issn 1756-168x (print) issn 2516-3353 (online) newsletter · editorial meeting reports ... beams...

ISSN 1756-168X (Print)

ISSN 2516-3353 (Online)

Newsletter

No. 35 November 2017

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

2

3

5

10

13

15

16

18

34

54

69

70

61

2


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

3


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.

4


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

5


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

6


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.

7


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

8


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.

9


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.

10


‘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

11


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,

http://www.britishpathe.com/search/query/zeta/recordcategories/Science++Technology

http://www.britishpathe.com/search/query/zeta/recordcategories/Science++Technology

12


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

13


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.

14


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

-------------------------------------------------------------------------------------------

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.

15


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

https://doi.org/10.1088/1361-6552/aa6cff

16


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

17


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.

18


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

19


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.

20


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.

21


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.

22


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


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.

24


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.

25


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!

26


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?

27


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.

28


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!

29


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.

30


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


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


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.

https://catalog.hathitrust.org/Record/008648381

http://gallica.bnf.fr/ark:/12148/bpt6k65766809?rk=42918;4

http://gallica.bnf.fr/ark:/12148/bpt6k65766809?rk=42918;4

33


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


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


(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


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.

37


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


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


[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


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


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


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


‘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)

44


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:-

45


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


(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

47


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

48


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,

49


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.

50


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

51


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.

52


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.

53


(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.

54


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.

55


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

56


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.

57


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

58


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

59


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

60


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

61


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.

62


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

63


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.

64


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.

65


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.

66


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.

67


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

68


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.

69


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.

70


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

[email protected]

mailto:[email protected]



issn 1756-168x (print) issn 2516-3353 (online) newsletter · editorial meeting reports ... beams...

Documents