator methods in
physical chemistry and after the discovery of artificial radio-nuclides in biology,
physiology and medicine.
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IOP History of Physics Newsletter November 2017
‘60 Years on from ZETA’ by Chris Warrick (UKAEA)
(from a seminar on nuclear fusion held on 14 June 2017 at the University of
Birmingham.)
Report by Chris O’Leary for the Nuclear Industry Group Newsletter
Chris gave a wide-ranging, historical perspective on fusion research,
starting with a discussion of the fusion processes of our nearest star, the sun.
He then discussed the development of nuclear fusion research in the early
twentieth century, taking-in the work on the Cockcroft-Walton accelerator
at Cambridge in the 1930s; the ‘pinch’ experimental work by Peter
Thonemann (who, incidentally, celebrated his 100th birthday on 3rd June
this year) at the Clarendon Laboratory in Oxford and that of George
Thomson and Alan Ware at Imperial College in the 1940s. This led to the
work at Atomic Energy Research Establishment (AERE) Harwell.
The fusion research at Harwell took place in ‘Hangar 7’ (it had been an
RAF airfield) and was classified due to the parallel research into its
application to weapons; this is the location where ZETA began
construction. There was ongoing dialogue with the US and a sharing of
information on each other’s efforts at this time.
Chris spoke about the huge interest generated by the visit of Soviet Premier
Nikita Krushcev and the famous nuclear physicist Igor Kurchatov in 1956
to Harwell, noting that Blackwell’s bookshop in Oxford changed its signage
to Russian in celebration of the event and permission had to be given at the
Prime Ministerial level by Churchill! There was much public focus on the
UK’s energy research programmes at this time, not just for ZETA.
During the visit, Kurchatov spoke openly about the Soviet fusion
programme and, from this, it was clear that they were at least level with UK
and US efforts; he was keen to discuss their research and share what they
were doing with the British researchers. The visit helped to declassify the
work in the UK pertaining to controlled fusion research which was moved
to another near-by site at Culham. It also led to a team of five scientists
from Culham spending a six-month period in the Russian fusion research
facility near Moscow, to help set up laser deflection apparatus. This
mandated five Russians spending the same period in the UK.
Chris remarked on the large number people smoking pipes in the shots of
ZETA and researchers, contrasting it with today’s health and safety
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IOP History of Physics Newsletter November 2017
regulations.
Chris highlighted the lack of diagnostic capability for ZETA and its
counterparts, and how this made it far more difficult for the scientists
working on the system compared to their modern counterparts, who can use
high performance computers and full instrumentation.
Chris showed a video titled ‘Taming the H Bomb (1958)’ from the British
Pathé News site at:
http://www.britishpathe.com/search/query/zeta/recordcategories/Science++
Technology
As an aside, he noted that the Manchester Science Museum has exhibits
from the ZETA programme.
Chris went on to discuss some alternative approaches, such as the Princeton
Stellerator 8 built by Lyman Spitzer in the 1950s, and the work at Lawrence
Livermore National Laboratory ‘magnetic mirrors’. He later compared the
tokamak, which are “easy to build but a beast to operate”, to stellerators, for
which the opposite is true.
An IAEA conference, ‘Atoms for Peace’ was held in 1965 at the opening of
the Culham Laboratory, during which Spitzer discussed the drawbacks of
the various approaches, and the drawbacks with each. The most promising
work seemed to be that of Lev Artsimovich from the USSR – who
described encouraging results from a so-called ‘Toroidálʹnaya kámera s
magnítnymi katúškami’ or Tokamak. The toroidal field was much (by a
factor of 500) larger than in classical ‘pinch’ devices.
Experiments on tokamaks took place throughout the 1960s and 1970s, and
the decision was eventually made by the European Commission to construct
a European tokamak called Joint European Torus, or JET, that would be 100
times bigger than existing devices; one of the major drivers for this being
the 1970s oil crisis. The design work was carried out at Culham by an
international team but the choice of site and director (of a different
nationality) took many years and reached a high political level.
The choice was eventually between Culham and a site near Garching in
Germany; Chris drew a connection between the decision to site JET at
Culham and the help the UK gave to the German government, via the SAS,
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IOP History of Physics Newsletter November 2017
in solving the Lufthansa Flight 181 hijacking by ‘Popular Front for the
Liberation of Palestine’ in 1977.
In discussing the construction of JET, Chris mentioned the construction
workers claims that they saw ghosts on the old airfield. He also discussed
the major differences between JET and the US Tokamak Fusion Test
Reactor (TFTR) experiment at Princeton. The European design used a D-
shaped toroid whereas the US adopted a spherical design; Chris discussed
why the former was seen as being superior.
Chris also discussed the ‘fortuitous’ discovery of H-mode by Fritz Wagner
in 1982 at Garching; this was to have a big impact on the development of
fusion research.
Chris concluded his talk by noting that there are more than 50 tokamaks
operating worldwide. The next generation experiment, the International
Thermonuclear Experimental Reactor or ITER, was conceived as early as
1985, but site selection did not take place until 2006, with first plasma
expected in 2025.
In the question and answer session at the end of Chris’ talk, Professor John
Allen, of the University of Oxford, noted that he had been present for the
Krushcev & Kurchatov visit, and sought to clear up a misunderstanding
about the publicity surrounding the claims that fusion had taken place. He
noted that the experimental team did not claim a thermonuclear reaction had
taken place, adding that British newspapers encouraged John Cockcroft to
confirm fusion had taken place, who eventually stated he was 90% certain
fusion had taken place. Other papers took this story up – there was
incredible press interest and even a BBC outside broadcast at the laboratory,
possibly due to the impact the work could have on the nation’s morale.
Chris wondered if there had also been pressure from the US to publish, in
light of the recent Sputnik success enjoyed by the Russians.
Professor Allen further noted that, for the Kurchatov lecture, he and the
other scientists were instructed by Mr Fry, the Division head, that: "You
must not, by your questions, give him any idea of what you are working on,
or what you are thinking about doing next".
My thanks to the Nuclear Industry Group for permission to reproduce this report - Editor
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IOP History of Physics Newsletter November 2017
Letters
December 2016*
Dear Sir,
After reading your piece in the History of Physics Group newsletter
December 2016, I was particularly interested in your mention of how
teaching the history of physics / science can assist in various way of the
learning of the subject itself.
I am a 29 year old student, studying with the Open University. Whilst the
OU is not as prestigious as many brick built Universities, it does give an
opportunity with the time to discover more, to delve into the why rather
than just the how. Whilst this is down to the individuals’ desire, the
indulgence in the history of science has certainly benefitted me in my quest
for understanding and knowledge.
So with your mention of some of your colleagues believing it ‘vital’ and
‘not simply adding a little light relief’ I am in full support of the comments,
where learning the history of the subject has enabled the understanding of
the current theories. In particular when it comes to both the science and
mathematics, the history and story as to why a particular methodology was
introduced can give an obvious expectation of the result, thus when an
unexpected result is achieved it makes it ever more interesting.
I believe the commonly known story that agrees with this is Newton’s
apple; would people outside science view gravity in the same way if there
wasn’t a story about a clever man in a picturesque setting and a falling
apple?
An interesting question though would be to view your comments
alternatively and say ‘where would we be if we ignored the history of
science?’
To understand the history of science is to understand the conduct,
convention and in many ways the expectations placed upon one to support
science as a discipline. It is not about how much you know, rather about the
processing of information. Would science as a general discipline descend
into chaos if we forgot the past? Probably not, though would science lose
the corner stone of what is being sought and why? Perhaps.
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IOP History of Physics Newsletter November 2017
Whilst I believe that which you mentioned is indisputable, the big questions
for me would be, do we take our roles in preserving the history of both
physics and science seriously enough? And, in the busy cosmopolitan world
we live in, is there a distinct decrease in time to understand all of a subject,
rather than that which will ‘just get you through’?
It is left for me to wish you a very happy Christmas and best wishes towards
a great Newsletter.
Yours faithfully,
Owen Murphy,
Astronomy and Planetary Sciences student,
Buckinghamshire.
---------
* Unfortunately this letter just missed the 2016 issue of the newsletter but I’m sure we may take his Christmas wishes as good for this year as well! Editor
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Disclaimer The History of Physics Group Newsletter expresses the views of the Editor or the named contributors, and not necessarily those of the Group nor of the Institute of Physics as a whole. Whilst every effort is made to ensure accuracy, information must be checked before use is made of it which could involve financial or other loss. The Editor would like to be told of any errors as soon as they are noted, please.
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IOP History of Physics Newsletter November 2017
John William Warren (1923 – 2016)
[Photo courtesy of Evening News June 1971]
Members of the History of Physics Group who were active in teaching
physics at undergraduate or senior-secondary level during the period from
the mid-sixties to the mid-nineties are very likely to have encountered the
critical writings of Dr John Warren. In addition to two books: The Teaching
of Physics (Butterworths 1965) and Understanding Force (John Murray
1979) he made over 50 contributions to the journal Physics Education. He
subjected the traditional teaching of many topics in physics, as purveyed in
text-books and examination papers, to a relentless scrutiny. This provoked
considerable reaction but, to his disappointment, did not result in significant
reform. Readers who wish to know more about the background to John
Warren’s life and work may like to consult the following article in which I
have attempted to do justice to his life-time’s mission to “restore truth and
coherence to science education”:
“The Quest for Rigour in Physics — the life and legacy of John William
Warren”
On-line version (including a supplement listing his articles and letters)
available at: https://doi.org/10.1088/1361-6552/aa6cff
and also in the July 2017 issue of Physics Education.
Stuart Leadstone, Banchory, Kincardineshire
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IOP History of Physics Newsletter November 2017
Features
Anti-matter or anti-substance?
by John W Warren
Axioms
1 That radiation transfers mass, linear momentum, energy and
angular momentum.
2 That the conservation laws for the above physical quantities are
strictly obeyed.
3 That inertial mass and gravitational mass are identical.
The Dirac Theory
This theory was initially applied to the electron. The number of electrons is
assumed to be constant for all time, i.e. it is what is now called a fermion.
The theory required that there must be an anti-particle to the electron having
positive electric charge: this was subsequently named a positron.
Experiments showing the production and so-called “annihilation” of
electron/positron pairs are well established. The positron is shown to have
positive charge because its tracks in magnetic and electric fields have the
opposite sense of curvature to those of the electron. The mass is clearly
positive because otherwise the combination of negative charge and negative
mass would give tracks of the same sense of curvature as the electron. The
threshold frequency of radiation required to produce an electron/positron
pair shows the mass of the positron to be equal in magnitude to that of the
electron. The frequency of the radiation emitted in pair-annihilation
confirms this. Similar results were later found for the proton and anti-
proton pair.
According to one interpretation of the theory of negative beta-decay this
process can be considered to be an example of pair-production, the anti-
neutrino being the uncharged anti-particle to the electron.
ν epn
Similarly, for positive beta-decay, the particle emitted is the neutrino, and
the positron can be regarded as the charged anti-particle of the neutrino.
ν enp
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IOP History of Physics Newsletter November 2017
Two related processes which may be classified as charge transfer are as
follows:
1. In electron capture a proton in the nucleus takes a negative charge from
an electron in the atom, becoming a neutron, and the electron becomes a
neutrino.
ν nep
2. In the Cowan-Reines experiment (1956) an anti-neutrino takes a
positive charge from a proton, becoming a positron, whilst the proton
becomes a neutron.
nep ν
Anti-particles
The Dirac theory requires that the mass of an anti-particle is the same in
both magnitude and sign as that of the associated particle. In order to
conserve particle number (lepton or baryon, as the case may be) an anti-
particle must be counted as minus a particle.
Matter and Substance
According to the S.I. the amount of matter in a body is expressed by its
mass, the base unit being the kilogram. The amount of substance in a
sample on the other hand is expressed by the number of elementary
entities of which the sample is composed, the base unit being the mole.
The term anti-matter carries the inescapable connotation of opposite (i.e.
negative) mass. The term is therefore inappropriate. On the other hand, in
a sample consisting of equal numbers of particles and anti-particles, the
total number of particles is zero. If the particle component is regarded as
substance then the anti-particle component is strictly anti-substance, not
anti-matter.
Gravity
It is clear that gravity is fundamentally different from electromagnetic and
nuclear interactions because the “interaction charge”, namely mass, exists in
only one form. One should therefore be circumspect regarding attempts to
develop theories of gravity similar to those for the other interactions, e.g.
unified field theories.
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IOP History of Physics Newsletter November 2017
A Laboratory in the Clouds - Horace-Bénédict de Saussure (1740 - 1799)
by Peter Tyson
Horace-Bénédict de Saussure, ‘Voyages dans les Alpes’ 1796
Mont Blanc was first climbed in August 1786 by Michel-Gabriel Paccard
and Jacques Balmat. The former, the local doctor, noted in his journal
simply, 'Our journey to Mont Blanc - Arrived 6:23 pm, left 6:57, stayed 34
min'. Paccard was a serious amateur scientist and, doubtless to his
companion's consternation so late in the day, at 18½º F and 3800m above
civilisation, busied himself with practical science. Of the greatest
importance, he made a scratch on the tube of a simple mercury barometer,
indicating a mercury level of (what is now) 254mm. In fact, it was largely to
do this that he had wanted to climb the mountain. Happily the pair returned
to Chamonix safe and relatively sound the following day. So, why the
barometer?
A century earlier, Edmund Halley had written,
'Now upon these principles, to determine the hight of the Mercury at any
assigned hight in the Air, and e contra having the height of the Mercury
given, to find the hight of the place where the Barometer stands, are
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IOP History of Physics Newsletter November 2017
Problems not more difficult than Curious; and which I thus resolve.'
Mariotte had noted that there would be 'changes within Barometers in
places at different heights, like at the bottom and top of a tall tower, or of a
mountain'. Sinclair, Boyle and Pascal had tested this by experiment. Halley
derived an exponential law for the decay of pressure in the atmosphere and
gave a table in which the barometer reading was the independent variable.
Later, he took a barometer up Snowdon – despite the 'Horrours of the
Neighbouring Precipices' – but used Caswell's earlier readings to calculate a
height of 1288 yards.1 It is not the place here to discuss the other parameters
but all the scientists were aware that this would be an approximation.
Despite the fact that the portable barometer dates back to 1695, some early
explorers still filled their barometers in situ, but when Deluc fitted a tap the
mercury could be retained in transit and the true mountain barometer was
born.
The ability to match studies on meteorology, botany and notably gravitation
with height, or to perform surveys with a height datum remote from
habitation and the sea, were important factors in the growth of mountain
exploration. And if the learned men of Oxford were surrounded by
somewhat modest hills, those in Geneva were spoiled in having the entire
range of the Alps at no great distance, although in the early days the char à
banc (a type of cart) could not be expected to take you all the way. In good
weather, they could find a viewpoint from which they could see in the
distance, peering over the top of the lower ranges, the shining glaciers of the
Mont Blanc massif. So it was that the imagination of Horace-Bénédict de
Saussure was fired during his youth, and at the age of twenty he walked
from his home in Geneva to the little-known village of Chamonix to see for
himself. He was not disappointed: he gazed up at the summit of Mont
Blanc, and decided he must go there. Over the years, Saussure would build
up a reputation as a consummate scientist and was granted a professorship.
Not only did he design his own equipment, he started to venture out into the
Alps with it, making numerous extended journeys amongst the mountains,
and often up them.2
An early mountain to be climbed was the Buet, which lies not far from
Mont Blanc. Whilst much lower – at 3 096m as compared with 4 810m -
1 Phil. Trans. 16 p104 and 19 p582 resp.
2 Described in the 4- or 8-volume Voyages dans les Alpes, 1796; section
number in footnotes refer to this work.
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IOP History of Physics Newsletter November 2017
it still carried permanent snow to some way beneath its summit. It was first
climbed in 1770 via a difficult route by the brothers Deluc, although we
may never have known about this since, in a passage which makes a
mountaineer's blood go cold, Deluc wrote:
"After spending some time looking around us, our attention turned to
ourselves when we discovered that we were only supported by a large mass
of snow [a cornice] above a fearful drop. Our first reaction was a fast
retreat but, having reflected, we realised that the addition of our weight to
this prodigious mass of snow, which had been held there surely for
centuries, was negligible for breaking it, so we stopped worrying and
turned back to the view."
The climb was a significant mountaineering achievement in itself but Jean-
André had wanted to make the ascent to investigate not only the barometric
pressure but also the boiling point of water which, Fahrenheit had observed,
increased with the ambient pressure. An easier route was found a few years
later and Saussure climbed the mountain twice to have a good look at Mont
Blanc, for which the Buet is a magnificent vantage point. On his second
ascent in 1778,3 partly due to the snow conditions his group made slow
going and even the guides, used to working high, started to feel the altitude
at 1400-1500 toises.4 Their leader devotes many pages to a discussion of
this topic.5 In spite of his fatigue, he spent a busy two hours on the snowcap.
Fellow scientist Marc-Auguste Pictet set up his Ramsden sextant and
measured the angle of elevation of Mont Blanc. An allowance was made for
atmospheric refraction, calculated to be 43½ seconds of arc and which had
to be subtracted from the observed 4°21'30" elevation. For a horizontal
distance of 65 443 French feet, a height difference of 4974 feet could be
deduced. 109 feet were then added to adjust for the curvature of the Earth.
A barometric height for the Buet of 8345 feet above the lake of Geneva
(~193 toises) finally gave a height for Mont Blanc equivalent to 2426 toises
above sea level.
3 2 §562.
4 1 toise = 1.949m (and for reference:) = 6 French feet; 1 foot = 12 F
inches; 1 inch = 12 F lines. [0 - 80ºR] ~ [0 - 100ºC]. Putting the science in
context, this all predates the metric system and theories of heat, electricity,
geology, glaciers and gases were all very much in their infancy. Lavoisier
defined elements the year that Saussure climbed Mont Blanc. 5 Conceding 'some readers may already, perhaps, have found this
digression on physiology too long' - a salutary note to authors.
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IOP History of Physics Newsletter November 2017
The news in 1786 that an ascent of Mont Blanc was practicable quickly
reached Saussure. He rushed to the mountain but was thwarted in making an
attempt himself by the weather. The following year, with 18 guides and
porters carrying a great deal of scientific equipment, and by now aged 47,
he stood on its summit after a further struggle with the thin air.6 In a not
atypical reaction for mountaineers, he says,
'the cost of the victory, gave me a kind of irritation. At the moment I
reached the highest point... I trod it with a kind of anger rather than with
pleasure', adding, 'After all, my aim was not only to reach the summit, it
was mainly to make the observations and perform the experiments which,
alone, gave the expedition any value'.
Nobody, however, even amongst scientists, could remain unmoved and it
was not long before he was entranced by the magnificence of his
surroundings. But there was work to be done: Guides put up the tent and his
small table for boiling water measurements and he managed to spend four
and a half hours on his experiments - tasks which he felt he could have
managed in three lower down.
The all-important reading on the barometer was found to be 16,, 0,, 14, 4 or
16 inches 014.4
/16 lines. A correction for the temperature of the mercury due
to Deluc was applied - but because he had never imagined that anyone
would work at such a height, some estimation was necessary... A
simultaneous barometer reading was being taken in Geneva, and an
allowance was made for the discrepancy between the two barometers. The
height difference was deduced from the algorithm, 'subtract the common
logs of the barometric heights and then multiply by 10 000 to get the height
difference in toises'. The rationale is that, for an exponential, the ratio of
two pressures would translate to a difference in logs, but the simple constant
was due to entirely fortuitous quirk of the units.7 As Saussure writes it:
Geneve 27,, 2,, 10, 85 == 5226, 85 sixteenths, of which the log is [3.]7182400
Mont-B. 16,, 0,, 14, 4 == 3086, 4 [3.]4894522
Difference in toises . . . . . 2287,878
6 7 §1991. Pressure down to about sixty percent of that at home.
7 Note also that, in subtracting logs for a ratio of barometric heights. units
are arbitrary. A single comma is a decimal point.
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IOP History of Physics Newsletter November 2017
It followed that Mont Blanc was 2480 toises above sea level. (He
emphasised that, at this point, the calculation takes no account of the
temperatures in the intervening air column.) 8
Parallel with the estimation of height on the basis of air pressure, the
relation between the boiling point of water and barometric height had
reached some refinement, thanks largely to Deluc. The apparatus was less
fragile than a barometer – and later mountaineers would realise the
possibilities of a cuppa. I shall leave it to Saussure to relate this experiment:
"To this end, Mr. Paul made for me a neat piece of apparatus in which the
thermometer was armed with a micrometer,9 so that I could distinguish
thousandths of a degree. Since Mr. Deluc had found so much trouble in
burning charcoal on the Buet due to the rarefied air I had no reason to
expect any more success on the summit of Mont-Blanc. So, to overcome this
difficulty, a lamp burning alcohol was made for me on the principle of Mr.
Argand's. It had a large diameter, and the water was boiled in a vessel
mounted on the top of a sheet metal chimney. I checked several times that
my thermometer went up to exactly 80 degrees [Réaumur 10
] in the boiling
water when the barometer was at 27 inches. I then took the apparatus to the
coast, where the barometer showed 28 inches 7 lines & 82 160ths
of a line
and the water boiled at 81º, 299. Now, on the summit of Mont-Blanc, the
barometer stood at 16 inches, 0 lines, & 144 160ths
of a line and the water
boiled at only 68º, 993, giving a temperature difference of 12º, 306.
According to Mr. de Luc's formula the difference would be 12, 405. The
discrepancy, barely a tenth of a degree over a range of 12 inches 6 lines on
the barometer, shows that his formula offers an accuracy as high as one
could possible wish."
The humidity was measured by means of a hair hygrometer, a type which
Saussure had invented. Having seen how a human hair tends to stretch when
it gets wet, he devised a mechanism to greatly magnify the extension: 'The
best way is to attach one of the ends of the hair to a fixed point, and to
attach the other to the circumference of a small cylinder or shaft, which
carries a light needle at one end.
8 7 §2003. In 1784 Saussure had watched an ascent of Montgolfier balloon in Lyon
and must have considered the possibilities... 9 7 §2011. Probably an attached sliding scale (cf vernier) similar to the old
engineers' diagonal scale, and viewed through lenses. 10 Incidentally, another mountain explorer, Martel, used the centigrade temperature
scale before Cristin's publication of it.
23
IOP History of Physics Newsletter November 2017
This indicates movement
of the shaft on a dial. The
hair is tensioned by means
of a counterweight of 2 to 4
grains suspended by a fine
silk thread wound around
the axle in the opposite
direction'.11
The simple
instrument did not have a
linear scale, though in
principle that used later on
the Col du Géant was
graduated from 0 (dry) to
100 (saturation).
Air and snow temperatures
were recorded and a
thermometer whose bulb
had been blackened, using
carbon black dissolved in
gum arabic syrup, was
exposed to solar radiation
as a crude actinometer.12
A compass bearing on the church in Chamonix and
a later reverse bearing established no discernible difference in magnetic
declination. As to 'atmospheric electricity', what we now understand as
electric potential was investigated by means of an electrometer in which
two pith balls, suspended on threads inside a case, repelled.13
The
atmosphere was charged positively but the balls gave a much smaller
deflection than the scientist expected right on the edge of a steep slope,
something he felt must be 'explained by the dryness of the air which,
reducing the conducting force, did not allow the penetration of the electric
fluid from above'.
11 A similar hygrometer was constructed in 1782, before Saussure published, by
Richer using silkworm gut. Obs. Phys. 2, p349. 12 The difference between sun and shade temperature has been frequently used to
indicate total radiation, and blackening the bulb of one of a pair of identical
thermometers renders the experiment more sensitive. Without standardisation
readings cannot even be compared between different instruments. Presumably
Saussure was aware of this, hence the heliothermometer. 13 3 §784 Based on a design by Cavallo, Phil. Trans. 70, and functioning much as
the enduring gold leaf electroscope.
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IOP History of Physics Newsletter November 2017
The experiments were being conducted at what Saussure believed to be the
highest point in the 'Old Continent',14
so the activity continued only as long
as the party dared remain on the summit. Finally, it was judged wise to start
the descent. That night, in a tent on the glacier and sheltered by a rock from
avalanche danger, Saussure reflected with true satisfaction on what he had
achieved after so many years of dreaming. And, even on his descent from
Mont Blanc, decided it wasn't enough: There and then he decided to
organise a more protracted stay, if not quite as high, at least in a spot
suitable for establishing a reasonable camp.
He already knew where, and by early June of 1788, he had assembled
another team. The Col du Géant 15
is a high glacier pass over the middle of
the Mont Blanc massif. The plan was for a longer stay, particularly in order
to study any variations of the properties of the environment over the course
of a day or more, research which, to have any validity, would entail working
for some time in the same place. He took two small canvas tents but had
also had a rough stone hut built in advance. The ascent was complicated by
a section which was heavily crevassed, but the Col was reached, almost
without incident.16
Here, Saussure had a shock: It was somewhat lower than
he had hoped, the hut was small and low, and it had been half-filled with
snow which had had blown in through the cracks between the stones. Nor
was the area greatly suitable for tents, even if the views were superb.
Sending most of the personnel back to Chamonix, Saussure kept four of the
best guides, along with his valet(!), and Théodore, his son of 20 who was to
help with the experiments.17
Whilst the others set about making camp on
some rocks, Saussure fell upon his instruments but, he says,
"I was mortified to find that both barometers were out of commission; the
dryness of the air since we left Chamonix had shrunk the corks in the taps
which kept in the mercury and both had lost some of their thread. However,
no air had got in and I proceded to cure one by reversing the process which
had caused the problem and, by keeping the instrument continually
wrapped in wet cloths, got the cork to expand again."
14 Saussure was familiar with the French academicians' expedition to the Andes, to
measure an arc of the meridian which helped to establish that the Earth was the
oblate spheroid Newton had predicted and contributed to the first definition of the
metre. 15 Formerly the Tacul, renamed by Saussure. Reached from Chamonix only in 1786
after a long interval due to many crevasses. 16 7 §2029. 17 Théodore ('Saussure le fils'), 1767 – 1845, would go on to distinguish himself in
the fields of plant chemistry and physiology.
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IOP History of Physics Newsletter November 2017
The following day the guides were predicting a change in the weather (and
country folk still beat computers). Sure enough that night a storm of
indescribable violence hit the camp, the wind reaching into the cabin as if
the walls were not there, so Saussure moved to a tent. The guides had to
hold down the poles to prevent its being carried away.
"Around seven in the morning, all this was joined by hail and lightning
which continued relentlessly; one bolt struck so close that we distinctly
heard a spark slide crackling down the wet fabric of the tent, right behind
where my son was sleeping. The air was so charged that, when I held the
point of the electrometer outside the tent the balls diverged as far as the
threads would let them.18
On most strikes the electricity changed sign."
The storm abated by about midday, so Saussure and his son started work
and set into a daily routine, taking shifts to enable observations to continue
throughout the night. Unsurprisingly, furs were barely enough protection
from the intense cold, especially when the wind rose in the evenings. The
small charcoal stoves could not be lit in the tents, and in the cabin burned
feebly, even when forced with bellows. At such times, says Saussure, they
felt less strongly about being no higher than they were.
Théodore took sightings on the sun and determined latitude but was unable
to add longitude because the watch intended for this had also ceased to
function properly early in the ascent, so they fell back on the triangulation
of known objects. Since a major objective was to compare various
formulae, a height independent of the barometer was needed and their cabin
was found by the same means to be 1223 toises above Chamonix. Taking a
mean of 85 barometer readings gave a pressure of (wait for it) 18 inches 11
lines 5688
/16000 line at an air temperature of 3 degrees 630
/1000 and at
Chamonix 17 degrees 288
/1000 . The height difference from Trembley's
formula was 1207 toises, 16 toises lower than that triangulated.
Since a mean could be calculated over the stay on the Col, an obvious study
was that of the temperature lapse rate. For 'ground level' Saussure notes that
Chamonix lies in an enclosed valley so that, in this context, the observatory
in Geneva would be a better choice. A (decimal) temperature of 17,285 ºR
in Geneva, was matched with 2,201º on the Col 1555 toises higher; the
previous year's figures for Mont Blanc had given Saussure, 22,6º in Geneva
and -2,3º on the mountain summit, 2257 toises higher. Whilst he appreciates
18 In retrospect, like Deluc's cornice, not a clever idea. Modern mountaineers are
very wary of ice axes in thunderstorms!
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IOP History of Physics Newsletter November 2017
all the complications he suggests 'one might conjecture that in summer,
between 45 and 47 degrees of latitude, the mean temperature of the air
decreases from sea level to the highest mountains by a hundredth of a
degree per toise', in today's terms a lapse rate of 1ºC for every 156m.
Unfortunately Saussure went on to use a (not unreasonable) exponential
model for the thermal expansion of a gas.19
The frequent arrival of humid air as the Col du Géant became enveloped in
cloud did not lend itself to a very meaningful study of atmospheric
electricity, although as we have seen the instrument became as excited as
the scientists during thunderstorms. But, we are told,
'Two or three days free of clouds nevertheless allowed me to check that the
electricity in calm weather followed exactly the same trend at this great
height as it did on the plain, that is to say it increased gradually from 4
a.m., when it was practically zero, until midday or 2 p.m. when it reached a
maximum'.
Saussure was particularly interested in any diurnal changes in magnetic
field and had acquired a large compass by Knight. He achieved useful
results, but only after a few teething troubles:
"The needle of this compass was 23 inches 8 lines long, and its scale could,
with the aid of a microscope, could be read to 20 seconds of arc.
Unfortunately the 6¼ ounce weight of this needle rapidly wore down the
point of the steel pivot and impaired its movement. I overcame this problem
by suspending the same needle by a silk thread in Mr. Coulomb's setup, but
was unable to employ, as he advised, single strands held together, without
twisting, by gum arabic. The weight of the needle broke one of them after
another and the needle fell to the bottom of the box. I had to resort to
fishing line [horsehair?] but as it seemed a bit stiff I needed to apply
Coulomb's principles to investigate the torsion. A copper bar was made of
the same shape, length and weight. I suspended it from the thread and set it
to perform oscillations in a box to shield it from draughts ... I did the same
with the magnetised needle ... Thus the copper needle was oscillating
against the torsion of the thread, the magnetised needle against this plus
that exerted by the magnetic force."
The relative torsions varied inversely as the squares of the periods and
experiments showed that the influence of the torsion on the compass needle
19 Perhaps due to Charles's law being abbreviated misleadingly, with 'of its volume'
omitting the reference to the ice point?
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IOP History of Physics Newsletter November 2017
would affect the deflection only by 1 part in 268, too small to detect on the
scale. Problem solved? Not quite. On their arrival at the Col du Géant,
Saussure, needing a firm mounting, had constructed a pillar of large slabs of
granite. When he started taking readings, he says, 20
"The first variations seemed a little odd, and I noticed that the entire
compass moved. I decided that the pillar was not firm, so I rebuilt it more
solidly. The same thing happened. I thought the ground underneath was not
sound and that it was subsiding under the pillar, so I excavated down to the
rock. The same happened again! I wasted a lot of time until I discovered
that the rock was not part of the mountain at all, but rested on ice and that
this was melting underneath it during the course of the day."
Like his observations in Chamonix and Geneva, the figures high on a
mountain showed that the needle swung from east to west and back during
the course of a day. Within this there were often fluctuations of smaller
magnitude starting in early evening. Saussure also took a magnetometer, 'in
which the force of a magnet is measured by the angular deflection it
produces on a copper bar hanging vertically, to the bottom of which is
attached a ball of iron', 21
but had doubts as to the physical law.
As befits someone known for his work on humidity, the scientist took
advantage of the low pressure (and implicitly density) to investigate the
factors which influence evaporation.22
He writes, 'To distinguish the
contributions of the four different factors, heat, dryness [sic], agitation and
the density of the air, I decided to start by excluding agitation and working
with still air. The experiments would be done first on the mountain, then on
the plain, and under a tent which was carefully closed... to get rates which
were measurable in times still short enough that hygrometer and
thermometer readings would not change appreciably, and so that I could
repeat the experiment to separate the respective influences'.
If perhaps a glorified washing line, the experiment was carefully designed.
A table of results showed the difference in the mass evaporated for the
differences in temperature and dryness between trials. After some maths
20 7 §2097. 21 7 §2104, 2 §458. This design was apparently his; the name of such an instrument
was coined at least as early as 1773 by Blondeau (the first Voyages appeared in
1779). Saussure variously applies the idea to detect iron in mineral samples or
mountains, indicate the strength of a magnet and measure the 'intensity of magnetic
force'. He acknowledges much early work by others. 22 7 §2059.
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IOP History of Physics Newsletter November 2017
based on a linear model, Saussure concludes that the weighting of a change
in dryness was greater than that of temperature in the ratio 4,188 to 1,386,
as compared with 1,938 to 2,775 on the plain. His observations on
perspiration at altitude will not be news to modern mountaineers, who drink
copiously even in winter.
A parallel study employed the cooling produced by forced evaporation.23
A
thermometer placed in a substance in which evaporation can take place
would in principle show a drop in temperature but, aware that the process
would be slow and cooling very small, Saussure sought to speed up the
evaporation in such a way that it could be performed outside the lab and
thus without recourse to the artificial control of temperature or humidity. He
enclosed the bulb of a thermometer in a wet sponge, attached a string and
whirled it around at great speed, getting a drop in temperature of 8º R or
more. [Essentially the sling psychrometer, possibly the first].
However, he says,
'at first I held the string directly in my hand and the rubbing on the string
as it turned against my fingers wore it away so quickly that one day it
broke, the thermometer shot out at a tangent,24
rose to a great height and
broke when it fell'. A suitable rotating linkage solved the problem, and he
continues, 'To determine the speed of rotation I practised to find out how
many revolutions I could count in a minute, in fact around 140. The bulb of
the thermometer therefore travelled in this time 140 times the circumference
of a circle of 5 feet in diameter, giving a speed of 36-37 feet per second'.
For comparison, each trial was preceded by a run in which the thermometer
was dry. The wetted sponge (spherical, and 10-11 lines in diameter) was
then brought to the temperature of the moving dry one so that only
evaporation would affect it – i.e. the forced convection was common to both
- and the experiment started. A similar analysis applied to that of the
experiment in still air showed the great significance of maintaining the
immediate surroundings of the bulb in the same state as the ambient air.
Overall, the inference was that, whilst evaporation is always more
pronounced on a mountain than below, the difference is less marked in a
wind than it is in still air.
Saussure has been credited with the invention of many instruments for
measuring physical variables. Most were developments of, or variations on,
earlier ones, but that used to measure the saturation of the blue of the sky
23 7 §2063. 24 Not radially – for someone who worked little with dynamics he evidently
understood the First law better than many today!
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IOP History of Physics Newsletter November 2017
was probably original. He had named it his 'cyanometer',25
and his travels
provided a fitting scenario because, as mountaineers had long known, the
sky becomes of a deeper blue the higher you go.
Cyanometer
To get some quantitative idea of the phenomenon Saussure painted strips of
paper in decreasing shades of blue, labelling them in sequence. From each
strip he cut three identical squares, assembling them into three identical
series, to allow simultaneous observations in different locations. The
version used on the Col was graduated by allocating 1 to a blue so pale that
a white circle (of standard size and at a standard distance) could just be
distinguished, then progressing by 1 for the next deepest blue on the same
criterion, up to 52 for black The blueness was investigated at different
angles of elevation: At midday on a typical fine day, as the angle of
elevation increased in 10° intervals from the horizon, 'blueness' values ran
11, 20, 31, 34, 37... after which the value stayed constant up to zenith.
Blueness at zenith during the course of the day was compared with that in
the valley. The figures are self-explanatory:
time of day IV VI VIII IX midday II IV VI VIII mean
Col du Géant 15,6 27,0 29,2 31,0 31,0 30,6 24,0 18,7 5,5 23,6 Chamonix 14,7 15,1 17,2 18,1 18,9 19.9 19,9 19.8 16,4 17,8
Anticipating work for which Tyndall is celebrated, Saussure writes that 'the
colour of the sky can be considered to be a measure of the amount of vapour
and suspensions in it, since it has been proved that it is otherwise quite
25 7 §2083. Paccard talked periodically to Saussure but, whilst he refers to a
cyanometer himself, does not claim its invention.
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IOP History of Physics Newsletter November 2017
black... the air is not completely transparent, its elements reflect ...
especially the blue rays...I say 'reflection', because ... mountains covered in
snow never appear blue, through however much air they are seen ... even at
30 leagues.' 26
Also related to what would become known as scattering was the
'diaphanometer' experiment on the transparency of the air, in which a series
of 16 circles whose diameters went up in geometric progression from 0,2 to
87,527 lines were viewed from an increasing distance until they
disappeared, up to 1356 feet. Despite pre-testing on the plain, the procedure
was found to be ineffective. Worse, relates Saussure,
'The experiment proved one of the most trying we had performed, due to the
fatigue on both eyes and body in judging the disappearances and in
measuring the distances at which they occurred, this against the glare from
the snow of the intense sunlight and in snow up to our knees.' 27
Another such question which could not be answered without evidence in the
field was, given that the air high in the mountains is relatively cold, was it
indeed absorbing little heat from the rays of the sun? Saussure had
investigated this in 1774. He needed to find out whether 'the direct rays of
the sun would, on the summit of a high mountain, have the same efficacy as
on the plain'. To this end, he says, 'I had constructed a box with half inch
thick deal walls, initially measuring a foot long and nine inches in width and
depth. The interior was lined with blackened cork an inch thick and the box
was closed with three glass sliding doors, one above the other, leaving an
inch and a half between them. Thus the sun's rays could reach a
thermometer at the bottom of the box. Heated by the action of the sun, it
was well insulated from the effect of the air outside, on one side by the
glass and enclosed air, on the others by the layers of wood and cork'.28
Saussure had taken his 'heliothermometer' to the top of the Cramont, a
modest mountain south of Mont Blanc. After allowing the temperature
inside to climb slowly to 50º, he exposed the window to the direct rays of
the sun for exactly an hour, during which time the temperature within rose
26 A league was notionally an hour of walking, here ~ 3 mi. Tyndall has a prominent
place himself in mountaineering history. 27
7 §2089. In hindsight, shimmering of the air and diffraction through a
very small pupil must have played a major part. 28
4 §932. Today we have triple glazing and the solar oven! This is all long
before our overarching theory of energy.
31
IOP History of Physics Newsletter November 2017
to 70º. The next day, fortuitously in identical conditions, he was able to
perform the experiment near the base of the mountain. Although the
ambient air was, of course, hotter, the temperature rise within the box
differed by only a degree, graphically illustrating that the air through a
difference in height of 777 toises made no appreciable difference to the
heating effect of the sun's rays.29
When the sun drops behind the mountain,
from feeling very hot we suddenly feel very cold, passing from radiative
heating to convective cooling.
Eventually, after the group had spent sixteen days on the Col, the provisions
ran out – strong suspicion resting on the guides, for whom the stay was
uncomfortable and rather boring. As he took his departure from the col,
Saussure knew he had accomplished much invaluable, and truly original,
research – and here we have considered only the physics. For all the
hardships and the trials, he had enjoyed his stay immensely; he was, one
might justifiably say, in his element. The culmination of all his work in the
mountains was to be the classic Voyages dans les Alpes, published in full in
1796. In the annals of mountaineering Saussure will be remembered for the
third ascent of Mont Blanc no more than in those of science as a true
pioneer of research in the field.
-----------------------------
In memory of Ivor Grattan-Guinness
Bibliography and Appendix
Most of the material is that recorded in Voyages dans les Alpes, 1796. This
is a massive work and the need for background and balance gives rise to
shortcomings in an article of this length. I have preserved most of the old
29 Of course mountaineers vulnerable to ultra violet must consider selective
absorption.
32
IOP History of Physics Newsletter November 2017
notation and units as of historical interest. Other relevant works are listed
below. Most are in French and to my knowledge no complete translations
exist. Facsimiles can often be found online, such as at HathiTrust, and are
indicated below with a dagger, † Unfortunately, digital searches are difficult
due to the vagaries of language and issues with accents, italics and old s's
(use f).
Any errors are most likely to do with an organic memory which is ageing
faster than Voyages.
(i) References are to the 8o
edition, Voyages dans les Alpes which comes in
8 volumes.† Mont Blanc summit and the Col du Géant come in Vol. 7.
There is an index in Vol. 8. This gives section numbers (§) which are more
useful than page numbers when referring to different formats.
https://catalog.hathitrust.org/Record/008648381
(ii) The cyanometer and diaphanometer are described at length in Mémoires
de l'Académie Royale des Sciences à Turin. 9 1788-1789, † pp409 and 425
resp.
(iii) The hair hygrometer is described in Saussure's Essais sur l'hygrometrie,
1783.†
(iv) Deluc's major scientific work was Recherches sur les modifications de
l'atmosphère,1784 in 4 volumes.†
His ascents of the Buet are described in Relation de différents voyages dans
les Alpes du Faucigny, D[eluc] et D[entand], 1776.
(v) Material on Saussure, mainly from the mountaineering viewpoint, can
be found in The life of Horace Benedict de Saussure, Freshfield, 1920. †
(archive.org) and The first ascent of Mont Blanc, Brown and de Beer, 1957.
(vi) Halley wrote two relevant papers in Phil. Trans., († Archive of All
Online Issues):
A Discourse of the Rule of the Decrease of the Height of the Mercury in the
Barometer, According as Places are Elevated Above the Surface of the
Earth, with an Attempt to Discover the True Reason of the Rising and
Falling of the Mercury, upon Change of of Weather: 1686 16 , p104.
33
IOP History of Physics Newsletter November 2017
A Letter from Mr. Halley of June the 7th. 97. Concerning the Torricellian
Experiment Tryed on the Top of Snowdon-Hill and the Success of It:
1695 19, p582.
(vii) A good work on the history of instruments is Scientific instruments of
the 17th
and 18th
centuries and their makers, Daumas, 1972 (first English
edition).
(viii) Martel's words were: "I took also a thermometer of my own make,
filled with Mercury, divided into a hundred equal Parts, from the freezing
Point to boiling Water, answering to 180 Parts of Fahrenheit's thermometer
beginning at 32, and ending at 212". His An account of the glacieres or ice
alps in Savoy...., 1744 is rare, and versions differ. It is reproduced in The
Early Mountaineers, Gribble, 1899, † (archive.org) p103. A relevant article
can be found in the British Journal for the History of Science 5 #4 (Dec.
1971): An Additional Factor in the History of the Centigrade Thermometer,
Bryden, pp 393-6. Note that the expedition described was in 1742.
(ix) For Théodore de Saussure, see for example Chemical Research on
Plant Growth: A translation of Théodore de Saussure's Recherches
chimiques sur la Végétation, Hill, 2013.
34
IOP History of Physics Newsletter November 2017
On Prof. W.H.Bragg’s December 1914 Letter to Michael Ernest Sadler, Vice-Chancellor of the University of Leeds
Christopher Hammond
University of Leeds
Summary
A seven page handwritten letter in the archives of the University of Leeds
(Registry: H Physics H12), dated 16th
December 1914 from William Henry
Bragg, Cavendish Professor of Physics to the Vice-Chancellor, Michael
Ernest Sadler, is here published in full for the first time, together with three
replies or memoranda from Senior Officers of the University. The historical
importance of this correspondence is that it throws new light (i) on the
development of X-ray crystallography following Max Laue’s discovery of
X-ray diffraction in 1912 (ii) on the problems of staffing and funding of the
Physics Department of the University in the months following the outbreak
of the First World War and (iii) the considerations which led to Bragg’s
resignation of the Cavendish Chair in 1915. These points are addressed in
the Discussion (4).
William Henry Bragg (1908) by Hammer & Co., Adelaide. (Courtesy: The Lady Adrian)
Michael Ernest Sadler (1914), by George Charles Beresford. (© Copyright: National Portrait
Gallery, London)
35
IOP History of Physics Newsletter November 2017
(1) Introduction: The Background
The two-year collaboration between William Henry Bragg (WHB),
Cavendish Professor of Physics in the University of Leeds and his son,
William Lawrence (WLB), then a student, later Fellow, of Trinity College,
Cambridge, which began in the summer of 19121 and ended when WLB
enlisted in the Leicestershire Royal Horse Artillery at the outbreak of the
First World War, established the new science of X-ray crystallography, the
importance of which cannot be over-estimated. In 1912, the structures, or
atomic arrangements in crystals, were unknown. Certainly, the evidence of
external form and symmetry, together with atom-packing considerations
and model-building, indicated possible structures for the elements and the
simplest inorganic compounds – but of direct experimental evidence there
was none. Laue’s discovery, which was communicated to WHB by Lars
Vegard, a former Leeds colleague in a letter of 26 June 1912, clearly
showed the existence of an internal order or pattern in the atomic
arrangements in crystals. And although Laue made substantial
contributions to an understanding of diffraction from crystals modelled as
three-dimensional gratings, it was the Braggs, combining an elegant
experimental technique (the spectrometer) with a simplicity in interpretation
of the data (Bragg’s Law) who first determined these atomic arrangements.
By the summer of 1914 the Braggs, in a series of papers, principally read to
the Royal Society, had established, by means of X-ray diffraction, the
structures of NaCl, ZnS (blende), CaF2, KI, KBr, diamond, copper, FeS2,
NaNO3, CaCO3, MnCO3, (Mn, Mg)(CO3)2 and had tentatively proposed
structures for quartz and sulphur2. They had the field of the determination
of crystal structures entirely to themselves: their closest potential rivals
were Torahiko Terada and Shoji Nishikawa in Japan. Terada independently
arrived at the notion of reflection from crystal planes by observation of the
movement of Laue spots as the crystal was gradually turned. Again,
independently of W.L. Bragg, Nishikawa determined the structure of
spinels. Terada’s and Nishikawa’s early work has been seriously
underrated3. The Braggs might have been rivalled by H.G.J. Moseley,
working first in Manchester and then Oxford, but largely as the result of a
‘Gentleman’s Agreement’ he chose to study the characteristic X-ray spectra
of the elements.
The importance of the Braggs’ work was early recognised, resulting in
invitations to WHB (but not WLB) to address a Leeds ‘Spring School’ in
April 1913, the Birmingham Meeting of the British Association in
36
IOP History of Physics Newsletter November 2017
September and most significant of all, an invitation to the Second Solvay
Conference in Brussels in October, the theme of which was ‘The Structure
of Matter’. This conference provided a ‘showcase’ for the Braggs’ work,
and the major contribution of WLB did not go unrecognised: a postcard was
sent to him in England for ‘advancing the cause of natural science’ and
signed by eighteen conference members including Sommerfeld, Curie,
Laue, Einstein, Lorentz, Rutherford, Langevin, Nernst and Voigt.
WHB’s burgeoning reputation led to invitations to visit Canada and the
United States in the late Summer/Autumn of 1914 (accepted) and the offer
of appointments at Edinburgh University, King’s College and University
College London (declined). At the same time it was becoming apparent in
the Autumn of 1914 that the war would ‘not be over by Christmas’ but
would be prolonged and that the country would need to muster its scientific
resources in its defence. In view of the deteriorating situation, and also as a
direct result of a telegram from Sadler, WHB curtailed his visit to the USA.
It is against this scientific and historical background that the importance of
WHB’s letter of 16th
December to Sadler should be assessed.
Michael Ernest Sadler, 1861-1943, was born in Barnsley. He went to
school at Rugby (where he became Head Boy of School House) and in 1880
to Trinity College, Oxford, as a classical scholar. He was elected President
of the Oxford Union in 1882. At Oxford he came under the influence of
John Ruskin which served to establish his life-long interest in, and concern
for, secondary educational reform. His pioneering work as Secretary to the
Oxford Extension Delegacy led, in 1903, to his appointment to a newly-
established Chair at Manchester University in the History and
Administration of Education. He was appointed to the Vice-Chancellorship
of Leeds University in 1911, a post he held until 1923, except for a two-year
period, 1917-19, when he was a member of the Calcutta University
Commission and for which work he received a knighthood. In 1923 he
returned to Oxford as Master of University College.
Sadler’s tenure at Leeds was a difficult one. In 1913 he provoked the
hostility of the local trade union movement by allowing students to help
maintain social services during a strike and in the war years when, in
accordance with his liberal views, he refused to participate in anti-German
propaganda. But despite the unfavourable economic situation, he oversaw a
substantial increase in student numbers.
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IOP History of Physics Newsletter November 2017
At Leeds, Sadler built up a substantial and important private collection of
paintings and sculpture and supported and encouraged the ‘avant garde’
artists of his day. Most significant of all, and an enduring legacy for the
University, was his commissioning of a War Memorial from Eric Gill,
which portrays ‘Christ Driving the Money Lenders out of the Temple’.
This caused an outcry at its unveiling in 1923 and indeed the portrayal is
still regarded as contentious. It is now displayed in the foyer of the Michael
Sadler Building in the University.
The letter, and the three accompanying replies, or memoranda, were
discovered by John Jenkin in the Leeds University Archives (H: Physics
H12) whilst researching his 2008 biography on William and Lawrence
Bragg1. An extract was included in the published book (p. 357). A
complete transcript of the seven page handwritten letter and the three
memoranda was prepared by the author and again an extract of WHB’s
letter was published in 20161. The letter, and the three memoranda, are
published here for the first time.
(2) Text of letter from William Henry Bragg, Cavendish Professor of
Physics4 to the Vice Chancellor of the University of Leeds, Michael
Ernest Sadler
The page numbers of the original handwritten letter on quarto sheets are
indicated in the square brackets.
[p.1]
The University
Dec 16/14
My dear Vice Chancellor
Since we discussed for a few moments a day or two ago the possibility of
increasing the output of research from the Physics Department I have been
considering the question very earnestly, and have come to the conclusion
that I had better set down in writing some account of our present position in
respect to research. There is a special reason for doing this just now,
because the position is of peculiar interest.
As you know we have been busy with a new development of physical
science concerned mainly with X-rays and with crystals. As regards X-
rays, a powerful method of analysis has been devised which is providing a
38
IOP History of Physics Newsletter November 2017
new insight into X-ray theory, and through that, into the general theory of
radiation. The practical applications are likely to be of no less importance
than the theoretical. As regards the crystals, studied necessarily at the same
time as the X-rays, a whole new crystallography has been founded which is
wider and far more fundamental than the old. The new work bears also on
most important chemical principles, on geology, on mineralogy and
generally in fact it is of the widest application. To speak frankly, I doubt if
any other new development in physics of equal interest has risen since the
indication of radioactivity, and before that of X-rays and wireless
telegraphy.
The beginnings of the new work were made by Dr Laue of Zurich5 in a
certain brilliant experiment, the details of which were published in June
1912.
[p.2]
The complexity of the experiment and especially of the mathematical form
of Laue’s explanation would however have hindered indefinitely the
progress of the new work, had it not been for the theoretical investigation of
my son, W.L. Bragg, first published in the Proceedings of the Cambridge
Philosophical Society, November 1912. My son showed that there was a far
simpler method of considering and interpreting Laue’s experiment: a
method which was at the same time suggestive of further progress. As we
have had a considerable experience of X-ray work, in the University of
Leeds we were able to follow up these suggestions and some remarkable
discoveries were made immediately. The further development of the
subject has been the work of the past two years. We have built five of the
new instruments (X-ray spectrometers)6 required for the work, one of which
was taken by my son to Cambridge and set up in the Cavendish Laboratory:
he has got excellent results from it but has been obliged to give it up for the
present as he has a commission in the army. The other four are set up in our
own laboratory. No one else has done any work on the new lines in
England, with the exception of Mr Moseley7 in Manchester, who
commenced to develop my son’s suggestions at about the same time as we
did. His success was only partial at first, but afterwards he made use of
some of our discoveries and did brilliant work on the spectra of X-rays,
which has excited worldwide interest and throws a new light on
fundamental points of chemistry, and also on the question of atomic
structure. His work could really have been done here, but we had not the
men nor
39
IOP History of Physics Newsletter November 2017
[p.3]
the implements to work out all the possible lines of development at one
time. We were fully occupied with the crystallographical and other sides.
Abroad, the amount of effective work has been very small. The new
science, for indeed it may so be called, has so far been worked out by
ourselves in Leeds, by my son who has worked sometimes in Cambridge
sometimes in our own laboratory, and by Moseley at Manchester and
afterwards Oxford.
The instruments are now being made for sale by W.G. Pye & Co. of
Cambridge8: two have already been sent to America. A book on the subject
is to appear very shortly9. My invitation to America was largely due to a
wish to hear about the new subject: and I was unable to comply with half
the further requests to lecture at different universities in the States and in
Canada. I lectured at the Sorbonne in Paris last Easter and was to have
lectured to the German Physical Society in Hanover last September.
I mention all these points in order to make clear the special nature of the
position which we occupy. It is really very strong. At present we have the
field almost to ourselves but presently of course there will be a large
addition to the number of workers.
We are pushing on with several lines of investigation: including some
which are very difficult and may not be productive immediately. But we
take the difficult cases because it seems right that we, who have had most
experience, should be the ones to attack them.
[p.4]
Besides myself these are working in the laboratory, Mr Porter10
, Mr
Quarmby11
and Dr Woeljar12
. Mr Porter’s work has been largely
interrupted by military training but he has now been told that he cannot be
accepted as an officer for medical reasons: his heart is not quite strong
enough. He will probably return now to the research work: unless indeed he
accepts a very alluring offer to join a commercial concern as a research
worker. Mr Quarmby is a student of last year and promises well, but has
not had much experience yet. Dr Woeljar is a very clever student who has
come over from Amsterdam to acquire experience in the new work: he is
likely to stay over Christmas and perhaps longer unless his finances break
down under the strain of present conditions.
40
IOP History of Physics Newsletter November 2017
Mr Peirce13
who was working with us, as an 1851 scholar from Sydney,
New South Wales, has got a commission in the army, and so also has our
demonstrator Mr Nuttall14
. Both these were good workers.
The special instruments we have used and are using have been built in our
own workshops. If we had not spent the money on the workshops, and had
not engaged the services of Jenkinson15
, who is a first class instrument
fitter, we could have done nothing.
The point is therefore, how can we best use our present advantage? We
must get out of it all we can before the rush of better equipped laboratories
and larger staffs deprives us of our lead. Our lead is certainly a fairly long
one, and we ought to do a great deal before we are overhauled: unless
anything untoward happens.
We can of course increase our staff: but this would undoubtedly be
expensive if we were to
[p.5]
engage assistants. A good research assistant would cost from £100 to £150
a year, depending on the quality of the man. Such a man would not be of
much use to us as a personal assistant, because it happens that I cannot work
comfortably except by myself. He would simply be an additional
independent worker and would be valuable in that way. In normal times
one might expect research students to come without pay, as Dr Woeljar has
done already. But the war has interfered and will continue to do so. Two
Russians were expected next year: and I feel sure there would have been
others. We have indeed lost through the war both Peirce and Nuttall. If
there were plenty of money and we could play a bold game, it would be
splendid to engage a first class young man, preferably of reputation, just as
Manchester has recently engaged Dr Bohr of Copenhagen16
. I do not know
what Bohr gets as a salary, perhaps £250 a year. I do not imagine however
that it is worthwhile to discuss such possibilities.
We might do a good deal immediately by rendering the services of the
present staff more effective. After all, we have the experience and can do
more than newcomers if we get the time. Now there is a quantity of routine
clerical work in the laboratory which takes much of the demonstrators time,
and mine also. Nor is it effectively done at present: from sheer lack of time.
It includes the keeping of the laboratory records, the filing and entering of
41
IOP History of Physics Newsletter November 2017
reports of students’ progress, the weekly printing of tutorial papers, and of
standard answers, the keeping of catalogues, of laboratory accounts, writing
[p.6]
letters, typing MS of papers, distribution of printed papers to other
laboratories and so forth. Many of these services are woefully behindhand
now, and we are torn between the desire to do the clerical work of the
laboratory efficiently and the desire to go on with the research work. I do
think we might have a junior clerk to ourselves, as I find most physical
laboratories do; an intelligent young typist could do quite well and would
keep us out of the mess I am afraid we often get into. It would be very
much better for the students: and would make us more efficient in the
laboratory. At present the relief could be especially great because we have
lost not only Peirce and Nuttall, but also our very efficient lecture assistant
who has joined the Leeds City Battalion.
Lastly, we must not, if possible, let ourselves suffer from lack of material.
We make our own special instruments but we use also older instruments of
standard patterns which go to complete the equipment. Our stock is not
quite sufficient: we want about £100 worth now: and have [word omitted] in
hand. The more workers we have, the more apparatus we want of course.
If we had plenty of money I could put together a first class equipment which
should include the new powerful X-ray tubes manufactured in the General
Electric Co: in this way we should greatly extend the compass of our work.
That could take £300. At present it seems more likely that this extension of
the work will be done by some who have this equipment and are buying our
spectrometer. At Cornell University I saw an equipment which had cost
more than twice as much as the sum just named.
To sum up, we have a splendid position just now, and we must try to keep
it. The workers
[p.7]
we have should not suffer from lack of tools; at present we want to spend
about £100, but we could spend many times that sum with great advantage
were it available.
We could save the present workers time and make our department run more
smoothly and efficiently if we had our own clerk.
42
IOP History of Physics Newsletter November 2017
Were there plenty of money we could add to our staff; and the best way
would be to engage a young man of ability who is interested in modern
physics.
There is one other line of research which should be discussed. The problem
of the electrification of fabrics during manufacture is of interest
scientifically and of practical importance to this district. Enough has been
done to show that much more could be done with profit. No other
university could do it more suitably as it takes in textile work on the one
hand and our own special work on X-rays and ionisation on the other. It
would take the whole time of a good experimenter. In this case it would be
directly profitable to engage a research worker at a cost of perhaps £120 or
£150 a year. We have tried to get on to this work two or three times: but it
is too exacting for those of us who have other work in hand.
Yours very sincerely
WH Bragg
(3) Memoranda in Reply from Three Senior University Officers
The University Archives do not include an acknowledgement or reply from
Sadler, but it is clear that he immediately forwarded the letter to the Pro-
Chancellor, A.G. Lupton, the Chairman of the Finance Committee, H.J.
Bowring and the University Secretary, A.E. Wheeler.
Arthur Greenhow Lupton, the first Pro-Chancellor of the University, was a
member of a long-established Leeds family – the cloth making firm of Wm.
Lupton & Co. dating back to 1773. He was awarded the Degree of Hon.
LLD in 1910 in recognition of his public service – but at the time his
greatest service lay concealed. In order to provide for the University’s
growth, and so as not to excite the interest of speculators, he privately
purchased land and property for the University – purchases which were not
disclosed until 1922.
H.J. Bowring was Chairman of the Finance Committee from 1902 (prior to
the University’s Royal Charter in 1904) until 1921. At the time (1920s)
when a relocation of the University to a more salubrious site on the outskirts
of Leeds (Weetwood) was being mooted, he urged the view that it was
43
IOP History of Physics Newsletter November 2017
‘more important to buy less romantic, slummy property adjoining the
cemetery’ (now St George’s Field, part of the University campus).
Archibald Edward Wheeler was Sadler’s private secretary 1911-12 and in
1912 was appointed to the new office of Secretary to the University. The
office was changed to that of Registrar in 1919, an office which Wheeler
held with distinction until 1945.
Memorandum from Arthur G. Lupton, Pro-Chancellor of the University
18 December 1914
Dear Sadler
This is a very interesting paper of Bragg’s and I am inclined to think he has
chosen a wise moment to suggest the need of more assistance in one way or
another.
We have always said that personality of the teachers is much more
important than spending money on Buildings. If it can in any way be
managed I should be inclined to give him the typist he asks for, and in
regard to that would not a woman typist etc. give a more reliable and higher
standard of person than a youth.
As to the whole question of the Department, your suggestion of considering
the whole position of the Electrical Department also is of much importance
Sincerely yours
Arthur Lupton
William Lupton & Co.
Whitehall Mills
Leeds
(also at Cliffe Mills, Pudsey)
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IOP History of Physics Newsletter November 2017
Memorandum from H.J. Bowring, Chairman of the Finance Committee
20 December 1914
Dear Sadler
I was most interested in Braggs letter which you handed to me the other day
and should very much like him to have facilities for enhancing his research.
If I remember rightly some of his difficulties are due to his assistants
undertaking military duties and in that case we might perhaps find the
means of helping him out of the extra savings we have just made in
connection with the payment of salaries of the ‘university militant’.
However I will try to have a word with you on the subject if I may in the
course of the next day or two. I return the Pro-chancellor’s letter.
Yours sincerely
H.J. Bowring
Blackwood
Moor Allerton
Leeds
Memorandum from Archibald Edward Wheeler, University Secretary
Professor Bragg’s memorandum of research work
Vice-Chancellor
I have read with great interest Professor Bragg’s important memorandum
and venture to think the University would be wise to do at once a good deal
more than he modestly asks. The future of the University, it seems to me,
depends on its being pre-eminent in at least some branches of its work. At
present our Physics Department is leading the world, and it is unlikely that
we shall ever get a better chance than this of drawing attention to the
University. Looked at from the purely material point of view of increasing
our fee and grant income, it would be a good speculation, I am sure, to
spend money liberally on Professor Bragg’s Department. I therefore
venture to make the following suggestions:-
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IOP History of Physics Newsletter November 2017
1. The appointment of a ‘first class young man’ at (say) £250 a year
(see Bragg pp. 3 & 4). As this appointment is made more
necessary by the absence of Mr Nuttall, the salary may be
provided, for the present, out of the savings on the salaries of those
who are on military service.
2. The appointment of a research worker at £120 or £150 a year (see
Bragg pp. 4 & 5). I do not know whether it would be possible to
combine this appointment with the one desired by Mr Perkin:
perhaps it is not reasonable to hope that the two types of work
could be done by a single worker. Alternatively, is it possible that
the Clothworkers’ Company would be so interested as to be willing
to provide funds in addition to the large contribution they already
make to the Textile and Dyeing Departments?
3. The appointment of a woman clerk at (say) £1 to 25/- a week.
4. A liberal grant for apparatus from the Research and Apparatus
funds, the balance unassigned being as follows:-
£
Apparatus: Arts & Science 205
Technology 155
Research: 193
Some part of these amounts should be kept in hand for other needs
that may arise during the present year.
The first three of these proposals if proceeded with should be considered by
the Board of Faculty and the Senate; the fourth by the Apparatus and
Research Committee.
A.E.W.
22/12/14
46
IOP History of Physics Newsletter November 2017
(4) Discussion
(i) The letter underlines the importance of instrumentation in scientific
research – an importance clearly recognised by WHB in his generous
acknowledgement of the contribution of Jenkinson. As he records on [p.4]
of his letter ‘if we had not spent the money in the workshops, and had not
engaged the services of Jenkinson, who is a first class instrument fitter we
could have done nothing’ [my italics]. The contribution of the engineer,
craftsman or mechanic in providing the necessary instrumentation for
scientific research is, I think, seriously underrated by historians of science.
Of all the five spectrometers made by Jenkinson (and Watts) in the Physics
Workshop in the period from the winter of 1912-13 to December 1914
perhaps only one survives – that in the Museum of the Royal Institution in
London. The spectrometer in the Physics Museum in the University of
Leeds is a later (commercial) model manufactured by W.G. Pye & Co.
(ii) There can be little doubt that the young men whom WHB names in his
letter he hoped would provide the initial core of his research group – a hope
of course dashed by the war and the deaths, in France, of three members of
the Physics Department – S.E. Peirce, F. Quarmby and A.E. Watts – as well
as his own younger son, Robert. Of all those named only Nuttall remained
up and until the appointment of Richard Whiddington to the Cavendish
Chair in 1919. WHB does not mention the established members of staff of
the Physics Department (established, that is, before his own appointment):
A.O. Allen (who was appointed Acting Head, 1915-19) and S.A. Shorter
(who was approaching retirement). But surprisingly he does not mention
Norman Campbell, Fellow of Trinity College, Cambridge and a
distinguished scientist in his own right. Campbell greatly admired WHB’s
work; he came to Leeds in 1910 and was appointed Honorary Fellow for
Research in Physics, an (unpaid) post which he resigned in 1916 to go to the
National Physical Laboratory. And although none of his many publications
were authored jointly, Campbell acknowledges the inspiration he gained
from WHB.
The University Officers were clearly far-sighted men. Wheeler may only
have had a layman’s understanding of the scientific content of WHB’s
work, but he clearly recognised its importance both scientifically and with
respect to the University ‘At present our Physics Department is leading the
world’. He also recognised WHB’s innate reticence ‘The University would
be wise to do at once a good deal more than he modestly asks’. These
views are echoed by Lupton ‘We have always said that the personality of
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IOP History of Physics Newsletter November 2017
the teachers is much more important than spending money on buildings’ –
views which were doubtless shared by Sadler himself. They were followed,
in the early months of 1915, by material support from the University,
largely in accordance with Wheeler’s recommendations and which would
presumably have been a factor in WHB’s refusal of the offer of the Quain
Chair in Physics at University College (10 March 1915). But later that
month (possibly the result of his ground-breaking Bakerian Lecture to the
Royal Society), University College increased its offer which WHB
accepted.
(iii) The grounds upon which he did so were explained in a letter to Arthur
Smithells17
, Professor of Chemistry and a close friend. Although reluctant
to leave Leeds, WHB realised, that in the continuation of the war, the Royal
Society would need to take on the role of an Advisory Body to the
Government and that in order to be closely involved in this endeavour he
would need to be in London, in the centre of things. There is no evidence of
dissatisfaction or any personal difficulties at the University – indeed the
contrary. In a letter to Sadler written two years later (March 10 1917) from
the Admiralty Experimental Station18
at Parkeston Quay, Harwich, WHB
requests the loan of a lathe from the Physics workshop, ending his letter
with the words ‘The University has been so exceedingly good already that I
have the greatest reluctance in proffering any further request’. Further, both
he and Gwendoline had established friendships at Leeds which were to
continue throughout their lives. This makes WLB’s comment, in a letter to
his mother, supporting his father’s move from ‘that deadly Leeds University
atmosphere’ so inexplicable19
.
A further, and perhaps more significant factor in WHB’s decision to leave
Leeds stems from his very keen sense of responsibility: in particular his
feeling that, despite his great scientific success and the prestige that he had
brought to the University (culminating in the award of the Nobel Prize for
Physics, jointly with WLB in 1915), he had failed to fulfil all the duties
expected of a Professor of Physics. The Yorkshire College of Science, out
of which the University had grown, owed its origin in 1874 to supply the
need for technical education to support local industries in the face of
increasing foreign competition. WHB recognised the importance of such
work, particularly in support of the textile industry, but, as he expresses in
the last sentence of his letter ‘We have tried to get on with this two or three
times, but it is too exacting for those of us who have other work in hand’.
Such concerns are also expressed in his letter to Arthur Smithells17
with
respect to the physical problems associated with the textile trade. He says ‘I
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IOP History of Physics Newsletter November 2017
would make a shot at it myself but I am not so well equipped as many
younger men and should have to give up my own research work’.
In 1928 WHB was able to recommend W.T. Astbury, one of his own
research workers at the Royal Institution, for the post of lecturer in Textile
Physics and Director of the Textile Physics Laboratory at the University of
Leeds – an appointment that had an enormous impact on the scientific
development of the textile industry. In doing so perhaps WHB felt that he
was assuaging his conscience and that he was fulfilling, in some degree, his
obligations to the University.
(5) Endnotes and References
1 The collaboration between WHB and WLB, and the events which led up
to it, have been described in several biographical accounts – most
recently:
John Jenkin (2008) William and Lawrence Bragg, Father and Son – the
most extraordinary collaboration in science. Oxford University Press,
Oxford.
John Meurig Thomas (2012) William Lawrence Bragg: The Pioneer of
X-ray Crystallography and his Pervasive Influence. Angewandte
Chemie Int. Ed., 51 p12946-12958
André Authier (2013) Early Days of X-ray Crystallography.
International Union of Crystallography/Oxford University Press,
Oxford.
Christopher Hammond (2016) ‘Whin Brow’: the house at which the new
science of X-ray crystallography began. Crystallography Reviews 22
p220-227.
2 These crystal structures were published in the following papers:
W.H. Bragg and W.L. Bragg (1913) The Reflection of X-rays by
Crystals I. Proc. Roy. Soc. A88 p424-438. [Proposed structure for NaCl,
Bragg’s law expressed as nλ = 2dsinθ for the first time.]
W.L. Bragg (1913) The Structure of some Crystals as Indicated by their
Diffraction of X-rays. Proc. Roy. Soc. A89 p248-277. [Determination of
crystal structures of NaCl, ZnS (blende), CaF2, KI, KBr.]
W.L. Bragg and W.H. Bragg (1913) The Structure of the Diamond.
Proc. Roy. Soc. A89 p277-291. [Also comparison of the structures of
diamond and ZnS (blende).]
W.L. Bragg (1914) The Analysis of Crystals in the X-ray Spectrometer.
Proc. Roy. Soc. A89 p468-489. [Analysis of NaCl, ZnS (blende), CaF2,
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IOP History of Physics Newsletter November 2017
FeS2, NaNO3, CaCO3, MnCO3, FeCO3, (Ca, Mg)(CO3)2. Estimates of
single-parameter shifts of S atoms in FeS2 and O atoms in CO3/NO3
‘rings’ from intensity measurements.]
W.H. Bragg (1914) The X-ray Spectra given by Crystals of Sulphur and
Quartz. Proc. Roy. Soc. A89 p575-580. [Incomplete solutions.]
W.L. Bragg (1914) The Crystalline Structure of Copper. Phil. Mag.
Series 6 28 p355-360.
3 Prof Shigeru Ohba of Keio University has brought my attention to the
early work and papers of Torahiko Terada. In a paper of 1913 On the
Transmission of X-rays through Crystals (Proc. Tokyo Math-Phys. Soc
7 (1913) 60-70) he describes the elliptical pattern of spots on a Laue
photograph as ‘formed by pencils of rays ‘reflected’ from a number of
planes intersecting one another in the crystallographic axis’ and that the
positions of the spots ‘may be explained by simple reflection from
different netplanes in the crystal’. In the same way he explains the
elongated shapes of the spots – but also is careful to note that by
‘reflected’ nothing more is meant than the geometrical relation to the
incident beam. However, Terada acknowledges the prior claim of WLB
in formulating the law of reflection – he received WLB’s seminal paper,
The Diffraction of Short Electromagnetic Waves by a Crystal, read to
the Cambridge Philosophical Society on November 11th
1912 and
published in 1913 (Proc. Cam. Phil. Soc. 7 43-57), after he had read his
own paper.
Terada went on to apply X-ray diffraction techniques to study the
Deformation of Rocksalt Crystal (Proc. Tokyo Math-Phys. Soc 7 (1914)
290-291) and the Molecular Structure of Common Alum (Proc. Tokyo
Math-Phys. Soc 7 (1914) 292-296). Further X-ray work was undertaken
by Shoji Nishikawa who studied fibrous, lamellar and powdered
specimens and then sheets of rolled metals. Independently of WLB he
analysed the Structure of some Crystals of the Spinel Group (Proc.
Tokyo Math-Phys. Soc. 8 (1915) p199-209).
4 The Cavendish Chair in Physics in the University of Leeds is named in
memory of Lord Frederick Cavendish, first president of the Yorkshire
College, who was assassinated in Phoenix Park, Dublin in 1882. The
Cavendish Laboratory in Cambridge is named after an earlier member of
the Cavendish family, Henry Cavendish (1731-1810), the reclusive and
eccentric scientist, who’s fortune of over a million pounds sterling
provided the endowment to the laboratory in 1871.
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IOP History of Physics Newsletter November 2017
5 The ‘certain brilliant experiment’ was made at the University of Munich
at which Laue was a ‘privatdozent’. He was subsequently (1912)
appointed to a Chair in Theoretical Physics at the University of Zurich, a
Chair which he resigned in July 1914 for a Chair at Frankfurt-am-Main.
Clearly, W.H. Bragg was unaware of Laue’s return to Germany.
6 Both W.H. and W.L. Bragg referred to the diffraction/reflection peaks as
spectra and the instrument as a spectrometer. They are now referred to
as diffraction or reflection peaks and the instrument a diffractometer.
7 Henry Gwynn Jeffreys Moseley was educated at Eton (King’s Scholar)
and Trinity College, Oxford (Millard Scholar). After graduating in
Natural Sciences in 1910 he was appointed Lecturer in Physics at
Manchester University to work on radioactivity under Ernest
Rutherford. However, encouraged by W.H. Bragg, he chose to study the
characteristic X-ray emission spectra of the elements using crystal
diffraction, continuing the work on his return to Oxford in 1913. His
work established the relationship between the wavelengths of the
spectral lines and (what is now called) atomic number Z and led to major
improvements in Mendeleev’s periodic table.
At the outbreak of the war, Moseley enlisted in the Army and was
commissioned in the Royal Engineers. His life and promising career
were cut short by a sniper’s bullet at Gallipoli in August 1915, at the age
of 27.
8 William George Pye trained as an instrument maker and joined the staff
of the Cavendish Laboratory in 1880. In 1896 he formed, together with
his wife, his own company, W.G. Pye & Co., for the manufacture of
precision scientific instruments for schools and Universities. He first
worked part-time with the Cavendish and, after 1899, full-time. By
1914 the company had expanded with a work force of 14 people.
9 X-rays and Crystal Structure, first published by G. Bell & Sons Ltd. In
1915. The final (4th
) edition was published in 1924. The book was then
expanded to become Volume 1 of The Crystalline State: A General
Survey by Sir Lawrence Bragg, first published in 1933 and last reprinted
in 1962. It remains a classic introductory text and is only marginally out
of date.
10 H.L. Porter, BSc (London) [not to be confused with A.B. Porter whose
development of Abbe theory was made use of by WLB in his work on
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IOP History of Physics Newsletter November 2017
the optical simulation of X-ray diffraction] joined the Physics
Department in the academic year 1910-11 as a Demonstrator. He
collaborated with WHB on the ionisation of materials by X-rays; work
which was jointly published in Proc. Roy, Soc. In 1911.
11 Frederick Quarmby graduated from the University of Leeds in July 1914
with a BSc degree. In 1915 he enlisted in the Duke of Wellington’s
(West Riding) Regiment as a Second Lieutenant. He was killed in
September 1916 near Thiepval in the Battle of the Somme at the age of
24. His name, F, Quarmby, is recorded in the University Roll of Honour
in the Parkinson Court.
12 Dr Ad Maas of the Boerhaave Museum identifies Dr Woeljar as Herman
Robert Woltjer who was awarded his PhD in 1914 for a thesis with
Pieter Zeeman on ‘magnetic splitting and temperature’. He then
continued research on low temperature magnetism with Kamerlingh
Onnes at Leiden. He presumably visited Leeds prior to taking up the
Leiden appointment but it is not known whether he intended to carry out
any collaborative research with WHB. Certainly, none of his research,
either before or after the Leeds visit, involved X-ray diffraction
techniques.
13 Sydney Ernest Peirce was awarded the BSc degree from Sydney
University in 1913 and on the strength of published research on the
ionisation caused by X-rays was, in the same year, awarded an 1851
Exhibition Scholarship. During his short time in Leeds he carried out
research on the absorption of X-rays, work which was published jointly
with WHB in Phil. Mag. In 1914. In the same year he was
commissioned as second Lieutenant in the King’s Own Yorkshire Light
Infantry and was awarded the Military Cross in 1915. He was killed in
France in December 1915 at the age of 20. His name, S.E. Peirce, is
recorded in the University Roll of Honour in the Parkinson Court.
14 John Mitchell Nuttall came to Leeds in 1912 from Rutherford’s
Laboratory at Manchester University where, together with Hans
Wilhelm Geiger, he established the relationship between the rate of
decay of radioactivity and the energies of the emitted α-particles (The
Geiger-Nuttall Rule). He became Captain in the Royal Engineers and in
1921 returned to Manchester in 1921 as Assistant Director of the
Physics Laboratories.
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IOP History of Physics Newsletter November 2017
15 Charles H. Jenkinson was a skilled instrument fitter. Prior to joining
WHB at Leeds he was a foreman with the Cambridge Scientific
Instrument Company – the Company founded in 1881 by Horace
Darwin (Charles Darwin’s youngest son) and Albert George Dew-
Smith. His value to WHB was such that he remained with WHB to the
end of his working life. The University Annual Reports 1912-14 also
list A.E. Watts as a mechanic (presumably Jenkinson’s assistant) in the
Physics Department. In 1915 Albert Edward Watts is recorded as being
on Active Service, like Peirce, as second Lieutenant in the King's Own
Yorkshire Light Infantry. He was killed in France in September 1916
and his name, A.E. Watts, is recorded in the Roll of Honour in the
Parkinson Court.
16 Rutherford’s engagement was a two-year Readership (in succession to
G.C. Darwin whose tenure had expired) at a salary of £200. Bohr’s
reputation at this time rested upon a ‘trilogy’ of papers, written in
Copenhagen and Manchester, which were to lead to the award of the
Nobel Prize for Physics in 1922. On his return to Copenhagen in 1916
Bohr took up the newly-established Chair in Theoretical Physics and
founded the Institute which now bears his name.
17 Letter: W.H. Bragg to A. Smithells (draft) 26 March 1915. In the Bragg
Archive at the Royal Institution. Quoted by Jenkin1, p358.
18 WHB took up the Quain Chair at University College at the
commencement of the new academic year (September 1915) but his
work there was forestalled by his appointment to a Government Panel
concerned with submarine acoustic detection methods. In April 1916 he
was seconded to be Resident Director of Civilian Scientists at the Naval
Research Station at Hawkcraig in the Firth of Forth. Collaboration with
the Naval Staff there proved to be difficult and within a year he moved
to the newly-established Admiralty Research Station at Harwich,
returning to University College at the end of the war.
19 Letter, early 1915 from WLB to Gwendoline Bragg. In the Bragg
Archive at the Royal Institution. Quoted by Jenkin1, p369.
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IOP History of Physics Newsletter November 2017
(6) Acknowledgements
I wish to thank Prof. Sir John Meurig Thomas F.R.S. for alerting me to the
historical importance of the correspondence reported in this paper and The
Lady Adrian and the Head of Special Collections, University of Leeds, for
giving permission for its publication.
In the preparation of this paper, I have greatly benefitted from the
constructive advice and helpful comments of John Jenkin, Lucy Adrian and
Sir John Meurig Thomas. Finally, I wish to thank Nick Brewster,
University Archivist, for his help in the preparation of the transcript, the
staff of Special Collections in the University of Leeds for help in searching
out historical material, Dr Ad Maas of the Boerhaave Museum, Amsterdam,
for identifying Dr Woeljar and Professor Shigeru Ohba of Keio University,
Japan for alerting me to the contributions of Torahiko Terada and Shoji
Nishikawa in the early analysis of X-ray diffraction by crystals.
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IOP History of Physics Newsletter November 2017
Book review
Crystal Clear – The Autobiographies of Sir
Lawrence and Lady Bragg.
Edited by A.M. Glazer & Patience Thomson
OUP 2015
ISBN-13: 978-0198744306
448pp £35
Essay review by Peter Ford
The world of physics is full of names: Newton’s Laws; Faraday’s Cage;
Young’s Interference; Maxwell’s Equations; Rayleigh Scattering; Planck’s
Constant; Heisenberg’s Uncertainty Principle; Schrodinger’s Cat; The Pauli
Exclusion Principle; The Dirac Delta Function. The list goes on and on.
One of the most important is Bragg’s Law enunciated by Lawrence Bragg
late in 1912. It relates to a beam of X-rays striking a crystal which results
in interference of the rays reflected at different lattice planes of the crystal
producing a characteristic X-ray diffraction pattern. Analysis of these
patterns has proved to be instrumental in determining the structure of the
crystal. The first structure to be determined was that of common salt (NaCl)
carried out by Lawrence Bragg and shortly afterwards, together with his
father William Henry Bragg, they determined the structure of diamond.
Subsequently, the technique of X-ray analysis has been developed by a
large number of people and used to determine the structure of ever more
complicated molecules. Probably the most famous of these was the
determination of the crystal structure of DNA by Crick and Watson in 1953,
which is widely regarded as one of the most important scientific
achievements in the second half of the twentieth century.
This work was carried out in Bragg’s own MRC Laboratory at Cambridge.
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IOP History of Physics Newsletter November 2017
The book “Crystal Clear” is the previously unpublished Autobiographies of
Sir Lawrence and Lady Bragg. It has been edited by Mike Glazer, Emeritus
Professor of Physics at Oxford University, a distinguished crystallographer,
and Patience Thomson, the younger daughter of Sir Lawrence and Lady
Bragg. It is a fascinating account of the lives of two remarkable people
with very different personalities, temperaments and abilities who married to
form a truly class act. Through their devotion and commitment to each
other and in their very different roles they played an important part in
British Society over many years. It is appropriate that this book was
published in 2015 since it marks the centenary of the award of the Nobel
Prize in Physics made jointly to Lawrence Bragg and his father, William
Henry Bragg, the only occasion that a Nobel Prize has ever been jointly
awarded to a father and son. Lawrence Bragg was the youngest person, at
twenty five years of age, to obtain a Nobel Prize in any discipline for the
following ninety nine years until he was upstaged by Malala Youzafsai in
2014, who at the age of seventeen was awarded the Nobel Prize for Peace.
In his Foreword to the book, Mike Glazer gives a brief account of the
history of X-rays leading to the discovery of Bragg’s Law. He also recounts
how the book came into existence. It was some years ago when he was
invited to a conference in Madrid to talk about the two Braggs, that he made
contact with Lady Heath (Margaret), the elder daughter of Lawrence Bragg
who lent him the family photograph album and the unpublished
autobiography of Sir Lawrence Bragg. Later he also obtained the
unpublished autobiography of his wife Alice Bragg. Rightly he felt that
these two autobiographies deserved to be read by a wide audience and the
resulting book reflects their lives played out during much of the twentieth
century, a time of momentous change.
The book opens with an interesting and novel introduction by their younger
daughter, Patience Thomson, and is titled “Meet my Mother and Father.”
Patience writes “My mother was beautiful – not just pretty, but beautiful”
and “Her great strength was her social confidence and personality. She was
the life and soul of parties, people fell for her and she made deep and
enduring friendships”. These two aspects of her character, combined with
an excellent education and her complete integrity, account for much of her
success and help to explain her considerable achievements in life such as
becoming Mayor of Cambridge in 1945 and later Chair of the National
Marriage Guidance Council. Patience Thomson describes her father as
follows: “Dad was not part of the Establishment. He had not been to public
or grammar school and had no English friends from schooldays….; he was
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IOP History of Physics Newsletter November 2017
a colonial from Australia. ….. He delegated administration whenever he
could. He was not clubbable and did not particularly relish dinners at the
High Table in Trinity ……. Modest and self-deprecating my father was
quick to acknowledge mistakes and quick to apologise, but could still get
very angry, so much so that he would go red in the face and start to
stammer”.
Early years
In his Autobiography William Lawrence Bragg describes growing up in
Australia. He was born in Adelaide in 1890, which at that time was still a
fairly undeveloped country. His father, William Henry Bragg, had been
asked to go out to Adelaide to become the Professor of Physics and
Mathematics at the University there shortly after graduating from Trinity
College, Cambridge. Lawrence Bragg describes his young life and early
schooling and recalls that he was great friends with his next door neighbour
Eric Gill, who was of the same age and later became one of the leading
sculptors in Britain following in his father’s footsteps. Lawrence Bragg’s
grandfather was Sir Charles Todd who set up the Overland Telegraph Link
between Adelaide and Darwin. In addition to being Postmaster General, he
was Astronomer Royal for South Australia. Lawrence spent a lot of time in
his company and this must have helped develop his interest in science. In
1897 his family returned to England for a year and we have an interesting
account of this visit through the eyes of a seven year old. On his return to
Adelaide he continued his schooling at St Peter’s College, the premier
Church of England School in South Australia and then entered Adelaide
University at the age of fifteen. He obtained a first class Honours Degree in
Mathematics at the age of eighteen and also studied physics. Academically
he was outstanding but he was also shy and gauche and a lot younger than
his fellow students which meant that he had difficulty fitting in with them.
In January 1904 the Australian Association for the Advancement of Science
met in New Zealand and William Henry Bragg, Lawrence’s father, gave the
presidential address in the mathematics-physics section. Up to that time,
William Bragg had never done research but preparing for this lecture
stimulated him to carry out some experiments on the passage of particles
through matter. He proved to be an outstanding experimentalist and
produced some classic work on the penetration of matter by alpha rays and
on the secondary beta rays. His investigations made, between 1904 and
1908, were highly regarded in the physics community and led to him being
invited to take the chair of Physics at Leeds University.
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IOP History of Physics Newsletter November 2017
They arrived back in England early in 1909 and later that year Lawrence
Bragg went up to Trinity College, Cambridge taking Part 1 in Mathematics
in his first year and then Part II switching to Physics obtaining his degree
again with first class honours in 1912. C.T.R. Wilson of cloud chamber
fame was his main lecturer and, though he had an appalling lecturing style,
the content was excellent and he taught him most of the physics that he
learnt especially optics, which was to prove so crucial in his explanation of
the diffraction of X-rays by crystals. During his time at Trinity College he
made a group of friends who did much to draw Lawrence Bragg out of his
shell and mature and develop him. In particular he formed a friendship with
Cecil Hopkinson who was studying engineering at Trinity and came from a
distinguished family of engineers. Cecil loved adventure and hardship and
did much to broaden his horizons such as introducing him to skiing and
boating both of which he loved and continued throughout his life.
Father and Son
Lawrence Bragg began research at the Cavendish Laboratory under J.J.
Thomson. It was not a satisfactory experience since there was inadequate
supervision and poor facilities, such as the lack of a first rate workshop,
which meant that students had to construct most of their own apparatus
which were often too crude to produce meaningful data. It was a frustrating
time for him. His breakthrough came when the German scientist von Laue
published his paper on the diffraction of X-rays by zinc-blende and other
crystals. Lawrence discussed these results with his father William Henry
Bragg while they were on holiday together on the Yorkshire coast. On his
return to Leeds, Lawrence set up an experiment in his father’s laboratory to
understand the nature of the spots observed on von Laue’s photographs. It
was a short while later back at Cambridge that it suddenly occurred to him
that the spots observed by von Laue were due to the reflection of X-ray
pulses by sheets of atoms in the crystal. He presented his ideas at a meeting
of the Cambridge Philosophical Society in November 1912 and wrote a
paper for the Proceedings of the Society entitled “The Diffraction of Short
Electromagnetic Waves by a Crystal”, which appeared early in 1913.
Following on from his ideas he was able to determine the crystal structure
of common salt (NaCl), which he published in the Proceedings of the Royal
Society in 1913. The structure consisted of alternating atoms of sodium and
chlorine arranged on a lattice. It is difficult today to appreciate how novel
Bragg’s structure appeared at the time. Several elderly but eminent
chemists were incensed that there were no NaCl molecules and were critical
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IOP History of Physics Newsletter November 2017
of the whole approach of X-ray analysis to determining molecular structure
developed by Bragg. The equipment available to Lawrence Bragg at the
Cavendish Laboratory was extremely primitive and so he was fortunate to
be able to combine forces with his father at Leeds, who had access to a first
class workshop, to have built a state of the art X-ray spectrometer. This
enabled Lawrence rapidly to obtain data on the structure of several crystals
and he wrote a seminal paper jointly with his father on the crystal structure
of diamond, which appeared in the Proceedings of the Royal Society
in1913.
William Henry Bragg, being by now a senior and highly respected scientist,
presented a lot of the new results at the British Association, the Solvay
Conference outside Brussels and in lectures he gave in Britain and also the
United States. This did produce a certain amount of tension between father
and son although on every possible occasion William Bragg emphasised the
outstanding contributions made by his son. In addition, they thought in very
similar ways and so it was often difficult to determine who had originally
come up with an idea or suggestion.
The First World War
The flow of research came to an abrupt end with the outbreak of the First
World War, which came out of the blue in August 1914. A series of
interlocking treaties between European countries and the murder of
Archduke Ferdinand, heir to the Austrian throne, at Sarajevo, precipitated
this devastating event which rapidly became out of control. Initially
Lawrence Bragg was in a mounted horse infantry unit which, used tactics
which had been developed during the Boer War. A year later in 1915 he
transferred to heading a sound ranging unit, which was developing
techniques to determine the positioning of enemy guns on the Western
Front. This was difficult to achieve, a major problem being able to
distinguish between the sonic boom of the shell, which was released with an
initial velocity greater than that of sound, and the low frequency sound
made by the actual gun, which the sound ranging equipment was trying to
pin-point. The development work was carried out in-situ on the Western
Front and involved some excellent applied physics. The First World War
was the first occasion that science was used in the pursuit of warfare.
It was while they were testing out their sound ranging equipment south of
Ypres, that Lawrence Bragg heard that he and his father had jointly been
awarded the 1915 Nobel Prize for Physics. He was billeted in the house of
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a kindly priest who celebrated the award with him by going to his cellar and
breaking open a bottle of Lachryma Christi.
The First World War caused a devastating loss of life with a huge number
of talented people being killed from which Britain perhaps has never fully
recovered. Lawrence Bragg’s younger brother Bob was killed at Gallipoli
as was Henry Moseley, a scientist set for a glorious career in physics and
who had already discovered Atomic Numbers and whose name had been
put forward for the Nobel Prize in Physics in 1914. In addition, Bragg’s
great friend, Cecil Hopkinson, died in 1917 from wounds that he had
received some time earlier.
Manchester and Marriage
After his discharge from the army, Lawrence Bragg spent a short time back
at Trinity College, Cambridge before being invited to take over
Rutherford’s chair at Manchester University on his appointment as head of
the Cavendish Laboratory, Cambridge. The Manchester chair was a
prestigious position for Bragg but one for which he felt that he was
singularly ill prepared.
During the short period at Cambridge, between being discharged from the
War and leaving for Manchester, Lawrence met Alice Hopkinson, a cousin
of his close friend Cecil Hopkinson. She was reading History at Newnham
College and was well known as a lively and highly attractive young lady.
Lawrence did propose marriage to her while he was at Cambridge, but this
was declined it appears on the grounds that she was having too good a time
and did not wish to tie herself down. In 1921, two years after arriving at
Manchester University, Lawrence Bragg was elected a Fellow of the Royal
Society and among the many congratulations that he received was a
handwritten letter from Alice. Shortly afterwards they re-met and became
engaged. Alice Hopkinson and Lawrence Bragg were married on 20th
December 1921, at Great St Mary’s Church in Cambridge.
Bragg described Manchester as a “dreadfully dirty and ugly place with a
vile climate, foggy and drizzly”. Initially, it was very difficult, mainly
because he had had no previous experience at working and lecturing at a
University in a more junior level. Many of the students at Manchester had
returned from War service and were frequently older and much brasher than
Bragg and quite a handful to control. Gradually things improved as he
became more experienced at running a large and important department and
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he was able to build up an excellent teaching and research team, which
specialised in a wide variety of studies using X-rays.
An important member of his department was Charles Darwin, grandson of
the Charles Darwin of evolution fame, who had been at Manchester during
Rutherford’s day. Before the First World War he had produced two seminal
papers on the theory of X-ray diffraction and much of their subsequent
analysis was based on these two papers. Darwin’s work enabled Bragg’s
team to determine the structure of a large number of increasingly
complicated materials such as the silicates and bring some order into
understanding the mineral kingdom.
Another key member of the Manchester staff was Reginald James who was
a fascinating person. He had volunteered to take part as a physicist in
Ernest Shackelton’s 1914 expedition to the Antarctic. Their ship was
trapped in an ice sheet and was crushed and sank, leaving the party stranded
on an ice floe which was slowly drifting north. Using some ingenious
astronomical observations, he was able to determine their position and
decide when the party was nearest to Elephant Island which they reached by
travelling in an open boat. Shackelton then made an epic boat journey to
South Georgia to summon help and a few months later the whole party was
rescued by a steam ship from Elephant Island.
James worked closely with Bragg on the sound ranging work during the
First World War and followed him to Manchester as a lecturer. He played
an important role in building up the “Manchester School” of X- ray analysis
after the War and co-authored a seminal review paper with Bragg and
Darwin on the structure of a variety of complicated materials. James and
his co-workers made measurements of thermal vibrations leading to a direct
measurement of the zero-point energy. Eventually James left Manchester to
become Head of the Physics Department at the University of Capetown.
During his time at Manchester, Bragg made several foreign trips. In 1922
he visited Stockholm to receive the Nobel Prize for Physics, which he and
his father had been jointly awarded in 1915, but the award ceremony had
been delayed due to the First World War. In 1927, he went to Italy for the
celebration of the centenary of the death of Alessandro Volta during which
Mussolini charmed the ladies by his presence.
But America beckoned and Bragg spent roughly six months as the guest of
the Massachusetts Institute of Technology. This was a valuable experience
and allowed him to work with a variety of students some of whom came to
Manchester to carry out research. Bragg built up a formidable experimental
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research team mainly specialising in all aspects of crystallography. This
was strengthened by some outstanding theoreticians. In addition to Charles
Darwin, there was Hans Bethe, Douglas Hartree, Nevill Mott and Rudolph
Peierls.
In the summer of 1937, Lawrence Bragg was invited to become Director of
the National Physical Laboratory (NPL) in Teddington, Middlesex. It had
been founded in 1900 with the aim to “bring scientific knowledge to bear
practically upon our everyday industrial and commercial life”, something
which it continues to follow to this day. Bragg was delighted about the
appointment, particularly since it meant that his wife and family would be
able to come to southern England away from the rather grim area of
Manchester with its bleak northern climate. The NPL was housed in the
beautiful and historic Bushy House which Queen Victoria had made
available for that purpose. However, it was to be a very short term
appointment since that year Lord Rutherford, Head of the Cavendish
Laboratory at Cambridge, died rather suddenly. Bragg was encouraged to
apply for the vacant position and was duly appointed.
Cambridge
He arrived in Cambridge in October 1938 at a difficult time. War with
Germany was again looming despite the Prime Minister Neville
Chamberlain bringing back from Munich a paper assuring us all that it was
“Peace in our Time”. By the summer of 1939, war appeared imminent.
John Cockcroft, who was later to share the 1951 Nobel Prize for Physics
with Ernest Walton for their artificial splitting of the atom, had been
appointed to the Jacksonian Chair having previously been head of the Mond
Low-Temperature Laboratory. He had devised a scheme to make
physicists available should war break out by producing a “Register of
Scientists”. This produced little interests among the heads of the army,
navy and air force research departments. The only people who seemed to
show interest was the radar research establishment and as a result many
clever young physicists became interested in radar and were involved in its
development during the war. The use of radar was very important during
the pursuance of the war. A major breakthrough was the development of
the powerful cavity magnetron at Birmingham University, which enabled
radar to be installed into aircraft and this was decisive in the submarine war
over the Atlantic.
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It was in 1938, that Bragg first began his association with protein research
which later produced such spectacular successes. Max Perutz, who had
come to the Cavendish Laboratory as a refugee from Austria, showed him
some X-ray diffraction pictures which he had obtained from haemoglobin
crystals. Bragg had a hunch that this work might be significant and
supported him. However, the work was soon to be put on hold. Perutz,
who was Jewish, was initially interned and then moved to Canada where he
worked on a fanciful and not totally unrealistic project to build a large
floating ice platform in the mid-Atlantic to be used as an air base.
Just before the outbreak of war, the Cavendish laboratory was expanded by
the opening of the Austin Wing the money having been supplied by the
motoring magnate Lord Austin. At the outbreak of war most of the
researchers at the Cavendish left for some form of war work and the
laboratory was also turned over to the war effort. Queen Mary College and
Bedford College were evacuated from London to Cambridge and physics
teaching was carried out at the Cavendish. Bragg was based in Cambridge
during the war except for a period of eight months in 1941 when he was in
Canada as Scientific Liaison Officer, a period which he enjoyed and found
most interesting except for the fact that he greatly missed his family. Much
of his time was spent running the Cavendish but in addition, he was
involved in sound ranging activities and with ASDIC, the admiralty
underwater acoustic system for detecting submarines. Both of these
involved quite extensive travelling around the country. One variation of the
sound ranging technique, which he had been prominent in developing in the
First World War, was using a novel method for the successful location of
the origin of V2 rockets fired by the Nazis on England towards the end of
the second war.
Difficult decisions
Peacetime proved to be a difficult period for Bragg. The two key
appointments in the laboratory were that of the Jacksonian Chair which was
held by Cockcroft and the Plummer Chair of Mathematical Physics, held by
Ralph Fowler, Rutherford’s son in law. It was clear that Cockcroft would
be appointed to the directorship of the new Atomic Energy Authority.
However, until that appointment was officially created he retained his
position as Jacksonian Professor. As a result, several highly suitable
candidates went instead to other Universities. In the end Otto Frisch was
appointed which proved very successful. By contrast, Fowler was suffering
from a long and debilitating illness and again several otherwise suitable
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candidates had become unavailable until the position was finally filled by
Douglas Hartree from Manchester. Bragg’s assistant in running the
Cavendish laboratory was John Ratcliffe who carried out pioneering
research work on radio waves in the ionosphere. He proved to be
invaluable.
Not unsurprisingly, Bragg had great soul searching as to whether to
continue research into nuclear physics, which Rutherford had pioneered so
effectively. Bragg did not have expertise in this area and to have continued
to work in it would have needed the building of a highly expensive particle
accelerator. This in turn would require an extremely able person to run and
direct operations and would also need huge funds and lots of manpower. In
addition, particle accelerators were being built in Birmingham, Liverpool
and Glasgow by people who had previously worked under Rutherford. In
the end the decision to discontinue nuclear research at Cambridge was made
and enabled Bragg to take the Cavendish Laboratory into new areas of
research such as the study of biological molecules by X-rays and radio-
astronomy both of which proved to be immensely fruitful.
After the war, Perutz returned to the Cavendish to continue his work on the
diffraction of X-rays by haemoglobin supported by the Medical Research
Council (MRC). Bragg was persuaded to see Sir Edward Mellanby, the
secretary of the MRC, who agreed to fund the creation of the MRC Unit for
Molecular Biology at Cambridge. This proved to be outstandingly
successful and in 1962 four Nobel Prizes were awarded to workers in the
unit, a unique achievement in the history of these prizes. The four people
were Max Perutz and John Kendrew for their work on haemoglobin and
myoglobin and Francis Crick and James Watson for their determination of
the structure of DNA. The MRC Unit for Molecular Biology at Cambridge
continues to this day to be a very important centre for research in this area.
The area of radio-astronomy at Cambridge was developed by Martin Ryle
who, together with Anthony Hewish, developed an interferometer whereby
interference fringes were produced by two aerials receiving signals from
radio stars. Good resolution was achieved through the wide spacing of the
aerials, which were in the form of a wire mattress standing about a foot or
two above the ground and covering a space of some 150 by 20 feet. It was
at the Cambridge radio-astronomy laboratory that pulsars were first
discovered in 1967 by Jocelyn Bell-Burnell. In 1974 Ryle and Hewish were
jointly awarded the Nobel Prize for Physics.
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By the late 1940s the Cavendish Laboratory was flourishing again.
Although there was some nuclear physics being carried out under Frisch,
the long shadow caused by Rutherford had largely gone away. Exciting
research was now focused on radio-astronomy and molecular biology and
there was also excellent work being carried out in the Mond Laboratory
under Brian Pippard and David Schoenberg who were among the first
people to determine the Fermi surfaces of metals. Another new and fruitful
area was that of electron microscopy which was pioneered at the Cavendish
by Vernon Coslett. Although Bragg himself was much occupied with
running the department, he was able to lead a group engaged in the X-ray
analysis of metals. Among those interested in metal physics was Egon
Orowan who had come to the Cavendish from Birmingham University. He
was one of the original people who put forward the theory of metal slip by
the movement of dislocations. Bragg and his colleagues were able to
produce an ingenious soap bubble raft, which could be made to simulate the
behaviour of dislocations. Nowadays this is sometimes an undergraduate
physics experiment.
It was during the early part of the 1950s that the autobiography of Lawrence
Bragg ends abruptly. The likely reason is that in 1954 he was appointed to
become director of the Royal Institution (RI) in London. He arrived at a
very difficult time since the previous director Edward Andrade had departed
following serious and acrimonious disagreements with the managers of the
RI. For many years Bragg was fully occupied initially in trying to save the
RI and then to build it up. In this he was remarkably successful. He was
able to develop the research programme, the most prominent being the first
determination of an enzyme structure by David Phillips and Louise
Johnson. In addition, he introduced the now famous lecture/demonstrations
to school children. Over a roughly ten year period he spoke to some two
hundred thousand people. In his introduction, Mike Glazer says that he was
one of these students. I was another and I well remember going to the RI to
hear Sir Lawrence in the late 1950s when I was at my grammar school in
North London. There must still be thousands of people still alive who were
inspired by attending the RI and hearing Sir Lawrence lecture and watching
a series of impressive experimental demonstrations. He finally retired in
1966 and died in 1971.
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The Lady’s perspective
The future wife of Lawrence Bragg had a very different upbringing from
him. Alice Hopkinson was the daughter of a very hard working and
conscientious medical doctor practicing in a suburb of Manchester. His
name was Albert and he came from a large and highly talented family. One
of his brothers, John, became an eminent electrical engineer and invented
the Hopkinson dynamo, which at one time was in widespread use. He,
along with several of his siblings, was an excellent rock climber although he
came to a tragic end when in 1898, John, two daughters and a son were all
killed in a mountaineering accident in the Swiss Alps. There is a plaque to
this effect in Free School Lane, Cambridge, between the old Cavendish
Laboratory and the Whipple Museum. John’s youngest son, Cecil, has
already been mentioned as the very close friend of Lawrence Bragg and he
was tragically killed at Gallipoli during the First World War. Another
uncle, Alfred, was twice elected to Parliament and became Vice-Chancellor
of Manchester University.
Her mother’s side of the family was also remarkably talented. Her maternal
grandfather, who became Sir Philip Cunliffe-Owen, was the second
Director of the South Kensington Museum before it became the Victoria
and Albert Museum. Alice Hopkinson’s grandmother was German and she
and Cunliffe-Owen had nine children. One of the daughters, Monica,
married Harry Wills, one of seven sons of Henry Overton Wills who owned
tobacco factories in Bristol. The family were great benefactors and among
the beneficiaries was the University of Bristol including the H.H. Wills
Physics Laboratory. Alice’s mother, Olga, was one of the last of the
children. She was small and shy and rather overawed by her older brothers
and sisters. Nevertheless, Olga was a talented lady being fluent in French
and German and being well read in art, literature and history as well as on a
more practical level having taken a teacher’s diploma in cooking. Alice
Hopkinson was the middle of five children, the second eldest Eric being a
very talented person who was also tragically killed in the First World War.
According to Alice “we lived in an ugly house, in an ugly Manchester
suburb” As a young child she went to the Lady Barn House School which
was highly regarded in the city. Afterwards she went to the prestigious St
Leonards at St Andrews, Scotland where she received an excellent
education. At the end of it she was uncertain what to do but was advised
“Go to Cambridge and read history, get a degree, then marry a man older
than yourself”. Alice did precisely that.
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After leaving school, Alice Hokinson spent a year at home helping her
parents who were profoundly saddened by the death of their son. The
following year, just before the Armistice was signed bringing to an end the
First World War, she went to Newnham College, Cambridge to study
history. She seemed to have had a marvellous time. Being vivacious and
attractive, Alice Hopkinson was much in demand and in addition to her
studies attended balls, dances, parties, teas and other social events. Her
parents had moved back to Cambridge. Her father, having spent thirty years
as a medical doctor in Manchester, then spent several years as a
demonstrator in the Anatomy Department at Cambridge where he was
greatly liked and respected. As noted earlier it was while at Newnham that
she first met Lawrence Bragg but he had to wait another couple of years
before he secured her affections, after he had moved to Manchester where
he had taken over the Chair in the University Physical Laboratories to
replace Rutherford.
Life in Manchester was not that easy for the young Mrs Bragg. They lived
in the suburb of Didsbury and each day Lawrence left shortly after breakfast
and had to work very hard developing the physics department at the
University. Manchester was still grey and grimy with a great deal of
drizzle. However, they had a good social life frequently giving or attending
dinner parties for university colleagues and friends. In addition, Alice often
entertained students, visitors to the department and staff to tea as well as
overnight guests. It was at their home in Didsbury that three of their four
children were born, initially two boys followed by a girl. Professor and Mrs
Bragg made several important travels abroad in connection with his work
and wonderful holidays as a family at home.
They lived in Didsbury for ten years before moving out to Alderley Edge in
Cheshire, which was much leafier and more rural than Manchester but still
within an easy commute to the city. It was here that their fourth child
Patience was born who is the co-editor of Crystal Clear. They had a
beautiful, large house high up on a hill with commanding views over the
Cheshire plains. They found an interesting new circle of friends and life
here was very pleasant.
Lawrence Bragg was head of the physical laboratories at Manchester for
eighteen years and although he had built up a powerful department felt the
urge to move on. As mentioned earlier he was appointed to become the
Director of the National Physical Laboratory at Teddington, Middlesex.
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IOP History of Physics Newsletter November 2017
It was while she was living at Teddington that Alice Bragg first met the
formidable Dowager-Marchioness of Reading who wanted her to join up to
a voluntary scheme (WVS), which she was launching on behalf of the
Home Office. War with Germany again seemed imminent. Alice became
one of half a million women recruited for Air Raid Precaution work (ARP).
On arrival at Cambridge, Lady Reading put Alice in charge of starting the
WVS in Cambridge and as a result Alice got to know a large number of
town people who were not directly associated with the University.
As soon as War was declared in 1939, life in Cambridge changed rapidly.
Many people went off to the War and a large number of refugees came into
the city to be housed temporarily. Like so many homes in Britain, the
Bragg residence became an open house with all manner of people dropping
in for meals, a cup of tea or living there for a short term. Lawrence and
Alice Bragg agonised as to whether to send their children over to the safety
of Canada but in the end decided not to. Lawrence was sent to Canada and
the
United States on a government mission in 1941 and was away for the best
part of a year, which was very difficult for all parties. While he was away
Alice was co-opted into the town’s Civil Defence Committee and shortly
afterwards was invited to become a town councillor representing Newnham,
the ward in which they lived. The War period was extremely taxing and
difficult for almost all people in Britain. The end in 1945 was a great relief
although conditions afterwards were slow to improve.
Immediately after the War, Alice was appointed Mayor of Cambridge, a
role which she carried out with characteristic aplomb. The main business
was taking the chair at the regular council meeting dressed in her full
mayor’s regalia. These meetings could become very tedious with some
councillors droning on and on. A big occasion was when she had to take
the salute when the local regiment was given the Freedom of the Borough.
It was also a poignant event since her brother Eric had been killed in the
First World War while serving in this regiment. She opened the local
Marshall’s Airport in Cambridge during which she was taken on a rather
precarious flight in a Tiger Moth.
Her position as Mayor of Cambridge only lasted a year and Alice Bragg had
acquitted herself extremely well. She returned to a normal life with Britain
in the grips of post war austerity. Lawrence Bragg was very busy trying to
build up the Cavendish Laboratory after the war. In 1951 she received a
letter from the Minister of Education inviting her to join the Advisory
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IOP History of Physics Newsletter November 2017
Council for Education in England and shortly afterwards she received a
letter from the Prime Minister, Mr Attlee, asking her to serve on the Royal
Commission for Marriage and Divorce.
A few years later they moved to the Royal Institution in London, which
Lawrence Bragg was charged with trying to revive. They lived in the
beautiful Director’s flat at the top of the Institution. In part because of its
central location, the flat was visited by numerous people, either for meals or
a short stay, and as always Alice Bragg was an excellent hostess. It was
while she was living in London that Alice was invited to serve on the Lord
Chancellor’s Advisory Committee for Legal Aid, which she did for fourteen
years. Another appointment, which meant an enormous amount to her, was
chairmanship of the National Marriage Guidance Council. She went around
the country getting to know local Marriage Guidance Councils. It was
important work in which Lawrence supported her enthusiastically
sometimes attending their Annual General Meeting. She was involved with
this for nearly twenty years.
The final years
During the early 1960s the fortunes of the Royal Institution were turned
around and it was recognised as a foremost science organisation within
Britain. This was in no small way due to the efforts of Sir Lawrence and his
introduction of the lectures for school students. However, there was
concern about his health. Several times he had bad pneumonia and twice he
underwent operations. In 1962 he was in hospital for five weeks. By this
time Sir Lawrence had become “The Grand Old Man of Science” receiving
numerous honorary doctorates. There was a big celebration in 1965 to mark
the fiftieth anniversary of his Nobel Prize for Physics. In addition they had
several marvellous trips abroad including to South Africa and India and in
1960 a trip round the world, which enabled him to show Alice his old
haunts in Adelaide, which he had left so many years before.
In 1966, at the age of seventy six, Sir Lawrence Bragg retired from the
Royal Institution. The couple went to live in a home that they had
purchased some years before in Suffolk where they could garden and
Lawrence could paint and go for walks and study the bird life. He died in
1971 having just finished a final book. Alice returned to live in Cambridge,
where she felt that she belonged, and lived happily in a secure
accommodation. She died in 1989.
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IOP History of Physics Newsletter November 2017
In this Essay Review I have concentrated on the scientific work of
Lawrence Bragg, although it should be clear that his wife made very
important contributions to British life. However, Crystal Clear describes
much more than just the work and personalities of Sir Lawrence and Lady
Bragg. We are given interesting insights into the four Bragg children and
their development, the houses that they lived in, some of which were
beautiful and interesting, their holidays and official travel and their wide
circle of friends. In addition we learn about their hobbies. Lawrence Bragg
was a keen hiker and bird watcher and had a great love of nature and also of
sailing. He was an accomplished amateur artist and the book contains many
of his sketches which add considerably to it as do the photographs many of
which were supplied by Patience Thomson.
For me Crystal Clear is an excellent read. The book is greatly enhanced by
the large number of footnotes giving thumbnail sketches of the many
prominent scientists, politicians, administrators and other with whom they
came into contact. All the profits from the sale of this book are to go
towards the Royal Institution in London. Sir Lawrence would have
approved.
*******
Forthcoming meetings The history of Nuclear Magnetic Resonance (NMR) and MRI in Britain -
now to be held in April 2018, details to follow and a meeting on Physicists
of London universities - yet to be arranged.
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IOP History of Physics Newsletter November 2017
History of Physics Group Committee 2016/17 Chairman Professor Andrew Whitaker
[email protected] Hon Secretary Dr. Vince Smith [email protected] Hon. Treasurer Dr. Chris Green [email protected]
Members
Mrs Kathleen Crennell
Professor John Dainton
Professor Edward Davis
Dr. Peter Ford
Dr. Jim Grozier
Professor Keith MacEwen.
Dr. Peter Rowlands
Dr. Neil Todd
Professor Denis Weaire
Newsletter Editor Mr Malcolm Cooper