Men and Women of Science

ca. 400 B.C.

Hippocrates establishes the fundamental principles of medical science.

Democritus proposes the first known atomic theory of matter.

ca. 345 B.C.

Aristotle develops theories about the nature of matter; he provides proofs of the earth’s spherical shape.

ca. 240 B.C.

Archimedes establishes fundamental principles of experimental science.

ca. 135 B.C.

Hipparchus discovers the precession of the equinoxes; he develops a system of star classification by magnitude.

ca. 7 B.C.

Strabo, a Greek geographer and historian, completes the 17-volume Geography, which noted that the rising and sinking of lands was due, partially, to volcanoes and earthquakes.

ca. A.D. 70

Pliny the Elder, a Roman scholar, writes the 37-volume Historia Naturalis that recorded all Roman knowledge of rocks, minerals, and fossils. Pliny dies in A.D. 79 observing the eruption of Vesuvius that destroyed the city of Pompeii.

ca. A.D. 150.

Ptolemy formulates the classical system of astronomy, which was accepted in the West for over 1,500 years.

ca. A.D 175

Galen discovers certain principles of the circulation of blood in animals and humans.

ca. A.D. 900

Rhazes a Persian-born physician, describes measles and smallpox.

ca. A.D. 1000

Avicenna, an Arab physician, produces a medical encyclopedia that accurately describes meningitis, tetanus, and many other diseases.

ca. 1247

Roger Bacon establishes certain principles of the modern, empirical, scientific method.

ca. 1514

Nicolaus Copernicus formulates the theory that the earth revolves around the sun; this overthrows the 1,500-year-old Ptolematic system.

ca. 1540

Phillippus Aureolus Paracelsus pioneers the application of chemistry to medicine.


Andreas Vesalius publishes a treatise containing the first accurate anatomical portrayal of the human body.

ca. 1550

Ambroise Pare introduces surgical techniques that anticipate modern surgery, earning him the title “father of modern surgery.”


Georgius Agricola, aphysician from Saxony, writes De Re Metallica, which becomes the basis for modern studies and books on metallurgy and mining.


Tycho Brahe sights a supernova, or exploding star, which disproves the ancient idea that the heavens cannot change.

ca. 1600

William Gilbert provides a foundation for the study of electricity and magnetism.


Galileo improves the telescope and observes the heavens; he helps found modern scientific method.

ca. 1618

Johannes Kepler formulates the laws of planetary motion.


Francis Bacon publishes The New Atlantis, which describes a modern research institution. This and earlier works by Bacon contributes to the modern scientific method.


William Harvey publishes a landmark treatise on the human heart and the circulation of blood.


Blaise Pascal invents the first calculating machine, which is the direct ancestor of modern calculators and cash registers.

ca. 1637-1644

Rene Descartes introduces the modern philosophy of rationalism, which contributes to the human will for knowledge and to the modern scientific method.


William Harvey publishes a treatise that establishes the foundation of the science of embryology.

ca. 1655

William Boyle and Robert Hooke build air pumps with which they investigate vacuums.


The Royal Society, an organization to promote the natural sciences, is founded in London.


Robert Boyle publishes a book that descibes his theory of matter.

Marcello Malpighi describes capillaries viewed through a microscope.


Robert Hooke observes and describes cells in cork.

ca. 1665-1666

Isaac Newton conducts his first investigation on gravity and motion.


The Academy of Sciences is founded in Paris.


Nicolaus Steno, a Danish physician, formulated the iaw of superposition—that is, layers of rock are always deposited with the oldest strata on the bottom and the youngest on the top.

Jan Swammerdam publishes a treatise on metamorphosisi of insects.

ca. 1678

Christian Huygens formulates the wave theory of light


Isaac Newton publishes his discoveries in optics.


Edmond Halley publishes Synopsis of the Astronomy of Comets, in which he describes and accurately predicts the reappearance of the comet that will come to bear his name.


Daniel Bernoulli develops the kinetic theory of gases.


Diderot and d’Alembert publish a 28-volume encyclopedia, in which they catalog the science and technology of their day.

ca. 1752

Joseph Black identifies carbon dioxide.


Carolus Linnaeus publishes a fundamental treatise on plant classification.


Immanuel Kant, a German philosopher, suggests that the sun and planets were formed from the same elements and in the same way.


Carolus Linnaeus publishes his treatise on animal classification.


Henry Cavendish discovers properties of hydrogen.


David Rittenhouse builds a precise model of the solar system.


Joseph Priestly and Carl Scheele independently discover oxygen.


Antoine Lavoisier gives the first accurate scientific explanation of combustion (fire).


Sir William Herschel discovers the planet Uranus.


Henry Cavendish discovers that water is a chemical compound composed of hydrogen and oxygen.


Charles Coulomb formulates the laws of attraction and repulsion between electrically charged particles.


Antoine Lavoisier publishes the first modern textbook on chemistry.

ca. 1791-1796

Benjamin Banneker, an American astronomer and mathematician, publishes a series of almanacs that include his own astronomical and tidal calculations.

ca. 1792-1795

Count Alessandro Volta builds the first electric battery—the voltaic pile.


Edward Jenner gives the first successful vaccination —for smallpox.

Pierre Simon de Laplace a French mathematician, proposes that the sun and planets are formed from a spinning cloud of gas called a nebula.

ca. 1800-1805

Baron Cuvier develops a system of classifying animals according to body types; he establishes the science of comparative anatomy.


John Dalton develops an atomic theory of chemical elements.


Humphry Davy isolates the elements sodium and potassium.


Amadeo Avogadro formulates the theory that equal volumes of all gases at the same temperature and pressure contain equal numbers of particles.


Jons Jacob Berzelius published his study of atomic weights of elements, using oxygen as a standard against which others are measured.


Hans Oersted discovers the magnetic field surronding a conductor carrying an electric current.

ca. 1822

Andre Ampere discovers the basic laws of electromagnetism.


Charles Babbage designs his first computer. His models were in many ways equal to the first computers of the electronic age.


Joseph Niepce produces the first photograph.


Robert Brown described the agitation of microscopic particles, now known as Brownian motion.


Caroline Herschel is awarded a gold medal from the Royal Astronomical Society for her catalog of nebulae.

Friedrich Wohler synthesizes the organic substance urea from inorganic materials.


Robert Brown discovers the nucleus in living cells.

Michael Faraday and Joseph Henry independently discover the principle of electromagnetic induction.


Charles Lyell publishes Principles of Geology, founding the modern science of geology.


Joseph Henry publishes his discoveries on self-induction.

ca. 1838

Matthias Schleiden and Theodor Schwann propose that the cell is a basic structural and functional unit of all living things.

ca. 1840

Louis Agassiz theorizes that huge sheets of ice once extended from the North Pole to Central Europe, dramatically changing the earth’s surface.

ca. 1845

Crawford Long and William T. G. Morton discover that ether gas could safely be used to put patients to sleep during surgery.


Johann Galle and Heinrich L. d’Arrest discover the planet Neptune.


Maria Mitchell, one of the first important astronomers in the U.S., discovers a new comet.


Elizabeth Blackwell is the first women to receive a medical degree in the U.S.


Hermann Helmholtz measures the speed of a human nerve impulse, proving that living matter could be analyzed in the same way as nonliving matter.

ca. 1850

James P. Joule discovers that energy and heat are interchangeable at a fixed rate.


Lord Kelvin publishes “On the Dynamical Theory of Heat,” which contains the second law of thermodynamics.

ca. 1855

Robert Bunsen and Gustaz Kirchhoff discover that atoms of each chemical element produce a certain set of spectral lines; this leads to the identification of the elements that make up a star.


Sir William Perkin creates the first synthetic dye.


Rudolf Virchow publishes Cellular Pathology, establishing the idea that diseases should be studied at the cellular level.

ca. 1863-1864

Louis Pasteur develops the process known as pasteurization.


James Clerk Maxwell predicts the existence of electromagnetic waves.


Joseph Lister pioneers antiseptic surgery.

Friedrich Kekule von Stradonitz describes the molecular structure of benzene, laying the foundations for modern organic chemistry.


Gregor Mendel publishes his pioneering work in heredity.


Dmitri Mendeleev proposes a form of the periodic table of elements.


Josiah Gibbs develops and publishes the phase rule, explaining the relationships between gases, solids, and liquids.


Robert Koch proves that bacteria cause anthrax, thereby proving the germ theory.


Robert Koch identifies the type of bacteria that causes tuberculosis.


Louis Pasteur administers the first successful rabies vaccine.


Heinrich Hertz discovers electromagnetic waves.


Albert Michelson and Edward Morley devise an experiment that disproves the existence of ether.


John Muir’s arguments for conservation helped pass the Yosemite National Park bill, creating Yosemite National Park and Sequoia National Park.


Daniel Hale Williams performs the first open-heart surgery.

ca. 1894

Shibasaburo Kitasato discovers the bacillus that causes bubonic plague.


Wilhelm Roentgen discovers X rays.

Guglielmo Marconi transmits the first telegraphic signal through air.


Antoine Henri Becquerel discovers natural radioactivity.


Sir Joseph John Thomson discovers the electron.


Pierre and Marie Curie isolate the radioactive element radium.

Gifford Pinchot is appointed chief of the U.S. Division of Forestry.


Max Planck originates the quantum theory.

Sigmund Freud publishes the Interpretation of Dreams, a landmark treatise on psychotherapy.


Hugo de Vries publishes his mutation theory of evolution.


Wilheim Wien discovers the atomic proton.

ca. 1903

Christiaan Eijkman and Frederick Hopkins demonstrate the existence of vitamins.


Sir William Ramsay receives the Nobei Prize in chemistry for isolating argon, helium, neon, krypton, and xenon.


Albert Einstein proposes the theory of relativity and a theory explaining the photoelectric effect.

Ernest Rutherford theorizes that the half-life of radioactive minerals could be used to determine the age of minerals.

ca. 1905

Elie Metchnikoff discovers the function of phagocytes in blood.


Ernest Rutherford confirms the existence of the proton in the atomic nucleus.


A.A. Michelson is the first American to win a Nobel prize in science.


Thomas Hunt Morgan and his associates identify the gene as the basic unit of heredity and the chromosome as the cellular structure on which genes reside.

Marie Curie publishes a fundamental treatise on radioactivity.


Marie Curie receives the Nobel Prize in chemistry for her work in isolating radium.


Ernest Rutherford formulates the modern nuclear theory of the atom.
Heike Onnes discovers superconductivity.


Henrietta Swan Leavitt publishes a table of her findings on the period lengths of variable stars.

Garrett Augustus Morgan designs a gas mask, winning first prize at the second International Exposition of Safety and Sanitation in 1914.


Robert Millikan measures the charge of the electron.


Niels Bohr publishes his theory of atomic structure.


Ernest Everett Just receives the Spingarn Medal for his study of fertilization in marine invertebrates and the role of the cell surface in the development of such organisms.

ca. 1916

George Washington Carver develops an enormous variety of industrial uses for American agricultural crops.


Gilbert Lewis descibes electron bonding between atoms.

Albert Einstein publishes his general theory of relativity.


Ernest Rutherford produces the first artificial disintegration of an atom.


John James Macleod and Sir Frederick Banting discover insulin.

Margaret Sanger is founder of the Birth Control League, later renamed Planned Parenthood Federation of America.


Louis De Broglie proposes the wave theory of the electron.


Erwin Schrodinger develops the principles of wave mechanics.

Lloyd A. Hail serves as technical director and chief chemist at Griffiths Laboratories in Chicago.


Thomas Hunt Morgan publishes The Theory of the Gene, a landmark study of genetics.


Hermann Joseph Muller publishes his discovery that X rays can cause genetic mutation.

Charles Elton, an English biologist, publishes Animal Ecology and Evolution, a landmark study of the balance of nature.


Sir Alexander Fleming discovers penicillin.

Margaret Mead publishes her first book, Coming of Age in Samoa.


Edwin Hubble demonstrates that the universe is expanding.

Louis Victor De Broglie receives the Nobel Prize for physics.


Karl Jansky detects radio waves outside the solar system.


Sir James Chadwick discovers the atomic neutron.


Enrico Fermi splits the atom.

Roger Tory Peterson publishes his first manual, Field Guide to the Birds.


Percy Lavon Julian creates synthetic phytosostigmine, a drug used to treat glaucoma.


Otto Hahn and Fritz Strassman split the uranium atom, and Lise Meitner and Otto Frisch

develop a mathematical theory to explain the split.


Ernest O. Lawrence receives the Nobel prize in physics for his invention of the cyclotron.

Helen Sawyer Hogg publishes her Catalogue of Variable Stars in Globular Clusters.


Karl Landsteiner and A.S. Weiner discover the Rh factor in human blood.

Glenn T. Seaborg discovers plutonium.


Helen Brooke Taussig and Alfred Blalock team up to develop an operation to help blue babies.


Enrico Fermi produces the first controlled nuclear chain reaction.


Selman Waksman discovers streptomycin.


Lloyd Quarterman works with Fermi’s team to create the first nuclear reactor.


Oswald Avery demonstrates that genes consist of DNA.

Alfred Blalock performs the first blue baby operation.


Alan Mathison Turing helps build the first British electronic digital computer.

ca. 1946

Melvin Calvin traces the chain of chemical reactions involved in photosynthesis.


John Bardeen, Walter Brattain, and William Shockley invent the transisitor.

Gerty T. Cori and her husband Carl F. Cori win the Nobel prize for physiology or medicine.


Grace Murray Hopper develops COBOL, one of the most widely used computer programming languages.

Jane Cooke Wright begins studying the effects of various chemotherapies on cancerous growths.


Edward Teller develops the first hydrogen bomb.


Rosalind Elsie Franklin discovers the helical structure of DNA.

Jonas Salk announces the development of the first trial polio vaccine.

Francis Crick, with James Watson, creates a three-dimensional model of the DNA molecule


Linus Pauling is the first sole recepient of the Nobel prize for chemistry.


Owen Chamberlain and Emilio Segre discover the antiproton.


The Soviet Union launches Sputnik I, the first artificial satellite.

Roger Revelle is among the first to study the problems of global warming and the greenhouse effect


Roslyn Yalow develops radioimmunassay


Jane Goodall begins studying chimpanzees.


Theodore H. Maiman builds the first laser.


Yuri Gagarin, a Russian cosmonaut, becomes the first human to orbit the earth in a spaceship.


Rachel Carson publishes Silent Spring, awakening America to the problems of pollution.


Dorothy Crowfoot Hodgkin wins the Nobel Prize for determining the structure of the vitamin B12 molecule.

Radio astronomers discover primordial, background radiation in the universe believed to originate in the “big bang.”


The United States makes the first manned landing on the moon.


John Bardeen, Leon Cooper, and John Robert Schrieffer receive a Nobel Prize in physics for developing the theory of superconductivity.


Burton Richter and Samuel C.C. Ting discover the psi particle.


Andrei Sakharov is the first citizen of the U.S.S.R. to be awarded the Nobel Peace Prize.


Scientists use genetically engineered bacteria to produce human insulin.


Walter Eugene Massey is director of the University of Chicago’s Argonne National Laboratory.

Steven Weinberg is awarded the Nobei prize for physics.

ca. 1980

Geneticists produce recombinant DNA in bacteria.

ca. 1981

Chemists begin work on the development of a solar-powered device that produces hydrogen fuel by means of the chemical breakdown of water.


Carlo Rubbia and his research team discover the W particle and Z particle.

Dian Fossey publishes Gorillas in the Mist

Scientists use genetic engineering to transfer human growth genes into mice, triggering twice-normal growth in the mice.

Barbara McClintock wins the Nobel Prize for physiology or medicine for her discovery that certain genes can change their position in the chromosomes of cells.


Benjamin Carson successfully separates conjoined twins.


Stephen William Hawking publishes A Brief History of Time.

Leon Lederman wins the Nobel prize in physics.


Mae Jemison is the first African-American woman to travel in space.