ńňđ. 16
(âńĺăî 21)



10 – 4
tionary effect in science (especially biology) that it M spectral class
must rank with the telescope, optical microscope 3000 temperature (K)
25 000 10 000 6000
+2.0 colour index
0.0 +0.6
– 0.6
and spectroscope as an outstanding device. Like
these devices it has no universally agreed single dis-
coverer; claims and counter-claims have been Hertzsprung–Russell diagram – schematic colour-magni-
made, but the award of a Nobel Prize to Ruska in tude diagram for many stars. The Sun, spectral type G,
1986 for the discovery makes him a central figure. lies in the main sequence.
Rutherford, Ernest, 1st Baron Rutherford

correlate well with their spectral class, which is physics. In his last year there he invented a sensi-
indicative of surface temperature and related to tive radio-wave detector, just 6 years after Hertz
their colour. He displayed his findings on a dia- had discovered radio waves and in the same year
gram of absolute magnitude vs spectral class, now that Marconi began to use radio for practical
known as the Hertzsprung–Russell (or H–R) dia- purposes.
gram – Hertzsprung had obtained similar results a In 1895 he won a scholarship to Cambridge to
few years earlier but his publication in an obscure work under J J Thomson; he borrowed money for
journal had received little attention. Russell went his passage to England and soon began research on
on to suggest that the diagram represented an evo- the conductivity produced in air by X-rays, recently
lutionary path, with stars evolving into hot, bright discovered by Röntgen. He was J J Thomson’s first
blue-white giants and ending as cooler red dwarfs. research student. Rutherford became a professor at
Although this simple theory was soon abandoned, McGill University, Montreal 3 years later. Within a
the diagram has remained a key tool in astro- short period he greatly extended the foundations
physics. In the modern view, a star is formed from of nuclear physics, taking advantage of collabora-
a cloud of gas (mainly hydrogen) and dust which tion with the chemist Soddy and a good supply of
contracts through gravity, eventually becoming the costly radium bromide. They produced nine
dense enough for the heat developed by contrac- papers in 18 months.
tion to initiate nuclear fusion reactions which con- Radioactivity had been discovered in uranium in
vert its hydrogen into helium. Its place in the main 1896 by Becquerel, and in thorium by G C Schmidt
sequence, and its later fate, depend on its mass. A (1865–1949); Pierre and Marie Curie had discov-
star of the Sun’s mass will spend 1010 years in the ered two more radioactive elements, radium and
main sequence before new core reactions begin, polonium. Rutherford’s studies revealed (1898)
and the star becomes a red giant. The next stage is that the radioactive emission consisted of at least
that of a white dwarf, but for heavier stars it may two kinds of rays; those which were less penetrat-
explode as a supernova, leaving a neutron star. ing he called alpha rays (helium nuclei), and the
Russell also studied chemical abundances in the others beta rays (electrons); 2 years later he discov-
Sun (a yellow dwarf) from the solar spectrum, con- ered a third, and even more penetrating kind,
cluding in 1929 that hydrogen makes up 60% of the gamma rays (electromagnetic waves). Together
Sun’s volume, at the time a surprisingly large with Soddy he proposed in 1903 that radioactive
figure, but now known to be an underestimate by decay occurs by successive transformations, with
over 20%. different and random amounts of time spent
Rutherford, Ernest, 1st Baron Rutherford (of between ejection of each of the successive rays,
Nelson) (1871–1937) New Zealand–British physi- sometimes years and sometimes fractions of a
cist: founded nuclear physics. second. While the process is random, it is governed
Born near Nelson in New Zealand into a wheel- by an average time in which half the atoms of a
wright’s large family, Rutherford showed wide- sample would be expected to decay. This idea that
ranging ability at school, won a scholarship to atoms of some elements are not permanent, but
Canterbury College, Christchurch, and in his final can disintegrate, was then revolutionary.
years there concentrated on mathematics and A skilful set of experiments was then designed
with T Royds (1884–1955) to examine alpha rays;
having found that the mass and charge were cor-
rect for helium nuclei, this was finally proved by
sending the rays into an evacuated thin glass vessel
and observing the build-up of helium gas inside.
In 1907 Rutherford returned to Britain, and in
Manchester he extended his study of alpha parti-
cles, working with Geiger on the detector named
after him, and inventing the scintillation screen for
observing them. Geiger and E Marsden (1889–1970)
made the surprising discovery that about one in
8000 particles striking a gold foil was deflected
back from it. As Rutherford put it ‘... quite the most
incredible event that has ever happened to me in
my life ... It was almost as if you fired a 15-inch shell
at a piece of tissue paper and it came back and hit
you.’ Knowing that collision with a comparatively
light electron could not produce such a large
deflection, he deduced (1911) that atoms possess a
very small but massive nucleus at their centre,
holding all the positive charge to balance that of all
the electrons about them. This was the first correct
model of the atom, and Bohr developed it during a
Ernest Rutherford as the youthful professor of physics at
3-month visit by showing which electronic orbits
McGill University, Montreal.
Rydberg, Johannes

beta rays gamma rays
alpha rays
radioactive material



lead block photographic plate


When radiation from a radioactive source such as radium passes through a magnetic field, it is split into three types.
The gamma radiation (short X-rays) is undeflected and the alpha rays (helium nuclei) and beta rays (electrons) are
deflected in opposing directions.

Ru zi˘ ka, Leopold [rougitchka] (1887–1976)
would be allowed by the ‘old’ quantum theory
(which Planck had introduced in 1900). Croatian–Swiss organic chemist: devised the iso-
The First World War caused Rutherford to work prene rule.
on sonic methods for detecting submarines, but Ru˘i˘ka grew up in Croatia when it was part of
in 1919 he returned to his research on succeeding Austria-Hungary and, after an education in Ger-
J J Thomson as Cavendish Professor of Physics at many and Switzerland, he finally became professor
Cambridge. Another major discovery occurred in ZĂĽrich. In 1916 he began work on perfumes; one
within months: he observed that nuclei could be famous study concerned the costly perfume fixa-
made to disintegrate by artificial means, rather tives in musk (from a Himalayan deer) and civet
than waiting for their natural disintegration. This (from an African wildcat). He found that the key com-
work he did himself, as young men were not yet pounds, muscone and civetone, are cyclic ketones.
back from the war. Alpha particles striking atomic What was remarkable is that both contain large
nuclei, such as nitrogen, would knock out a proton rings of carbon atoms (16- and 17-membered respec-
to leave a different and lighter nucleus. Between tively). It had been thought that such large rings
1920 and 1924 Rutherford and Chadwick showed could not exist. In fact, Ru˘i˘ka’s work showed them
that most light atoms could be broken up by using to be stable, and he devised methods of synthesis. He
alpha particles. Chadwick’s later discovery of the also worked on steroids, specially the male sex hor-
neutron, and the nuclear disintegrations of heavier mones; his synthesis of testosterone made him rich
atoms achieved by Cockcroft and E T S Walton and he became a major collector of early Dutch
(1903–95) using a linear accelerator, owed much paintings. His work on terpenes led to the isoprene
to discussions with Rutherford. These and other rule, which proposes that terpenes have structures
major discoveries in his laboratory made 1932 a based on units of the five-carbon isoprene molecule,
‘marvellous year’ for nuclear physics. He also was joined head-to-tail (1920). In this form, or in its later
involved, together with M Oliphant (1901–2000) version (which proposes the biogenesis of these com-
and P Harteck, in the first nuclear fusion reaction pounds from isopentenyl pyrophosphate) the rule
(1934) by bombarding deuterium with deuterium has proved a valuable guide to structure. Ru˘i˘ka zc
nuclei to produce tritium. He had predicted the shared a Nobel Prize in 1939.
Rydberg, Johannes (Robert) [rüdberg] (1854–
existence of the neutron, and the deuteron, as early
as 1920. 1919) Swedish spectroscopist: early theorist on
Rutherford initiated and directed the beginnings atomic number.
of nuclear physics. He received the Nobel Prize for Educated at Lund, Rydberg stayed there for his
chemistry in 1908 and the simplicity and power of entire career, as professor of physics from 1901. He
his work gives him a place as one of the greatest was fascinated by Mendelayev’s periodic table of
experimental physicists of all time. In personality he the elements and he had the brilliant and valuable
was forceful, exuberant and enormously likable, intuition that the periodicity was related to atomic
with physicist friends worldwide, many of them spectra and atomic structure. Working on atomic
former students of his. He was not, of course, always emission spectra in 1890, he found a simple general
right; his response to a suggestion that nuclear formula for the frequency of some of the spectral
energy might one day be useful was that the idea was lines. He introduced the useful idea of wave num-
bers (1/λ, where λ is the wavelength); and showed
‘all moonshine’. But that was in the early 1930s; by
1936 he saw some prospect of useful atomic energy. that Balmer’s equation giving the frequencies of
Ryle, Martin

Ryle, (Sir) Martin (1918–84) British astronomer:
many lines in the hydrogen spectrum could be gen-
eralized in the form 1/λ = R(1/m2 – 1/n2). Within 30 produced first detailed map of the radio sky.
years successive spectral series were found fitting Ryle was a key figure in the development of radio
this formula, with simple integral values for n astronomy after the Second World War, following
and m; the Balmer series is that having m = 2 and n = the pioneering discoveries of Jansky and Reber. He
3,4,5 etc. The constant R is known as the Rydberg began a series of surveys at Cambridge in the 1950s,
constant. Rydberg himself never reached his goal culminating in 1959 in a definitive catalogue of
of relating spectra to atomic structure, but his the strengths and positions of 500 radio sources
view that a relation between structure and spectra (increased to 5000 in 1965). By using radio dishes
must exist was valuable and reached fruition separated by up to 5 km, Ryle was able to obtain a
with Bohr’s work on atomic structure in 1913, large effective aperture and to produce detailed
from which Rydberg’s formula emerges with a radio maps of areas of sky. In this way pulsars,
value of R calculated in excellent agreement with quasars and radio galaxies could be studied. In
experiment. showing that the distant parts of the universe
Rydberg’s study of the periodic table led him in appear different from the nearer parts, Ryle’s
1897 to see the importance of atomic number results supported the ‘Big Bang’ view of its origin
(rather than atomic weight), a view confirmed by (rather than a ‘steady-state’ theory) and led to
Moseley in 1913; and in 1906 he stated for the first major public disputes with Hoyle.
time that 2 ,8 and 18 (ie 2n2 where n = 1, 2, 3) are the He was honoured as Astronomer Royal (1972–4)
numbers of elements in the early periods. He also and shared the Nobel Prize for physics in 1974.
corrected the number of lanthanides to 32. (Portrait on p. 172)

Sabin, Albert (Bruce) [saybin] (1906–93) US virolo- of a public health subcommittee, and an energetic
gist and developer of an oral poliomyelitis vaccine. supporter of public health reforms.
Polish by birth, the Sabin family emigrated to the She was the first woman elected to the National
USA in 1921, and Albert Sabin studied at New York Academy of Sciences of the USA in 1925.
Sabine, Wallace Clement [sabin] (1868–1919) US
Medical School. During the Second World War he
devised vaccines for the US army, notably one physicist: the founder of architectural acoustics.
against dengue fever. After the war, working at the A midwesterner from a farming family, Sabine
University of Cincinnati, he attacked the problem did well as a physics student at Harvard and
of finding a safe and effective live attenuated vac- became an instructor there in 1890. Except for war
cine against polio. This disease was then a major work in the First World War (he was in effect the
problem, with 57 000 mainly young cases in the first chief scientist for the US Air Force, in 1917–18)
USA in 1952. J E Salk (1914–95) used culture meth- he never left Harvard. Some 5 years later Harvard
ods due to Enders to develop in the 1950s a dead president C W Eliot asked for his help: the acoustics
vaccine, killed by formaldehyde, which was widely of a major new lecture theatre were so bad as to
used despite the difficulty that it needed several make it useless. Little was then known of architec-
injections to give protection and was only 80–90% tural acoustics, but Sabine saw that such problems
effective. must arise from the size, shape, and materials of a
Sabin’s live vaccine was attenuated by culture in room, which affect the reverberation time. For
monkey kidney tissue and could be given by mouth speech this should be 1–2 s and for music about
as a single dose on a sugar lump. After trials with 25% longer. In the disastrous new theatre this time
volunteers in an Ohio reformatory, Sabin per- was 5.5 s, so that a speaker had the first and last
suaded the USSR to use it on a large scale in the late words of a sentence mingled. Since size and shape
1950s. It was quickly seen as better than Salk’s vac- are not easily altered, Sabine worked on the mate-
cine: the US public health service approved it in rials; he and two helpers spent many nights (after
1960 and the UK changed to Sabin’s vaccine in midnight, when the street was quiet) moving cush-
1962. The two men were highly competitive. Sabin ions from another large theatre to the disaster area,
continued to work on viruses, and was awarded the making tests, and returning them before dawn.
US National Medal of Science in 1970. Authority was dismayed by the delay and after 2
Sabin, Florence (Rena) [saybin] (1871–1953) US years demanded action; Sabine prescribed 22 hair-
anatomist and histologist: ensured the passage of felt blankets, and the place was rendered usable for
vital public health legislation. the next 75 years.
Florence Sabin’s mother died when she was 4 and He had devised an electrically-blown organ pipe
she was brought up largely by her uncle and grand- and drum recorder to measure reverberation time
parents. She went to Smith College and gained a BS at 512 Hz, and he now worked hard to develop a for-
degree in 1893, taught for 3 years to save money, mula that would allow calculation of the acoustics
then entered Johns Hopkins Medical School and of an unbuilt hall. With the aid of more massive
received the MD degree in 1900. After a year’s cushion-moving experiments, he derived, in 1898,
internship she became the school’s first woman fac- the Sabine formula: T = KV/Sa,where T is the time in
ulty member (1902) as an assistant in anatomy. She seconds for a sound to decay 60 decibels in the hall;
was appointed professor of histology in 1917, and K is a near-constant, inversely proportional to the
had a long association with Johns Hopkins. She speed of sound; V the volume of the room; S is the
worked on the lymphatic system, an area at the total area of all the room surfaces; and a is the aver-
time little understood. Her findings were that the age sound absorption coefficient of these surfaces
lymphatic channels represented a one-way system, (it varies from about 0.01 for plaster to 1.0 for an
closed at their collecting ends, where the fluids open window). With its aid, he was able to advise on
entered by seepage, and that they arose from pre- a projected new Boston Symphony Hall, opened in
existing veins; a view at first highly controversial 1900. However, musicians were critical of the
but proved correct. She also studied the origin of result; this was probably because an orchestra of 90
blood vessels and plasma and the development sounded thin in such a large hall; today with 104
of blood cells in embryos. In 1925 Sabin moved players the sound is fuller. From 1904 he was much
to the Rockefeller Institute in New York where in demand to advise on architectural acoustics, and
she remained until her retirement in 1938. Her his methods have been in use ever since.
Sachs, Julius von (1832–97) German botanist: pio-
research there was a study of tuberculosis and the
development of immunity to it. neer of plant physiology.
Retiring from research in 1938, she returned to Sachs was an assistant to Purkinje at Prague, and
her home in Denver and in 1944 became chairman after various posts in Germany became professor at
Saha, Meghnad

WĂĽrzburg from 1868. During nearly half a century ‘baryon asymmetry of the universe’ he proposed
he made massive contributions to plant physiol- that the original universe was neutral and had no
ogy, which before him was largely neglected. Much such asymmetry; the asymmetry built up following
apparatus and technique now familiar is due to the ‘Big Bang’, as a result of non-stationary processes
him, and his many pupils continued to develop the in the expansion of the early universe, together
subject. His early work was on stored nutrients in with his idea that protons are inherently unstable
(with a lifetime perhaps of 1050 years) and the fact
seeds and on the culture of plants in nutrient solu-
tions (hydroponics). He studied the uptake of min- that particle–antiparticle symmetry can be vio-
erals by plants, and the influence of temperature lated. This last fact had been shown experimentally
on plant growth, and discovered the ‘law of cardi- by others in 1964, but confirmation of the ultimate
nal points’. In 1861 he showed that photosynthesis instability of protons (whose decay would involve
actually occurs in chloroplasts and that the first disposing of three quarks) has yet to be observed,
‘visible’ product of carbon dioxide uptake is starch, perhaps because it is too rare an event: the pro-
posed proton lifetime is 1020 times the present age
deposited in the chloroplasts. He studied etiolation
and the formation of flowers and roots; and geo- of the universe.
tropism, phototropism and hydrotropism. When, During the 1970s the Soviet state became more
after about 1880, he moved more towards theory, repressive, while Sakharov became increasingly
he was less successful; and his authority held back active as a human rights supporter, especially after
new views and delayed discoveries. In his last years his marriage to his Jewish second wife in 1971. He
he strongly attacked Darwin’s views on evolution. was awarded the Nobel Peace Prize in 1975 but not
Saha, Meghnad (1894–1956) Indian astrophysicist: permitted to collect it, and his outright condemna-
demonstrated that elements in stars are ionized in tion of Soviet aggression in Afghanistan in 1979 led
proportion to their temperature. to his arrest in 1980 and exile in the ‘closed city’ of
The son of a small shopkeeper in Dacca, Saha was Gorky. In 1986 the new leader of the USSR,
educated at Presidency College, Calcutta and after- Gorbachev, recalled him to Moscow and to relative
wards visited Europe. He taught at the University of freedom, but by then he was exhausted and ill, and
Allahabad and in 1938 he was appointed professor in his remaining years his role as an advocate for
of physics at Calcutta. The absorption lines in the change in his country to a democratic multi-party
spectra of stars vary widely, with some showing state with a free-market economy was mainly sym-
only hydrogen and helium lines and others show- bolic. There is no doubt that for many years he had
ing numerous metal lines. In 1920 Saha demon- been a moral leader of the opposition to the com-
strated that this did not necessarily represent a munist regime in Russia, but he was never a direct
true variation in elemental composition, but a dif- and fully effective political figure and he was
ferent degree of ionization of the metal atoms, elected to the Congress of People’s Deputies only
which was related to temperature by Saha’s equa- shortly before his death.
Salam, Abdus (1926–96) Pakistani theoretical
tion for a monatomic gas. At higher temperatures
the metal atoms exist only in ionized form and the physicist: developed unified theory of the weak
absorption lines of neutral metal atoms become nuclear force and electromagnetism.
very weak. The proportions of the various ions of Salam’s early career shifted between Punjab
the same metal can be used to estimate stellar tem- University, Cambridge University and Lahore,
perature. Russell used Saha’s results to estimate where he became a professor at the Government
the amount of hydrogen in the Sun. College and Punjab University. He then lectured at
Sakharov, Andrei Dmitriyevich [sakarof] (1921– Cambridge (1954–6) and in 1957 became professor
89) Russian nuclear physicist and political activist. of theoretical physics at Imperial College of Science
The son of a physics teacher, Sakharov was born and Technology, London. Salam’s concern for his
and educated in Moscow, where he graduated in subject in developing countries led to his setting up
1942. From that time he worked in the Lebedev the International Centre of Theoretical Physics in
Institute of Physics, and from 1948 he was the key Trieste in 1964.
figure in developing the Soviet hydrogen bomb, Physicists recognize four basic forces in nature:
which was exploded in 1962, when he received the gravity, electromagnetism and the ‘strong’ and
highest honours from the state for this work. But ‘weak’ nuclear forces, which are active only within
he had long been concerned about the pollution nuclear range. In 1979 Salam won the Nobel Prize
effects of nuclear weapon testing, and after he for physics together with Weinberg and Glashow.
had published his underground essay Thoughts on Independently each had produced a theory explain-
Progress, Peaceful Co-existence and Intellectual Freedom ing both the ‘weak’ nuclear force and ‘electromag-
(1968) he was seen by the state as a possibly subver- netic’ interactions. This led to the prediction of
sive critic and was excluded from secret work. neutral currents, later found by experiments at
From 1965 Sakarov became interested in cosmol- CERN (European Organization for Nuclear Research)
ogy, and especially in the problem of ‘what was in 1973, and ‘intermediate vector bosons’, first seen
before the “Big Bang”?’ In a major paper of 1967 he in 1983.
Sandage, Allan Rex (1926– ) US astronomer:
attempted to explain why the universe is built of
protons, neutrons and electrons while the corre- made first identification of an optical object with a
sponding anti-particles are rare. To explain this quasar.
Sargant, Ethel

Sandage studied at the University of Illinois and Sanger, a physician’s son, graduated in Cam-
the California Institute of Technology before join- bridge in 1939 and researched there through his
ing the Hale Observatories, initially as an assistant career, on the staff of the Medical Research Council
to Hubble. Although radio galaxies had been dis- laboratories from 1951. In the early 1940s he
covered in the 1940s, it was some years before com- devised a method using 2,4-dinitrofluorobenzene
pact radio emitters (‘quasi-stellar radio sources’ (Sanger’s reagent) to label the amino acid at the
or quasars) were found by use of improved radio ‘free amino’ end of a protein chain. By combining
telescopes, and only in 1960 that the first strong this method with the acid or enzymic break-up of
compact radio source (3C 48) was matched with the longer protein chains to give shorter, identifi-
the position of an optical bright star, by Sandage. able fragments, Sanger was able to deduce the
Others were located in the 1960s, and M Schmidt sequence of amino acids in the chains of the pro-
showed they have massive redshifts, implying high tein hormone insulin; by the early 1950s he had
speeds of recession; this is now regarded as a defin- worked out the sequence of the 51 amino acids in
ing feature, rather than intense radio emission, its two-chain molecule and found the small differ-
which Sandage showed is absent for 90% of quasars ences in the sequence in insulins from pig, sheep,
(so the word is better now regarded as defining horse and whale.
‘quasi-stellar objects’). Typically quasars are bluish After he was awarded a Nobel Prize for this, in
objects, intensely luminous, double-lobed in shape, 1958, he moved on to the bigger problem of the
emitting synchrotron radiation which is variable structure of nucleic acids. These biological macro-
over weeks or months. molecules have double helical chains of nucleotides
Their origin and huge energy generation is mys- whose base sequence determines the information
terious: consensus opinion regards them as the carried by the genes. He worked first on RNA, whose
most distant visible objects in the universe, so that chains are of modest length, and then moved to
DNA, which has very long chains with up to 108
they are now seen as they were billions of years ago.
They are best explained as the cores of infant galax- units in a chain. Sanger used a highly ingenious
ies, having a massive black hole at their centre. The combination of radioactive labelling, gel elec-
Seyfert galaxies may represent a more mature trophoresis and selective enzymes which can split
stage. Intensive study of quasars continues; over or grow DNA chains at specific points.
1500 are now known. By 1977 he and his group were able to deduce the
Early in his career, working as Hubble’s successor full sequence of bases in the DNA of the virus Phi X
and refining his studies on the size and age of the 174, with over 5400 bases. Mitochondrial DNA, with
universe, Sandage showed that its expansion was 17 000 bases, soon followed. Such methods, by
accelerating less than had been thought: and in 1984, led to the full base sequence in Epstein–Barr
1956 he deduced an age for the universe (about 15 virus (EBV), whose genome (the complete set of
billion years) which has not been much changed by genes of an organism) is over 150 000 bases long.
later studies. For his nucleic acid work Sanger shared the 1980
Sanger, Frederick (1918– ) British biochemist: Nobel Prize and became the first to win two Nobel
pioneer of chemical studies on the structure of pro- Prizes for chemistry. His work has given new, sur-
teins and nucleic acids; the only double Nobel lau- prising and detailed knowledge of both proteins
reate in chemistry. and genes and has stimulated others in this field.
Santorio, Santorio (Ital), Sanctorius (Lat) (1561–
1636) Italian physician: applied physics to medicine.
A graduate of Padua, Santorio was physician to
the king of Poland for 14 years before returning to
Padua as professor of theoretical medicine in 1611.
He was a colleague of Galileo and Santorio’s med-
ical research was doubtless influenced by him:
Galileo worked on pendulums and thermometers,
but it was Santorio who used a pendulum to com-
pare pulse rates (no clocks were then available), and
he invented the clinical thermometer in 1612 and
later explained its use. He was the first to apply
quantitative methods in medicine and is best
known for his work on metabolism. He examined
the change in body weight with diet, sleep, activity
and disease, and for 30 years spent much time sus-
pended from a steelyard, weighing himself and his
solid and liquid input and output and deducing the
amount of ‘insensible perspiration’ lost through
the skin and lungs.
Sargant, Ethel (1863–1918) British botanist who
suggested a new interpretation of the relationship
between mono- and dicotyledons.
Frederick Sanger
Schaudinn, Fritz Richard

Schawlow, Arthur (Leonard) [showloh] (1921–99)
Ethel Sargant studied natural science at Girton
College, Cambridge (1881–5), and spent a year at US physicist: co-inventor of the laser.
the Jodrell laboratory at Kew Gardens training in Schawlow’s early work was at Toronto and his
research methods; in 1897 she visited several labo- postdoctoral research was with Townes at Colum-
ratories in Europe. For many years she cared for her bia University. The two remained in contact;
elderly mother and an invalid sister, and worked Schawlow married Townes’s sister. After 10 years at
first from a laboratory built in the grounds of her Bell Telephone Laboratories, a professorship for
mother’s house and later from her own home in Schawlow at Stanford followed in 1961.
Cambridge. She acted as research adviser to the Townes and Schawlow collaborated to extend the
Cambridge students of botany. maser principle to light by devising the laser,
She worked in the cytology and the anatomical although the first working laser was constructed by
morphology of plants, and her earliest work con- Maiman in 1960. (For an account of masers and
cerned the presence of centrosomes in higher lasers see Townes’s entry.) From the early 1970s
plants. She moved to a general study of oogenesis Schawlow used laser methods to simplify atomic
and spermatogenesis in Lilium martagon. Her work spectra, and to give improved values for basic phys-
demonstrating the existence of the synaptic phase ical quantities, such as the Rydberg constant, and
in living cells was published in the Annals of Botany extraordinarily precise values for the electronic
in 1896 and 1897. energy levels in the hydrogen atom. Schawlow
Sargant’s study of monocotyledonous seedlings shared a Nobel Prize in 1981 for his work on laser
resulted in her suggestion that both mono- and spectroscopy. A fellow prizewinner was N B
dicotyledons evolved from a common ancestral Bloembergen (1920– ) who had also devised
stock and that the single seed-leaf in the mono- improved masers and lasers, and used the latter to
cotyledon was homologous to the pair in the induce ruptures of specific chemical bonds. The
dicotyledon. These findings were discussed in third prizewinner was K M B Siegbahn (1918– )
A Theory of the Origin of Monocotyledons Founded on who, like his father K M G Siegbahn (1886–1978;
the Structure of Their Seedlings, The Evolution of Nobelist in 1924), worked with X-rays. The younger
Monocotyledons and The Reconstruction of a Race of Siegbahn studied the electron emission caused by
Primitive Angiosperms, published between 1903 and X-ray irradiation of molecules, and showed that it
1908. could be used as an analytical method.
Scheele, Carl Wilhelm [sheeluh] (1742–86) Swedish
She was elected a Fellow of the Linnean Society in
1904, and was the first woman to serve on its coun- chemist: a discoverer of chemical elements (chlo-
cil. At the 1913 Birmingham meeting of the British rine, and oxygen) and of many chemical compounds.
Association for the Advancement of Science she Scheele was trained as an apothecary, at a time
was elected president of the botanical section, when they made most of their own drugs and had
becoming the first woman to preside over a section. available a range of minerals, plants and simple
She was elected to an honorary fellowship of Girton equipment for chemical operations. He had a pas-
College in 1913. sion for chemical experimentation which is proba-
Schaudinn, Fritz Richard [showdin] (1871–1906) bly unsurpassed, but he was unlucky in that some
German zoologist and microbiologist: identified of his major discoveries were also made by others at
the organism responsible for syphilis. nearly the same time and they published sooner.
After starting university work as a student of Nevertheless his renown led to prestigious job
philology at Berlin, Schaudinn turned to science offers, which he refused, preferring to take a series
and specialized in zoology. During his short career of posts as an assistant apothecary. This left him
he worked in Berlin, especially on those protozoa able to experiment freely in his limited leisure time
(notably trypanosomes) that cause human disease. but the overwork, the poor conditions and the
He demonstrated the alternation of generations in absorption of hazardous chemicals may have led to
Foraminifera and worked out the life-cycle of the his early death.
Coccidiae (scale insect). He distinguished between Scheele first made the reactive green gas chlorine
the amoeba causing tropical dysentery (Entamoeba in 1774 from hydrochloric acid and MnO2, but the
histolytica) and its harmless relative Entamoeba coli fact that it is an element became known by Davy’s
which lives in the human intestinal lining; his work of 1810. Earlier, in 1773, Scheele had shown
work included experimental self-infection with that air is a mixture (of ‘fire air’ and ‘foul air’ as he
both organisms. His best-known discovery, made named its components) and he made oxygen in sev-
in 1905 with the dermatologist P E Hoffmann eral different ways (e.g. by heating HgO, or KNO3, or
(1868–1959), was of the pale threadlike undulating Hg(NO3)2; or MnO2 with H2SO4), but his book on this
spirochaete, now named Treponema pallidum, that did not appear until 1777. Before then, in 1774,
causes syphilis. Proof that this causes venereal Priestley had published his discovery of oxygen.
syphilis was not easy and its acceptance was The two men were similar in their skill as experi-
delayed. He also worked on malaria, proved an menters, their limited interest in theory and their
earlier guess that the parasite of human hook- adherence to the phlogiston theory.
worm enters through the skin of the feet, and Scheele made a variety of new acids in the 1770s
described many new animals first observed by him (phosphoric, molybdic, tungstic and arsenic acids)
on expeditions to the Arctic. as well as HF, SiF4, AsH3 and other reactive and very
Schrieffer, John Robert

toxic compounds. In the 1780s he made a number before he took a course in engineering and set up
of new organic acids, and fairly pure hydrocyanic his own workshop to build telescopes. He ground
acid (recording its taste!). His death at 43 is unsur- and polished the mirrors unaided, despite having
prising; he was a fanatical, prolific and probably lost his right arm in an accident with explosives.
unwise chemical discoverer. From 1926 he worked with the Hamburg Observatory
Schiaparelli, Giovanni Virginio [skyaparelee] staff; he was an alcoholic and died in a mental
(1835–1910) Italian astronomer: demonstrated that hospital.
meteors follow cometary orbits; observed Martian Before his work, large telescopes gave good
surface features. images only in the centre of the field; further from
Educated in Italy, Germany and Russia, Schia- the optical axis the images of stars showed a tail
parelli was director of the Milan Observatory for 40 (coma), which made making star maps difficult.
years. In 1866 he showed that meteors follow Schmidt designed in 1930 a reflecting telescope
cometary orbits and he identified the comets asso- with a spherical mirror, and with a smaller glass
ciated with the annual Leonid and Perseid meteor corrector plate in front, at the centre of curvature.
showers. In 1877 Mars made one of its closest The specially shaped aspherical plate provides the
approaches to Earth, enabling Schiaparelli to dis- telescope with good definition over a wide field at
cover its southern polar ice cap and to identify the low power. The telescope is usually used as a
direction of the axis of rotation. He also saw what camera, and it revolutionized optical astronomy.
he thought to be many dark lines crisscrossing From this design other catadioptric systems were
the planet and termed them ‘canali’ (channels). developed, such as the Maksutov, which has a
Schiaparelli himself believed these to be natural spherical meniscus corrector plate; it is compact
features, but the American astronomer Lowell and, like the Schmidt camera, combines useful fea-
suggested that they were irrigation features con- tures of reflecting and refracting telescopes.
Schmidt, Maarten [shmit] (1929– ) Dutch–US
structed by a Martian civilization (mistranslating
‘canali’ as ‘canals’), and thus started a long con- astronomer: explained optical spectra of quasars as
troversy that was only finally laid to rest by the due to their relativistic velocities.
Mariner space probes. Schmidt studied at the universities of Groningen
Schleiden, Jakob Mathias [shliyden] (1804–81) and Leiden, moving to the California Institute of
German botanist: a founder of cell theory. Technology in 1959. He became director of the Hale
Schleiden studied law in Heidelberg and prac- Observatories in 1978.
tised it in his birthplace, Hamburg; but his interest Following the identification of a quasar with a
in botany grew and he studied it at three universi- faint optical object with a highly unusual spectrum
ties, graduating at Jena in 1831. He lectured on in 1960 by Sandage, Schmidt studied the spectrum
botany there from 1839, and became a private of another optically identified quasar, 3C 273, and
teacher of botany after 1864. He was a skilful micro- discovered that the peculiarities of its spectrum
scopist, and from about 1840 good compound were caused by a massive redshift. The quasar
microscopes became available that were largely appeared to be receding at nearly 16% of the speed
achromatic. By 1880, thanks to improved designs of light, leading to what is normally the ultraviolet
by Abbe, oil-immersion objectives and better sec- part of the spectrum being observed in the visible
tioning and staining of specimens, the instrument region. Such high velocities are now interpreted as
reached a high point, with good resolution at mag- implying that quasars are very distant objects.
nifications up to 2000 Ă—. Plant cells (ie delimited Schmidt also found that the number of quasars
spaces within walls) had been observed two cen- increases with distance from Earth, a finding that
turies earlier by Hooke and others, but Schleiden’s provided evidence for the ‘Big Bang’ theory for the
studies convinced him of their importance, and by origin of the universe rather than the rival steady-
1838 he argued that all the various plant structures state theory.
Schrieffer, John Robert [shreefer] (1931– ) US
are composed of cells or their derivatives. He accu-
rately observed many features and activities in physicist: contributor to the BCS theory of super-
plant cells (eg cytoplasmic streaming); he recog- conductivity.
nized the importance of the nucleus in cell divi- After studying electrical engineering and physics
sion, but believed (wrongly) that new cells were at Massachusetts Institute of Technology and the
formed by budding from its surface. University of Illinois, Schrieffer started working for
Despite some uncritical attitudes and a quick his PhD under Bardeen. Initially he worked on elec-
temper his ability was great; he has been named as trical conduction on semiconductor surfaces, but
‘the reformer of scientific botany’ and he initiated moved to superconductivity as his thesis topic. A
Schwann’s work, which led to their joint creation close and fruitful collaboration with Bardeen and
of cell theory. He was a popular writer and lecturer Cooper gave rise to the BCS (Bardeen, Cooper,
on a wide range of matters and frequently engaged Schrieffer) theory in 1957, for which all three shared
in harsh combative debates on scientific theories. the 1972 Nobel Prize for physics (see account under
Schmidt, Bernhard Voldemar [shmit] (1879– Bardeen and Cooper). Schrieffer became professor
1935) Estonian–German optical engineer: designer of physics at the University of Pennsylvania in 1964.
of a novel telescope system. He has also done research on dilute alloys, ferro-
As a young man, Schmidt had several dull jobs magnetism and surface physics.
Schrödinger, Erwin

In the formulation of BCS theory Schrieffer con- 1925 by Born, Jordan and Heisenberg. The com-
tributed particularly to the generalization from bined theory, together with Pauli’s exclusion prin-
the properties of a single Cooper pair to that of a ciple, was used by Dirac to set out quantum
solid containing many pairs. Using a statistical mechanics in virtually complete form by the year’s
approach he found a suitable quantum mechanical end.
wave function that possesses the correct properties. While quantum mechanics had great predictive
Schrödinger, Erwin [shroedinger] (1887–1961) power and correctly described a wealth of previ-
Austrian physicist: the founder of wave mechanics. ously unexplained phenomena, Schrödinger saw in
Schrödinger was the son of a prosperous oilcloth it an awkward problem. Relating the wave function
manufacturer; he was educated by a private tutor to the particle (for example an electron) is difficult.
and by his father before going to the University of Born put forward the now-accepted explanation
Vienna. After his doctorate in physics in 1910 he that the wave amplitude describes the probability
joined the staff there. During the First World War of finding the particle at that point. Schrödinger,
he served as an artillery officer in an isolated fort, like Broglie and Einstein, opposed this, and
which gave him time to read physics; from 1920 he together they argued against a probabilistic quan-
spent short periods of time as a student at Jena, tum mechanics. Born’s view condemns physics to
Stuttgart, Breslau and ZĂĽrich. He began to produce describing only the likelihood of one event follow-
inspired work, and early in 1926 published a series ing another and is not able to definitely predict
of papers founding wave mechanics. As a result he cause and effect, as classical theories sought to do.
succeeded Planck as professor of theoretical Schrödinger had an informal manner much liked
physics at Berlin (1927), but chose to leave once by his colleagues and students; throughout his life
Hitler had assumed power in 1933. He moved to he travelled with walking-boots and rucksack, which
Oxford, but became homesick and returned to Graz caused him some problems in gaining entrance to
in Austria in 1936. When the Germans moved into the Solvay conferences for Nobel laureates.
Schwabe, Samuel Heinrich [schvahbuh] (1789–
Austria in 1938 Schrödinger fled for his life, set-
tling in Dublin and working at the Institute for 1875) German astronomer: discovered the sunspot
Advanced Studies created for him there, as a result cycle.
of the Irish Taoiseach (prime minister) de Valera’s Schwabe studied pharmacy in Berlin but,
mathematical interests. After 17 happy years in although he took over his mother’s pharmacy busi-
Eire, he became a professor at the University of ness, his real enthusiasm was in astronomy. When
Vienna, having refused to return until Soviet occu- he was 40 he sold the business and expanded to full
pation ceased. Shortly after arriving he became ill time his interest in astronomy. From 1826 he had
and never fully recovered. observed the Sun, projecting its image from a small
Schrödinger began to think about the conse- (2 inch/5 cm) telescope, in an effort to find a hypo-
quences of Broglie’s ideas when they were pub- thetical planet within the orbit of Mercury, hoping
lished in 1924. The latter had postulated that any to see it in transit across the Sun’s disc. In this way
particle has a wave associated with it and the prop- he became interested in sunspots, and observed
erties of the particle result from a combination of them daily for the rest of his long life.
its particle-like and wave-like nature. Schrödinger By 1843 he could announce that they appeared to
and Broglie both realized that a partial differential increase and decrease in number over a 10-year
equation called a wave equation would describe period. Later study of records by the Swiss
the motion of a particle, and deduced an equation astronomer J R Wolf (1816–93) confirmed this, and
of this type. This approach of considering the wave refined the periodicity to 11.1 years. At about the
function alone avoided the difficulties which Bohr’s same time J Lamont (1805–79) showed that the
old quantum theory of particles had involved, but Earth’s magnetic field also varied over about a 10-
was difficult to apply in practice. Schrödinger then year cycle, which alternated between weak and
used Hamilton’s method for describing particle strong, and that the trend of the cycle could also be
motion, and wrote this in wave form to give observed in Earth’s weather conditions and in
‘Schrödinger’s equation’. Unlike the previous equa- plant growth.
tion this ignores relativistic effects, but is much All attempts to observe a new ‘innermost planet’
easier to visualize (as standing waves around the have failed. Leverrier’s prediction of it in 1845 (he
nucleus) and to apply to real situations. When even named it Vulcan) was based on perturbations
applied to the hydrogen atom the equation gives in Mercury’s orbit, which by 1916 were deduced to
the correct energy levels of an electron in the atom, result from relativity effects.
without the ad hoc assumptions of Bohr’s model of Schwabe was the first to record Jupiter’s Great
the atom. These energy levels had been measured Red Spot, in a sketch of 1831.
Schwann, Theodor [shvahn] (1810–82) German
experimentally by using the lines observed in the
hydrogen spectrum. For this considerable achieve- physiologist: the major figure in the creation of cell
ment he shared the 1933 Nobel Prize for physics theory in biology.
with Dirac. Schwann went to school in Cologne and then
Schrödinger’s theory was known as wave mechan- studied medicine, graduating in Berlin in 1834. He
ics (1926), and was shown by Dirac to be mathemat- stayed there as assistant to J MĂĽller for 4 years,
ically equivalent to matrix mechanics, devised in when most of his best work was done. Early in this
Schwinger, Julian Seymour

period he studied digestion, and isolated from the the Fields Medal for mathematics in 1950 for major
stomach lining the proteolytic enzyme pepsin; it contributions to functional analysis. Increasingly,
was the first enzyme to be isolated from an animal mathematical physicists had needed to use the
Dirac delta function δ(x) to perform calculations
source. He went on to study fermentation and
showed in 1836 (independently of Cagniard de la with properties such as mass, energy, impulse, etc.,
Tour) that it was a result of the life processes of the concentrated at a single point or instant when x =
yeast cells; this led him to doubt the idea of sponta- 0. The delta function was treated as zero, unless x =
neous generation, and so he repeated and improved 0 when it was infinite; however the area under the
the experiments on this done by Spallanzani. He curve or integral was taken to be unity. The prob-
confirmed that no microorganisms appeared and lem was that this definition was insufficient to
make δ(x) a function in the strict sense, and it could
no putrefaction occurred in a sterile broth to which
only sterile air was admitted. His results did not not be manipulated mathematically. Schwartz suc-
prevent all belief in spontaneous generation, cessfully offered a generalized definition, which
which persisted until Pasteur’s work a few years was a rigorous function. Following this the delta
later. function has become a crucial element of many
Schwann’s work on fermentation led to quite important areas of mathematical physics such as
vicious (if comical) attacks in papers by the potential theory, partial differential equations and
chemists Liebig and Wöhler, to the extent that Green’s functions.
Schwarzschild, Karl [shvah(r)ts-shilt] (1873–1916)
Schwann saw no prospect of a career in Germany,
and in 1838 he emigrated to Belgium. There he German astronomer: predicted existence of black
became a mystic, solitary and depressed, and did holes.
little more in science. Schwarzschild became interested in astronomy
He had in 1838 discovered the Schwann cells com- as a schoolboy and published papers on binary
posing the myelin sheath around peripheral nerve orbits at 16. He became director of the Potsdam
axons; and he showed that an egg (whether large or observatory in 1909. Although an excellent obser-
small) is a single cell which when fertilized devel- vational astronomer who made great advances in
ops into a complex organism, a central idea in photographic methods, Schwarzschild’s lasting
embryology. Schwann’s most famous work, on the contributions are theoretical and were largely
cell theory, began through discussions with his made during the last year of his life. In 1916, while
friend, the botanist Schleiden, who had argued serving on the Russian front, Schwarzschild wrote
that all plant structures are cells. Animal tissues two papers on Einstein’s recently published gen-
are more difficult for the microscopist, being soft, eral theory of relativity, giving the first solution to
of low contrast and subject to rapid decay; and even the complex partial differential equations of the
more than plant cells, those of animals show great theory.
diversity. However, Schwann became convinced He also developed the idea that when a star con-
that animal tissues, like plants, are based on cells tracts under gravity, there will come a point at
and he became, with Schleiden, a principal advo- which the gravitational field is so intense that
cate for the cell theory, whose main points are that nothing, not even light, can escape. The radius to
(1) the entire plant or animal is made up of cells or which a star of given mass must contract to reach
of substances thrown off by cells; (2) the cells have this stage is known as the Schwarzschild radius.
a life that is to some extent their own; and (3) this Stars that have contracted below this limit are now
individual life of the cells is subordinated to that of known as black holes. As an example, the Sun
the organism as a whole. This theory, well defined would become a black hole if it shrank until its
in Schwann’s book in 1839, soon became dominant radius was only 2.5 km. The idea that a star with its
in biology; the cell has been seen ever since as a nat- mass sufficiently concentrated would emit no light
ural unit of form, of function and of reproduction, and so become invisible was foreseen in an unso-
at the microscopic level. This last dominance is phisticated way by Priestley and by Michell in the
summarized in Virchow’s phrase of 1855, ‘all cells 18th-c.
arise from pre-existing cells’. Virchow saw the Schwarzschild’s son Martin (1912–97), also an
study of affected cells as central to pathology and astronomer, was distinguished for his work on the
physiology. evolution of stars and galaxies. He was an early user
In shaping much biological research, the theory of balloons carrying telescopes to study the Sun, at
was beneficial; but it was unfortunate that heights, in 1959, of over 24 000 m/80 000 ft. He also
Schwann accepted the older Schleiden’s erroneous worked on the range of mass shown by stars: the
idea that new cells are formed by ‘budding’ from a range is now thought to be from one-100th that of
nucleus, which was to prove a false trail for many the Sun, up to about 65 solar masses.
Schwinger, Julian Seymour [shwingger] (1918–
biologists for half a century. Neither of them had
any notion of the formation of cells by division; and 94) US physicist: one of the founders of quantum
neither regarded the cytoplasm as important. electrodynamics (QED).
Schwartz, Laurent (1915– ) French mathematician. Schwinger was a graduate of Columbia Univer-
Schwartz was educated at the École Normale sity, New York, gaining his doctorate at age 20.
Supérieure and the Faculty of Science in Paris. Later Research with Oppenheimer at the University of
he became a professor at Nancy. He was awarded California at Berkeley followed and he joined the
Seaborg, Glenn Theodore

work on the atomic bomb during 1943–5. In 1946 nium and one by plutonium). Seaborg realized in
he became one of Harvard’s youngest-ever profes- 1944 that the series of elements from actinium (89)
sors. As a talented 18-year-old, he had published ele- onwards, could be classed within the periodic table
gant work on neutron scattering by magnetic as a new transition series, akin to the lanthanides;
materials. Even when he became world-famous he named the new series (now seen as numbers
among physicists, he remained rather unworldly 89–103) the actinides. They are all radioactive and
and preferred to work alone. the transuranic members (numbers 93 onwards)
Schwinger studied the papers by Dirac, Heisen- occur only in minute traces in nature. Seaborg and
berg and Pauli on the quantum mechanics of the McMillan shared the Nobel Prize for chemistry in
electron and attempted to produce a fully quan- 1951.
Sedgwick, Adam (1785–1873) British geologist:
tum mechanical electrodynamics that was consis-
tent with Einstein’s theory of relativity. Feynman, identified the Cambrian period.
Dyson and Tomonaga, as well as Schwinger, all After graduating in mathematics in 1808,
arrived independently at a correct theory within a Sedgwick remained at Cambridge for the rest of his
short time. The details of how electrons interact life, being appointed professor of geology in 1818.
with electromagnetic fields were then understood In 1835 he worked out the stratigraphic succession
for the first time. Feynman, Tomonaga and of fossil-bearing rocks in North Wales, naming the
Schwinger shared the 1963 Nobel Prize for physics, oldest of them the Cambrian period (now dated at
for this work on QED theory. 500–570 million years ago). In South Wales his
Thereafter Schwinger studied synchrotron radia- friend Murchison had simultaneously worked out
tion, which is the particular sort of electromag- the Silurian system, some strata of which over-
netic radiation emitted when a charged particle lapped with Sedgwick’s Cambrian system. In a cele-
changes speed or direction in a magnetic field. brated dispute the two were to argue about which
Seaborg, Glenn Theodore (1912–99) US nuclear system these common strata should be assigned to
chemist: discoverer of transuranic elements of the for almost 40 years; the matter was only resolved
actinide series. after their deaths when C Lapworth (1842–1920)
After he obtained his PhD in chemistry at the proposed in 1879 that the Upper Cambrian and
University of California at Berkeley, in 1937, Lower Silurian be renamed the Ordovician. Sedgwick
Seaborg worked with Lewis, joined the staff and and Murchison also identified the Devonian system
became professor of chemistry in 1945. He was to be in south-west England.
linked with the University of California for the rest Sedgwick’s skill was in palaeontology and stratig-
of his career, with absences on government work raphy, and his expert fieldwork greatly illuminated
during the Second World War and from 1961–71, the geology of the British Isles, despite his rejection
when he was chairman of the US Atomic Energy of uniformitarianism, theories of evolution and
Commission. ideas on ice ages. Darwin was a pupil of his and
The heaviest element that occurs in nature in fair became a friend, but this did not affect Sedgwick’s
quantity is uranium, with atomic number 92. In antagonism to his ideas, in large part on religious
the 1930s more than one research group bom- grounds.
Seebeck, Thomas Johann [zaybek] (1770–1831)
barded uranium with neutrons and examined the
results, and believed that elements heavier than Estonian–German physicist: discovered the ther-
uranium (‘transuranic elements’) had been formed. moelectric effect.
Then came the proposal in 1939 by Meitner and A member of a wealthy merchant family, Seebeck
Frisch that fission had occurred; the uranium went to Germany to study medicine. He qualified in
nucleus accepts the neutron and then breaks up to 1802 but thereafter spent his time in research in
give two or more nuclei of middle-range mass. But physics. His best-known work was done in Berlin in
in 1940 McMillan and P Abelson (1913– ) showed 1822, when he showed that, if a circuit is made of a
that transuranic elements can in fact be made; loop of two metals with two junctions, then when
some of the uranium nuclei struck by neutrons do the junctions are at different temperatures a cur-
not undergo fission but form a new element, the rent flows (eg if copper and iron are used and the
first to be discovered beyond uranium, which they junctions are at 0°C and 100°C, the circuit has an
named neptunium. From 1940 Seaborg became EMF of about a millivolt). Seebeck himself did not
involved in the work, found a new way of making grasp that a current was generated (he saw only
an isotope of neptunium (atomic number 93) and that a nearby compass needle was affected) and
went on to extend the research by making heavier called the effect ‘thermomagnetism’. Later it was
transuranic elements. Seaborg was a key figure in realized that whenever two different metals are in
the work which resulted in making and identifying contact, an EMF is set up. whose magnitude
nine of them, from plutonium (atomic number 94) depends on the temperature (the thermoelectric or
through to nobelium (102). In much of this a Seebeck effect). The effect is used in the thermo-
cyclotron was used to generate the bombarding couple for temperature measurement.
particles, and the work was directed in part to In 1834 the watchmaker J C A Peltier (1785–1845)
study the basic chemistry of the new elements, and found the converse effect: when a current is passed
in part to produce an atomic bomb (of the first two through a junction of two different conductors, a
of these, exploded in 1945, one was fuelled by ura- thermal effect occurs (heating or cooling, depend-
Shannon, Claude Elwood

ing on the direction of the current, ie whether the his native Buda in 1850 and a few years later
current adds to or opposes the EMF of the junction). became insane. He died from a septic finger infec-
The related Thomson effect is the development of tion of the same kind as his colleague in Vienna in
an EMF between the ends of a single metal rod 1847. Only after Lister’s success in antiseptic
when these ends are at different temperatures. surgery, in the 1870s, did antiseptic procedures in
These two effects are mainly of theoretical interest. midwifery become widespread.
Segrè, Emilio Gino [segray] (1905–89) Italian–US Puerperal fever was due to a streptococcal infec-
physicist: discovered the antiproton. tion, but this was not fully understood until the
Segrè attended school and became a university 1880s. Strangely, the advance in obstetrics could
student of engineering in his home city of Rome. have been made much earlier; the procedures to
Then in 1927 he changed over to physics and avoid the fever had been proposed by A Gordon
became the first research student to work with (1752–99) of Aberdeen in 1795 and by the literary
Fermi, obtaining his doctorate at Rome in 1928. He anatomist Oliver Wendell Holmes (1809–94) of
rose to hold a laboratory directorship in Palermo, Harvard in 1843, but the former was largely
but was dismissed for racial reasons by the Fascist ignored and the latter abused.
Serre, Jean-Pierre [sair] (1926– ) French math-
government in 1938. He took a post at the
University of California at Berkeley, and had an ematician: revolutionized homotropy theory.
active part during the Second World War in the A graduate of the École Normale Supérieure,
Manhattan Project to develop the atomic bomb at and a teacher at the universities of Nancy and
Los Alamos. Princeton, Serre held a professorship at the Collège
Segrè has the distinction of being involved in the de France from 1956. He was a contributor to the
discovery of three elements: technetium (1937), Bourbaki group.
astatine (1940) and plutonium (1940). Technetium H Cartan (1904– ) and Serre collaborated in
was made by using Lawrence’s cyclotron to irradi- recasting the theory of the complex variable in a
ate molybdenum with deuterium nuclei, and was new way, in terms of the branch of mathematics
the world’s first purely artificial element to be called cohomology theory. Serre also advanced
made. It is radioactive, and one isotope is much homotropy theory, particularly with reference to
used in medical diagnosis. the homotropy of spheres. As a result Serre was able
After the war Segrè joined in the hunt for a novel to link homotropy and homology theory for the
particle predicted by Dirac, the antiproton. In 1955 first time. The principal advantage gained was that
the Berkeley bevatron proton accelerator reached algebraic methods could then be used on the prob-
the threshold energy for producing antiprotons by lems of homotropy theory, producing powerful
proton–proton collision, 6 GeV. A beam of particles new results.
Seyfert, Carl Keenan [sayfert] (1911–60) US
obtained by proton collisions on a copper target
contained a few antiprotons, among many other astronomer: discovered Seyfert galaxies.
secondary particles. Segrè and his group devised an Seyfert studied at Harvard and subsequently held
apparatus and performed an experiment for detect- appointments at a number of American observato-
ing these antiprotons. Segrè and Chamberlain ries. In 1951 he became director of the Dyer
received the 1959 Nobel Prize for physics ‘for the Observatory at Vanderbilt University, Tennessee.
discovery of the antiproton’. In 1943 Seyfert discovered a class of spiral galax-
Semmelweis, Ignaz Phillip [zemelviys] (1818–65) ies that have small bright blue nuclei in relation to
Hungarian physician: pioneer in treatment of their spiral arms and that show broad emission
sepsis. lines in their spectra, indicating the presence of hot
Semmelweis graduated in medicine in Vienna in ionized gas. These Seyfert galaxies also emit large
1844 and stayed there to specialize in obstetrics, amounts of energy throughout the electromag-
working under J Klein in the General Hospital’s netic spectrum, from X-rays through to radio wave-
obstetric wards. There 10–30% of the women died lengths, and are believed to be related to quasars.
from puerperal (childbirth) fever. Semmelweis About 2–5% of all galaxies are Seyfert galaxies. In
studied the records and found that, in the clinic several ways Seyferts resemble quasars, but they
staffed by medical students, the mortality due to are less luminous; it is clearly possible that they are
the fever was three times that in the clinic staffed mature descendants of quasars.
Shannon, Claude Elwood (1916– ) US math-
by midwives. He also noted that the mortality had
risen since Klein’s appointment as head of the ematician: pioneer of communication theory.
unit. Then, when a colleague died in 1847 from a Shannon graduated from the University of
scalpel wound made in a post-mortem dissection, Michigan in 1936, going on to conduct research at
Semmelweis noted that his illness was closely simi- the Massachusetts Institute of Technology before
lar to puerperal fever. He deduced that something joining Bell Telephone Laboratories. In 1948, by
was conveyed on the hands of the medical staff quantifying the information content of a message
from the dissecting rooms to the patients. By insist- and analysing its flow, he established the founda-
ing that they washed their hands in disinfectant, tions of communication theory. Communication
Semmelweis reduced the mortality to 1%. However, theory is concerned with the best way to transmit
his success produced opposition rather than imita- messages, and the ways in which the signal may be
tion; discouraged and persecuted he returned to degraded or misunderstood. It is of central impor-
Shapley, Harlow

tance to the design of electronic circuits and com- Brattain in trying to produce semiconductor
puters, as well as to communications systems. devices to replace vacuum tubes. It had long been
Shannon also worked on the binary logic of digital known that some crystals (eg PbS) would act as rec-
circuits. He coined the term ‘bit’ for a unit of infor- tifiers (ie would pass current in only one direction).
mation (short for binary digit, 0 or 1). However, J A Fleming’s diodes (then known as
Shapley, Harlow (1885–1972) US astronomer: dis- valves in the UK) had replaced these. The new work
covered structure of our Galaxy. showed that germanium crystals were better recti-
The son of a farmer, Shapley was a teenage crime fiers, their effect depending on traces of impurity.
reporter on two newspapers before entering the Using a germanium rectifier with metal contacts
University of Missouri, intending to study journal- including a needle touching the crystal, they
ism; he soon changed to astronomy. In 1915, using invented the point-contact transistor (1947). A
Leavitt’s ‘Cepheid variable’ method of estimating month later Shockley developed the junction tran-
stellar distances, Shapley was able to provide the sistor (transfer of current across a resistor) which
first reasonable picture of the structure and size of uses the junction between two differently treated
our own Galaxy. He studied the distribution of parts of a silicon crystal; such solid-state semicon-
globular star clusters, by means of the Cepheids ductors can both rectify and amplify current. These
within them, and showed that they are concen- small, reliable devices led to the miniaturization of
trated disproportionately in the direction of circuits in radio, TV and computer equipment.
Sagittarius. This, he argued, must be the centre of Shockley, Bardeen and Brattain shared a Nobel
our disc-shaped Galaxy, and in 1920 he estimated Prize in 1956. From 1963 Shockley was a professor
the Sun to be about 50 000 light years from the of engineering at Stanford.
galactic centre. The overall diameter of our Galaxy After 1965 Shockley became a controversial figure
(the Milky Way) he believed to be about 300 000 through his support of the view that intelligence is
light years (both figures have since been shown to largely hereditary and that the rapid reproduction
be overestimates). However, he underestimated the of some racial groups can damage the intelligence
distances of some spiral nebulae, and better values of the overall population.
Sidgwick, Nevil Vincent (1873–1952) British theo-
were got later by Hubble. Shapley directed the Hale
Observatory at Harvard from 1921–52. retical chemist: systematizer of valence theory.
Sherrington, Sir Charles Scott (1857–1952) Sidgwick maintained a family tradition for intel-
British neurophysiologist: made important studies lectual virtuosity by getting a First in science at
of the nervous system. Oxford and then another First in classics 2 years
A Cambridge graduate in medicine, Sherrington later, a feat which has probably proved unrepeat-
studied also in Germany under Virchow and Koch, able. After further study in Germany he took a post
researched in bacteriology and afterwards taught in Oxford in 1901 and kept it for his lifetime. He
physiology at London and Liverpool, and at Oxford was an odd person in several ways; he looked
from 1913–35. He was a sports enthusiast, includ- middle-aged when young and changed only slowly
ing Sunday-morning parachute jumps (from the afterwards; his own experimental work was unim-
tower of a London hospital) among his many activi- portant; his best ideas came after he was 50; and his
ties. His main work was on reflex motor activity in great influence in chemistry is largely due to three
vertebrates, detailing the nature of muscle opera- books. In each of them, he brought together a mass
tion at the spinal level. He began with a close study of work by others, added his own ideas and pro-
of the knee-jerk reflex and its control, and the hind- duced a coherent and unified account that clarified
limb scratch reflex in the dog. A whole range of con- chemical ideas and pointed the way to new work.
cepts and words in neurology are due to him The first was his Organic Chemistry of Nitrogen (1910);
(including synapse, proprioceptor, motor unit, the second was the Electronic Theory of Valency (1927),
neuron pool and others) and his book The Integrative in which his own major contribution to chemical
Action of the Nervous System (1906) is a classic of neu- theory was to develop the idea of bonds in which
rology. He continued to be an active experimenter, one atom donated both electrons forming the cova-
especially on the reflex system, until 1935, publish- lent bond, a concept which gave new life to the
ing over 300 papers on this. He shared a Nobel Prize whole chemistry of metal complexes. His last book
with Adrian in 1932. He has been called ‘the was Chemical Elements and their Compounds (1950), a
William Harvey of the nervous system’. vast review that he was able to produce because of
Shockley, William Bradford (1910–89) US physi- the cessation of normal published research in the
cist: invented the junction transistor. Second World War. In British science he was distin-
The son of two American mining engineers, and guished by his pungent wit and his wealth, and in
born in London, Shockley was educated at the the USA he was for years the best-known British
California Institute of Technology and Massachu- scientist.
Siemens, Sir Charles William [zeemuhns] (1823–
setts Institute of Technology. He began work at the
Bell Telephone Laboratories in 1936, directed US 83) German–British engineer: co-inventor of the
anti-submarine warfare research (1942–4) and Siemens–Martin open-hearth steel furnace.
served as consultant to the secretary for war in 1945. Born Karl Wilhelm in Hanover, Siemens was
After returning to Bell Laboratories at the end of one of a large family of brothers (see below for
the war Shockley collaborated with Bardeen and E W Siemens), several of whom were outstanding
Smeaton, John

engineers. Charles came to England at the age of 20 De Sitter studied at the University of Groningen
and worked on a method of using waste heat from and, after a time at the Cape Town Observatory, was
blast furnaces to improve efficiency, by pre-heating appointed professor of astronomy at Leiden in 1908
the air blast. In 1861, together with his brother and director of the Leiden Observatory in 1919.
Frederick (1826–1904), he designed an open-hearth In 1916 Einstein published his theory of general
steel furnace, which both utilized waste heat and relativity and found a solution to the relativity
incorporated a gas-producer, which allowed the equations that yielded a static universe. De Sitter
use of low-grade coal as fuel. By the end of the 19th- showed soon afterwards that there was another
c more steel was produced by this method (the solution, an expanding universe that contained no
Siemens–Martin method) than any other. Frederick matter, the de Sitter universe. In 1927 Lemaître
Siemens used a similar furnace in glass manufacture. and Friedmann both found a further possible solu-
Siemens, (Ernst) Werner von [zeemuhns] (1816– tion, an expanding universe containing matter.
92) German electrical engineer: developed electric- Soon afterwards it was shown that a transforma-
ity generation through application of the ‘dynamo tion of the de Sitter universe yielded a similar,
principle’. but mathematically much simpler, solution now
Siemens was the eldest of the four Siemens broth- known as the Einstein–de Sitter universe.
Slipher, Vesto Melvin (1875–1969) US astronomer:
ers and was educated at LĂĽbeck, and later at the
army engineering school in Berlin, where he was discovered the general recession of other galaxies
imprisoned for duelling. His interests were wide- from Earth.
ranging – electroplating, discharge tubes to gener- Slipher studied at the University of Indiana, and
ate ozone, a standard of electrical resistance using then spent over 50 years working at the Lowell
mercury, and electrolytic refining, to name a few. Observatory, Arizona, becoming its director in
He made several innovations to existing tele- 1926.
graphs, including seamless insulation for the wire, Slipher used spectroscopic techniques to mea-
which enabled the company he founded (Siemens sure the very small Doppler shift in light reflected
& Halske, 1847) to become a leading supplier of from the edges of planetary discs, thereby deter-
such systems, including the London–Calcutta line mining the periods of rotation of Uranus, Jupiter,
in 1870. In 1867 he revolutionized electricity gen- Saturn, Venus and Mars in 1912. He extended his
eration by using self-generated electricity to power methods to spiral galaxies, discovering that the
electromagnets (the ‘dynamo principle’), doing Andromeda galaxy is approaching our own Galaxy
at a speed of about 300 km s –1, and went on to mea-
away with the expensive permanent magnets pre-
viously used in such generators. This enabled his sure similar radial velocities for a further 14 spiral
company to become a pioneer in the fields of elec- galaxies, almost all of which are receding from the
tric traction and electricity generating equipment. Earth, and at at even greater speeds. His results
The SI unit of electrical conductance, the siemens later led Hubble to propose that all galaxies (out-
(S), is named after him. side the Local Group, which includes the Andro-
Simpson, Thomas (1710–61) British mathema- meda galaxy) are moving away from one another at
tician: contributed to calculus. velocities proportional to their separation.
Smeaton, John (1724–92) Pioneer of British civil
Simpson’s life involved a series of strange
episodes, but his total contribution to 18th-c math- engineering and of the use of models in engineer-
ematics is substantial. Growing up in the weaving ing science.
trade in the Midlands, he married at 20 a widow of A youthful enthusiasm for mechanisms led
40 (who outlived him, and drew a Crown pension Smeaton to train as an instrument maker and to
for his work until her death at 102). After seeing a leave Yorkshire for London, where he opened his
solar eclipse Simpson became obsessed by astrology own shop and where he could attend meetings of
and soon acquired some local good reputation in it, the Royal Society. In the early 1750s he improved
but this changed when he ‘raised a devil’ from a girl the air-pump, and also devised a pyrometer which
who then had fits, and the Simpsons left the area he used to measure the thermal expansion of mate-
hurriedly. In London he combined weaving and rials. Realizing that dock and harbour projects
mathematics, and his reputation in the latter offered more interest and profit than small-scale
secured him the professorship at Woolwich in 1743 work he toured such projects in the Netherlands,
and fellowship of the Royal Society in 1745. He was and in 1756 he was appointed to plan and build a
also editor of The Ladies Diary. He wrote on calculus, replacement lighthouse at Eddystone. The result
probability, statistics, geometry and algebra, but was so successful that the design and shape (based
his most enduring result is the method for finding on the trunk of the oak tree) have been much used
the area under a curve known as Simpson’s rule. ever since; and Smeaton had a prosperous career in
The result is exact if the curve is parabolic, and can dock, harbour and canal work. He described him-
be used as a close approximation in other cases. He self as a civil engineer (as distinct from the familiar
also devised a method for finding the volume of any military engineer) and he effectively created civil
solid bounded by planes, if two of them are parallel. engineering in the UK. He gave it a scientific basis;
Sitter, Willem de (1872–1934) Dutch cosmologist he had a clear view of the concepts of momentum,
and mathematician: proposed expanding universe energy, power and work, and he used models to
solution to equations of general relativity. elucidate problems with windmills and water-
Smith, Hamilton

wheels. For the latter, using a two-metre wheel and published his work on Texas cattle fever, showing
a moveable reservoir, he showed by 1759 that an that it is transmitted by a tick. The complex cycle of
overshot wheel was twice as efficient as an under- transmission he had carefully worked out was
shot wheel and that power loss (which he esti- doubted by many, but was never refuted; it led both
mated) was mainly due to turbulence. He also to control of the fever and to easier acceptance,
improved steam engines (again using models) and within 10 years, of ideas on the place of the mos-
he devised the roller-chain, which is valuable in quito in human malaria and yellow fever. In 1895
heavy engineering, and is most familiar on bicycles. he moved to Harvard and in 1914 to the Rockefeller
Smith, Hamilton (Othanel) (1931– ) US molecu- Institute, developing his work in animal pathology
lar biologist: isolated and studied restriction and in parasitology. He was an austere, hardwork-
enzymes. ing and self-effacing person; many of his peers
Smith graduated in mathematics in 1952, and in thought him comparable as a scientist with Koch,
medicine in 1956 at Johns Hopkins University, but he carried little fame in the minds of the mass
where in 1973 he became professor of microbiol- of his countrymen.
Smith, William (1769–1839) British geologist and
ogy. In the early 1970s he obtained an enzyme from
the bacterium Haemophilus influenzae (the strain surveyor: pioneer of geological mapping; proposed
later known as Hind II) that cleaved DNA at specific principle of superposition.
sites in relation to the sequence of bases. An early The son of a blacksmith, Smith became a canal
example of such a restriction enzyme had been surveyor, an occupation which gave him ample
obtained in the 1960s from Escherichia coli by W opportunity to study the varying geology of much
Arber (1929– ), and Smith confirmed and ampli- of England and Wales. He discovered that geologi-
fied this work before extending it to Hind II. By the cal strata could be reliably identified at different
later 1970s Smith and other workers, especially D places on the basis of the fossils they contained,
Nathans (1928– ) (who collaborated with Smith in and he also proposed the principle of superposition
some of the research) had isolated many such – that if a stratum overlies another then it was laid
enzymes. By allowing the controlled splitting of down at a later time. In 1815 he published the first
genes to give genetically active fragments, the stratigraphic map of England and Wales, at a scale
restriction enzymes allowed the possibility of of 5 miles per inch, following this with more
genetic engineering and of DNA sequencing to be detailed geological maps of over 20 counties.
developed. Smith, Arber and Nathans shared a Business difficulties after 1812 caused him to sell
Nobel Prize in 1978. his fine collection of 2000 fossils to the British
Smith, Michael (1932– ) British–Canadian bio- Museum but he got only £600. Never a theorist, his
chemist. relationship with the academic geological estab-
Born in Blackpool, UK, and educated at lishment was cool until late in his life, when he was
Manchester and the University of British Columbia, awarded the Geological Society’s highest honour,
he returned to the latter as professor of biochem- in 1831. He is now seen as ‘the father of English
istry in 1970. By 1978 he had devised a method of geology’ or more precisely as the founder of strati-
‘site-specific mutagenesis’ which allows mutations graphical geology.
Snel or Snell, Willebrord (1580–1626) Dutch physi-
to be induced at specific locations on genes. The
value of this is the fact that the resulting altered cist: discovered law concerning refraction of light
genetic code both gives information and leads to passing between media.
production of a new enzyme or protein, with novel Snel studied law and mathematics in a number of
properties. Older methods for inducing mutations European universities and in 1613 succeeded his
(radiation or mutagenic chemicals) gave random
mutations, yielding outcomes hard to interpret.
Smith shared the Nobel Prize for chemistry in
1993 with Kary Mullis.
Smith, Theobald (1859–1934) US microbiologist:
studied modes of transmission of cattle diseases.
Smith graduated in medicine in 1883; he chose
not to enter medical practice but to move into vet-
erinary work in the new US Bureau of Animal
Industry founded to combat infectious diseases in
farm animals. At his parents’ home German was
spoken, and young Smith’s fluency in it gave him
the advantage of being able to read the reports of
Koch and Ehrlich. Smith became the leading
American bacteriologist of his generation and the
first of distinction not to be trained in Europe. His
successful studies on the nature and control of
animal diseases began with his work on hog
cholera in 1889; in 1896 he distinguished between
bovine and human tubercle bacilli; and in 1893 he William Smith aged 69
Soddy, Frederick

Snyder, Solomon Halbert (1938– ) US pharma-
father in the new university of Leiden, as professor
of mathematics. He continued to publish transla- cologist: suggested existence of endorphins.
tions of mathematical work, but also became Educated at Georgetown University, Snyder
involved in geodesy, and has been described as ‘the worked at Johns Hopkins University from 1965. His
father of triangulation’. Starting with his own work which led to the discovery of the body’s nat-
house, and with the spires of town churches as ref- ural pain relievers, the endorphins, began with the
erence points, he soon mapped a substantial local knowledge that some drugs are effective in very
area. His best-known discovery, Snel’s Law, or the small concentration; thus the synthetic drug etor-
second law of refraction of light waves, was proba- phine (an analogue of morphine) relieves pain in
bly made in about 1621 after much experimenta- doses of only 0.0001 g. To be so effective, the drug
tion. In modern form, it states that for light passing must act on some highly selective receptor sites,
from one isotropic medium to another, the ratio of and Snyder and Candace Pert née Beebe (1946– )
the sine of the angle of incidence to the sine of the used morphine-like drugs with radioactive labels to
angle of refraction is constant for light of a partic- locate these sites. Success in a difficult search came
ular wavelength; ie sin θ1/sin θ2 = constant. The law in 1973 when they reported that receptor sites are
can be deduced from Fermat’s principle. It is found located in the mammalian limbic system, which is
that the value of the constant is equal to the ratio of in a region in the centre of the brain associated
the velocity of light in material (1) to that in mater- with the perception of pain. Clearly these receptors
ial (2), and this is known as the relative refractive have not evolved in order to accept synthetic drugs,
index. and their existence implies that natural morphine-
Snow, John (1813–58) British physician: pioneer of like substances must also exist. Within a few years
anaesthesiology and epidemiology. such substances, endorphins, were found by other
As a very young medical apprentice Snow was workers; they are highly potent analgesics (pain-
sent to Sunderland to work on victims of England’s relievers) and are now known to be peptides formed
first cholera epidemic, which entered through that in the pituitary gland. Their existence may be rele-
seaport in 1831. The disease was not curable, and vant to the analgesia obtained in acupuncture.
Soddy, Frederick (1877–1956) British radio-
was often fatal, and the experience gave Snow an
interest in cholera that led him to study its epi- chemist; proposed theory of radioactive decay
demiology in the London outbreak of 1854. He was (with Rutherford); pioneer theorist and experi-
then practising in Soho; at that time Pasteur’s menter in radiochemistry.
work on microorganisms had not appeared and the The youngest of seven children, Soddy grew up to
cholera vibrio was not to be described by Koch until become a forceful, talented and eccentric individ-
1884. Snow believed, however, that the disease was ual. After graduating in chemistry from Oxford, he
due to a living, water-borne organism, he had sen- found a job as demonstrator at McGill University in
sible views on disinfection and he surveyed the inci- Montreal. Rutherford was there as professor of
dence of cases and their relation to water supply, physics, and his work needed a chemist. Together
concluding that faecal contamination of Thames during 1900–03 they offered a brilliant and simple
water was a major culprit. A plot of cases in his own answer to the question: what is radioactivity? Their
parish pointed to the Broad Street pump as a focus; disintegration theory proposed that heavy atoms
a sewer pipe passed close to its well. Snow per- are unstable; that such an element could undergo
suaded the council to remove the pump handle, spontaneous atomic disintegration, losing some
and dramatic improvement followed. From then mass and charge from its atoms and forming a new
on, contamination of water by faeces was seen to be element. The process could recur, so that a series of
a key factor in the spread of cholera. A tavern, the such changes occurred. They went on to predict
‘John Snow’, now marks the place of the pump. that helium gas should be a decay product of
From 1840 Snow had been interested in the phys- radium. In 1903, working with Ramsay in London,
iology of respiration and so, when anaesthetic Soddy used 52 mg of radium bromide, collected gas
inhalation methods came into the UK in 1846, in from it and showed this to contain helium.
the form of knowledge of the use of diethyl ether In 1913, Soddy gave the clearest of the statements
((C2H5)2O) by dental and general surgeons in the of the radioactive displacement law that emerged
USA, Snow was well placed to experiment on the about that time: that emission of an alpha-particle
new technique. He devised an apparatus for its use (helium nucleus) from an atom reduces its atomic
which gave proper control, and divided the stages number by two; whereas the emission of a beta-
of anaesthesia into five degrees. In 1847 J Y Simpson particle (an electron) increases the atomic number
(1811–70) introduced trichloromethane (chloro- by one.
form, CHCl3) as an anaesthetic in obstetrics; again, It was Soddy who gave the name ‘isotopes’ to
Snow applied physiological principles and devices atoms with the same atomic number (and there-
to its use, and became an expert operator with it fore the same chemical properties) but differing in
and the first specialist anaesthetist. As such, he was mass. In 1920 he foresaw their value in finding the
called to give it to Queen Victoria in 1853 for the age of rocks; back in 1906 he had foreseen the use
birth of her seventh child, Prince Leopold, and her of atomic energy from uranium, which he also
use of it gave the procedure respectability and did lived to see (1945). In 1919 he was appointed pro-
much to overcome religious and medical prejudice. fessor in Oxford. He was frustrated there in his
Somerville, Mary

efforts to change chemical teaching and research She published on astronomy, physics, mathematics,
arrangements, and his interest in chemistry faded chemistry and geography.
after his Nobel Prize award (1921). His new concern Her work began when Henry Brougham asked her
was for political and economic schemes which to translate Laplace’s Mécanique céleste for his
would ensure that the benefits of science became Society for the Diffusion of Useful Knowledge. It
widely available, but he was unsuccessful as an was said that perhaps 20 men in France and 10 in
advocate for his ideas. England could read and understand Laplace’s
Somerville, Mary, née Fairfax, formerly Greig work. Somerville translated, condensed and sim-
(1780–1872) Popular writer on scientific subjects. plified it, and her Mechanism of the Heavens was pub-
Mary Fairfax was born in Jedburgh, Scotland, the lished in 1831. Its high level of mathematics reduced
daughter of an officer in the Royal Navy. She had its general sale. However, it became the recom-
little education, but taught herself French, Latin mended reading for mathematical students at
and Greek late at night to avoid parental criticism. Cambridge and was a standard text for the rest of
Introduced to algebra by a ladies’ magazine article, the century. She had popular success with On the
she began her mathematical education by studying Connexion of the Physical Sciences (1834), in which she
Euclid’s work, smuggled to her by her younger stressed the increasing interdependence of the vari-
brother’s tutor. Her parents objected to her math- ous branches of science, covering physical astron-
ematical studies and removed the candles so that omy, mechanics, magnetism, electricity, heat and
she could not read at night, so she memorized the sound. In a later edition she repeated a suggestion
problems and worked them in her head. current among astronomers that analysis of the per-
This self-education was halted in 1804 with her turbations of Uranus might yield the orbit of an
first marriage but, widowed after 3 years, she unseen planet. Adams, while an undergraduate, read
returned to Scotland and renewed her studies. her comment and computed the orbit of the hypo-
William Wallace, professor of mathematics at thetical planet, later to be found and named as
Edinburgh University, taught her further math- Neptune. Her third book Physical Geography (1848)
ematics and she studied Newton’s Principia. Her surveyed geology, topography, hydrography, meteor-
second husband, William Somerville, a former ology, ocean-ography, geographical botany and
army doctor, approved and encouraged her scien- zoology and became her most popular book; it was
tific interests. They moved to London and she used widely as a textbook. In 1869 Somerville
began to study current work in mathematics and received the Victoria Medal of the Royal Geographical
astronomy. Through her husband, a Fellow of the Society. After her death one of the first women’s
Royal Society, she met the major international colleges in Oxford was named in her memory.
Sommerfeld, Arnold [zomerfelt] (1868–1951)
scientists, who appreciated her ability. The
Somervilles were popular hosts and she combined German physicist: developed Bohr’s theory of
caring for her six children with her studies, enter- atomic spectra.
taining, socializing and writing. Educated at Königsberg, Sommerfeld spent most
Mary Somerville, able to understand and discuss of his career at Munich. He worked on a variety of
recent scientific developments with researchers, problems, including gyroscopes, X-ray and electron
and sometimes to suggest useful directions for diffraction and radio waves, but his well-known
future investigation, was ideally placed to write in work is especially on the theory of atomic spectra.
the field of popular science. Maxwell said of her Here he developed Bohr’s theory of atomic struc-
that she ‘put into definite, intelligible and commu- ture, replacing the idea of circular electron orbits
nicable form, the guiding ideas that are already by elliptic orbits (with the nucleus at a focus) and
working in the minds of men of science… but which introducing a new azimuthal quantum number;
they cannot yet shape into a definite statement’. the ellipticity should result in relativistic effects
being shown in the fine structure of atomic spec-
tra, as was confirmed in some detail by F Paschen
(1865–1947) the next year (1916). Sommerfeld was
influential in physics not only for his application of
relativity and quantum theory to the understand-
ing of a variety of spectra (X-ray, atomic and molec-
ular spectra) but through his pupils, who included
Bethe, Debye, Heisenberg, Heitler and Pauli.
Sorby, Henry Clifton (1826–1908) British geologist
and metallurgist: created petrological microscopy
and metallography.
Sorby was born and lived in Sheffield, Yorkshire,
then a town and dominated by steel-, tool- and cut-
lery-making. His family had been cutlers since the
16th-c, but the business was sold in 1844; as a
result, Sorby was wealthy, allowing him to become
an archetypal Victorian gentleman-amateur scien-
tist, with wide-ranging interests largely in geology
Mary Somerville
Panel: The entry of women into chemistry in Britain

THE ENTRY OF WOMEN INTO lations, Marie Lavoisier rescued her husband’s papers
CHEMISTRY IN BRITAIN from his killers, preventing their suppression or incor-
poration in others’ work, printed them at her own
Any amateur’s participation in science before 1800 expense and presented them to eminent scientists
was gained through public lectures, membership of around Europe.
an appropriate society, with its lectures and publica- MARIE CURIE had her own well recorded struggles.
tions, and the availability of basic instruments and a Together with PIERRE CURIE and HENRI BECQUEREL she
home laboratory. HUMPHRY DAVY’S lectures at the was awarded a Nobel Prize for physics, and later the
Royal Institution created a large new audience of unshared Nobel Prize for chemistry. The possible
potential scientists. Among them was JANE MARCET, applications of radium as a treatment for cancer as
who found that she needed help in understanding the well as the value of X-rays and the novelty of a
lectures and in following the discussions. With her woman scientist made her a public figure and a
husband, a physician and Fellow of the Royal Society source of encouragement for those women who
whose hobby was chemistry, she lived among the sci- wished for a scientific career.
entific circle in London. She decided to share her new The opening of universities to women in the later
knowledge with others struggling to understand the part of the 19th-c gave them the opportunity to work
public lectures, and Conversations on Chemistry in a laboratory, but to gain an opening in the male-
(1805) was the result. This was an immense success dominated world of research in physical science often
both in Britain and in Europe and the USA, and went required the assistance of men in the field. The bio-
into 16 updated editions. Later, MARY SOMERVILLE was chemist F G HOPKINS provided research places for
to continue the explanation of science to amateurs women in his biochemical laboratory in Cambridge,
with her very successful book The Connexion of the despite much criticism. In the 1920s and 1930s
Physical Sciences (1835). almost half the research places in his laboratory went
The great interest in science generated in the early to women. Not surprisingly, it was to his laboratory
19th-c did not result in active participation by that the women trained in chemical science gravi-
amateur female chemical scientists. Unlike those tated, as well as the biologists. Similarly, they went
women interested in astronomy, the biological sci- to the Cambridge laboratories of Sir Michael Foster
ences or geology, who followed their own research (1836–1907), the physiologist, who provided
and published in the appropriate journals of provin- research places and to the Cavendish (Cambridge
cial and national scientific societies, there appear to physics) laboratories of W H AND W L BRAGG, who also
be no papers submitted by women to the British sci- enabled women to find places. Another enabler was
entific journals on chemical subjects before the entry ERNEST RUTHERFORD. The early women in chemical
of women into universities. sciences tended to be in biological, physical and
In Britain Elizabeth Fulhame, about whom little is inorganic chemistry rather than organic chemistry.
known, appears to be the first female independent These early enablers may have had an influence in
researcher in chemistry. Her interest began with a the flow of women into biological sciences. In the
search for a method of depositing thin layers of metal USA women at first researched mostly in applied
on cloth and paper. She enthused over LAVOISIER’S analytical chemistry.
new theory of combustion and devised her own vari- Many of the early British women biochemists went
ation on it. Her ideas on combustion, although erro- into teaching and the administration of the women’s
neous, show strange pre-echoes of modern Gaia colleges; the pressure to do so must have been great.
theory: she wrote that her ideas ‘may serve to show One such was Marion Greenwood (1862–1932), who
how nature is always the same, and maintains her obtained Class 1 in both parts of the Cambridge
equilibrium by preserving the same quantities of air Natural Sciences Tripos Examinations of 1882 and
and water on the surface of our globe’. Her Essay on 1883 and became demonstrator in physiology at
Combustion (1794) was reprinted in the USA in 1810 Newnham College, Cambridge. She researched in
and she was elected an honorary member of the Foster’s physiology laboratory on the role played by
Philadelphia Chemical Society. acid in protozoan digestion, and became head of the
Access to laboratory materials may have been as women’s laboratory (the Balfour Laboratory) in 1890.
difficult for the potential female chemists as was Eleanor Balfour Sidgwick (1845–1936) had an
access to instruments for the female astronomers. interest in mathematics, encouraged by her mother,
MARIE LAVOISIER was introduced to work in the labo- and studied with her brother-in-law John Strutt (later
ratory as an assistant to her husband in much the LORD RAYLEIGH). She was also interested in education
same way as CAROLINE HERSCHEL was introduced to for women and in the new women’s colleges. She
the telescope as an assistant to her brother. Apart was first secretary to the principal of Newnham and
from her help to her husband in notetaking and trans- assisted in the teaching there and became treasurer

Sorby, Henry Clifton

of the college 1876–1919, vice-principal in 1880 and (by X-ray diffraction methods) led to her becoming
principal 1892–1911. She never completed her the first woman Fellow of the Royal Society, and pro-
studies at Cambridge, but in 1880 began research fessor of chemistry at University College London .
work with Rayleigh, who was then professor of May Sybil Leslie (1887–1937) moved into indus-
experimental physics. She worked in electrochemistry trial chemistry. She graduated with first class honours
and the result was published jointly in two papers in from the University of Leeds in 1908 and worked with
Philosophical Transactions. Marie Curie in Paris and later with Rutherford in
Ida Freund (1863–1914) came to Britain from Manchester, where she continued research on
Vienna in 1881, studied at Girton College, Cambridge thorium and actinium. During the First World War she
and gained a Class 1 in her examinations. She worked in a war factory in Litherland (and later in
became lecturer in chemistry at Newnham College North Wales), initially as a research chemist, but later
and ran the chemistry laboratory there despite being as chemist in charge of the laboratory. This unusual
confined to a wheelchair, having lost a leg in a position for a woman no doubt came about through
cycling accident in her youth. Her impact, however, the departure of the men to the war. Her work was on
was, like Jane Marcet’s, in science writing, but unlike the chemical reactions involved in the formation of
Marcet not at a popular level. Her book The Study of nitric acid and the best conditions for making it in
Chemical Composition (1905) became a definitive large quantities for munitions.
classic in its area of chemical history. Ida Smedley MacLean (1877–1944) attended the
Frances Mary Gore Micklethwait (1868–1950) King Edward VI High School for Girls in Birmingham,
was able to pursue a career in chemistry. At the age which had a high reputation for science and a
of 30 she became a student at the Royal College number of Cambridge-trained staff. She was a
of Science (now Imperial College, London) and student at Newnham and took her examinations in
graduated in 1901. She carried out research there 1898. She worked on the chemistry and metabolism
for the next 13 years at a time when it was difficult of fats at the Lister Institute of Preventative Medicine
for a woman to do so. She worked mainly with Sir in London and was one of the founders of the British
Gilbert Morgan (1870–1940), doing valuable work Federation of University Women. She worked for the
on diazo reactions and organo-arsenic compounds. admission of women to the Chemical Society of
Her work in the First World War was undisclosed, but London, which, like the Geological Society of London,
was probably on explosives, and led to her MBE in had been slow in admitting them to its fellowship.
1919. She was the first woman to be elected in 1920.
Rutherford said of HARRIET BROOKS: ‘next to Mme Resistance to employing women in the chemical
Curie she is the most pre-eminent woman physicist in industry was forceful and prolonged. In the interwar
the department of radioactivity’. She gained a first years the number of posts in science-based industry
class honours degree in 1898 at McGill University, was limited, and was further reduced by a long period
Montreal and joined Rutherford’s research group of recession. In these circumstances, it is unsurprising
there. Her work led Rutherford and SODDY to the real- that in chemistry (as in other professions and trades)
ization that a transmutation of one element to a male workforce protected its job opportunities as
another had occurred; this entirely novel idea was best it could. The phrase ‘the already overcrowded
central to the whole development of nuclear physics state of the profession’ is recurrent in arguments
and chemistry. rejecting the admission of women.
One of the ‘Bragg pupils’, KATHLEEN LONSDALE, is
strictly a physicist but her contributions to chemistry

but including forensic work, archaeology, optics is best known and that created petrography and
and marine biology. Most notably, he fathered metallography respectively. By the 1850s he had
metallography, sedimentology and microscopical developed cutting methods used for fossil woods
petrography. His first published research, done in and gemstones to make for himself rock sections
his early 20s, was on the deposition of water-borne down to one-1000th of an inch thick. Examined by
sediments, which form sedimentary rocks, on transmission microscopy (especially using a micro-
which he experimented, in part using the River scope fitted with the new Nicol polarizing prisms,
Rother on his estate. At this time he also studied which he had by 1861), minerals gave Sorby much
limestones (notably present in his home area) by new information, especially on the origin of slates
microscopy, concluding that they are formed from and granites. Petrologists have used his methods
minute organisms (mainly coccoliths). Like his other ever since, despite a slow early acceptance of them.
geological ideas, these are now fully accepted; then In the 1860s he became interested in meteorites,
they were controversial. as igneous rocks from outside the Earth. Many
However, it is his work in making and studying contain an iron–nickel alloy, and at about the same
thin rock sections and polished metal surfaces that time Sorby was examining locally made iron and
Sperry, Roger Wolcott

linity and pH 7 neutrality, at 25°C. The value is
measured practically by a meter with a glass elec-
trode or by suitable indicator papers.
Spallanzani, Lazzaro [spalantsahnee] (1729–99)
Italian biologist: pioneer of experimental physiology.
Spallanzani first studied law, but his cousin
Laura Bassi, who was professor of physics at
Bologna, encouraged his interest in science. He
became a priest and eventually professor of natural
history at Pavia, and was an enthusiastic traveller
in pursuit of specimens for the natural history
museum there. His other enthusiasm was experi-
mental physiology and especially reproduction.
The older biologists had largely believed (with
Aristotle) in spontaneous generation (eg from
mud or an animal corpse). A fellow Italian, F Redi
(1626–97), had shown in the 17th-c that insects
developed on meat only from deposited eggs;
Spallanzani showed in 1765 that well-boiled broth,
hermetically sealed, remained sterile. (Despite this,
Henry Sorby it was not until Pasteur’s work, a century later,
that the idea of spontaneous generation was
steel samples, whose polished or acid etched sur- largely abandoned.) He also studied digestion,
faces revealed their structure. He was later the first which Galen had thought to be a kind of cooking by
to show, in the 1880s, that carbon steel is a two- stomach heat, while RĂ©aumur had experimented
phase alloy, with its phases identified by him as with buzzards and concluded it was solvent action.
iron and iron carbide: metallography had really Spallanzani experimented with many animals and
begun. one man (himself) and showed that gastric juice is
In the 1860s he devised spectroscopic methods for the active digestive agent. He was the first to
detecting traces of blood. However, spectroscopy observe blood passing from arteries to veins in a
also led him into error. Studying zircons, and espe- warm-blooded animal (the chick). He achieved arti-
cially jargons from Ceylon, he found absorption ficial insemination of amphibians, silkworms and
lines, which he at first thought arose from a new a spaniel bitch, although he did not grasp the
element, jargonium. Strongly pressed by Crookes importance of spermatozoa (which had been dis-
to publish this idea, he did so in 1869. Within the covered much earlier) and believed that the ovum
year, he realized that ‘jargonium’ was in fact ura- contained all the parts that appeared later in the
nium. The ‘jargonium fallacy’ was his only major embryo. He worked on the senses of bats, and found
error in research, and it injured the credibility of that blinded bats could still catch insects and navi-
his blood tests for forensic use. gate well enough to avoid even thin silk threads. (L
Sorby bought a yacht in 1878 and afterwards Jurine showed they lost their skill if their ears were
spent 6 months each year sailing, with marine zool- covered, which was not explained until 1941 – bats
ogy and work on tidal flow and estuary sedimenta- use sonar.) His interest in zoology was mainly in
tion included. On shore, he was the central figure marine biology, including sponges and Torpedo, and
in creating Firth College, which became Sheffield in rotifers and tardigrads.
Spencer Jones, Sir Harold (1890–1960) British
When he died he had published over 150 papers astronomer: discovered slowing down of Earth’s
on a great range of topics, over 62 years: and rotation.
ridicule was no longer directed to ‘the strange idea Spencer Jones was educated at Cambridge
of studying mountains and railway lines with a University, becoming chief assistant to the
microscope’. Astronomer Royal. He later spent 10 years as
Sörensen, Sören [soerensen] (1868–1939) Danish astronomer at the Royal Observatory at the Cape of
biochemist: invented pH scale for measuring acidity. Good Hope before being appointed Astronomer
Sörensen studied chemistry at Copenhagen. Royal. Spencer Jones organized an international
From 1901 he was director of the Carlsberg project to accurately determine the Earth–Sun dis-
Laboratory and worked on amino acids, proteins tance (the astronomical unit) in 1931, using a close
and enzymes. His fame rests on his invention in approach of the asteroid Eros, the result being a
1909 of the pH scale. The pH of a solution is defined great improvement over previous values. More
as log (1/[H+]) where [H+] is the concentration of importantly, he discovered in 1939 that the Earth’s
hydrogen ions in moles per litre. The scale is rigor- rotation was slowing down by about a second per
ous enough for physical chemists but is also year, thus explaining some anomalies that had
useable by non-specialists, and it is universally been observed in the orbits of the Moon and planets.
Sperry, Roger Wolcott (1913–94) US neurobiolo-
employed. For a solution, a pH of 1–7 indicates
diminishing acidity; 7–14 shows increasing alka- gist: made important studies of brain function.
Stahl, Georg Ernst

Sperry was a student of psychology at Oberlin range of chemical reactions in a consistent way,
College and of zoology at Chicago, and worked in and it pointed to further experiments. It was dis-
several centres before joining the California placed, but not easily, from chemistry by Lavoisier’s
Institute of Technology in 1954 as professor of psy- work on oxygen, oxidation and reduction.
chobiology. His ingenious experimentation chal- In medicine, Stahl’s best work was on mental ill-
lenged previous theories of brain function and led ness. He was one of the first to see that some mental
to new ones. states are of physical origin, while others are func-
Although a mammal cannot repair a severed tional; and he recognized the influence of the body
optic nerve, an amphibian can. Sperry studied this on the mind and vice versa.
Stanley, Wendell Meredith (1904–71) US bio-
regeneration and found that, even with obstacles
in its path, the new nerve would find its way to its chemist and virologist: isolated the first crystalline
original synaptic connection in the brain. Again, if virus.
the optic nerve of a salamander was severed, and In his early years as a student Stanley’s main
the eye removed and replaced after a rotation of interest was football and he planned to become a
180°, the animal when offered food on its right side coach. However, his interest in chemistry increased
would aim to the left, showing that the fibres had and after graduating at Illinois in 1929 he worked
remade their old functional connection. in Germany with Wieland, and then joined the
Sperry did much work on the brain in higher ani- Rockefeller Institute at Princeton in 1931. At about
mals. The brain consists of two similar halves (con- that time Northrop proved that several enzymes
taining roughly 109 interconnected cells) with are crystallizable and are proteins. Stanley set out
many nerve fibres (commissures) linking the two to find if the viruses could be purified by similar
sides. It was well known that the two halves con- methods. Viruses are infective agents, too small to
trolled muscles on the opposite side of the body. be filterable like bacteria and able to reproduce
Sperry examined animals in which all commis- themselves in living cells. Stanley worked on the
sures were severed to give a ‘split brain’, and found virus causing mosaic disease in tobacco plants
(surprisingly) that in many ways monkeys and cats (‘TMV’) and in 1935 he obtained it in fine needle-
so modified behave as if they had two brains. Human like crystals. By 1938 others found that it is a
patients are sometimes commissurotomized to pre- nucleoprotein. His work showed that a crystalline
vent severe epilepsy spreading, and Sperry found ‘chemical’ could also be ‘living’ (a new concept)
that such split-brain patients, although normal in and, since its infective part is the nucleic acid por-
many ways, show that usually the right hemi- tion of the molecule, the work also suggested that
sphere specializes in non-verbal processes (eg emo- reproduction in living systems might be under-
tions and spatial relationships) while the left (as standable in chemical terms, involving nucleic acid
has long been known) is dominant in language pro- – as was later shown by others to be the case.
cessing. If a split-brain person picks up an unseen Stanley’s later work in virology included the iso-
object (for example, a pencil) in the left hand, the lation of an influenza virus, and the preparation of
‘feel’ goes to the right hemisphere; but the person a vaccine against it, during the Second World War.
could not say what was held, as ‘putting it into He shared a Nobel Prize in 1946.
Stark, Johannes [shtah(r)k] (1874–1957) German
words’ calls for links with the left hemisphere. A
woman shown a picture of a nude woman in her physicist.
left visual field only said she saw nothing, but Stark had an extraordinary career, marked by
she blushed and giggled. Sperry’s results point to changes of his views in physics, conflict with col-
discrete pathways in the brain carrying specific leagues and his involvement in a racist political
types of information, and have implications for movement and ultimate imprisonment.
theories of consciousness. He shared a Nobel Prize His training followed conventional lines and he
in 1981. became a lecturer at Göttingen in 1900, afterwards
Stahl, Georg Ernst [shtahl] (1660–1734) German holding chairs in four German universities. In 1902
chemist and physician; developed phlogiston theory he predicted that rapidly moving positive ions in a
of combustion. discharge tube (‘canal rays’) should show a Doppler
A clergyman’s son, Stahl trained in medicine at effect (a change of frequency of the light emitted
Jena and later taught medicine and chemistry. He from them, due to their rapid movement). In 1905
took a theory of combustion due to J J Becher (1635– he demonstrated this for hydrogen ions, showing
82) and developed it well enough to dominate high skill as an experimenter: it was the first detec-
chemical theory for a century. The theory was that tion of the effect from a terrestrial light-source.
when a substance burned it was losing ‘phlogiston’. Then in 1913 he looked for an electrical analogy to
This was a principle of fire, perhaps akin to heat; the Zeeman effect, in which spectral lines are split
and the idea was used to explain what we now call by a magnetic field. He found it, again using hydro-
the oxidation of metals and the reduction of ores to gen, and a very high-voltage field. This discovery of
metal. To account for the observed weight changes, the Stark effect, along with his earlier work, led to
phlogiston had to have negative weight. (Later, the award to him of the Nobel Prize for physics in
Cavendish and Priestley thought hydrogen might 1919.
be pure phlogiston.) The theory was erroneous but Meanwhile he had embarked on the strange
not ludicrous. It could be made to account for a reversals of his opinion on theory, and the ferocious
Stefan, Josef


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