. 11
( 21)


mental study of metabolism, Krebs shared a Nobel
Prize in 1953 with F Lipmann (1899“1986), who
worked out important details of the cycle.
Krogh, (Schack) August [krawg] (1874“1949) Danish
physiologist: studied physiology of respiration.
A shipbuilder™s son, young Krogh was always an
enthusiast for experiment, and soon after begin-
Sonya Kovalevsky
Kühne, Wilhelm

ning medicine at Copenhagen he moved to zoology
and to medical physiology. He spent his life in
Copenhagen as a zoophysiologist. As a student he
worked in his room on the hydrostatic mechanism
of Corethra larvae, devising methods for analysing
gas in their air bladders and showing that they
˜function like the diving tanks of a submarine™. He
went on to study gas exchange in the animal lung,
and the whole problem of how an animal responds
to a ˜call for oxygen™, both in vertebrates and in
insects. In this, the behaviour of the capillaries is
critical, and Krogh studied their movement and
expansion in the frog™s tongue, and from this devel-
oped a general picture of the behaviour and
response of the capillary system and its regulatory
mechanism, which involves both nerves and hor-
mones. He won the Nobel Prize in 1920.
Kronecker, Leopold (1823“91) German mathe-
matician: developed algebraic number theory and
invented the Kronecker delta.
Kronecker was born into a rich Jewish family and
was taught at school by E E Kummer (1810“93), who
Sir Harold Kroto
became a lifelong friend. From this time sprang his
interest in number theory and arithmetic, and he
went on to take his degree at Berlin (1843), receiv- in art and design and in the sciences, and his later
ing his doctorate in 1845 for research on complex work involved some fusion of all these interests.
units. Kronecker spent the next 10 years managing Graduation in science at Sheffield, followed by
the family estate and an uncle™s banking business: work in spectroscopy there and in Ottawa, led to a
he prospered and married. When he returned to lectureship in the young University of Sussex by
Berlin to do mathematics he was financially inde- 1970. Using microwave spectroscopy, he studied
pendent, and only lectured at the Berlin Academy the molecules present in stellar atmospheres, and
from 1861 for his own pleasure. He declined the found that some had long carbon chains. This
chair at Göttingen (1868) but accepted Kummer™s caused him in 1985 to work with Robert Curl and
old chair at Berlin, holding it until his death. Kro- Richard Smalley, both at Rice University, Houston,
necker was a man of wide culture, supporting the TX; the latter had developed a laser device to vapor-
arts and interested in philosophy and Christian ize metals to give a plasma containing clusters of
theology, he became a Christian shortly before his metal atoms.
death. An account of this work, which led to the discov-
In his early mathematical research on complex ery of the fullerenes, is given in the panel on the dif-
units Kronecker nearly anticipated Kummer™s ferent forms of carbon (p. 208): a discovery which
famous concept of ideal numbers, and his work on involved contributions from spectroscopy, astron-
number theory, algebra and elliptic functions uni- omy, physics, chemistry and artistic design.
fied much previous research. On algebraic num- Curl, Kroto and Smalley shared the Nobel Prize
bers he rederived much of existing theory without for chemistry in 1996.
Kühne, Wilhelm [künuh] (1837“1900) German
referring to what he (incorrectly) claimed were the
ill-defined complex and irrational numbers. He physiologist: discovered reversible photosensitivity
once made the comment in an after-dinner speech: of animal eye pigment.
˜God made the integers, all else is the work of man™. Although Kühne was a medical man, taught by
He was often in debate with Weierstrass and G Virchow and Bernard, and a professor of physiol-
Cantor (1845“1918) and this gave rise to his system ogy (mainly at Heidelberg), his selection and
of axioms (1870) to support a formalist viewpoint. approach to problems was rather that of a chemist.
In linear algebra Kronecker invented the Kronecker He worked on trypsin from pancreatic juice and
delta (σmn = 1 if m = n and σmn = 0 otherwise), and coined the name enzyme (Greek, ˜in yeast™) for the
established its use when evaluating determinants. class of ˜ferments™ which activate chemical change
It is famous as the first example of a tensor quantity in living cells. Other compounds that interested
being used. him were proteins; he studied post-mortem change
Kroto, Sir Harold W (1939“ ) British chemist: co- in muscle and found the protein myosin to be the
discoverer of a novel group of carbon molecules, cause of rigor mortis. In the 1860s he separated var-
the fullerenes. ious types of egg albumen; and when in 1876 F Boll
Kroto, the child of pre-Second World War escapees (1849“79) discovered a photosensitive protein pig-
from Germany, grew up in Bolton, Lancashire, ment in the retina of a frog™s eye, Kühne took up the
where his father set up a business making and dec- study of this ˜visual purple™ (now known as
orating toy balloons. Young Kroto™s interests were rhodopsin) and showed that it is bleached by light
Panel: The different forms of carbon


(1) (2) (3)

Space lattice Space lattice of graphite Fullerene, C60
of diamond

Several of the chemical elements exist in more than linked to form 12 pentagons dispersed among 20
one form, known as allotropic forms or simply hexagons, so that it resembles a European football (an
allotropes. The allotropes of a given element consist icosahedron). The larger C70 would have 25 hexagons,
of the same atoms, and the differences between them and be rugby-ball shaped. Because of the clear similar-
arise from differences in the arrangement of these ity to the geodesic buildings created by the architect
atoms, the way they are bonded to one another. Buckminster Fuller, the class of new compounds were
Two forms of carbon occur in nature as mineral named fullerenes (and informally buckyballs).
deposits and have long been known and used. One of Earlier, in 1983, W Kr¤tschmer of the Max Planck
them is diamond, the hardest, most brilliant and most Institute in Heidelberg, with D Huffman and L Lamb
prized of gemstones. In a diamond every atom at Arizona University in Tucson, had studied the ultra-
(except the minority at the surface) is surrounded by violet spectra obtained from an electric arc between
four neighbours, equally spaced around it, as was graphite electrodes in a helium atmosphere, and they
first shown by W H AND W L BRAGG by X-ray diffraction re-examined this in 1989, soon finding that C60 was
methods. Graphite, the other long-known form of formed in the arc and gathering evidence from its
carbon, is very different: black, soft and used in spectra confirming the ˜buckyball™ structure. By 1990
pencils and as a lubricant. Its carbon atoms are they showed that soot from their arc partly dissolved
arranged in net-like flat sheets, with each atom being in benzene to give a magenta solution and evapora-
a member of a six-atom ring; the sheets are fairly well tion of this gave orange crystals of C60, now easily
apart and are only weakly bonded to one another. studied in a range of ways which left its structure in
Both diamond and graphite have industrial uses, and no doubt at all. And C70 can be made in the same
both are made synthetically to supplement supplies way. C36 has also been made and is probably the
from mineral deposits. Carbon black, soot and coke smallest possible fullerene.
all have disorganized, graphite-like structures. These strange substances, now easily available,
The third rather recently discovered form of carbon, offer a whole new range of interesting prospects to
the fullerenes, form a very different and highly surpris- chemists and physicists. They are certainly present in
ing group. Probably the long delay in their discovery “ sooty flames, and in interstellar dust. Larger mole-
compared with diamond and graphite -“ stems from cules on the same pattern have been made and
the fact that there is no natural path which concen- others can be expected, including the hyperfullerenes
trates them and exposes them for discovery. They C240, C540 and C960. They offer novel possibilities both
exist as discrete molecules (whereas diamond and for chemistry and electronics. Compounds of C60
graphite are giant extended molecules, of indefinite include an insulator, a conductor, a semiconductor, a
size); their molecular structure is weirdly novel; and superconductor, and a ferromagnet which strongly
their discovery was achieved by research groups fol- suggests an interesting future in layered microelec-
lowing rather disparate routes. The first suggestions tronic devices. A further variant of carbon structure is
the carbon nanotube (a nanometre is 10“9 m). These
that carbon atoms could form molecules in the form of
these hollow closed cage-like structures were made in thin, strong and hollow cylinders of carbon atoms
the 1960s and 1970s, but the first sample was were discovered in 1993 by groups led by Sumio
obtained in 1990. Iijima in Japan and by D Bethune in California, and
The first good evidence for the existence of such were made in quantity in 1995 by R E Smalley in
compounds came in 1985, when R F Curl (1933“ ) and Texas. They are essentially rolled-up sheets (known
R E Smalley (1943“ ) at Rice University in Texas, as graphene) of a one-atom-thick single layer of
working with H W KROTO of Sussex University, UK, graphite. Depending on the arrangement of atoms in
laser-vaporized graphite in a jet of helium and showed the nanotube, it can either be a near-perfect metallic
that the carbon fragments were rich in C60 and C70 mol- conductor, or a semiconductor. Multiwall nanotubes
ecules. They proposed that these remarkably stable are also known. Technical uses, not only in nanoelec-
molecules were closed shells of carbon atoms, with C60 tronics, must lie ahead.
being a spheroidal structure with its carbon atoms

Kuiper, Gerard Peter

and regenerated in the dark. The retina works, he early American space flights, including the Ranger
showed, like a renewable photographic plate; he and Mariner missions.
obtained a pattern of crossbars of a window on the In the 1950s Kuiper predicted that a belt of debris,
retina of a rabbit that had been kept in the dark, left after the formation of the Solar System, could
exposed to a window and killed. It needed new tech- exist beyond the most distant planet, Pluto. In 1988
niques, in the 1930s, for G Wald (1906“97) and it was suggested that this Kuiper belt could explain
others to advance knowledge of the mode of action the origin of short-period comets such as Halley™s,
of rhodopsin. which appear and return at intervals of a few years
Kuiper, Gerard Peter [kiyper] (1905“73) Dutch“US or decades; and in 1993 the first two such objects, a
astronomer: discovered Miranda and Nereid. few score miles across and named 1992 QBI and
Educated in Leiden, Kuiper moved to the USA in 1993 FW, were discovered. By 2000 it was generally
1933. He discovered two new satellites: Miranda, agreed that many thousands of these objects exist,
the fifth satellite of Uranus, and Nereid, the second as residues left over from the formation of the Solar
satellite of Neptune, in 1948 and 1949. He also stud- System. Rock-like and ice-rich, they appear to have
ied the planetary atmospheres, detecting carbon sizes up to a few hundred km, and to be the source
dioxide on Mars and methane on Titan, the largest of asteroids and of short-period comets. The planet
Saturnian satellite. Kuiper was involved with the Pluto may be a Kuiper object.

La«nnec, Ren© Th©ophile Hyacinthe [laynek] Lagrange, Joseph Louis, comte (Count) [lagrãzh]
(1781“1826) French physician: invented the stetho- (1736“1813) French mathematician: revolution-
scope. ized mechanics.
La«nnec studied at the Charit© hospital in Paris Born of a French father and Italian mother in
and qualified as a doctor in 1804. Despite ill-health Turin, Lagrange saw the family wealth frittered
he did much to advance clinical diagnosis and his away when he was a teenager. He took to mathe-
writing on disease is modern in approach. It was matics early and became a professor at the Royal
well known that listening to chest sounds (aus- Artillery School in Turin at 19. He moved in 1766 to
cultation) was useful in diagnosis, and tapping succeed Euler as Director of the Berlin Academy of
the chest (percussion) had been shown by J L Sciences. In 1797 he was in Paris as professor of
Auenbrugger (1722“1809), in 1761, to be informa- mathematics at the École Polytechnique. His first
tive also. wife died young; when he was 56 he married a
In 1816 La«nnec met a difficulty in hearing the teenage girl, remaining happily married until his
heart action of a plump and shy young woman, and death. He was a highly productive mathematician
solved it by connecting his ear to her chest with a but his health broke down as a result of overwork
paper tube. He was surprised to find that the heart and he suffered periodically from intense spells of
sounds were then louder and clearer. He soon depression; he virtually gave up mathematics by
replaced his paper tube with a wooden tube 30 cm his late 40s. He was modest and widely liked.
long “ the first stethoscope. It was not until the end The great book for which he is known, Analytical
of the century that the binaural stethoscope, with Mechanics, was started when he was 19, but despite
rubber tubes to both ears, replaced the simple tube early progress was only finished and published
in general use and became the physician™s most when he was 52. It developed mechanics, and used
readily identifiable instrument. La«nnec was able a powerful combination of the calculus of varia-
to link chest sounds with a range of diseases, tions and the calculus of four-dimensional space to
mainly of the heart and lungs, and described his treat mechanical problems generally. The book
results in his book On Mediate Auscultation (1819). He does not use geometric methods as Newton did
was an outstanding clinician. (there are no diagrams!).
Lagrange made contributions to the gravitational
three-body problem and to number theory; he
proved some of Fermat™s unproven theorems and
solved the ancient problem of finding an integer x
such that (nx2 + 1) is a square where n is another
integer (not a square).
Lagrange worked with Lavoisier on weights and
measures, and in effect was the father of the metric
system. Napoleon thought very highly of him.
Lamarck, Jean (Baptiste Pierre Antoine de
Monet) (1744“1829) French naturalist: proposed
early ideas on variation and on evolution.
Lamarck™s fame is peculiar. Part of his work, on
classification and on variation, was widely
approved in his own time and later; but some of his
ideas on evolution were strongly attacked then and
since, and partly so through misunderstanding of
his emphasis and meaning.
The 11th and youngest child of poor aristocrats,
he joined the army at 16, served in the Seven Years™
War, and then (for health reasons) gave up the army
and, after working in a bank, began to study medi-
cine. His interest first focused on botany, and his
writing on this (especially his introduction of an
easy key for classification) impressed the famous
naturalist Buffon; he became botanist to the king
in 1781 and, after the Revolution, a professor of
zoology in Paris in 1793. After that he worked
mainly in zoology, especially on the invertebrates
R T H La«nnec
Landsteiner, Karl

(a term he introduced; he was also a very early user ments requiring polarized light and in sunglasses,
of the word ˜biology™). After 1800 he put forward where it is useful because reflected sunlight is
general ideas on plant and animal species, which partly polarized. Land abandoned his degree course
he began to believe are not ˜fixed™. One reason for to develop his inventions; the best-known is an
his view is that domesticated animals vary greatly ingenious camera in which a multi-layered film is
from their wild originals. He proposed that in used with developing chemicals included, which
Nature it is the environment which produces are released to process the film in seconds and give
change; his most quoted example is the giraffe™s an acceptable colour print. He never graduated in
neck which he thought was a result, over genera- the usual sense but Harvard awarded him an hon-
tions, of the animal reaching up for food. A facet of orary doctorate in 1957 to add to his exceptionally
his views was that such a change could be inher- large collection of honorary degrees.
Landau, Lev Davidovitch [landow] (1908“68)
ited; this attracted ridicule and was largely aban-
doned after the work of Darwin and Mendel. Russian theoretical physicist: explained remar-
Somewhat unfairly, ˜Lamarckism™ is linked with kable properties of liquid helium.
the idea of inheritance of a characteristic acquired Landau was the son of a petroleum engineer and
in life. In this form Lamarck has few supporters (the a doctor, and attended the universities of Baku and
Soviet botanist T D Lysenko (1898“1976) was one), Leningrad. In 1929 he met Bohr in Copenhagen,
although recent claims have been made that forming a long-lasting and productive working
acquired immunological tolerance in mice can be friendship. In 1932 he moved to Kharkov, becoming
inherited. More broadly, Lamarck and Buffon can professor of physics in 1935. In 1937 Kapitsa, set-
now be seen as having views on common descent, a ting up the Institute of Physical Problems in
˜chain of being™ for living things, which formed a Moscow, asked Landau to be director of theoretical
precursor to the theory of evolution offered by physics. A professorship at Moscow State University
Darwin and Wallace. followed in 1943. As a notable teacher and person-
Lamb, Hubert Horace (1913“ ) British climatolo- ality Landau (known as Dau) created a strong
gist: pioneered study of palaeoclimates. school of theoretical physics in Moscow, contribut-
After graduating in natural science and geogra- ing to statistical physics, thermodynamics, low-
phy from Cambridge, Lamb spent most of his pro- temperature physics, atomic and nuclear physics,
fessional career at the Meteorological Office before astrophysics, quantum mechanics, particle physics
establishing the Climate Research Unit at the and quantum electrodynamics. He published from
University of East Anglia in 1973. 1938, with E M Lifshitz (1917“69), a famous series of
Lamb developed the view, controversial at the textbooks. Landau explained the superfluidity (van-
time, that there have been long-term variations in ishing viscosity below 2.19 K) and superconductiv-
climate. Using a variety of historical sources (such ity properties of helium II using the concepts of a
as ship™s logs and the variations in tree-ring width) phonon (quantized vibrational excitation) and a
he produced a number of definitive studies of past roton (quantized rotational excitation). He was
climate, including daily weather classifications for awarded the Nobel Prize in 1962 for this work and
Britain back to 1861, monthly temperature charts other contributions to condensed matter physics.
back to 1750 and a list of major volcanic eruptions Sadly, he was critically injured in a motor accident
and a corresponding dust veil index back to 1500. in 1962 and never recovered, dying 6 years later.
Landsteiner, Karl (1868“1943) Austrian“US immu-
These indices have since been extended by other
palaeoclimatic indicators, such as oxygen isotope nologist: discoverer of human blood groups.
measurements on lake and deep sea sediments. Born and educated in Vienna, Landsteiner gradu-
Together, such data have proved invaluable in the ated there in medicine in 1891, and spent the next
study of past climates and have shown beyond 5 years in university research in chemistry, partly
doubt that definite trends in climate occur on a with E Fischer in Würzburg. He held posts in
variety of time scales. pathology in Vienna until 1919, then moved to the
Land, Edwin Herbert (1909“91) US inventor: Netherlands and finally, in 1922, to the Rockefeller
invented Polaroid® and a fast photographic process. Institute in New York. His work in medical science
To obtain polarized light (ie light in which the was wide-ranging, but his results in immunology
electromagnetic vibrations are all in one plane) the and especially on blood groups outshine the rest.
early method was the use of a Nicol prism. Later it Before 1900, blood transfusion had an unpre-
was realized that passing light through some dictable outcome. In that year Landsteiner showed
organic crystals gave polarized light (ie the crystals that the blood serum from one patient would often
are dichroic) but the crystals could not be grown to cause the red blood cells of another to ˜clump™
large size. While Land was a Harvard student, he (agglutinate). He went on to show that all human
realized that very small crystals would serve the blood can be grouped in terms of the presence or
purpose if they were all aligned together and not absence of antigens (A and B) in the red cells and the
randomly orientated; and he found a way of doing corresponding antibodies in the serum. Either anti-
this, with the aligned crystals (of quinine iodosul- gen may be present (blood groups A and B) or both
phate) embedded in a clear plastic sheet of any (AB) or neither (O), giving four groups of this kind.
required size. The result was given the trade name Using this idea, simple tests for grouping blood
Polaroid®, and it is widely used in scientific instru- samples and R Lewisohn™s discovery in 1914 that
Langevin, Paul

sodium citrate prevents clotting “ and helped by trometer and a galvanometer, allows very precise
refrigeration “ blood banks and blood transfusion measurement of the energy of radiation at differ-
were widely used by the time of the Second World ent wavelengths. This enabled him to study the
War. Other blood antigens were later found, for solar spectrum at wavelengths of up to 5.3 µm in
example the MNP system (in 1927) and the Rhesus the far infrared, to measure variations in the solar
factor (1940), both discovered by Landsteiner and flux and also to quantify the selective absorption of
his co-workers and both (like the A, B, AB and O energy by the Earth™s atmosphere.
types) inheritable. Other blood group systems have Being interested in the possibility of manned
since been found. The complexity of blood types flight, in 1896 Langley constructed a steam-pow-
now known leads to millions of blood-type combi- ered model aircraft, which achieved flights of up to
nations. 1200 m in length, and which was the first heavier-
Landsteiner™s work won him a Nobel Prize in 1930 than-air machine to fly; however a full-sized ver-
and has been valuable not only for safe transfusion sion failed to leave the ground.
Langmuir, Irving (1881“1957) US chemical physi-
but also in paternity cases, in forensic work and in
anthropology for tracing race migration. cist: inventor of ideas and devices, often related to
Langevin, Paul [lãzhv˜ (1872“1946) French physi-
i] surfaces.
cist: established modern theory of magnetism and Langmuir was the third of four sons and was only
invented sonar. 17 when his father died; but the latter worked in
Langevin was a student of Perrin in Paris and later insurance and the family was financially secure.
worked there with Pierre Curie; in between he The young man attended the School of Mines at
spent nearly a year with J J Thomson in Cambridge. Columbia (New York) and then studied at
His interests in physics were wide-ranging and he Göttingen with Nernst. His work there, on the dis-
became the leading French physicist of his time. sociation of gases by a hot platinum wire, began an
Work on ionized gases led him to study the mag- interest in surface chemistry which he never lost.
netic properties of gases; most are feebly diamag- In 1901 he joined the General Electric Company
netic (repelled by a magnetic field) but ozone (O3) is research centre at Schenectady, NY, and worked
paramagnetic (weakly attracted into the field). there for 41 years. An early success for him was the
Langevin showed in 1905 that magnetic behaviour improvement of tungsten filament lamps, by fill-
could be understood in terms of the electrons pre- ing them with inert gas (argon) at low pressure to
sent in atoms; electrons had recently (1895) been reduce evaporation and by using a coiled-coil fila-
discovered by Thomson. ment. Further work on hot filaments led to the dis-
In the First World War, he worked on a method covery of atomic hydrogen and the invention of a
for detecting U-boats by echo-sounding, using the welding torch using its recombination to H2 to
reflection of ultrasonic waves (ie sound waves of achieve 6000°C.
very high frequency, and not audible). Curie had In 1919“21 he worked on ideas of atomic struc-
studied the piezoelectric effect “ the small change ture, developing the ideas of Lewis to form the
in the size of some crystals produced by an electric Lewis“Langmuir octet theory of valence, which was
field. Langevin used radio circuitry to produce simple and useful in explaining a range of chemi-
rapid changes in electric potential in a crystal, so cal phenomena. The words electrovalence and
that it vibrated and formed an ultrasonic genera- covalence were first used by him. His interest in hot
tor. Reflection of the waves for submarine detec- surfaces moved to thermionic emission, where his
tion was developed too late for the First World War, work advanced both theory and practice. His study
but was used in the Second World War as ˜sonar™. It of surface films on liquids allowed some deduc-
is used also to survey the seabed, to detect fish tions on molecular size and shape; and his work on
shoals, and in medical scanning.
Shortly before the Second World War, Langevin
worked out how to slow down fast neutrons, a
method essential for the later work by others on
atomic reactors. After France fell to the Germans in
1940, he was outspoken in his anti-Fascist views
and was soon under house arrest; his daughter was
sent to Auschwitz and his son-in-law was executed.
Langevin escaped to Switzerland and survived to
return to his Paris job, as director of a research
Langley, Samuel Pierpont (1834“1906) US astro-
nomer and aviation pioneer: invented the bolome-
ter and pioneered infrared astronomy.
Langley was mainly self-educated as an engineer
and astronomer. His most important contribution
to astronomy was the invention of the bolometer, a
device consisting of a thin, blackened platinum
wire which, when used in conjunction with a spec- Irving Langmuir
Laue, Max von

gas films on solids led to the Langmuir adsorption Larmor was active in the final phase of classical
isotherm, the first important theory of the adsorp- physics that laid the ground for the breakthroughs
tion of gases on solid surfaces. in relativity and quantum mechanics. He incor-
His ideas on surface adsorption advanced under- rectly believed in the ether (ie an absolute space-
standing of heterogeneous catalysis. He was time frame) and that it was involved in all wave
awarded the Nobel Prize for chemistry in 1932 propagation. He contributed to electromagnetic
largely for this, becoming the first scientist fully theory, optics, mechanics and the dynamics of the
employed in industry to receive a Nobel Prize. He Earth. In electrodynamics he showed (1897) that
went on to work on electric discharges in gases, and the plane of an orbiting electron in an atom wob-
made the first full studies of plasmas (a word he bles (or precesses) when in a magnetic field (Larmor
coined). He was a keen sailor and flyer, and his stud- precession). The expression for the power radiated
ies of atmospheric physics led to trials in weather by an accelerated electron (proportional to the
control (eg rain-making by seeding clouds with square of its charge and the square of its accelera-
solid CO2). He had a wide range of interests, includ- tion) is also due to him.
Lartet, Edouard Armand Isidore Hippolyte
ing music, conservation and Scouting, and his dis-
tinctions include having Mount Langmuir in [lah(r)tay] (1801“71) French palaeontologist:
Alaska named after him. demonstrated that man had lived in Europe during
Laplace, Pierre Simon, marquis de [lahplas] the Ice Age, and discovered Cro-Magnon Man.
(1749“1827) French mathematician, astronomer The son of a wealthy landowner, Lartet studied
and mathematical physicist: developed celestial law at Toulouse before taking over the manage-
mechanics; suggested hypothesis for origin of the ment of the family estates. He became interested
solar system. in fossils and discovered two early primates,
Although from a poor family, Laplace™s talent led Pliopithecus (an ancestor of the gibbon) in 1836 and
him to become an assistant to Lavoisier in thermo- Dryopithecus (an early ape) in 1856. In 1863 he dis-
chemistry. Later he moved to astronomy, and covered the first evidence that man had been living
became a minister and senator, skilfully contriving in Europe during the Ice Age when he found, in a
to hold a state office despite violent political cave at La Madeleine in southern France, a piece of
changes. Laplace™s most important work was on ivory with the figure of a woolly mammoth carved
celestial mechanics. In 1773 he showed that gravi- on it. This was also the first evidence, provided it
tational perturbations of one planet by another was not a forgery, that man had lived at the same
would not lead to instabilities in their orbits time as animals now extinct, and 5 years later, at
(Newton had believed that such small irregulari- Cro-Magnon in the Dordogne, he found several
ties would, without divine intervention, eventually skeletons of Cro-Magnon Man, the earliest known
lead to the end of the world). He later proved two fossilized man in Europe (although a relatively
theorems involving the mean distances and eccen- recent ancestor by hominid standards).
la Tour, Charles Cagniard de see Cagniard de la
tricities of the planetary orbits and showed that the
solar system has long-term stability. In 1796
Laue, Max (Theodor Felix) von [low-uh] (1879“
Laplace proposed in a note that the Sun and planets
were formed from a rotating disc of gas; he did not 1960) German physicist: suggested a classic experi-
know that Kant had made a similar suggestion; ment to show diffraction of X-rays by atoms in
modified forms of this nebular hypothesis are still crystals.
accepted. Between 1799 and 1825 he published Von Laue studied physics at four German univer-
his five-volume opus M©canique c©leste (Celestial sities and was also an art student for 2 years. He
Mechanics), which incorporated developments in then taught physics at three universities before set-
celestial mechanics since Newton as well as his own tling in Berlin in 1919. He remained professor of
important contributions. (The book has its oddity: theoretical physics there until 1943, when his long-
frequently the phrase ˜it is obvious that™ occurs, in standing antagonism to the racist policy of the
mathematical equations, when it is far from obvi- National Socialist party led him to resign. From
ous. And Napoleon is said to have remarked, criti- 1946 he worked to rebuild German science. His
cally, that it made no mention of God.) Laplace is early work on optics gave support for Einstein™s rel-
also remembered for putting probability theory on ativity theory, but he is now best known for his
a firm foundation, and for developing the concept work with X-rays.
of a ˜potential™ and its description by the Laplace Early in this century it had been suggested that X-
equation. In the fields in which Laplace worked and rays were electromagnetic waves like light but of
where Newton had worked previously, he is seen as very short wavelength, although some physicists
second only to Newton in his talent. thought otherwise. It was also believed that the
Larmor, Sir Joseph (1857“1942) British physicist: atoms in crystals were in regular array, in accord
worked out the electrodynamics of electrons. with their external regularity. Von Laue realized
Larmor was educated at Queen™s University Bel- that if both these ideas were true, then the spacing
fast and Cambridge and took posts at Queen™s Col- between layers of atoms in a crystal should be of the
order of size (10“10 m) to bring about diffraction of
lege Galway and Cambridge. In 1903 he became
Lucasian Professor of Mathematics there. He was X-rays. In 1912 he tested this idea; an assistant W
also a member of Parliament for 11 years. Friedrich (1883“1968) and a student, P Knipping
Laughlin, Robert B

(1883“1935), passed a narrow beam of X-rays more readily. When an electron is added it excites
through a crystal of CuSO45H2O and obtained a dif- the fluid of condensed bosons, and quasiparticles
fraction pattern of spots on a photographic film are created within it. Laughlin predicted these
placed behind it; a crystal of ZnS served even better. effects theoretically, and they have exactly the frac-
The experiment proved the wave-nature of X-rays tional charge observed in Störmer and Tsui™s exper-
and also gave the basis on which the Braggs later iments. These three people shared the Nobel Prize
created X-ray crystallography. Einstein called the for physics in 1998.
Laurent, Auguste [lohrã] (1807/8“53) French or-
experiment ˜one of the most beautiful in physics™
and von Laue was awarded the Nobel Prize in 1914. ganic chemist: classifier of organic compounds.
Always enjoying fast motorcycling and car driving, Laurent was an organic chemist of much talent
he was killed in his car, aged 80. and energy, who studied under Dumas. Thereafter
Laughlin, Robert B (1950“ ) US physicist: co-dis- his life was fraught with misfortune to an operatic
coverer of a new form of quantum fluid. extent; employers swindled him, posts he hoped
As a reclusive boy growing up in out-going for were unavailable or were found to lack facili-
California, Laughlin™s interest in physics began ties, a business venture failed and his contributions
when his parents gave him a colour TV in kit form. to theory brought him abuse until almost the end
He constructed it, but to learn something of how it of his life. His last post, as underpaid assayer to the
worked he experimented with discarded TV sets Mint, provided a damp cellar as laboratory and he
(and gave himself some severe electric shocks). died of lung disease just before his book Methods of
Undeterred, he made sodium by electrolysis of Chemistry (1854) was published, leaving a near-des-
fused sodium hydroxide, and was severely burned titute family. He was a skilful experimenter with a
by it in the process. More safely, he taught himself passion for classification; in particular, he devel-
some higher mathematics, and entered Berkeley in oped Dumas™s ideas on organic substitution. He rec-
1968 to study electrical engineering, but soon ognized that organic compounds could be classed
moved to physics, and graduated best in maths. in ˜types™, and he used this, and his idea of a nucleus
Military service in a missile training school ended of carbon atoms within an organic compound, to
in Europe, which he celebrated in traditional fash- organize much of the organic chemistry of his
ion by burning his boots (but non-traditionally he time. This led to vigorous debate, from which a
filled them first with 3kg of nitrate mixed with clearer view of organic compounds emerged by
sugar, giving a 10 m high flameshow). 1860. Laurent also did valuable work in benzene
At MIT as a postgraduate from 1974 he focused on and related chemistry. His work in organic chemi-
solid state physics, which led on to work at Bell Labs cal theory is interwoven with Gerhardt™s work.
Lavoisier, Antoine Laurent [lavwazyay] (1743“94)
and then at the Livermore lab, where his Nobel
Prize work began. From 1984 he worked at French chemist and social reformer; creator of the
Stanford. Quantum fluids are those in which parti- Chemical Revolution and victim of the French
cles combine and form a condensed fluid with Revolution.
unusual properties. Aside from high-energy collid- Lavoisier™s father was a prosperous lawyer in Paris
ers, they form a crucial arena in which the quan- and the boy studied law after leaving school.
tum behaviour of matter can be observed. Liquid
helium, superconductors and superfluids are
examples, as is the Hall effect. This originated in
1879, when electrons moving through a gold film
were observed to be deflected by a perpendicular
magnetic field. The quantum version of this was
discovered by von Klitzing a century later. At low
temperatures and very high field strengths the elec-
trons move as if on a single surface, and the Hall
resistance changes in integral quantum steps
(rather than linearly) with field strength. This
effect occurs because of the selected quantized cir-
cular paths which the electrons may move along.
One of the biggest surprises in modern physics
occurred in 1982 when Horst Störmer (1949“ )
and Daniel Tsui (1939“ ) observed fractional
values in addition to the integer quanta seen by von
Klitzing. A year later Laughlin set out the theoreti-
cal explanation, predicting fractionally charged
quasiparticles as being responsible. These have
now been seen directly, confirming his model. The
electrons (as fermions with spin one half) do not Detail from the best-known scientific portrait: A L
condense easily, however they combine with mag- Lavoisier with his wife and co-worker Marie Anne,
netic field flux quanta. Together they form bosons painted by J L David in 1788. She had studied drawing
(particles of integer spin) which combine much with David, the leading French painter of his time.
Lavoisier, Antoine Laurent

Solar furnace built for the Acad©mie des Sciences in 1774. The 4-ft lens A was made of two pieces of glass, each moulded
as part of a 16-ft sphere: the interior was filled with ethanol. A similar furnace was used by Lavoisier in 1772 in his exper-
iments on heating metals and their oxides, and diamond, without flame or access to air. The device is early in state-
supported Big Science, the 18th-c equivalent of a modern particle accelerator.

However, he had been interested in science at school he used his own work, and that of others, to form a
and later a family friend, Guettard, the geologist, general theory of combustion, oxidation and the
took him on field trips. Lavoisier worked on the first composition of the air, in an original way. His new
geological map of France; this work, and his compe- theory soon displaced ˜phlogiston™ from most
tition essay on a method of street-lighting, was so chemists™ minds and directed chemistry into new
good that he was elected to the Royal Academy of and valuable paths. He showed that water was a
Sciences in 1768, when he was only 25. In the same compound of hydrogen and oxygen; Cavendish™s
year he bought a part-share as a ˜tax-farmer™, to give work on this was skilful, but it was Lavoisier who
him an income while he followed his new interest, first explained the results. (Similarly, Scheele and
chemistry. The tax-collecting company had leased Priestley had made oxygen before him, but failed to
from the Government the right to collect some indi- understand its significance.)
rect taxes for 6 years. The investment proved reason- From 1776 he lived and worked happily at the
able; he worked hard on company business; and at 28 Royal Arsenal, in effective charge of gunpowder
he met and married Marie Anne Paulze, the 14-year- production and research. It was there, with Laplace
old daughter of a fellow tax-farmer (see next entry). as Lavoisier™s co-worker, that Black™s early work
She became the expert assistant in his chemical on calorimetry was extended; an ingenious ice
work. His involvement in the tax-farm was to prove calorimeter was made for this, and heats of com-
unfortunate. bustion and respiration were measured; this was
Lavoisier worked on a scheme for improving the the beginning of thermochemistry and also
water supply to Paris and on methods of purifying showed that animal respiration is essentially a slow
water. He showed in 1770 that water cannot be con- combustion process. (A young assistant to Lavoisier
verted into earth, as was then widely believed. In at the Arsenal, E I du Pont (1771“1834), emigrated
this, as in all his work, he used the law of conserva- to America and in 1802 began making gunpowder
tion of matter: that, in chemical operations, matter on the banks of the Brandywine River in Delaware.
is not created or destroyed. He went on to show that The venture prospered and founded a major US
air is a mixture of two gases: oxygen, which com- chemical industry.) In 1787, with three other
bines with reactive metals on heating and which French chemists, Lavoisier introduced the method
supports combustion and respiration; and the of naming chemical compounds which has been
unreactive nitrogen. He found that metals combine used ever since. His main contributions to chem-
with oxygen to give oxides which are basic (˜alka- istry were elegantly set out in his Elementary Treatise
line™), whereas the non-metals (S,P,C) give acidic on Chemistry (1789), with fine plates by his wife. In it
oxides. In this work he used the sort of logic he he gave his definition of a chemical element, as ˜the
admired in Joseph Black™s studies on lime; and he last point which analysis can reach™; this was
was helped by information from Priestley; but Boyle™s view, but Lavoisier used it experimentally
Lavoisier, Marie Anne Pierrette

and gave a working list of elements. The book had mined that his reputation should not be over-
enormous influence on chemistry, comparable with looked and his claims should be known and recog-
Newton™s Principia in physics a century earlier. nized. She petitioned for the return of the estate
Lavoisier had remarkable energy: from 1778 he and, having obtained his books and papers, she
ran an experimental farm near Blois to improve the edited and privately published Lavoisier™s unfin-
poor level of French agriculture; he developed ished memoirs. She presented copies to the great
schemes for improving public education, equitable scientific societies and eminent scientists around
taxation, savings banks, old age insurance and Europe.
other welfare schemes. His liberal and generous Marie Lavoisier blamed friends and scientific
views found too few imitators, however, and by associates of Lavoisier, especially members of the
1789 revolution had begun. All might have gone Convention, for not protesting against her hus-
well for Lavoisier for, although the tax-collecting band™s imprisonment and for not pointing out his
firm was a natural target, its affairs were in good past valuable work for France and his future scien-
order and charges against the tax-farmers could be tific worth. Bitterly, she held them responsible for
refuted. But revolution followed its usual pattern his death.
of moving to extremism, and Marat, a leading She again opened her home as a meeting place to
figure in the Terror, had early in his career pursued the leaders of science in France, to Delambre,
scientific ambitions “ his worthless pamphlet Cuvier, Lagrange, Laplace, Berthollet, Arago,
Physical Researches on Fire had been condemned by Biot, Humboldt and others; she did not receive
Lavoisier. A new charge of ˜counter-revolutionary those who had failed to use their political influence
activity™ was speedily contrived, which ensured a to try to save her husband.
guilty verdict, and France™s greatest scientist was In 1805 Marie married Benjamin Thompson,
guillotined the next day. Count Rumford, but the marriage was not a suc-
Lavoisier, Marie Anne Pierrette, n©e Paulze cess and they separated 4 years later.
Lawes, Sir John Bennet (1814“1900) British agri-
[lavwazyay] (1758“1836) French illustrator, transla-
tor and assistant to Lavoisier. culturalist: founder of Rothamsted Experimental
Marie Paulze™s mother was a niece of the Abb© Station.
Terray, France™s controller general of finance in 1771 Lawes had an amateur interest in chemistry, but
and one of the most powerful men of the kingdom. after inheriting a farm estate at Rothamsted in
Terray proposed a marriage between the 13-year-old 1834 he became an enthusiast for agricultural
Marie and the 50-year-old penniless brother of a chemistry. He found that ground bones (˜mineral
valued acquaintance. To save her from this unwel- phosphates™) were effective in some fields but not
come alliance Marie™s father, a parliamentary lawyer in others, and soon discovered that acid treatment
and financier, quickly arranged a marriage for her of bones made a universally effective fertilizer (it
with a colleague in the Ferme G©n©rale, the 28-year- converts the insoluble tricalcium phosphate into
old Antoine Lavoisier. It was to be a very successful soluble monocalcium phosphate, a conversion that
marriage. acidic soils perform naturally). Despite bitter oppo-
Marie Lavoisier assisted her husband™s scientific sition from his mother (who was against ˜trade™) he
work; she became his laboratory assistant, kept the began to make and sell ˜superphosphate™ prepared
laboratory records, made sketches of his experi- from bone or mineral phosphate and sulphuric
ments and illustrated his classic Trait© de chimie acid, and used the profits to finance further exper-
(1789, Elementary Treatise on Chemistry). Marie iments at Rothamsted. Aided by a chemist, J H
Lavoisier was a skilled artist, engraver and painter, Gilbert (1817“1901), much valuable work was done
having studied under Louis David (1748“1825) (who there, including the demonstration by 1851 that, as
painted the only known portrait of Lavoisier from well as minerals, plant growth generally requires
life). She learned English, and sought tuition in nitrogenous manure (in conflict with Liebig™s
Latin from her brother, in order to translate the new views). In 1889 Lawes put Rothamsted under con-
chemical treatises from England, which included trol of a trust and its scientific studies of agricul-
the works of Priestley and Cavendish; Lavoisier ture continued. Eight field experiments are still
was not a good linguist. running there after 150 years.
Lawrence, Ernest Orlando (1901“58) US physicist:
Because of his involvement with the Ferme
G©n©rale (a tax-gathering consortium) Antoine invented the cyclotron and produced new radioac-
Lavoisier was arrested and imprisoned during the tive elements.
˜Terror™ in November 1793. His estate was confis- Lawrence™s father was head of a teacher™s college
cated, including his library and laboratory instru- and his mother had taught mathematics. The boy
ments. Marie was imprisoned, but later released, grew up in South Dakota; he was tall, energetic,
and took refuge with a family servant. Despite her fond of tennis and physics, and impatient of ˜cul-
efforts to gain his release and the difficulty the ture™ and of inactivity throughout his life. He stud-
National Convention faced in finding a support- ied at South Dakota, Minnesota and Yale and in
able charge, Lavoisier was executed in May 1794, 1928 moved to a post at the University of California
together with Marie™s father. at Berkeley, becoming director of the Radiation
Marie Lavoisier clearly understood the position Laboratory in 1936.
her husband should hold in science and was deter- From 1929 Lawrence worked to produce suffi-
Leavitt, Henrietta

early ancestor of man. Further discoveries fol-
lowed, including in 1960 the remains of Homo
habilis, a tool-making hominid with a relatively
north to
large brain. Leakey™s findings established East Africa
as the possible birthplace of man and traced his
magnetic ancestry further back than had been possible previ-
ously. His son Richard (1944“ ) is also a noted East
A African palaeoanthropologist. (See panel overleaf.)
Leakey, Mary (Douglas), n©e Nicol (1913“96) British
palaeoanthropologist: discovered several hominids.
Mary Nicol had a somewhat unconventional
upbringing, travelling a good deal and lacking a
regular formal education. Her father was a land-
scape painter. Interested in archaeology and early
man, she attended lectures at University College,
Lawrence™s cyclotron. The oscillator reverses the PD
London, and between 1930 and 1933 worked on sev-
between the dees several million times per second.
eral archaeological digs in England. Her ability as
Positive ions (eg protons, H+) are released at the centre
an illustrator brought her into contact with Louis
and are accelerated into nearly circular paths until they
Leakey, whom she joined in 1935 on an archaeo-
emerge with a high energy. The spiral path is actually
logical expedition to Olduvai Gorge, East Africa,
many kilometres long; ie the spiral is ˜tightly wound™.
and married the following year. She spent much of
ciently energetic particles for nuclear reactions, her life searching for hominids in East Africa, and
having noted Eddington™s suggestion that stars made many of the discoveries for which she and her
may be ˜powered™ by nuclear reactions. Linear husband became well-known. In 1959 she found
accelerators for making high-energy particles were the skull of Zinjanthropus boisei, a species of
awkwardly long and used high voltages. Lawrence Australopithecus and a possible ancestor of man. It is
decided to accelerate particles on a spiral path notable as the first hominid to be reliably dated, by
within a pair of semi-cylinders (˜dees™) mounted in the K/Ar method, at 1.75 million years. In 1976 Mary
a vacuum between the poles of an electromagnet. Leakey led an expedition to Laetoli, Tanzania, on
An AC voltage at high frequency applied to the dees which the earliest evidence of man™s ancestors yet
gave the particles their impetus. The first small found was discovered: two sets of hominid foot-
cyclotron (using a 10 cm magnet) operated in 1931. prints in a layer of volcanic ash provided indis-
Later and larger cyclotrons achieved proton beams putable evidence that man™s predecessors walked
of 8 — 104 eV, and converted lithium nuclei to upright 3.75 million years ago. (See panel overleaf.)
Leavitt, Henrietta (Swan) (1868“1921) US
helium nuclei to confirm Cockcroft and Walton™s
first nuclear transformation (1932). Hundreds of astronomer: discoverer of the period“luminosity
new radioactive isotopes were eventually produced, relation of Cepheid variable stars.
including most of the transuranium elements; Henrietta Leavitt did well as a student at Radcliffe
Lawrence investigated their use in medicine. (despite her deafness) and joined the Harvard
Mesons and antiparticles were generated and stud- Observatory in 1895, originally as a volunteer assis-
ied, with Lawrence coordinating the efforts of a tant. While studying photographic plates made at
team. Lawrencium (Lr, atomic number 103) was
named for him, and he received the 1939 Nobel
Prize for physics. In 1940 his team isolated pluto-
nium and neptunium, and he contributed to the
development of the atomic bomb.
Leakey, Louis (Seymour Bazett) (1895“1972)
British“Kenyan archaeologist and palaeoanthro-
pologist: discovered several hominids.
The son of a British missionary working in British
East Africa (now Kenya), Leakey became interested
in Stone Age man while he was young. He studied
anthropology at Cambridge, reading French and
Kikuyu (the language of the Kenyans among whom
he had been brought up) and taking part in a
British Museum expedition to Tanganyika in his
second year. Between 1926 and 1935 he organized a
series of archaeological and palaeontological expe-
ditions to East Africa, the later ones visiting
Olduvai Gorge, Tanganyika (now Tanzania), where
a German lepidopterist had found fossils in 1911.
During expeditions there he found hominid skulls
and stone tools, which he believed to represent an Henrietta Leavitt
Panel: The quest for human origins

THE QUEST FOR HUMAN ORIGINS afarensis about 3.1 million years old, in the Afar valley of
north-eastern Ethiopia. Tantalizingly, 2 years later MARY
LEAKEY discovered the footprints, but no remains, of a
hominid walking upright at Laetoli on volcanic ash dated
as 3.75 million years old.
The oldest hominid currently known is 4.4 million
years old and again hails from the Afar valley.
Australopithecus ramidus was found in1994 by a
Japanese/American/Ethiopian team; far from being a
complete skeleton, the remains consist of 50 fragments of
bone and teeth from a group of 17“20 individuals, includ-
ing jaw and skull fragments and a complete left arm. Pre-
dating the use of stone tools by almost 2 million years, A.
ramidus lived in a woodland area also inhabited by
Homo habilis Homo erectus Homo sapiens monkeys, antelopes, sabre-toothed cats, rhinos and
elephants, and was probably predominantly vegetarian.
Although these hominids walked upright like humans, it
is thought that they would have slept in trees, and resem-
The search for the earliest human ancestors has
bled apes in other ways.
been an area of science very much dominated by individu-
Human skeletal remains dated as being between
als, often with strongly held views about the interpreta-
500 000 and 300 000 years old appear to be the earliest
tion of their finds. The story of the discoverers tells much
(˜archaic™) examples of Homo sapiens. Debate continues
about the history of the subject.
on whether he was contemporary with, or a successor to,
Not surprisingly, many of the earlier finds were made
late populations of H. erectus.
in heavily populated Europe, with several discoveries in
The classification of these finds, and the interpreta-
the 19th-c of evidence of early habitation in caves. In
tion of their interrelationships and migrations, can be
1863 LARTET discovered the first evidence that man had
assisted by DNA analysis. In 1995, DNA studies at Yale
lived in Europe during the last ice age and soon after-
on part of the Y chromosome of 38 living men from
wards found several skeletons of Cro-Magnon Man, the
around the world showed the samples to be surprisingly
earliest human predecessor found in Europe. although a
similar. The simplest explanation for this lack of ˜genetic
relatively recent ancestor in evolutionary terms.
scrambling™ is that modern humans are genetically
The publication of DARWIN™S ideas on evolution in 1858
young, ie only a few hundred thousand years old, and
led to a conscious search for a ˜missing link™ between
that they developed from a single homogeneous colony
humans and the apes, and in 1891 DUBOIS discovered
fragments of Homo erectus (Java Man), a hominid (see and not from separated and scattered centres.
Mitochondrial DNA studies show that African, Asian and
end of LINNAEUS entry) that walked upright about 0.5“1.5
European populations probably shared a common ances-
million years ago. Like many after him, Dubois™s interpre-
try more than 100 000 years ago, but division (following
tation of his finds was widely ridiculed at the time, but
the Out of Africa movements) occurred some 40 000
accepted later after Otto Zdansky found other examples
of Homo erectus near Peking in 1926. So strongly was years ago so that Asian and European populations are
biochemically closer to one another than either now is to
opinion divided about Darwin™s theory and the nature of
any African population.
human ancestry that some were tempted to fabricate
Current thinking, on the basis of both fossil finds and
evidence, such as the ˜discovery™ in 1912 of Piltdown
genetic evidence from modern human and ape popula-
Man, widely accepted as one of our early ancestors until
tions, suggests that the split between humans and apes
conclusively shown to be a fake in 1953.
occurred some time between 5 and 8 million years ago
It is commonly accepted today that the human family,
and that hominids who could merge in a human crowd
the Hominidae, originated in Africa from ape-like ances-
today without much difficulty first appeared not more
tors, whence they migrated across the globe. This Out of
than 100 000 years ago. But although these ancestors of
Africa theory is reflected by the subsequent pattern of
100 000 years ago had language and social awareness, it
hominid discoveries. In 1924 DART had announced the
seems (judging by their cave art) that another 50 000
discovery of a hominid twice as old as Java Man;
Australopithecus africanus, from Taung, Botswana, was years passed before religious and supernatural belief
systems appeared.
1.2“2.5 million years old. The ˜Taung baby™ was the first
We are not descended from apes, but we and they are
truly primitive ancestor within the human family to be
linked to an earlier ancestral species: they are cousins
found; soon afterwards BROOM found a second example
and not forefathers. Modern humans (Homo sapiens),
at Sterkfontein, followed in 1938 by the first specimen of
Australopithecus robustus (1“2 million years old). able to speak, are in evolutionary terms successful, but to
a catastrophic extent: our numbers are 6 billion (the UN
In 1960, LOUIS LEAKEY in the Olduvai Gorge in East
Africa found Homo habilis, a large-brained hominid that figure for October 1999) and seem set for continual
made and used tools.
Note: For further work on human origins, see
A major step back in time was achieved in 1974 when
JOHANSON discovered ˜Lucy™, a female Australopithecus Chronology for 2002 (p 407).

Lederberg, Joshua

Harvard™s field station in Peru, she deduced in 1912 laws due to van ™t Hoff; they are (1) increase in
that Cepheid variable stars have a simple relation- pressure favours the system having the smaller
ship between the period of a given star and its lumi- volume, and (2) rise in temperature favours the
nosity; based on this, Hertzsprung suggested that system formed with absorption of heat. Thus for
the equilibrium N2 + 3H2 ” 2NH3 in which the
their distances could be calculated. The method
soon proved invaluable for measuring stellar dis- volume diminishes when the reaction proceeds to
tances. From 1915 Shapley used this method to the right, an increase of pressure will shift the equi-
obtain the first rough estimates of the size and librium in favour of ammonia formation. Also, as
shape of our Galaxy. It was not until 1924 that ammonia formation is exothermic, rise in temper-
Eddington found an acceptable theoretical reason ature favours the reactants.
Leclanch©, Georges [luhklãshay] (1839“82) French
for the relationship that Leavitt had first observed.
Lebedev, Pyotr Nicolayevich (1866“1912) Russian engineer: devised carbon“zinc electrical cell.
physicist. Educated in Paris, Leclanch© was employed as a
Lebedev studied physics at Strasbourg and Berlin railway engineer from 1860. By 1866 he had devised
and became professor of physics at Moscow in 1902. his carbon“zinc electrical cell, which was soon
Maxwell™s theory of electromagnetic radiation adopted by the Belgian telegraphic service.
implied that radiation should exert a very small Modified to the non-spillable form of the familiar
pressure on matter. Crookes™s radiometer appeared dry cell, it has been greatly used; this has a carbon
to confirm this, but it was soon shown that the rod as the positive pole, surrounded by a wet paste
apparent effect of light pressure in it was due to of carbon black, manganese dioxide and ammo-
traces of gas. However, with better vacua Lebedev nium chloride, with a thickener such as sawdust,
was able to measure the effect of light pressure, and inside a zinc container which is the negative pole.
Lederberg, Joshua [layderberg] (1925“ ) US
to show that it is twice as great on reflecting as on
absorbing surfaces. geneticist: pioneer of bacterial genetics.
For the small particles of cosmic dust, light pres- A New Yorker almost from birth, Lederberg grad-
sure can exceed gravitational attraction, and uated in biological science at Columbia University
Lebedev concluded that this is why a comet™s tail and then enrolled there in 1944 as a medical stu-
points away from the Sun. However, the effect of dent during his service in the US Naval Reserve. At
the solar wind on a comet™s tail is now known to be that time bacteria were not thought to have genes,
much greater in this case than the light pressure. or sex. During his course on medical bacteriology,
Lebesque, Henri Leon [luhbeg] (1875“1941) French Lederberg began experiments to test this and in
mathematician: introduced the modern definition 1946 went to Yale to work on it with the experi-
of the integral. enced microbiologist E L Tatum (1909“75). They
Lebesque was a product of the École Normale were skilful and lucky in the choice of the intesti-
Sup©rieure and from 1921 taught at the Collège de nal bacterium Escherichia coli strain K-12 for their
France. His main contributions were to set theory, work, and within weeks showed that mutants of
the calculus of variations and function theory. He this strain crossed; in a large colony, a few re-
and E Borel (1871“1956) built the modern theory of produced by sexual mating (˜conjugation™). Leder-
functions of a real variable, and Lebesque in partic- berg went on to show that this is not uncommon
ular produced a new general definition of the inte- and can be used to map bacterial genes; bacterial
gral (1902), developed beyond the Riemannian genetics had begun and its methods became valu-
definition. This led to important advances in calcu- able to geneticists, as had earlier use of the fruit fly
lus, curve rectification and trigonometric series, Drosophila and the fungus Neurospora.
and initiated measure theory. His next major discovery, made with Zinder in
Le Chatelier, Henri Louis [luh shatlyay] (1850“ 1952, was that bacteriophage (a bacteria-infecting
1936) French physical chemist and metallurgist: virus) could transfer genetic material between
devised a much-used but doubtful principle. strains of bacteria (˜transduction™) to produce
As a young man, Le Chatelier was much influ- recombinant types. For the first time genes had been
enced by his father Louis, an engineer who was deliberately inserted into cells, a basis for ˜genetic
Inspector General of Mines for France. Tuition from engineering™. In 1957, with G Nossal (1931“ ),
his father and family friends such as Deville aided Lederberg showed that immune cells produce
him and shaped his interests, and he became a pro- single types of antibody, a result which was basic to
fessor in the École des Mines in 1877. His early the development of monoclonal antibodies by
research was on cement (his grandfather operated others. With his first wife, Lederberg obtained the
lime kilns); he worked also on the structure of first firm evidence that adaptive mutations in bac-
alloys, on flames and on thermometry. In the 1880s teria can occur spontaneously; this had been an
he developed the idea known as Le Chatelier™s prin- unproved assumption in the theory of evolution.
ciple: this states that if the conditions (tempera- After Yale, Lederberg taught genetics at Wisconsin
ture, pressure, or volume) of a chemical system and at Stanford and became president of
initially at equilibrium are changed, then the equi- Rockefeller University in 1978. At age 33, he had
librium will shift in the direction that will tend to shared a Nobel Prize with Beadle and Tatum in
annul the change, if possible. The principle has 1958. Aside from his work on bacterial genetics,
been much criticized, and it is best replaced by two he researched on artificial intelligence and the
Lee, Tsung Dao

specific problem of computerizing some of the draper, he later had his own shop in Delft and a
work of organic chemists by devising a linear nota- paid post in local government. He became an
tion for organic molecular structures. In collabora- enthusiastic user of microscopes. The compound
tion with E A Feigenbaum, these studies pioneered microscope was in use before 1650 but was opti-
the development of ˜expert systems™. cally poor, and Leeuwenhoek preferred to use a
Lee, Tsung Dao (1926“ ) Chinese“US theoretical small single lens, doubly convex and of very short
physicist: demonstrated that parity is not con- focus (1“3 mm). He ground these himself and
served in the weak nuclear interaction. mounted them between metal plates; in all he
Lee studied for his degree in China. His work was made some hundreds of these magnifiers. He was a
interrupted by the Japanese invasion during the passionate microscopist, ingenious, secretive and
Second World War; he fled to another province. In with the advantage of having very unusual eye-
1946 he won a grant to Chicago, studying astro- sight, so that he could use magnifications of 50— to
physics under Fermi; work at Princeton (1951“3) 200— with his ultra-small lenses (possibly he used a
and Columbia followed. He held a post at Columbia second lens, as an eyepiece). He also used ˜a secret
from 1956. method™, which may have been dark-ground illu-
While the electromagnetic and strong nuclear mination, or the enclosure of his specimens in a
interactions conserve parity (ie are identical in a drop of liquid in some cases. His results were
mirror-image of the physical system) Lee and Yang mostly sent to the Royal Society in illustrated let-
showed in 1956 that this is not so for the weak ters (375 of them); unsystematic, enthusiastic and
nuclear interaction. They deduced this extraordi- written in Nether-Dutch, and his fame attracted
nary result, with far-reaching implications, by con- visits by other microscopists and even royalty.
sidering nuclear beta-decay (electron emission). He was the discoverer or an early observer of
They suggested a number of experiments, and in blood capillaries, red blood cells, protozoa, bacteria
the ensuing months their conclusion was verified (in 1683), rotifers, Hydra, Volvox and spermatozoa
by Wu. Lee and Yang also argued (1960) that the (of dog). He was opposed to the idea of spontaneous
very light neutral particle called the neutrino (see generation, which was not disproved until Pasteur™s
Fermi) produced in electron emission was different work a century and a half later. He ground 419
from the neutrino associated with muon emission. lenses and lived, actively researching, to age 90.
Lehmann, Inge [layman] (1888“1993) Danish seis-
This was verified by experiment in 1961. In the
same paper they predicted the existence of the W- mologist: discovered solid inner core within
boson as the heavy particle conveying the weak Earth™s outer liquid core.
nuclear force, and this has since been shown exper- Inge Lehmann studied mathematics in Copen-
imentally. They also indicated the existence of neu- hagen and in Cambridge, and afterwards worked in
tral weak currents, first observed in 1973. Lee and insurance until she was 30, before returning to
Yang became the first Chinese to win a Nobel Prize, study science in Copenhagen. From 1928 she
in 1957. headed seismological work at the Danish Geodetic
Leeuwenhoek, Antony van [layvenhook] (1632“ Institute, dealing with seismic data recorded from
1723) Dutch microscopist: observed blood cor- all parts of Europe. At that time the Earth was
puscles, protozoa, bacteria and spermatozoa. believed to consist simply of a liquid core, shown to
Leeuwenhoek had no formal training in science exist by Gutenberg, surrounded by the mantle and
and rather limited schooling. Apprenticed to a then the crust. But in 1936 Lehmann observed that
compressional P waves travelling through the
Earth™s core from an earthquake undergo a marked
increase in velocity at a depth of about 5150 km.
She argued from this that there is a solid inner core
within the liquid core, extending about 1200 km
from the Earth™s centre. It is believed that this inner
core consists of solid iron and nickel, the very high
pressure making the metal solid despite its high
temperature. (See diagram at Gutenberg.)
Leibniz, Gottfried Wilhelm [liybnits] (1646“1716)
German mathematician: one of the greatest poly-
maths in history.
The son of a Lutheran professor of moral philoso-
phy, Leibniz developed an interest in a wide range
of subjects from his father™s library. He attended
the universities of Leipzig, Jena and Altdorf, where
he received his doctorate in law in 1666. Leibniz
was to show talent in law, religion, statecraft,
history, literature and philosophy as well as math-
He took up a career as a somewhat shady lawyer
and diplomat, working initially for the elector of
Antony van Leeuwenhoek
Lenz, Heinrich Friedrich Emil

Mainz. During two trips to London in 1673 and the ˜Big Bang™ (so named, disparagingly, by Hoyle in
1676 Huygens and Boyle interested him in current the 1950s). Although the importance of Lema®tre™s
work in mathematics, and in his spare moments work was not fully appreciated at the time, the ˜Big
Leibniz proceeded to make the immense discover- Bang™ theory is now accepted as the best model for
ies of both the calculus (independently from the origin of the universe.
Lenard, Phillipp Eduard Anton [laynah(r)t]
Newton) and combinatorial analysis. Leibniz was
at the same time much involved with establishing (1862“1947) German physicist: investigated the
the legal rights of the legitimate and many illegiti- photoelectric effect and cathode rays.
mate members of the household of the three elec- Lenard, the son of a wine-merchant, was educated
tors whom he served in succession. Frequently on at Budapest and in Germany, where he became pro-
the move and prolifically noting his thoughts on fessor at Kiel in 1898.
many subjects, he was involved in diplomacy and Before 1914 Lenard made a series of fundamental
in making plans for a French invasion of Egypt. His contributions to physics. He took the known fact
talents were dissipated in the sordid tasks of his that ultraviolet light falling on some metals causes
master™s power-broking. He also became involved electron emission (the photoelectric effect) and
in an unsuccessful attempt to unite the Catholic showed that this occurred only with light below a
and Protestant churches in 1683 and in the found- critical wavelength; that the electron velocity
ing of the Berlin Academy of Sciences (1700). When increases with falling wavelength and is indepen-
his last employer, the elector of Hanover, had been dent of light intensity; and finally that increasing
steered into becoming George I of England, Leibniz the light intensity produces a larger number of
was discarded and left behind to write the emitted electrons (1902). Einstein explained all
Brunswick family history. He died neglected, these observations in 1905 and, with Planck, intro-
dogged by illness and in the midst of controversy duced light quanta (photons) into physics, prepar-
over his invention of the calculus. ing the way for the development of quantum
In mathematics Leibniz had tremendous flair. He theory.
invented a calculating machine (1672) far beyond Lenard showed that cathode rays are an electron
Pascal™s, which could only add and subtract; beam and received the 1905 Nobel Prize for physics
Leibnitz™s could also multiply, divide and find for this work. The cathode rays would penetrate air
square roots. When a young man he conceived of a and thin metal sheets and he deduced that atoms
universal language for logic and began the study of contained much empty space and both positive and
symbolic logic. Later came his construction of the negative charge (1903). Rutherford™s work con-
differential and integral calculus, and a fierce pri- firmed and extended this picture of the atom
ority dispute on this with Newton; Leibniz did his (1911).
work following Newton (after 1665) but indepen- Lenard had disputes over priority with Röntgen
dently. The notation now used in calculus is that (Lenard having narrowly failed to discover X-rays)
due to Leibniz. A minor part of his work was on infi- and with J J Thomson, but his case does not appear
nite series, where he discovered in 1674 an amus- strong. Lenard™s book Great Men of Science (1934) is
ing relation between π and all the odd numbers: marred by his omission of contemporaries with
π/4 = 1“1/3 + 1/5 “ 1/7 + 1/9¦ which had earlier been whom he had quarrelled. He was distressed that
found by Gregory. Germany lost the First World War, and afterwards
Lema®tre, Georges Edouard (Abb©) [luhmay- by the death of his son and the loss of his savings by
truh] (1894“1966) Belgian astronomer and cosmol- massive inflation. He developed an extreme dislike
ogist: originator of the ˜Big Bang™ theory for the of the increasing mathematical sophistication of
origin of the universe. physics through the influence of Einstein and
Lema®tre studied at the University of Louvain, others. From 1919 Lenard argued for the establish-
and afterwards trained and was ordained as a ment of ˜German physics™ untainted by Jewish the-
Catholic priest. He then spent some time at the ories, attacking Einstein as a socialist, pacifist and
Cambridge and Harvard observatories before a Jew, but above all for being a theoretician. As the
becoming professor of astronomy at Louvain in only leading scientist who was a Nazi supporter,
1927, where he remained for the rest of his career. Lenard acquired increasing power. In the 1930s a
Lema®tre was an originator of the ˜Big Bang™ generation of disillusioned scientists left Germany,
theory for the origin of the universe. In 1927 he most of Germany™s capacity to achieve creative
found a solution to Einstein™s equations of relativ- physical science departing with them.
Lenz, Heinrich Friedrich Emil [lents] (1804“65)
ity that resulted in an expanding universe
(Einstein™s own solution was a static one), and 2 Russian physicist: discovered Lenz™s Law.
years later Hubble showed observationally that this Lenz studied chemistry and physics at the Uni-
was indeed the case. Independently, the Russian versity of Dorpat (later Tartu), served as geophysi-
Friedmann came to similar conclusions. However, cist on a voyage around the world when he was 19
Lema®tre further suggested that, by backward and, on his return, was appointed to the staff of St
extrapolation, the universe must at one time have Petersburg Academy of Science, eventually becom-
been small and highly compressed, which he ing dean of mathematics and physics.
referred to as the ˜primal atom™. He conjectured On his voyage around the world Lenz made some
that radioactive decay had resulted in an explosion, important investigations of barometric pressure
Lepaute, Nicole-Reine

and of sea temperature and salinity, establishing and was appointed to the new Rockefeller Institute
(and explaining) the difference in salt content for Medical Research in New York, where he spent
between the Atlantic and Pacific Oceans and the the rest of his life. He was small, energetic, artistic
Indian Ocean. However, he is best remembered for and multilingual, prone to toss his heavy shock of
his work on electromagnetism; Lenz™s Law states hair about and devoted to his own experimentation
that the current induced by an electromagnetic despite having a team of co-workers. His work
force always flows in the direction to oppose the ranged over a large area of tissue constituents and
force producing it. This is a special case of the more was notably productive in sugar chemistry.
general law of conservation of energy. He also His best-known work concerns nucleic acids,
showed that the resistance of eight metals which had first been isolated in Hoppe-Seyler™s lab-
increases with temperature and discovered (inde- oratory, in 1869. It is now known that nucleic acids
pendently from Joule) the proportionality between are long, chain-like molecules, constructed from
the production of heat and the square of the current repeating units:
flowing in a wire. base O base O
¦ ¦ ¦ ¦
Lepaute, Nicole-Reine, n©e Etable de Labrière [luh-
∼ sugar”O”P”O”sugar”O”P”O ∼
poht] (1723“88) French astronomical computer.
¦ ¦
Married to Jean-Andr© Lepaute (1720“1789), the
royal clockmaker, Nicole-Reine Lepaute investigated O O
oscillations of pendulums of different lengths; the in which the bases are of four different kinds.
result of this work was included in her husband™s Levene™s important contribution was to show
Trait© d™horlogerie (1755). She was employed by that the sugar component came in two kinds, both
J J Lalande (1732“1807), director of the Paris of them unknown until he isolated them by break-
Observatory, to assist A-C Clairaut (1713“65) to ing down nucleic acids. The first sugar, isolated in
determine the extent of the gravitational attrac- 1909, was soon shown to be ribose. The second
tion of Jupiter and of Saturn on Halley™s comet and sugar, 2-deoxyribose, was not discovered for another
the exact time of its return in 1759. Lalande gave 20 years. This was because 2-deoxyribose is
Lepaute full credit for her work. She calculated the destroyed by acid used to break up the chain, and a
path of the 1764 eclipse of the Sun for all of Europe non-destructive enzyme for the purpose could not
and the resultant chart was published by the be found. Success was eventually achieved by pass-
French government. During 1759“74 she helped ing a solution of this nucleic acid through a gas-
Lalande with the annual Connaissance des temps (an trointestinal segment of a dog, by introducing it
almanac for the use of astronomers and navigators through a gastric fistula and withdrawing it
published by the Acad©mie des Sciences), and from through an intestinal fistula, a difficult procedure.
1774“83 she worked on the seventh and eighth With Levene™s identification of 2-deoxyribose, it
volumes of the Ephemeris, making the computa- was clear that the nucleic acid found in cells is of
tions for the positions of the Sun, Moon and planets two kinds, ribonucleic acid and deoxyribonucleic
covering the decade to 1784 and the period up to acid, and their abbreviations (RNA and DNA)
1792. A crater on the Moon is named after her. became familiar.
Levene, Phoebus (Aaron) [luhveen] (1869“1940) The more detailed structure of the nucleic acids
Russian“US biochemist, who showed that ˜nucleic (notably the precise mode of linkage of base and
acid™ is of two kinds (RNA and DNA) and defined the phosphate groups to the sugar) was elucidated
difference between them. especially by the work of A R Todd (1907“ ); and
Levene™s father was a prosperous Jewish shirt- then in 1953 Crick and Watson virtually created
maker in St Petersburg, and the boy was able to molecular biology by showing that the sequence of
become a student in the Imperial Medical Academy the four bases (in groups of three) along the DNA
there. Pavlov taught physiology, and Borodin chains form a code of genetic information which
chemistry, in the Academy; the latter apparently directs the synthesis of RNA, which in turn directs
influenced Levene the most, because he afterwards the synthesis of proteins. They also showed that
inclined more towards chemistry than medicine. In DNA exists in cells in the form of a double helix of
1891 the family emigrated to the USA and after two entwined strands of DNA, whose uncoiling pro-
completing his MD degree in St Petersburg Levene vides templates for their own replication. With
began his medical practice in the Russian-Jewish their work genetics and heredity had found its
colony on New York™s East Side. He and a brother-in- basis at the molecular level, with Levene™s work
law shared a small office; the brother-in-law, a (from a quarter of a century earlier) forming a key
socialist lawyer, was very similar in appearance to part of these later developments.
Leverrier, Urbain Jean Joseph [luhveryay] (1811“
Levene and, as neither of them could afford to lose
a client, it was their custom to ˜bluff it out™ for one 77) French astronomer: predicted position of
another when alone in the office. Neptune and discovered advance of perihelion of
Levene continued to spend much time studying Mercury.
chemistry and in about 1900 decided to abandon Leverrier was a student and then a teacher at the
medical practice for medicinal chemistry. He École Polytechnique, initially in chemistry and
worked for a year with Emil Fischer in Berlin; by later in astronomy. Realizing that the irregularity
1905 he had a reputation in biochemical research of the orbit of Uranus was due to the influence of
Libby, Willard Frank

an undiscovered planet further out, Leverrier suc- and published them in 1916; they were then publi-
ceeded in computing the mass and orbit of the per- cized and expanded by Langmuir and later by
turbing body. He sent his prediction of the missing Sidgwick. In developed form (as in his work of
planet™s position to Johann Galle (1812“1910) in 1923) Lewis™s ideas focused on the arrangement of
Berlin, who discovered Neptune on his first night of electrons around atomic nuclei. He assumed that
looking, 23 September 1846. Although Leverrier elements heavier than the lightest two (H and He)
initially received the credit for the discovery, it had a pair of electrons surrounding the nucleus,
soon became clear that Adams had made the same with further electrons (in number to balance the
prediction a year earlier; this led to a celebrated dis- nuclear charge) in groups, with a group of eight as
pute, not made easier by Leverrier™s arrogance and especially stable. Bonding between atoms of the
violent temper. lighter elements occurred in such a way that atoms
Leverrier was the first to appreciate the advance gained or lost outer electrons to create octets,
of the perihelion (the point of its orbit nearest the either by transfer (electrovalence) or by sharing
Sun) of Mercury, and predicted the existence of a (covalence). Noting that nearly all chemical com-
planet between Mercury and the Sun to explain it, pounds contain an even number of electrons, he
even going so far as to name it Vulcan. No such concluded that the electron pair is especially
planet has ever been found, and the advance of the important, and a shared pair can be equated with a
perihelion was subsequently explained using covalent bond. The familiar ˜dot diagrams™ showing
Einstein™s theory of general relativity. the electronic structure of many simple com-
Levi-Montalcini, Rita [layee montalcheenee] pounds are devised on this simple theory.
(1909“ ) Italian neurophysiologist: discovered Lewis also saw the importance of electron pairs in
nerve growth factor. another context. He defined a base as a substance
Montalcini™s training was difficult; her Italian- that has a pair that can be used to complete the
Jewish family long opposed her entry to medical stable shell of another atom; and an acid as a sub-
school, and when she graduated the Second World stance able to accept a pair from another atom to
War began and as a non-Aryan she had to go into form a stable group of electrons. This very general
hiding. Her early research, with her medical school concept of Lewis acids and bases has proved valuable.
instructor G Levi on the neuroembryology of the Probably no man did more to advance chemical
chick, was done in her bedroom; eggs were easy to theory in the 20th-c, but he was always a diffident
secure (by pretending she had young children) and as well as an attractive and engaging person, with
could be eaten after experimentation. In 1947 she an unorthodox mind.
Libby, Willard Frank (1908“80) US chemist: devel-
went to Washington University in St Louis and in
1949, with V Hamburger, showed that the embryonic oped radiocarbon dating technique.
nervous system produces many more nerve cells than Libby taught at the University of California at
are needed; the number of survivors depends on the Berkeley (where he had graduated) until 1941,
volume of tissue they need to serve. From this clue, when he joined the Manhattan Project developing
she went on to discover the nerve growth factor (NGF), the atom bomb. After the war he moved to the
which appears to be critically involved in the growth Institute of Nuclear Studies at the University of
of nerves of all kinds, including those of the central Chicago, returning to California in 1959.
nervous system. In 1939 Serge Korff (1906“ ) discovered carbon-
With the biochemist S Cohen (1917“ ) she 14, a radioactive isotope of carbon with a half-life of
showed that male mouse saliva is a good source of 5730 years, and showed that it is produced in the
NGF; and he went on to discover the related epider- upper atmosphere by the action of cosmic rays on
mal growth factor (EGF). In 1979 Levi-Montalcini nitrogen atoms. In 1947 Libby and his colleagues
retired from directing the Laboratory for Cell used this discovery to develop their radiocarbon
Biology in Rome, and in 1986 she shared the Nobel dating technique, which has proved to be invalu-
Prize with Cohen; she was then 77. able in archaeology and Quaternary geology. The
Lewis, Gilbert Newton (1875“1946) US physical technique is based on the fact that living biological
chemist: major contributor to theory of chemical material contains carbon-14 and carbon-12 in equi-
bonding. librium with the atmosphere (which contains a
A Harvard graduate, Lewis studied in Germany very small but approximately constant proportion
for 2 years and then went to the Philippines as a of carbon-14 to carbon-12). However, when the
government chemist. From 1905“12 he was at the organism dies it stops taking up carbon dioxide
Massachusetts Institute of Technology and then from the atmosphere and so the proportion of
spent the rest of his career at the University of carbon-14 to carbon-12 starts to diminish as the
California at Berkeley. carbon-14 undergoes radioactive decay. By measur-
Lewis developed Gibbs™ ideas on chemical ther- ing the proportion of carbon-14 to carbon-12, there-
modynamics and made the experimental measure- fore, the time since death may be determined. The
ments that allowed the outcome of a range of technique is applicable with reasonable accuracy
chemical reactions to be predicted by calculation. in dating organic objects up to about 40 000 years
He was also a pioneer in taking ideas concerning old, but greater accuracy can be achieved by cali-
electrons from physics and applying them in chem- brating the technique with objects of known age,
istry. From 1902 he shaped his ideas on this subject and this has been done back to about 5000 years
Panel: A history of agriculture in the developed world

A HISTORY OF AGRICULTURE IN THE (1739“1808) invented the Scotch plough for use on
DEVELOPED WORLD heavy ground and James Smith (1789“1850)
designed the subsoil plough for use on land with poor
Until the middle of the 18th-c the authorities on drainage. One of the most influential figures was
agriculture were Roman writers such as Lucius Robert Ransome (1753“1830), who invented a self-
Columella (1st-c) and Rutilius Taurus Aemilianus sharpening plough and also designed one that could
Palladius (4th-c); the ability of agriculture to support be dismantled and modified, thus obviating the
a non-agricultural community remained strictly necessity for small farmers to have several expensive
limited. Innovation began in the Low Countries at pieces of equipment.
the very end of the 17th-c, but new ideas were taken Other inventors produced other pieces of machin-
up and developed in Britain where, because of the ery. Jethro TULL (1674“1741) invented the seed drill in
lower population density, there was greater 1701, and the horse hoe a few years afterwards. The
opportunity for them to produce dramatic increases effect of these two inventions, although not felt until
in productivity. two generations later because of the scepticism with
Agricultural reforms were of three types. The first which they were received, revolutionized the way in
were innovations in husbandry, such as the selective which cereals were cultivated and greatly improved
stock-breeding methods developed by Robert yield. James Meikle (c.1690“1717), an East Lothian
Bakewell (1725“95) in Leicestershire in the middle of miller, produced a winnowing machine around 1720
the 18th-c, and the four-year rotation of crops and his son Andrew Meikle, besides inventing the
devised slightly earlier by Charles, Viscount fantail which allowed windmills to turn into the wind
Townshend “ ˜Turnip™ Townshend (1674“1738). automatically and thus to work more efficiently, also
Samuel Marsden (1764“1838) pioneered the breed- invented the first effective threshing drum. His
ing of Australian sheep for wool, and this work was design, which used a revolving drum and longitudinal
carried on in the middle of the 19th-c by John beater bars, is essentially the same as that used in
MacArthur (1767“1834) and especially by his wife modern combine harvesters.
Elizabeth (1766“1850), who introduced the merino At the same time, steam power was coming into
sheep to New South Wales. William James Farrer use on the farm, following the inventions of Richard
(1895“1906) emigrated to Australia in 1870 and, by Trevithick (1771“1833) and WATT. Steam threshing
his scientific breeding of specialist strains of wheat, was introduced by the Shropshire ironmaster John
was almost single-handedly responsible for the Wilkinson (1728“1808) in 1798, and the use of steam
success of the Australian wheat industry. power rapidly spread. Steam ploughing came into
Except in undeveloped areas, the advances that use during the 1850s in places where the fields were
could be made by improvements in methods were long and flat enough to make it economic, and
limited. In the middle of the 18th-c, however, continued until steam power was superseded by
advances in technology began to make a great differ- the diesel engine and by the ubiquitous tractors
ence to agriculture. One of the first areas of improve- produced by such manufacturers as Harry George
ment was plough design. The plough with an iron Ferguson (1884“1960) and Henry Ford (1863“1947).
coulter was invented by ancient Egyptians, and had Where horse power was still necessary, however,
not been much altered until several improved types other inventions improved productivity. James
were brought out in the mid-18th-c. In 1771 James Smith™s (1789“1850) experimental reaper of 1811
Arbuthnot introduced the use of a mould-board, did not work because the speed of the horses
which was much more efficient. James Anderson affected the action of the gathering drum, but an

ago. This calibration is desirable because the rate of before the Germans besieged it. A year in a mental
production of carbon-14 in the atmosphere varies hospital interrupted later work at Leipzig, and he
slightly with time. Libby was awarded the 1960 then returned to a post created for him at
Nobel Prize for chemistry for his work. Christiania in Norway (now Oslo University).
Lie, Marius Sophus [lee] (1842“99) Norwegian Lie, along with his close friend Klein, introduced
mathematician: discovered the theory of continu- group theory into geometry, using it to classify
ous transformation groups. geometries. Lie discovered the contact transforma-
Lie was inspired to study mathematics by reading tion which maps curves into surfaces (1870). Work
Poncelet and J Plücker (1801“68) on geometry, and on transformation groups followed (1873) and he
spent his life fruitfully developing the latter™s idea invented Lie groups, which use continuous or infin-
of creating geometries from shapes as elements of itesimal transformations. Lie used these groups to
space rather than points. Research in Berlin (with classify partial differential equations, making the
Klein) and in Paris was somewhat marred by being traditional methods of solution all reduce to a
arrested as a German spy (1870), but this false single principle. The Lie group also gave the basis
charge was soon dropped and he left Paris just for the growth of modern topology.
Liebig, Justus, Freiherr

effective reaper was designed in 1827 by Patrick Bell food chains was fully appreciated, notably by RACHEL
(1799“1869). When sent to America, this machine CARSON in the 1960s, and bans on its use in the UK
enabled the production of the first commercially suc- and USA soon followed. In Germany organophospho-
cessful reaping machines by Obed Hussey (in 1833) rus esters were made and tested for use in chemical
and Cyrus Hall McCormick (in 1834). Mechanical warfare, and some of these (eg Parathion) found
reapers caught on very quickly thereafter, and by major uses as insecticides after 1945. Rodenticides to
1870 a quarter of all the harvest in Britain was being reduce food losses were also needed, and after 1939
cut mechanically. In the 20th-c the development of work by K P Link in Wisconsin led to warfarin which
diesel and electric power, and machinery in general, was highly effective: its anticoagulant effect on
came together with the production of ever more animal blood also causes it to find important use in
complex and efficient pieces of equipment, such as medicine.
the combine harvester and the electric milking Another wartime effort was directed to finding
machine. As in other areas, however, these were chemicals to destroy the enemy™s crops. One result
the products of research teams and commercial was ˜2,4-D™, which has a valuable selective action in
companies rather than individual pioneers. attacking dicotyledons but hardly affects mono-
The above advances were largely technological, or cotyledons (which include cereals). Although not
the direct result of farming experience, such as the used in war, it has been much used as an agricultural
use of liming to reduce the soil acidity that results herbicide as a result. Unselective destruction of all
from sustained crop removal. Agricultural science above-ground plant growth without soil toxicity is
began with LAVOISIER™S work, was enhanced by achieved by paraquat, which was marketed as able to
DAVY™S lectures and his book on the subject (1813), replace the plough and is widely used. Unselective
and emerged fully with LIEBIG™S books Chemistry and crop destruction, notably by ˜Agent Orange™, was
its Applications to Agriculture and Physiology (1840) employed during the Vietnam War.
and The Natural Laws of Husbandry (1862). By the More recently, emphasis in agricultural science
middle of the 19th-c studies by BOUSSINGAULT, LAWES has moved from newer pesticides and fungicides
and others had shown the importance of nitrogen towards ˜greener™ methods of biological control, by
(N), phosphorus (P) and potassium (K) in plant nutri- methods such as the use of one insect species to
tion, chemical fertilizers were supplementing the use control another, or the use of insect hormones to
of manure and Lawes had founded the agricultural achieve deception and facilitate trapping. Modern
research centre at his Rothamsted estate in 1842. By genetics has opened up a range of techniques with
the early 20th-c the long-neglected fundamental applications in agriculture, and the ˜green revolution™
work in genetics by MENDEL was being applied in has led to great interest not only in improved strains
agricultural botany by BIFFEN and others. S M of animals and food crops but also in the better
Babcock (1843“1931) in the USA had developed understanding and management of ecosystems. The
scientific dairying. ELEANOR ORMEROD had effectively importance of such advances, especially in the less
created the study of agricultural entomology and developed countries, was signalled by the award of
given a scientific basis for insect pest control. the Nobel Prize not for science but for peace in 1970
The Second World War intensified studies on food to Norman E Borlaug (1914“ ) of the USA, in
production, and on animal and human nutrition. recognition of his work on the development of a
Some insecticides had been used since the 1870s; but new short-stemmed wheat.
DDT, introduced by P H MÜLLER from 1939, was highly
Sukie Hunter
effective and widely used, until its injurious effects in

Liebig, Justus, Freiherr (Baron) von [leebikh] In 1826 his work showed that the fulminates, and
(1803“73) German organic chemist; the greatest the very different cyanates (made by Wöhler) had
chemical educator of his time. the same molecular formulae. This sort of phenom-
As a druggist™s son, Liebig was attracted early to enon (isomerism) could not then be explained, but
chemistry. In 1822 he went to study in Paris (then it showed that a molecule was not merely a collec-
the centre for chemistry) and became assistant to tion of atoms; they were arranged in particular
Gay-Lussac. By 1825 he became professor in the ways, with each arrangement corresponding to one
very small university at Giessen, near Frankfurt. He compound and one set of properties. The work
stayed there for nearly 30 years, and set up his led also to his friendship with Wöhler and their
famous laboratory for students of practical chem- valuable joint work on the benzoyl group. The
istry. It was not the first, as he claimed; but, like his friendship survived when Liebig™s combative nature
research group of graduate students, it was the had eventually spoiled all his other chemical
model on which systematic training in chemistry friendships.
was afterwards based elsewhere. His university is By 1830, Liebig had developed a method for the
now the Justus von Liebig University. analysis of organic compounds which was quick
Lind, James

(out of 118) to scurvy in 3 years. Only by 1795 was
lime juice given regularly to sailors; even so, cases
were still reported in the following century, from
prisons, the Crimean War and polar expeditions
(possibly including Scott™s). By 1907, Norwegian
workers had induced scurvy experimentally in
guinea pigs, Hopkins™s classic work on vitamins
had begun and in 1928 Szent-Gyorgy isolated vita-
min C (ascorbic acid), present in citrus fruit, defi-
ciency of which leads to scurvy.
Lindblad, Bertil (1895“1965) Swedish astronomer:
proposed rotation of our Galaxy.
Lindblad graduated at Uppsala and spent 2 years
in research in astronomy in the USA before becom-
ing director of the new Stockholm Observatory in
1927 and spending his career there. Jacobus
Kapteyn (1851“1922) had discovered from a survey
of stellar motion in 1904 that most stars fell into
two groups, or streams, moving in opposite direc-
tions in the sky. Kapteyn™s interpretation of this
Justus von Liebig
was that our Solar System lies near the centre of our
Galaxy (the Milky Way). However, Shapley pro-
and accurate, by burning them in a stream of air posed that the centre of the Galaxy was some
and oxidizing the products fully to CO2 and H2O; 50 000 light years away, in the direction of the
collecting and weighing this CO2 and H2O gave a constellation Sagittarius, and so a lively debate
direct way to find the percentages of carbon and between astronomers ensued. Lindblad studied
hydrogen in the organic compound. Liebig and his Kapteyn™s results and concluded that Shapley™s
students used this method to analyse hundreds of idea was correct, provided that the speed of rota-
organic compounds, and the results were basic for tion of stars about the centre of the Galaxy depends
the great advances to be made (notably by Kekul©) on their distance from it (the ˜differential rotation™
in organic chemistry after about 1850. theory). Soon afterwards, in 1927, Oort™s study of
In his middle age, from 1840, Liebig worked on stellar motion provided support for Lindblad™s
what we would now call biochemistry. He argued views, which inspired a number of Swedish
(correctly) that carbohydrates and fats are the fuel astronomers (including his son Per Olaf Lindblad)
of the animal body and (incorrectly) that fermenta- to work on stellar motion.
Lindemann, Frederick Alexander, 1st Vis-
tion did not involve living cells. In agriculture, he
count Cherwell (1886“1957) British physicist:
argued (rightly) for the use of potassium- and phos-
phorus-containing fertilizers but underrated the personal scientific adviser to Churchill in the
importance of nitrogen, and of soil structure, in fer- Second World War.
tility. He always played a vigorous “ sometimes Lindemann™s background, talents and position
ferocious “ part in debates on chemical theory; his were all unusual. His father, a prosperous engineer,
pupils dominated organic chemical teaching; and emigrated to the UK from Alsace rather than
his views moved agriculture towards chemistry. He become a German citizen after the Franco-Prussian
made a good deal of money out of his scientific War of 1870. Lindemann studied physics in France
work and attracted criticism for this. and Germany, took a doctorate with Nernst in
Lind, James (1716“94) British physician: redis- 1910 and in the First World War worked at the
covered cure for scurvy. Royal Aircraft Establishment at Farnborough on
A surgeon™s apprentice at 15, Lind became a naval the problem of how to take an aircraft out of an
surgeon. Scurvy (˜the plague of the sea™) was first uncontrolled spin, a situation often fatal for the
seen in sailors at the end of the Middle Ages when pilot. He learned to fly, despite poor sight, and per-
sea voyages began to take months. The surgeon sonally tested and proved his theory on the spin
John Woodall (1556?“1643) described in his book problem.
The Surgeon™s Mate the prevention and cure of scurvy In 1919 he became professor of physics at Oxford
by eating citrus fruit (such as limes, oranges and and head of its run-down Clarendon Laboratory,
lemons) but this was soon forgotten. In 1747 Lind which he built up to effectiveness and a leading
experimented by dividing a dozen scorbutic sailors position in low temperature physics. Although he
into six pairs given different diets for 14 days. He made valuable contributions to the theory of spe-
found that citrus fruit with the diet gave much cific heats (he proved that the melting point of a
improvement in 6 days; and in 1754 he published A crystal depends on the amplitude of the atomic
Treatise on the Scurvy. Adoption of the treatment and vibrations), to several laboratory instruments and
use of fruit to prevent the disease was slow, even to pure mathematics and chemical kinetics,
although Cook used the method in his great south- his attitude to science was that of a keen amateur.
ern explorations of the 1770s, losing only one man As an amateur tennis player he had to leave his
Linnaeus, Carl

first prize behind after the European Tournament to list the species and gather them into related
in Germany in July 1914 in order to return hastily groups (genera).
to the UK. He competed at Wimbledon while he was Linnaeus™s lasting service to taxonomy was his
an Oxford professor. His Rolls-Royce cars formed introduction in 1749 of binomial nomenclature; he
a travelling office, and his aristocratic friends gave each plant a latinesque generic noun followed
included Churchill from 1921. The novelist Vita by a specific adjective. This became the basis for
Sackville-West wrote in 1925 that at a large house- modern nomenclature. Until that time plants had
party at Blenheim she sat between Churchill and ˜a been given a name and short Latin description of
scientist called Lindemann who is absolutely their distinguishing features, unsatisfactory both
thrilling™. When Churchill became Prime Minister as a name and description and leading to a tangled
in 1940, Lindemann became his independent sci- overgrowth, strangling further development. The
entific adviser, at times in conflict with his old Linnaean system helped pave the way towards
friend H Tizard (1885“1959), the government™s notions of evolution, an idea Linnaeus rejected
senior scientist. With the advantage of hindsight, it emphatically; he insisted no new species had been
is clear that Tizard was right to give very high pri- formed since Creation and that none had become
ority to radar in air defence, and Lindemann™s extinct.
opposition was wrong; the latter was probably in Linnaeus was an excellent teacher and his stu-
error also in his belief that heavy bombing of dents travelled widely, imbued with his enthusi-
Germany was a direct route to victory (Tizard asm, in search of new forms of life; it is estimated
believed that air defence of Atlantic shipping was that one in three died in the search.
more valuable). Linnaeus had a complex, self-conscious personal-
Churchill frequently preferred ˜the prof™s™ advice, ity. He had a tidy mind and absolute belief in the
including for example Lindemann™s enthusiasm value of his system. He was skilful in getting others
for heavy area bombing. He was a minister to accept his system, even though that meant set-
(Paymaster-General) from 1942“5 and 1951“3, and ting aside much of their own work. He cleared the
he largely created the UK Atomic Energy Authority way for development in biology without taking
in 1954, having been involved in the decision to part in it. The Linnaean system based on plant
make the atomic bomb. He became Baron Cherwell sexual organs was completely artificial, but con-
in 1941, resumed his professorship in 1953 and was venient. By his success he stifled some aspects
made a viscount in 1956. of botanical development for a century. After
Linnaeus, Carl [linayuhs], from 1762 Carl von Linn© Linnaeus™s death his collection was bought by Sir
(1707“78) Swedish botanist: the great classifier of James Smith (1759“1828). The London-based Linnean
plants; popularized binomial nomenclature. Society, founded by Smith in 1788, purchased the
Linnaeus began his training in medicine at the books and herbarium specimens in 1828.
University of Lund in 1727 but his father, a pastor Modern classification of living organisms has the
and enthusiastic gardener, was unable to maintain species at the lowest level with (in order of increas-
his education. Linnaeus became interested in ing generality) the genus, family, order, class,
plants, and moved to the university at Uppsala with phylum (for animals) division (for plants) and king-
the help of a benefactor. Here he investigated the dom. Some of these categories may be further sub-
newly proposed theory that plants exhibit sexual- divided.
ity. O Rudbeck (1630“1702) (of Rudbeckia) arranged Thus modern man (Homo sapiens sapiens) belongs
that Linnaeus should take over his unwanted lec- to the species Homo sapiens and subspecies sapiens;
tures on botany, and attendance rose from 80 to his genus is Homo; family Hominidae; order
400. He began to form a taxonomic system based on Primates; class Mammalia; phylum Chordata; king-
the plant sex organs, stamens and pistils. In 1732, dom Animalia.
Linnaeus undertook a visit to Lapland and in 1733“ Each category has its own definition: eg Primates,
5 to mainland Europe, in order to examine its flora which includes gorillas, chimpanzees and humans,
and animal life. has defining features that include upright posture,
Deciding to earn his living as a physician (out of opposable thumbs, large brain and similar blood
necessity), he went to Holland to qualify (1735). plasma proteins. The family Hominidae includes
While there he published Systema naturae, in which modern man and fossil man species from the
he divided flowering plants into classes depending Pleistocene onwards.
on their stamens and subdivided them into orders After Darwin™s work on evolution it was natural
according to the number of their pistils. This to try and link classification with evolution. By the
system, though useful for ordering of the many end of the 20th-c, classification could be based
new species being discovered, only partly showed not only on morphology (i.e. form and structure)
the relationship between plants. but also on genetic comparisons. These point to
Linnaeus returned to Sweden as a practising descent for all animals from an ancestor living
physician in 1738, gaining patients in court circles. over 600 million years ago; the fossil record begins


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