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Light is a Messenger. The Life and Science of William Lawrence Bragg. By Graeme K. Hunter

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Light is a Messenger
The Life and Science of William
Lawrence Bragg. By
Graeme K. Hunter.
Oxford University
Press, Oxford
2004. 322 pp.,
£ 35.00.—ISBN
William Lawrence Bragg (1890–1971),
the first seer of crystal structure, has not
previously been an attractive subject for
biographers, unlike lesser giants of British crystallography such as Rosalind
Franklin or John Desmond Bernal. In
the first book-length biography of
Bragg, Graeme Hunter quips: “Franklin
is of interest because of sexual politics,
and Bernal because of sex and politics”.
Bragg, on the other hand, an Edwardian
gentleman (Jack Dunitz described him
as “courtesy itself”), was circumspect
and consequently a bit dull. Bragg4s life,
Hunter implores in the introduction, is
not “entirely devoid of interest or historiographical significance” (my italics).
This is hardly a recommendation. Perhaps a beleaguered reader with a stack
of books higher than the nightstand will
slip this one to the bottom of the pile
after reading Hunter4s apology for
taking an interest in such a dud. That
would be unfortunate. Light is a Messenger is a first-rate biography of a
scientist who, save for his great rival
Linus Pauling, contributed more to
structural chemistry than any other
individual. Max Perutz said: “If we
think of Bragg as an artist and compare
him to, say, Giotto, it is as though he had
himself invented three-dimensional rep-
resentation, and then lived through all
the styles of European painting from the
Renaissance to the present day, to be
finally confronted with computer art”.
Only a mediocre biographer would
render such a life as devoid of interest.
Hunter, on the contrary, is at the top of
his game.
It is true that Bragg4s life lacks the
dramatic arc of struggle followed by
triumph or tragedy. He triumphed first,
and was richly rewarded throughout his
life. For 56 years, he was a Nobel
laureate—the youngest awardee ever—
and he enjoyed 50 of these years with his
wife, Alice Hopkinson, mayor of Cambridge and mother of his four children.
Nevertheless, there is great drama in
Bragg4s complex psyche, well captured
by Hunter, which influenced, and was
influenced by, the full sweep of science,
physics, chemistry, and biology in the
20th century.
The essential tensions in Bragg4s life
were his relationships with his father,
William Henry Bragg, and to a lesser
extent with Ernest Rutherford and
Pauling. Father and son collaborated
on the Nobel-winning research on crystal-structure determination using Xrays. But Bragg was jealous that his
father would be credited for his insights.
He frequently expressed this frustration,
and was sometimes niggardly in sharing
credit for work that was collaborative.
Bragg, as the first guest lecturer of the
Nobel Foundation in 1965, celebrating
the jubilee of the physics prize that he
shared with his father, felt it necessary to
remind the audience that he had not
been “just following in his father4s footsteps”. William Henry, for his part,
seems to be continually trying to
remain in the background so that his
son, Willy, could stand in the spotlight.
Days before his death, Bragg wrote to
his close friend Perutz: “I hope that
there are many things your son is
tremendously good at which you can4t
do at all, because that is the best
foundation for a father–son relationship”. This is an odd pronouncement,
stemming from a wish to have had a less
able father with a narrower shadow.
Unfortunately, Bragg never seemed to
appreciate his great fortune in having
grown up around X-ray tubes. When
Willy was six years old in Adelaide, he
badly fractured his elbow in a tricycle
- 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
accident precipitated by his brother Bob
(killed at Gallipoli with Henry Mosley).
Despite the fact that X-rays had been
discovered only in the previous year,
William Henry rigged up a radiographic
apparatus to help judge and set the
break, albeit imperfectly. This intervention, probably the first diagnostic use of
X-rays in Australia, is an extraordinary
foreshadow of their remarkable collaboration that, likewise, never set just
The Braggs left Australia in 1909.
William Henry took a professorship in
Leeds, as Willy began his studies at
Cambridge. Their historic experiments
began almost immediately on learning
of the discovery of X-ray diffraction,
only to be interrupted by World War I.
Bragg learned of his Nobel prize while
working as a sound ranger, using arrays
of microphones to pinpoint enemy gun
Now, world-famous, Bragg inherited
Rutherford4s professorship in Manchester after the war. He would later inherit
Rutherford4s positions in Cambridge in
1938 and at the Royal Institution in
1954. Rutherford had big shoes that
even the likes of Bragg found hard to
fill. Bragg4s sister Gwendy likened her
brother4s burden of following the charismatic Rutherford to that of a chamber
group, “however excellent”, standing in
for the full orchestra at the Albert Hall.
Bragg was not considered a bona fide
physicist by many of his subordinates.
The structure of the atom was at the
forefront of physics in 1919, and Rutherford and his student Bohr were the
atom4s chief architects. Bragg was considered a crystallographer, a term that
he viewed as pejorative. Bragg ultimately triumphed in Manchester on his
own terms, developing X-ray intensity
measurements and the 2D Fourier
series, and by the force of his good
nature—except where his father was
concerned—turned round his detractors. On his departure from Manchester,
the university senate passed a motion
that read: “By his kindness and modesty,
by the generosity of his appreciation of
the work of others, and by the ease with
which he could be approached, he made
himself the trusted friend of his staff, his
colleagues in research, and his students”. Bragg left the comfort of such
gracious senators only to relive the
Angew. Chem. Int. Ed. 2006, 45, 2332 – 2333
unfavorable comparisons with Rutherford when he ascended to the Cavendish
Chair of Experimental Physics at Cambridge University, the very top of the
“greasy pole of British physics”. Hunter
re-emphasizes that almost all of Bragg4s
great professional successes were oddly
qualified, and extracted psychic costs.
Again, Bragg ultimately triumphed
when his group ushered structural biology into being with myoglobin, hemoglobin, and DNA. His well-nurtured
Cambridge team of Kendrew, Perutz,
Watson, and Crick comprised half of the
1962 Nobel awardees, a spectacular
validation of Bragg4s life4s work. By
this time, Bragg had moved on to the
Royal Institution, succeeding not only
Rutherford but his father as well, masochistically inviting comparisons to
whom he consistently failed to measure
up. Yet again, according to Hunter,
“Bragg had taken up a poisoned chalice”. In a familiar pattern, he was at first
not welcome, but held firm, righted the
troubled institution, and on his 75th
birthday enjoyed the unraveling by his
team of the structure and function of
lysozyme, a crowning achievement for
X-ray analysis.
Bragg was never comfortable with
his command of chemistry, let alone
biology. He was a classical physicist who
failed to conquer quantum theory. Then,
suddenly there appeared Linus Pauling,
a chemistry encyclopedia, having mastered X-ray analysis and the new physics. Pauling bested Bragg on the structure of mica and on the alpha helix. He
Angew. Chem. Int. Ed. 2006, 45, 2332 – 2333
corrected Bragg4s structure of cyanite,
and generalized much of Bragg4s work
on silicate minerals in what have
become known as Pauling4s rules of
crystal packing. Bragg consistently
declined to engage Pauling in discussions of their common interests whenever they met. Was Bragg exercising his
famous decorum, or was he intimidated? Sometimes Bragg4s best and
worst traits worked in tandem. Did he
allow Perutz to pursue the folly of
hemoglobin because he was a courageous visionary, or because he was an
indifferent administrator who loathed
confrontation? Perhaps some of both.
Hunter4s Bragg is loveably human.
Light is a Messenger will appeal
especially to readers of Angewandte
Chemie, because it doubles as a history
of X-ray crystallography. Many scientific biographies fail to successfully integrate science and biography, or fail to
convey the substance of the science,
either because the authors lack the
command of the technical subjects or
because technical material will limit
readership. Hunter insistently leads his
readers through the foundation of
Bragg4s equation in classical optics, the
development of Fourier synthesis, and
solutions to the phase problem. Often
he enlists Bragg, a master of popular
exposition, in the service of explaining
difficult ideas. We learn that Bragg
invented many tools that are staples of
the contemporary crystallographer4s
education, such as the optical transform
and the bubble-raft model of crystal
dislocations. However, some of Bragg4s
important scientific contributions are
de-emphasized at the expense of the
main theme, the development of X-ray
analysis. The paper of Bragg4s that I
have studied most closely, “The Refractive Indices of Calcite and Aragonite”
(Proc. Roy. Soc. Ser. A, 1924, 105, 370–
385), which may well be the first attempt
to reckon the physical properties of a
crystal from the determined atom positions and physical first principles, is
dismissed as an excursion into “non-Xray means”. Occasionally, Hunter is
given to hyperbole. Illustrating the
“full rein” of Bragg4s “gifts for simplification” by a description of the structure
of mica as “two slices of bread with
butter in between” is the analogy that
any instructor would use before lunch.
But these are quibbles. All in all, Hunter
has synthesized the published record,
mountains of correspondence, and
dozens of interviews into a seamless
and admirable portrait of science and
In his last year, 1971, an ailing Bragg,
according to Hunter, encountered a
confident postdoc in front of a display
on crystal imperfections. The young man
asked “How much can I assume that you
know about diffraction?” Bragg replied
“a little”. Courtesy itself.
Bart Kahr
Department of Chemistry
University of Washington (USA)
DOI: 10.1002/anie.200485381
- 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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hunters, william, messenger, light, bragg, graeme, life, lawrence, science
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