APPENDIX 1
A CHRONOLOGY OF THE ATOMIC VIEW OF NATURE
c. 550   THALES of Miletus (Greece, c. 640-546 B.C.) recorded the attractive properties of 
   B.C.       rubbed amber and of lodestone.
c. 450   LEUCIPPUS (Greece) proposed an atomic concept of matter. 
  B.C.
c.400    DEMOCRITUS of Abdera (Greece, c. 460-357 B.C.), pupil of Leucippus,  was the most 
   B.C.      famous of the atomists in ancient times. He taught: "The only existing things are the 
                atoms and empty space; all else is mere opinion.
c. 335   ARISTOTLE (Greece, 384-322 B.C.) held that all matter was basically com posed of the 
  B.C.      same continuous primordial stuff.
c.300    EPICURUS of Samos (Greece, c. 342-270 B.C.) founded a philosophical  system based on 
   B.C.     the atomism of Democritus.
c.300    ZENO of Cition (Greece, c. 336-264 B.C.) founded the Stoic school of philosophy which 
   B.C.      held that matter, space, etc. were continuous.
c. 60     TITUS LUCRETIUS CARUS (Rome, c. 96-55 B.C.) attempted to formulate a rational 
  B.C.       explanation of natural phenomena by extending the beliefs of Democritus and Epicurus. 
                His poem,  De Rerum Natura, is the most complete record of Greek atomism extant. 
               The atomism of antiquity was primarily a system of metaphysics. The atomic view of 
                matter in the modern sense was barely introduced in its most elementary form by the 
                beginning of the 19th century.
c. 400   SAINT AUGUSTINE (Aurelius Augustinus) (North Africa, 354-430) was the first to report 
                that  the forces exerted by rubbed amber and by lodestone are different properties.
c. 1600  WILLIAM GILBERT (England, 1540-1603) made the first detailed study of magnetism 
                and also showed that, in addition to amber, many other materials can be electrified.
1638     GALILEO GALILEI (Italy, 1564-1642) published Discorsi e Dimostrazioni 
                Matematiche intorno a due nuove Scienze attenti alla Mecanica e Movimenti locali 
                (Discourses and Mathematical Demonstrations concerning Two New Sciences 
                 pertaining to Mechanics and Local Motions, usually contracted to Two New Sciences). 
                This account of Galileo's contributions to science establishes him as the founder of 
                dynamics. He was the first to  make extensive use of the experimental 
             method to study natural phenomena.  From his time on, induction from 
                experiment replaced the teleology of the  scholastics as a guiding  principle in the 
                organization of the natural sciences.


1650-   ROBERT BOYLE (England, 1627-1691), ROBERT HOOKE (England, 1635 1703), and 
 1700    ISAAC NEWTON (England, 1642-1727) gave qualitative explanations of Boyle's law by 
                assuming a kinetic theory of gases.
1675    JEAN PICARD (France, 1620-1682) observed the luminous glow in the Torricellian vacuum 
               of a barometer produced by motion of the mercury when the instrument was carried from 
               place to place.  << probably not related to Jean Luc Picard : ST-TNG >>
1675    ISAAC NEWTON (England) developed a corpuscular theory of light.
1676    OLE CHRISTENSEN ROEMER (Denmark, 1644-1710) was the first to show that the 
               velocity of light is finite. His conclusion was based on the variations of the time intervals 
               between consecutive eclipses of one of the moons of Jupiter during the course of the 
               revolution of the earth around the sun.
1678    CHRISTIAN HUYGENS (CHRISTIAAN HUYGHENS) (Netherlands, 1629-1695) 
               developed a wave theory of light in which light was regarded as composed of longitudinal 
               "pulses" consisting of compressions and rarefactions, similar to sound, in an extremely 
               thin, all-pervading medium which he called the aether. The concept that light is a periodic 
               wave motion was introduced in about 1750 by Leonard (Leonhard) Euler (Switzerland, 
              Germany,  Russia, 1707-1783).
                   Not only did Huygens correctly account for the refraction of light by transparent bodies 
               by means of spherical emanations (wavelets), but also, by using both spherical and 
               spheroidal wavelets, he became the first one to explain double refraction, a phenomenon 
               that was discovered in 1669 by Erasmus Bartholinus (Denmark, 1625-1692).
1687   ISAAC NEWTON (England, 1642-1727) published Philosophiae Naturalis Principia 
               Mathematica (Mathematical Principles of Natural Philosophy) which contains the 
               fundamental laws of classical dynamics and the law of gravitation.The synthesis involved 
               in obtaining these laws is one of the greatest achievements of the human mind.
1705   FRANCIS HAUKSBEE (England, d. 1713) made a "powerful" electrostatic generator and 
              discovered the conditions for producing luminous electric discharges in gases.
1728   JAMES BRADLEY (England, 1693-1762) explained the aberration of light from stars by 
              taking the vector sum of the orbital velocity of the earth v and the free-space velocity of 
              light c, and showed that the angle of aberration was a function of the ratio of these 
              velocities,  v/c.  On this basis, he also showed that the revolution of the earth around the 
              sun correctly accounted for the observed cyclic change in the aberration of starlight. (The 
              Anti-Copernicans, still numerous in the first half of the 18th century, were unable to refute 
              this explanation of the change.) Bradley's work is the first of many instances that seemed 
              to show that the value of the velocity of light depends on the motion of the observer.


1731   STEPHEN GRAY (England, 1666/7-1736) discovered the conduction of electricity.
1734   CHARLES FRANCOIS de CISTERNAY DUFAY (France, 1698-1739) showed that there 
              are two kinds of electrification, resinous and vitreous, and then proposed a two-fluid 
              theory of electric discharge. He also found that the air in the vicinity of a hot body is 
              conducting.
1738  DANIEL BERNOULLI (Switzerland, 1700-1782) was the first to devise a quantitative 
              kinetic theory of gases.
1745  EWALD JURGEN von KLEIST (Germany, d. 1748) and 
          PEITER VAN MUSSCHENBROEK (Netherlands, 1692-1761) 
             independently made the first capacitors, called Leyden jars.
1752  BENJAMIN FRANKLIN (USA, 1707-1790) experimentally verified the electrical 
            nature of lightning and introduced the one-fluid theory of flow of electricity -
            from surplus of positive to deficiency or negative. His theory contained the 
           first clear statement of the law of conservation of electric charge.
1753  JOHN CANTON (England, 1718-1772) discovered the facts of electrostatic induction.
1766  HENRY CAVENDISH (England, 1731-1810) discovered hydrogen. Within the next score 
             of years he found the inverse square law of force action between electric charges and other 
             important laws of electricity but, because of excessive shyness, he withheld announcement 
             of his experiments. The great extent of his work was not known until James 
          Clerk Maxwell published Cavendish's papers in 1879.
1785 CHARLES AUGUSTIN COULOMB (France, 1736-1806) determined the law of force action 
             between electric charges.
1789  ANTOINE LAURENT LAVOISIER (France, 1734-1794) published a book containing a 
             well-founded concept of chemical elements and the verification of the law of conservation 
             of matter in chemical reactions.
1791  BRYAN HIGGINS (Ireland, 1737-1820) and WILLIAM HIGGINS (Ireland, c. 1769-1825) 
             reported the first of a series of experiments leading to the laws of chemical combination.
1799  JOSEPH Louis PROUST (France, Spain, 1754-1826) established the law of definite 
             proportions for chemical compounds.
1800  ALESSANDRO GUISEPPE ANTONIO ANASTASIO VOLTA (Italy, 1745-1827) made the 
             first voltaic pile (battery), based on his discovery of the fundamental conditions necessary 
             to  produce the "animal electricity" that had first been observed in 1780 by Aloisio (or 
             Luigi) Galvani (Italy, 17371798).
1801  THOMAS YOUNG (England, 1773-1829) showed that his interference experiments verified 
             the  wave theory of light.


1803   JOHN DALTON (England, 1766-1844) published the first of a series of papers 
           introducing atomic weights, establishing the law of multiple proportions, and founding 
             the atomic theory of matter.
1808   JOSEPH Louis GAY-LuSSAC (France, 1778-1850) discovered the law of combining volumes 
             of gases.
1810-   ETIENNE LOUIS MALUS (France, 1775-1812), 
  1875  DOMINIQUE FRANCOIS JEAN ARAGO (France, 1786-1853), 
           AUGUSTIN JEAN FRESNEL (France, 17881827), 
           JEAN BERNARD LEON FOUCAULT (France, 1819-1868), 
           HIPPOLYTE Louis FIZEAU (France, 1819-1896), and 
           MARIE ALFRED CORNU (France, 1841-1902) established conclusively, through many 
              experiments, especially in physical optics, that light is a transverse wave.  Several of these 
              men made precise measurements of the velocity of light in various media.  In 1818 Arago 
              found that- the refraction of a prism for starlight was the same for light incident in the 
              direction of the earth's orbital velocity v as for that coming in the opposite direction.  This 
              unexpected null result was explained that same year by Fresnel's ether-drag theory, which 
              assumed partial ether entrainment in transparent media by an amount depending upon the 
              first power of v.  This theory appeared fully verified by the measurements of the speed of 
              light in moving water by Fizeau in 1851 and, in 1871, by the observations of the aberration 
              of starlight with a water-filled telescope by GEORGE BIDDELL AIRY (England, 
              1801-1892).
1811  LORENZO ROMANO AMADEO AVOGADRO (Italy, 1776-1856) introduced Avogadro's 
              hypothesis and differentiated between atoms and molecules.
1813  JONS JACOB BERZELIUS (Sweden, 1779-1848) introduced the present symbols for the 
              chemical elements.
1815  WILLIAM PROUT (England, 1875-1850) proposed that all elements are composed of an 
              integral number of hydrogen atoms.
1815-  JOSEPH FRAUNHOFER (Germany, 1787-1826) noted the spectral lines of several 
 1820      elements, obtained the first grating spectra, and observed the Fraunhofer (absorption) 
               lines in solar spectra. 
1819  PIERRE LOUIS DULONG (France, 1785-1838) and 
          ALEXIS THERESE PETIT (France, 1791-1821) found the law of constancy of molar 
              specific heat capacities of elements.
1820  HANS CHRISTIAN OERSTED (Denmark, 1777-1851) discovered that an electric current 
              produces a magnetic field. This initiated the study of electromagnetism.
1821  THOMAS JOHANN SEEBECK (Russia, Germany, 1770-1831) discovered 
              thermoelectricity.
1823  ANDRE MARIE AMPERE (France, 1775-1836) published his mathematical theory of 
              electromagnetism and the laws of magnetic field produced by currents.  Some of these 
              laws were also discovered independently by JEAN BAPTISTE BIOT (France, 1774-1862) 
              and FELIX SAVART (France, 1791-1841). 


1826   GEORG SIMON OHM (Germany, 1787-1854) discovered Ohm's law.
1827   ROBERT BROWN (England, 1773-1858) discovered Brownian movement.
1831   MICHAEL FARADAY (England, 1791-1867) and JOSEPH HENRY (USA, 1797-1878) 
               independently discovered electromagnetic induction.
1833   MICHAEL FARADAY (England) discovered the laws of electrolysisand
            introduced the terms "anode" and "cathode."
1835   JOSEPH HENRY (USA) discovered self-induction and, in 1842, oscillatory electric 
              discharge.
1842   JOHANN CHRISTIAN DOPPLER (Austria, 1803-1853) deduced a relation that showed 
              that the observed frequency of waves depends upon the relative motion of the source and 
              the observer.
1842   JULIUS ROBERT MAYER (Germany, 1814-1878) calculated the mechanical equivalent 
              of heat theoretically from the specific heats of gases and vaguely proposed a law of 
              conservation of energy based on "Ex nihilo, nihil fit." His work was not published for 
              several years.
1843  JAMES PRESCOTT JOULE (England, 1814-1889) published the first of a series of reliable 
             experimental results that showed the constancy of the relation between mechanical energy 
             and heat-a basic step toward the law of conservation of energy.
1847  HERMANN LUDWIG FERDINAND VON HELMOLTZ (Germany, 1821-1894) proposed 
             the law of conservation of "force" (energy).
1848  WILLIAM THOMSON (Lord Kelvin, 1st Baron) (Ireland, Scotland, 18241907) introduced 
             absolute temperature.
1850  RUDOLPH JULIUS EMANUEL CLAUSIUS (Germany, 1822-1888) announced the second 
             law of thermodynamics.  Lord Kelvin independently found the same law in 1852.
1850-  AUGUST KARL KROENIG (Germany, 1822-1879), 
  1900 RUDOLPH JULIUS  EMANUEL CLAUSIUS (Germany), 
           JAMES CLERK MAXWELL (Scotland, England, 1831-1879), 
           LUDWIG BOLTZMANN (Austria, 1844-1906), and 
           JOSIAH WILLARD GIBBS (USA, 1839-1903) developed the kinetic theory of gases 
              and founded statistical mechanics. Maxwell derived his speed distribution law in 1860, 
              Clausius introduced the concept of entropy in 1865, and Boltzmann related entropy to 
              thermodynamic probability in 1877.
1858  STANISLAO CANNIZZARO (Italy, 1826-1910) resolved the conflicting values of atomic 
             weights by clarifying the terms "atomic," "molecular," and "equivalent" weights.
1859  GUSTAV ROBERT KIRCHHOFF (Germany, 1824-1887) showed that the ratio of the 
             emittance to the absorptance for a given wavelength of radiation is the same for all 
             surfaces at the same temperature, and introduced the concept of cavity (Hohlraum) or 
             blackbody radiation.


1859   HEINRICH GEISSLER (Germany, 1814-1879) and 
           JULIUS PLUECKER (Germany, 1801-1868) discovered the "rays" 
               (now called cathode rays) from the negative electrode in gaseous discharge tubes.
1863   JAMES ALEXANDER REINA NEWLANDS (England, 1837-1898) Stated the law of 
                octaves, a limited and elementary form of the periodic table of the elements.
1864   JAMES CLERK MAXWELL (Scotland, England, 1831-1879) wrote A Dynamical 
             Theory of the Electromagnetic Field, a paper synthesizing electricity, 
              magnetism, and light.  This  was probably the greatest work since 
              Newton's Principia.
1865   JOSEPH LOSCHMIDT (Germany, 1821-1895) used the equations of the kinetic theory of
               gases to make the first determination of Avogadro's number and of molecular diameters.
1869   DMITRI IVANOVICH MENDELEEV (Russia, 1834-1907) and 
           JULIUS LOTHAR MEYER (Germany, 1830-1895) independently introduced the periodic 
               table of the elements, a concise summary of years of experimental and theoretical 
               chemistry. The table is both mnemonic and heuristic.
1869   JOHANN WILHELM HITTORF (Germany, 1824-1914) observed the deflection of rays 
               from the cathode in a discharge tube, by means of a magnetic field.
1871   CROMWELL FLEETWOOD VARLEY (England, 1828-1883) found that the rays from 
              the cathode are negatively charged.
1876    EUGEN GOLDSTEIN (Germany, 1850-1930) introduced the name "cathode rays" and 
                began experiments leading eventually to the discovery of the positive counterpart, 
                Kanalstrahlen (channel or canal rays). In 1886 he suggested that the aurora is due to 
                cathode rays from the sun.
1877  WILLIAM RAMSAY (England, 1852-1916) and, independently, 
           JOSEPH DELSAULX (France, 1828-1891) and 
           IGNACE J. J. CARBONELLE (France, 1829-1889) advanced the first rather complete 
               qualitative explanation of Brownian movement by attributing it to molecular impact. 
               Some years later Ramsay discovered several of the noble gases, and made important 
               contributions to the study of radioactivity. He was awarded the Nobel prize for chemistry 
               in 1904.
1879    EDWIN HERBERT HALL (USA, 1855-1938) discovered the existence of a potential 
               difference between the opposite edges of a metal strip carrying a longitudinal electric 
               current, when the plane of the strip is set normal to a magnetic field. This is called the 
               Hall effect.
1879    WILLIAM CROOKES (England, 1832-1919) began a long series of brilliant experiments 
               On the discharge of electricity through gases.
1879    JOSEF STEFAN (Austria, 1835-1893) announced Stefan's law, which gives the total 
               energy radiated by a blackbody. This was the first successful attempt to connect 
               absolute temperature and radiation.


1881    JULIUS ELSTER (Germany, 1854-1920) and HANS GEITEL (1855-1923) started a long, 
               systematic investigation of electrical effects produced by incandescent solids.
1883    THOMAS ALVA EDISON (USA, 1847-1931) discovered the Edison effect, the 
               emission of negative electricity from incandescent filaments in a vacuum.
1884    JOHANN JAKOB BALMER (Switzerland, 1825-1898) found an empirical wavelength 
               relation for a spectral series of hydrogen. This was the first series equation found for 
               any spectrum.
1887    SVANTE AUGUST ARRHENIUS (Sweden, 1859-1927) conclusively established the ion 
               dissociation theory of electrolytes which grew from suggestions made by Clausius in 1857.
               Arrhenius was awarded the Nobel prize for chemistry in 1903.
1887    ALBERT ABRAHAM MICHELSON (Germany, USA, 1852-1931) and 
           EDWARD WILLIAMS MORLEY (USA, 1838-1923) performed the first precision 
               experiment that showed that the earth has no ether drift. In a letter to Nature in 1879 
               Maxwell pointed out that evidence of ether drift had to be sought in second-order 
               effects-those depending on v2/c2.  These are involved in interference methods. The first 
               trial by Michelson in 1881 gave inconclusive results. Michelson was awarded the Nobel 
               prize for physics in 1907.
1887    HEINRICH RUDOLPH HERTZ (Germany, 1857-1894) discovered the photoelectric 
               effect while verifying the existence of the electromagnetic waves predicted by Maxwell.
1888    WILHELM HALLWACHS (Germany, 1859-1922) showed that only negative charges are 
               emitted in the photoelectric effect.
1890    JOHANNES ROBERT RYDBERG (Sweden, 1854-1919) found an empirical wavelength 
               relation for complex series of spectral lines.
1891   JOHNSTONE STONEY (England, 1826-1911) introduced the name "electron" for an 
              elementary unit of negative charge in electrolysis.
1892   GEORGE FRANCIS FITZGERALD (Ireland, 1851-1901) and 
           HENDRIK ANTOON LORENTZ (Netherlands, 1853-1929) independently made the 
           ad hoc assumption of contraction of length to account for the null result of the 
           Michelson-Morley experiment. As Lorentz successively refined his electric theory of 
           matter to conform with the results of new experiments, he obtained the space and time 
           transformations later derived by Einstein. For later work Lorentz was awarded the Nobel 
           prize for physics jointly with P. Zeeman in 1902.
1893   WILHELM WIEN (Germany, 1864-1928) derived his blackbody radiation displacement 
              law.  His blackbody radiation law was announced in 1896. He was awarded the Nobel 
              prize for physics in 1911.


1893   PHILIPP EDUARD ANTON VON LENARD (Hungary, Germany, 1862-1947) 
              investigated cathode rays by passing them through a Lenard window (thin-window) tube 
              into air.  For this and later work he was awarded the Nobel prize for physics in 1905.
1895   JEAN BAPTISTE PERRIN (France, 1870-1942) demonstrated conclusively that cathode 
              rays are negatively charged. For this and later work he was awarded the Nobel prize for 
              physics in 1926.
1895   WILHELM CONRAD ROENTGEN (Germany, 1845-1923) discovered x-rays.  He was 
             awarded the Nobel prize for physics in 1901.
1896   ANTOINE HENRI BECQUEREL (France, 1852-1908) discovered the radioactivity of 
              uranium.  He was awarded the Nobel prize for physics jointly with the Curies in 1903.
1896   PIETER ZEEMAN (Netherlands, 1865-1943) observed the splitting of spectral lines 
              radiated by excited atoms in an intense magnetic field. The early theory of this effect was 
              derived by H. A. LORENTZ (Netherlands). They were jointly awarded the Nobel prize for 
              physics in 1902.
1896   OLIVER LODGE (England, 1851-1940) reported that, contrary to expectations, there was 
              no detectable ether drag on light passing between two large closely spaced disks of steel 
              rotating at enormous speeds even when the disks were strongly magnetized or electrified.
1897   JOSEPH JOHN THOMSON (England, 1856-1940) determined q/m for cathode rays.  He 
              was awarded the Nobel prize for physics in 1906.
1897   ERNEST RUTHERFORD (Lord Rutherford of Nelson, 1st Baron) 
           (New Zealand, Canada,  England, 1871-1937) showed that the radiation from 
         uranium was complex, consisting of "soft" (alpha) and "hard" (beta) rays
           He was awarded the Nobel prize for chemistry in 1908.
1898   PIERRE CURIE (France, 1859-1906) and 
           MARIE SKLODOWSKA CURIE (Poland, France, 1867-1934) isolated radium and 
              polonium.  They were awarded the Nobel prize for physics jointly with H. Becquerel in 
              1903.  Marie Curie was also awarded the Nobel prize for chemistry in 1911.
1899   HENRI BECQUEREL (France), 
           STEFAN MEYER (Austria, 1872-1949) and 
           EGON VON SCHWEIDLER (Austria, 1873-1948), and 
           FREDERICK OTTO GIESEL (Germany, 1852-1927) independently observed 
              the magnetic deflection of alpha and beta rays.
1899   JULIUS ELSTER (Germany) and HANS GEITEL (Germany) determined the law of 
              radioactive decay experimentally.
1899   PHILIPP LENARD (Germany) showed that photoelectric emission is due to electrons.
1899  J. J. THOMSON (England) showed that the Edison effect is due to electrons.


1899   OTTO LUMMER (Russia, Germany, 1860-1925) and 
           ERNST GEORG PRINGSHEIM (Germany, 1881-1917), and also 
           FERDINAND KURLBAUM (Germany, 1857-1927) and 
           HEINRICH RUBENS (Germany, 1865-1922) made precise measurements of the 
               intensity-wavelength distribution of blackbody radiation.
1900   JOHN WILLIAM STRUTT (Lord Rayleigh, 3rd Baron), (England, 1842-1919) announced 
              a blackbody radiation law.  The derivation of this law was re-examined in collaboration
              with JAMES HOPWOOD JEANS (England, 1877-1946) and, after publication in 1905, 
             became known as the RayleighJeans law.  Rayleigh was awarded the Nobel prize for 
             physics in 1904.
1900   MAX KARL ERNST LUDWIG PLANCK (Germany, 1858-1947) introduced the 
              quantum theory of radiation-a revolutionary concept. He was awarded the Nobel prize 
              for physics in 1918.
1900   HENRI BECQUEREL (France) showed that beta rays are identical with cathode-ray 
              corpuscles.
1900   PAUL VILLARD (France, 1860-1934) discovered gamma rays.
1902   PHILIPP LENARD (Germany) discovered photoelectric threshold frequency and also that 
              the kinetic energy of photoelectrons is independent of the intensity of the incident light.
1903   FREDERIC THOMAS TROUTON (Ireland, England, 1863-1922) and 
           H. R. NOBLE (England) were unable to observe any orienting torque on a suspended, 
              charged capacitor as predicted on the basis of an ether drift (a second-order effect).
1903   ERNEST RUTHERFORD (England) and 
           FREDERIC SODDY (England, 1877-1956) showed that every radioactive process is a 
              transmutation of elements.  Soddy was awarded the Nobel prize for chemistry in 1921.
1903   WILLIAM CROOKES (England), and, independently, 
           JULIUS ELSTER (Germany) and HANS GEITEL (Germany) found that 
              the luminescence produced when alpha particles strike zinc sulfide consists of discrete 
              flashes of light of scintillations. This led to a method of counting individual alpha particles.
1904   WILLIAM RAMSAY (England) and FREDERIC SODDY (England) discovered the 
              remarkable occurrence of helium in all radium compounds.
1904   DEWITT BRISTOL BRACE (USA, 1859-1905) found no trace of the double refraction 
              predicted for an isotropic transparent body when it is rotated from parallel to the ether 
              drift to normal to it (a second-order effect). This type of experiment had been suggested 
              by the elder Lord Rayleigh.
1904   JOHN AMBROSE FLEMING (England, 1849-1945) applied the Edison effect to make the
              first thermionic valve ("radio" tube).
1904   MARYAN VON SMOLUCHOWSKI (Austria, 1872-1919) proposed a statistical theory of 
              Brownian movement.


1905   ALBERT EINSTEIN (Germany, Switzerland, USA, 1879-1955) completed the statistical 
              theory of Brownian movement, introduced the quantum explanation of the photoelectric 
              effect, and announced the special theory of relativity.  He was awarded the Nobel prize for
              physics in 1921.  The citation stated that the award was "for his contributions to 
              mathematical physics, and especially for his discovery of the law of the photoelectric 
              effect."
1905   EGON VON SCHWEIDLER (Austria) derived the law of radioactive decay from 
              probability theory-not obtainable from causality.
1906   OWEN WILLANS RICHARDSON (England, 1879-1959) began a long series of important 
              investigations on the emission of electricity from hot bodies (thermionic emission).  He 
              was awarded the Nobel prize for physics in 1928.
1906   LEE DE FOREST (USA, 1873-1961) made the first audion (triode) by introducing a grid 
              into a Fleming valve.
1907-   J. J. THOMSON (England) devised methods of positive-ray analysis.  This  was the 
  1912    beginning of mass spectroscopy.
1908   WALTER RITZ (Switzerland, 1878-1909) announced the combination principle for 
               computing the frequencies of spectral lines.
1908   LOUIS CARL HEINRICH FRIEDRICH PASCHEN (Germany, 1865-1947) experimentally
              verified the existence of a spectral series of hydrogen in the near infrared predicted by 
              the Rydberg-Ritz relation.
1908   CHARLES GLOVER BARKLA (England, 1877-1944) discovered from absorption 
               experiments that the secondary x-rays of various elements are composed of groups 
               of characteristic x-rays which he called the K, L, and 117 radiations, and demonstrated 
               the polarization of x-rays.  He was awarded the Nobel prize for physics in 1917.
1908   JEAN PERRIN (France) verified experimentally the several equations for Brownian 
              movement, obtained good values of Avogadro's number, and showed that equipartition 
              of energy held for small particles suspended in a stationary liquid.
1908   HERMANN MINKOWSKI (Lithuania, Germany, 1864-1909) developed a geometrical 
              interpretation of the special theory of relativity in which time and the three space 
             coordinates all had the same validity in a fourdimensional continuum.
1908-   ALFRED HEINRICH BUCHERER (Germany, 1863-1927), 
  1910   E. HUPKA (Ger many), and 
           CHARLES EUGENE GUYE (France, 1866-1942) and 
           SIMON RATNOWSKY (Russia, Switzerland, 1884-1945) independently 
                made precision measurements of the mass of an electron as a function of its velocity. 
               The results verified the Lorentz-Einstein mass variation relation.
1909    GUGLIELMO MARCONI (Italy, 1874-1937) and 
           CARL FERDINAND BRAUN (Germany, 1850-1918) were jointly awarded the Nobel 
                prize for physics - the former for combining the basic knowledge about Hertzian waves 
               to produce wireless telegraphy, and the latter for the study, production, and use of 
               electrical oscillators. Braun also developed the Braun tube, called the "cathode-ray" 
               tube in the USA.


1909    ERNEST RUTHERFORD (England) and 
           THOMAS ROYDS (England, 18841955) showed that alpha particles are doubly 
               ionized helium atoms. 1909- T. WULF (France) observed the rate of leak of charge 
               from a highly 1910 insulated electroscope placed at the top of the Eiffel Tower, and 
             ALBERT GOCKEL (Switzerland, 1860-1927) studied the same effect in balloon ascents 
               up to 4500 meters.  Both found the leakage rate greater than at the surface of the earth. 
              Their results were unexpected because the effect at ground level bad been ascribed to 
              local radioactivity of the soil.
1909-    ROBERT ANDREWS MILLIKAN (USA, 1868-1953) established the law of  multiple 
 1911        proportions for electric charges and made the first precise determination of the 
                 electronic charge.  He was awarded the Nobel prize for physics in 1923.
1910-    VICTOR FRANZ HESS (Austria, USA, 1883-1964) and 
  1912    WERNER KOL HOERSTER (Austria, 1887-1945) discovered cosmic rays. 
                 Hess was awarded the Nobel prize for physics jointly with C. D. Anderson in 1936.
1911    PETER JOSEPH WILHELM DEBYE (Netherlands, Switzerland, Germany, USA, 
               1884-1966) used the quantum theory to obtain a rather complete theory of specific heats, 
               and later applied the quantum concept to many problems in physical chemistry.  He was 
               awarded the Nobel prize for chemistry in 1936.
1911-   ERNEST RUTHERFORD (England), 
 1913   HANS GEIGER (Germany), and 
           ERNEST  MARSDEN (England, b. 1889) showed that a nuclear model of the atom was 
               required to explain their experiments on alpha-particle scattering by thin metal foils.
1911    CHARLES THOMSON BEES WILSON (Scotland, England, 1869-1959) made the first 
               expansion cloud chamber.  This is the most important device in nuclear physics.  He was 
               awarded the Nobel prize for physics jointly with A. H. COMPTON in 1927.
1912    MAX FELIX THEODOR von LADE (Germany, 1879-1960) with 
           WALTER FRIEDRICH (Germany, b. 1883) and 
           PAUL C. M. KNIPPING (Germany, 1883-1935) established the wave nature of x-rays by 
               crystal diffraction.  Laue was awarded the Nobel prize for physics in 1914.
1912    HANS GEIGER (Germany, 1882-1945) and JOHN MITCHELL NUTTALL (England, 
               1890-1958) obtained an empirical law relating the energy of an emitted alpha particle to 
               the disintegration constant of the parent nucleus.
1913    HANS GEIGER (Germany) published a detailed description of the pointdischarge counter 
               tube which was developed from a simpler form first made in 1908.  This instrument was 
               greatly improved in 1928.


1913    FREDERICK SODDY (England) and 
           KASIMIR FAJANS (Poland, Germany, b. 1887) announced the laws of displacement in 
               the periodic table for elements undergoing radioactive decay.  Soddy introduced the 
               term "isotopes."
1913    GEORGE CHARLES DE HEVESY (Hungary, Germany, Sweden, 1885-1966) and 
           FRITZ ADOLF PANETH (Austria, 1887-1959) used radium-D, an isotope of lead, to study
               the solubility and the chemistry of lead compounds. This was the first use of an isotope as 
               a tracer element. Hevesy was awarded the Nobel prize for chemistry in 1943.
1913    NIELS HENRIK DAVID BOHR (Denmark, 1885-1962) developed the first successful 
               theory of atomic structure.  He was awarded the Nobel prize for physics in 1922.
1913    JOHANNES STARK (Germany, 1874-1957) observed the splitting of spectral lines 
               radiated by excited atoms in an intense electric field. He was awarded the Nobel prize 
               for physics in 1919.
1913    JAMES FRANCK (Germany, USA, 1882-1964) and 
            GUSTAV HERTZ (Germany b. 1887) 
               supported the Bohr atomic theory with their measurements of ionization and resonance 
               potentials.  They were awarded the Nobel prize for physics in 1925.
1913    WILLIAM HENRY BRAGG (England, 1862-1942) and son, 
           WILLIAM LAWRENCE BRAGG (Australia, England, b. 1890), studied x-ray 
                "reflection" from crystals and devised an x-ray spectrometer.  They were awarded the 
                Nobel prize for physics in 1915.
1914 HENRY GWYN JEFFREY MOSELEY (England, 1884-1915) made x-ray spectrograms of 
                the elements and established the identity of the ordinal number of an element in the 
                periodic table with its nuclear charge (atomic number).
1914    KARL MANNE GEORG SIEGBAHN (Sweden, b. 1886) began a long series of pioneer 
               researches in the theory and application of precision x-ray spectroscopy. He was awarded 
               the Nobel prize for physics in 1924.
1915    ARNOLD JOHANNES WILHELM SOMMERFELD (Germany, 1868-1951) improved 
               the Bohr atomic model by introducing elliptical orbits and relativistic effects.
1915    WILLIAM DUANE (USA, 1872-1935) and 
           FRANKLIN LIVINGSTON HUNT (USA, b. 1883) showed that the short-wavelength 
               limit of emitted xradiation is determined by the quantum theory.
1915    ALBERT EINSTEIN (Germany, USA) announced the general theory of relativity. It 
               considers the observations of phenomena on accelerated reference frames.
1916    R. A. MILLIKAN (USA) experimentally verified Einstein's photoelectric equation.


1916    P. J. W. DEBYE (Netherlands, Switzerland, USA) 
           PAUL SCHERRER (Switzerland, b. 1890), and, independently, 
            ALBERT WALLACE HULL (USA, 1880-1966) obtained the first x-ray powder 
               diffraction patterns.
1916    THEODORE LYMAN (USA, 1874-1954) found the Lyman series lines predicted by 
               Bohr's theory of the hydrogen atom. Lyman had observed at least one of these lines 
               as early as 1906.
1919    ERNEST RUTHERFORD (England) produced hydrogen and oxygen by alpha-particle 
               bombardment of nitrogen, the first "man-made" transmutation of an element.
1919    FRANCIS WILLIAM ASTON (England, 1877-1945) made the first highprecision 
               determinations of isotopic masses. He was awarded the Nobel prize for chemistry in 1922.
1919    The observations made during a total solar eclipse in this year by an expedition from the 
               Royal Astronomical Society and the Royal Society of London confirmed the deviation of 
               starlight in the gravitational field of the sun as predicted by the general theory of 
               relativity.  The strongest support for this theory came later from the agreement between 
               the calculated and observed values of the precession of the perihelion of Mercury.
1921    OTTO STERN (Germany, USA, b. 1888) and 
            WALTER GERLACH (Germany, b. 1889) verified the space quantization of silver atoms 
            in a magnetic field and measured their magnetic moment. Stern was awarded the Nobel 
            prize for physics in 1943.
1923    ARTHUR HOLLY COMPTON (USA, 1892-1962) discovered the Compton effect, which 
               showed that a photon has momentum. He was awarded the Nobel prize for physics jointly 
               with C. T. R. WILSON in 1927.
1924    EDWARD VICTOR APPLETON (England, 1892-1965) began a series of experiments that 
               established the existence and properties of ionized layers in the high atmosphere.  Such 
               layers had been postulated in 1902 by ARTHUR EDWIN KENNELLY (India, USA, 
               1861-1939) and, independently, by OLIVER HEAVISIDE (England, 1850-1925) to 
               account for-long-distance wireless telegraphy.  Appleton was awarded the Nobel prize 
               for physics in 1947.
1924    SATYENDRANATH BOSE (India, b. 1894) and 
           A. EINSTEIN independently developed the statistics "obeyed" by bosons, a 
               collective name for photons, nuclei of even mass number, and certain other particles.
1924    Louis VICTOR, DUC DE BROGLIE (France, b. 1892) introduced the concept of 
               de Broglie waves, the beginning of the wave theory of matter.  He was awarded the 
               Nobel prize for physics in 1929.
1925    WALTER M. ELSASSER (Germany, USA, b. 1904) predicted from de Broglie theory that 
               electrons could be diffracted by crystals.


1925    CHARLES DRUMMOND ELLIS (England, b. 1895) and 
           W. A. WOOSTER (England) established that in a number of elements the emission of 
               either an alpha or a beta particle precedes the radiation of gamma rays, and thus the 
               latter should be associated with the daughter product, not with the parent.
1925    PIERRE VICTOR AUGER (France, b. 1899) discovered a type of energy transition in 
               which an atom goes from a higher to a lower state by ejecting one of its own electrons, 
               without the emission of electromagnetic radiation.
1925    GEORGE EUGENE UHLENBECK (Java, Netherlands, USA, b. 1900) and 
           SAMUEL ABRAHAM GOUDSMIT (Netherlands, USA, b. 1902) introduced spin 
               and magnetic moment of the electron into atomic theory.
1925    WOLFGANG PAULI (Austria, Switzerland, 1900-1958) announced the exclusion principle
               He was awarded the Nobel prize for physics in 1945.
1925    PATRICK MAYNARD STUART BLACKETT (England, b. 1897) obtained the first 
               cloud-chamber tracks of the induced transmutation of nitrogen and of other elements, and
               later made many cosmic-ray studies. He was awarded the Nobel prize for physics in 1948.
1925    MAX BORN (Bermany, b. 1882), 
            WERNER KARL HEISENBERG (Germany, b. 1901), and 
           PASCUAL JORDAN (Germany, b. 1902) developed quantum mechanics.  Later, Born 
               originated the statistical interpretation of wave mechanics, and he was awarded the 
               Nobel prize for physics jointly with W. BOTHE in 1954.
1926    ERWIN SCHROEDINGER (Austria, Ireland, 1887-1961) proposed the wavemechanical 
               theory of the hydrogen atom. He was awarded the Nobel prize for physics jointly with 
               P. A. M. DIRAC in 1933.
1926   ENRICO FERMI (Italy, USA, 1901-1954) and 
           PAUL ADRIEN MAURICE DIRAC (England, b. 1902) independently developed the 
               statistics "obeyed" by fermions, a collective name for nuclei of odd mass number, some 
               particles, and electrons, particularly the electron gas in a conductor.  Each was awarded 
               the Nobel prize for work listed later in this chronology.
1926    EUGENE PAUL WIGNER (Hungary, USA, b. 1902) published the first of a long series of 
               important papers on the application of group theory in quantum mechanics.  He was 
               awarded the Nobel prize for physics jointly with MARIA MAYER and J. H. D. JENSEN 
               in 1963.
1927    WERNER HEISENBERG (Germany) announced the "Unbestimmtheit Prinzip" 
             (indeterminacy or uncertainty principle). He was awarded the Nobel prize for physics 
               in 1932.
1927    CLINTON JOSEPH DAVISSON (USA, 1881-1958), and 
           LESTER HALBERT GERMER (USA, b. 1896) obtained electron diffraction from single 
            crystals, and GEORGE PAGET THOMSON (England, b. 1892) obtained powder diffraction
            patterns using electrons. Their work verified the existence of de Broglie waves.  Davisson 
            and Thomson were awarded the Nobel prize for physics in 1937.


1928    EDWARD UHLER CONDON (USA, b. 1902) and 
            RONALD WILFRID GURNEY (England, USA, 1898-1953) and, independently, 
           GEORGE GAMOW (Russia, USA, b. 1904) solved the nuclear problem of alpha-particle 
               emission by means of wave mechanics and derived the Geiger-Nuttall law.
1928    P. A. M. DIRAC (England) developed relativistic quantum mechanics and predicted the 
               existence of the positron.  He was awarded the Nobel prize for physics jointly with 
               E. SCHROEDINGER in 1933.
1928    CHANDRASEKHARA VENKATA RAMAN (India, b. 1888) discovered the Raman effect.
               This is the presence, in light scattered from molecules, of frequencies differing from that 
               of the incident light by amounts characteristic of the scattering substance and independent
               of the incident frequency.  He was awarded the Nobel prize for physics in 1930.
1928    DMITRI VLADIMIROVICH SKOBELTSYN (Russia, b. 1892) obtained the first 
               cloud-chamber photographs of cosmic rays.  These showed that the rays either were, or 
               produced, many charged, high-energy particles.
1928    HANS GEIGER (Germany) and 
           W. MUELLER (Germany) developed the Geiger point counter (1913) into a greatly 
               improved form, called the Geiger-Mueller counter.
1928    WALTHER WILHELM GEORG FRANZ BOTHE (Germany, 1891-1957) and 
           W. KOLHOERSTER (Austria) applied G-M tubes to make coincidence counters and other 
               ingenious devices for cosmic-ray study.  Bothe was awarded the Nobel prize for physics 
               jointly with M. BORN in 1954.
1929    OTTO STERN (Germany) obtained crystal diffraction of a beam of helium atoms.
1930    W. BOTHE (Germany) and H. BECKER (Germany) observed a puzzling penetrating 
                "radiation" from beryllium bombarded with alpha particles.
1930    JACOB CLAY (Netherlands, b. 1882) discovered that cosmic-ray intensity decreased in 
               going toward the geomagnetic equator.  This latitude effect was investigated exhaustively 
               by A. H. COMPTON, R. A. MILLIKAN, and others.
1930-    FREDRIK CARL MUELERTZ STOERMER (Norway, 1874-1957) applied his 1934 
                theory of the motion of charged particles in the magnetic field of the earth, originally 
                developed to account for the aurora borealis, to cosmic rays. This theory of the cause of 
                geomagnetic effects was greatly expanded in 1933 by GEORGES LEMAITRE (Belgium,
                1894-1966) and MANUEL SANDOVAL VALLARTA (Mexico, b. 1899). Further
                theoretical work was done by WILLIAM FRANCIS GRAY SWANN (England, USA, 
                1884-1962) and others.
1930-    IRA FORRY ZARTMAN (USA, b. 1899) and C. C. Ko (China, USA) experi1933 mentally 
                 verified the Maxwell distribution law of molecular speeds.
1931    THOMAS HOPE JOHNSON (USA, b. 1899) obtained crystal diffraction of a beam of 
                 hydrogen atoms.


1931    ROBERT JEMISON VAN DE GRAAFF (USA, 1901-1967) constructed the first reliable, 
                high-voltage, electrostatic generator for nuclear research.
1931    WOLFGANG PAULI (Austria, Switzerland) proposed a hypothesis of betadecay processes 
               postulating that a "new," small, neutral particle was emitted simultaneously with the
               electron. 
1931    HAROLD CLAYTON UREY (USA, b. 1893), 
           FERDINAND GRAFT BRICKWEDDE (USA, b. 1903), and 
           GEORGE MOSELEY MURPHY (USA, b. 1903) discovered deuterium and made the first 
               heavy water.  Urey was awarded the Nobel prize for chemistry in 1934.
1932    ROY JAMES KENNEDY (USA, b. 1897) and 
           EDWARD MOULTON THORNDIKE (USA, b. 1905) sought to detect the ether drift with 
               a very stable and refined form of interferometer having arms of unequal length. Both the 
               length and the time transformations of the special theory of relativity had to be used to 
               account for the null result.
1932    ERNEST ORLANDO LAWRENCE (USA, 1901-1958) and 
           MILTON STANLEY LIVINGSTON (USA, b. 1905) made the first cyclotron
                Lawrence  was awarded the Nobel prize for physics in 1939.
1932    JOHN DOUGLAS COCKCROFT (England, b. 1897) and 
           ERNEST, THOMAS SINTON WALTON (Ireland, b. 1903) accomplished the 
               transmutation of lithium by bombarding it with high-energy protons, and so obtained the 
               first direct verification of Einstein's law of mass-energy equivalence. This was also the 
               first time a high-voltage accelerator was used successfully to produce a nuclear reaction. 
               They were awarded the Nobel prize for physics in 1951.
1932  JAMES CHADWICK (England, b. 1891) discovered the neutronThis particle 
                 accounted for Bothe and Becker's penetrating "radiation."  He was awarded the Nobel 
                 prize for physics in 1935.
1932    BRUNO BENEDETTO Rossi (Italy, USA, b. 1905) found an initial increase with thickness 
                in the cosmic-ray intensity "transmitted" by an absorber and explained this by cosmic-ray
                showers.  A transition to decreasing intensities was observed beyond a certain thickness.
1932    CARL DAVID ANDERSON (USA, b. 1905) discovered the positron during cosmic-ray 
                research.  He was awarded the Nobel prize for physics jointly with V. F. HESS in 1936.
1933    P. M. S. BLACKETT (England) and G. P. S. OCCHIALINI (England) obtained the first 
                cloud-chamber photographs of electron-positron pair production.
1933    JEAN VALENTIN THIBAUD (France, 1901-1960) and FREDERIC JOLIOT (France, 
                1900-1958) observed the radiation produced by electron-positron annihilation. They also 
                showed that the mass of the positron is equal to that of the electron.


1933    T. H. JOHNSON (USA) and 
           JABEZ CURRY STREET (USA, b. 1906) observed that the cosmic-ray intensity from the 
               west exceeded that from the east. This east-west asymmetry shows that there is an excess
               of positively charged particles in the primary cosmic-ray beam.
1934    PAVEL ALEKSEJEVIC CHERENKOV (Russia, b. 1904) observed the weak, bluish glow 
                in transparent substances when irradiated with high-energy beta particles. The theory of 
                this Cherenkov radiation was given by IGOR JEVGENEVIC TAMM (Russia, b. 1895) 
                and ILYA MICHAJLOVIC FRANK (Russia, b. 1908) three years later.  These three 
                scientists were jointly awarded the Nobel prize for physics in 1958.
1934    S. MOHOROVICIC (Yugoslavia) predicted the existence of a transitory non-nuclear 
               "element" (later called positronium) preceding electronpositron annihilation.
1934    IRENE JOLIOT-CURIE (France, 1897-1956) and FREDERIC JOLIOT (France) 
               discovered artificial (induced) radioactivity. They were awarded the Nobel prize for 
               chemistry in 1935.
1934    ENRICO FERMI (Italy, USA) developed Pauli's theory of beta decay and named the 
               "new" particle the neutrino (little neutron). It is postulated in Fermi's theory that the 
               neutron is radioactive, disintegrating into a proton with the formation of an electron and 
              a neutrino just before beta emission. He also began a series of experiments in 
              collaboration with EDUARDO AMALDI (Italy, b. 1908), OSCAR D'AGOSTINO (Italy), 
            FRANCO RASETTI (Italy, USA, b. 1901) and EMILIO GINO SEGRE (Italy, USA, b. 
              1905) to produce transuranic elements by irradiating uranium with neutrons. They were 
              granted a patent on the graphite moderator in 1955. Fermi was awarded the Nobel prize 
              for physics in 1938.
1935-   ISIDOR ISAAC RABI (Austria, USA, b. 1898) made precise determinations of nuclear 
 1939       magnetic moments in beams of atoms by his radiofrequency resonance method. He was 
                awarded the Nobel prize for physics in 1944.
1935    HIDEKI YUKAWA (Japan, b. 1907) announced his theory of nuclear binding forces 
                involving the postulate of a particle having a mass intermediate between that of the 
                electron and the proton.  He was awarded the Nobel prize for physics in 1949.
1936    C. D. ANDERSON (USA) and SETH HENRY NEDDERMEYER (USA, b. 1907) 
              discovered, during cosmic-ray research, a particle of the type postulated by Yukawa. 
                They called it the "mesotron" (later changed to "meson").
1936    MARIETTA BLAU (Austria, b. 1894) was the first to use nuclear track plates.
1937    NIELS BOHR (Denmark) introduced the liquid-drop model of the nucleus. 
1938    IRENE JOLIOT-CURIE (France) and 
            PAVLE SAVITCH (Yugoslavia, b. 1908) found indications of the existence of lanthanum 
               in uranium after it was irradiated with neutrons.


1938    OTTO HAHN (Germany, b. 1879) and 
            FRITZ STRASSMANN (Germany, b. 1902) discovered that bombarding uranium with 
                neutrons produces alkali earth elements. Hahn was awarded the Nobel prize for 
                chemistry in 1944.
1939   LISE MEITNER (Austria, Germany, Sweden, b. 1878) and 
           OTTO RICHARD FRISCH (Austria, Germany, England, b. 1904) proposed nuclear 
                splitting to explain Hahn's results on the disintegration of uranium by- neutrons and 
                predicted the release of an enormous amount of energy per fission.
1939    NIELS BOHR (Denmark) and 
            JOHN ARCHIBALD WHEELER (USA, b. 1911) developed the theory of nuclear fission.
1939    HANS ALBRECHT BETHE (Germany, USA, b. 1906) and 
            CARL FRIEDRICH VON WEIZSAECKER (Germany, b. 1912) independently proposed
               two sets of nuclear reactions to account for stellar energies: the carbon cycle and the 
               proton-proton chain.
1940    JOHN RAY DUNNING (USA, b. 1907), 
            EUGENE THEODORE BOOTH (USA, b. 1912), and 
            ARISTID V. GROSSE (Russia, USA, b. 1905) showed that it is U235, the less abundant 
                isotope of uranium, that is fissioned by slow neutrons.
1940    Louis LEPRINCE-RINGUET (France, b. 1901) obtained the first cloudchamber photograph
                of a meson-electron collision, from which the mass of the meson could be deduced.
1940    DONALD WILLIAM KERST (USA, b. 1911) made the first betatron, an induction type 
                accelerator.
1940    EDWIN MATTISON MCMILLAN (USA, b. 1907) and 
            PHILIP HAGUE ABELSON (USA, b. 1913) produced the first transuranic element, 
                neptunium; and 
            GLENN THEODORE SEABORG (USA, b. 1912), 
            EDWIN MATTISON MCMILLAN (USA), 
            JOSEPH WILLIAM KENNEDY (USA, b. 1917), and 
            ARTHUR CHARLES WAHL (USA, b. 1917) prepared the second transuranic element, 
               plutonium.   MCMILLAN and SEABORG were awarded the Nobel prize for chemistry 
               in 1951.
1942    ENRICO FERMI (Italy, USA), 
           LEO SZILARD (Hungary, Germany, USA, 1898-1964), and associates 
              built the first successful self-sustaining fission reactor. It was first put into operation on 
               December 2 and operated at a power level of one-half watt. It was located in Chicago, 
               Illinois.
1945    J. ROBERT OPPENHEIMER (USA, b. 1904), then Director of the Los Alamos Scientific 
               Laboratory, and the many scientists engaged there in a "crash" program of basic nuclear 
               research and development saw the culmination of their work in the detonation of the first 
               nuclear bomb at Almagordo, New Mexico, on July 16.
1945    E. M. MCMILLAN (USA) and 
           VLADIMIR IOSIFOVICH VEKSLER (Russia, 1907-1966) independently proposed the 
                  principle of the synchrotron, the type of accelerator which produces very high-energy 
                  particles, as in the Cosmotron, Bevatron, etc.


1946    FELIX BLOCH (Switzerland, USA, b. 1905) devised the magnetic induction method and, 
                independently, 
           EDWARD MILLS PURCELL (USA, b. 1912) originated the magnetic resonance 
                absorption method for determining nuclear magnetic moments, using liquids or solids in 
                bulk (not beams).  This led to the nuclear resonance spectrometer.  They were awarded 
                the Nobel prize for physics in 1952.
1947    POLYKARP KUSCH (Germany, USA, b. 1911) made high-precision determinations of the 
                magnetic moment of the electron and found a small but theoretically significant difference
                between the predicted value and the experimental results. Kusch was awarded the Nobel 
                prize for physics jointly with W. R. LAMB in 1955.
1947    WILLIS EUGENE LAMB, JR., (USA, b. 1913) and 
            ROBERT E. RETHERFORD (USA) observed, during the course of spectral 
               measurements of the fine structure of hydrogen in the microwave region, a small 
              displacement (the "Lamb shift") of an energy level from its theoretical position as 
              predicted by Dirac's quantum theory of the electron.Lamb was awarded the Nobel prize 
              for physics jointly with P. KUSCH in 1955.
1947    H. A. BETHE (Germany, USA) and, independently, 
           JULIAN SEYMOUR SCHWINGER (USA, b. 1918) explained the discrepancies found 
                by KUSCH and by LAMB as resulting from an interaction of electrons with the radiation 
                field.  Schwinger was awarded the Nobel prize for physics jointly with R. P. FEYNMAN 
                and S. TOMONAGA In 1965.
1947    HARTMUT PAUL KALLMANN (Germany, USA, b. 1896) and, independently, 
           JOHN WESLEY COLTMAN (USA, b. 1915) and 
           FITZ-HUGH BALL MARSHALL (USA, b. 1912) developed scintillation counters.
1947    CECIL FRANK POWELL (England, b. 1903), 
           G. P. S. OCCHIALINI (England), and 
           CESARE MANSUETO GIULIO LATTES (Brazil, England, b. 1924) 
               discovered the pi-meson. Powell was awarded the Nobel prize for physics in 1950.
1947    GEORGE DIXON ROCHESTER (England, b. 1908) and 
           CLIFFORD CHARLES BUTLER (England, b. 1922) 
               discovered V-particles and hyperons.
1948    EUGENE GARDNER (USA, 1913-1950) and 
            C. M. G. LATTES (Brazil, England, USA) were the first to produce mesons in the 
                laboratory.
1948-   WILLARD FRANK LIBBY (USA, b. 1908) and collaborators developed the 
  1950     techniques of radiocarbon dating. He was awarded the Nobel prize for chemistry in 1960.
1949    MARIA GOEPPERT MAYER (Germany, USA, b. 1906) and, independently, 
           OTTO HAXEL (Germany, b. 1909), 
           JOHANNES HANS DANIEL JENSEN (Germany, b. 1907), and 
           HANS EDWARD SUESS (Austria, Germany, USA, b. 1909) developed the shell theory 
               of the nucleus, which assumes a spherical distribution of nucleons.  Mayer and Jensen 
               were awarded the Nobel prize for physics jointly with E. P. WIGNER in 1963.


1950    ARTHUR HAWLEY SNELL (Canada, USA, b. 1911) and associates 
                   at the Oak Ridge National Laboratory and 
           JOHN MICHAEL ROBSON (England, Canada, b. 1920) and his associates 
                  at the Chalk River Laboratory experimentally verified that the free neutron 
                   is radioactive.
1950    Scientists began intensified research on light-element fusion reactions.
1951    MARTIN DEUTSCH (Austria, USA, b. 1917) experimentally confirmed the prediction of 
               the existence of positronium.
1952    Brookhaven National Laboratory was the first to achieve the acceleration of particles to 
               the giga-electron-volt energy range: 2.3-Gev protons.
1952    AAGE BOHR (Denmark, b. 1922) and 
           BEN ROY MOTTELSON (Denmark b. 1926) developed the unified (collective) shell 
              model of the nucleus, which assumes a nonspherical nuclear core.  The possibility of a 
              distorted core had been suggested in 1950 by LEO JAMES RAINWATER (USA, b. 1917).
1952    DONALD ARTHUR GLASER (USA, b. 1926) made the first bubble chamber.  He was 
                awarded the Nobel prize for physics in 1960.
1952    The first large-scale, terrestrial thermonuclear reaction was produced when a "hydrogen 
                fusion device" was tested at Einewetok atoll on November 1.
1953    MURRAY GELL-MANN (USA, b. 1929) introduced the strangeness numbers for nucleons,
                mesons, and hyperons, and found that strangeness is conserved in strong interactions.
1953    ROBERT HOFSTADTER (USA, b. 1915) and collaborators started a series of experiments
                on the scattering of high-energy electrons by atoms.  The results led to the determination 
                of the charge distribution and structure of nuclei and nucleons.  Hofstadter was awarded 
                the Nobel prize for physics jointly with R. L. Mossbauer in 1961.
1954    JAMES POWER GORDON (USA, b. 1928), 
           H. J. ZEIGER (USA, b. 1925) and 
           CHARLES HARD TOWNES (USA, b. 1915) made the first maser [molecular (formerly, 
               microwave) amplification by stimulated emission of radiation].  In this device, many 
               molecules which have been put into high energy states are induced to emit their energy 
               as radiation by a weak incoming signal of the same frequency.  Townes was awarded the 
               Nobel prize for physics jointly with N. BASOV and A. PROKHORV in 1964.
1955    OWEN CHAMBERLAIN (USA, b. 1920), 
           EMILIO GINO SEGRE (Italy, USA, b. 1905), 
           CLYDE EDWARD WIEGAND (USA, b. 1915), and 
           THOMAS JOHN YPSILANTIS (USA, b. 1928) created proton-antiproton pairs.
                Chamberlain and Segre were awarded the Nobel prize for physics in 1959.
1956    Luis WALTER ALVAREZ (USA, b. 1911) and collaborators accomplished cold fusion of 
                deuterium with the negative mu-meson as a catalyst.
1956    JOHN BARDEEN (USA, b. 1908), 
           WALTER HOUSER BRATTAIN (China, USA, b. 1902), and 
           WILLIAM SHOCKLEY (England, USA, b. 1910) were awarded the Nobel prize for physics
               in recognition of their work in theory of the solid state, particularly semiconductors. 
1956   FREDERIC REINES (USA, b. 1915) and 
           CLYDE LORRAIN COWAN, JR. (USA, b. 1919) and collaborators experimentally 
              confirmed the existence of the neutrino.
1956   The world's first full-scale nuclear power plant was put into operation on October 17 at 
              Calder Hall, England.  The gas-cooled reactors develop 360 megawatts of thermal power 
              to deliver 78 megawatts of electrical power.
1956   TSUNG DAO LEE (CHINA, USA, b. 1926) and 
           CHEN NING YANG (China, USA, b. 1922) deduced theoretically that hre law of 
              conservation of parity (the invariance of spatial inversion) is invalid for weak interactions.
              They were awarded the Nobel prize for physics in 1957.
1956    CHINN-SHIUNG Wu (China, USA, b. 1915) and collaborators performed the first 
               experiment that demonstrated the violation of conservation of parity.  They observed the
               beta emission from Co^60 at very low temperatures. 


1956       Hoosick , N.Y.         Dist. #2 Sends five onto High School, inc. AJD 


1957    JOHN BARDEEN (USA), 
           LEON N. COOPER (USA, b. 1930) and 
           JOHN ROBERT SCHRIEFFER (USA, b. 1931) announced the first comprehensive 
               theory of superconductivity.
1958    C. H. TOWNES (USA), 
           JOHN PERRY CEDARHOLM (USA, b. 1927), 
           GEORGE FRANCIS BLAND (USA, b. 1927), and 
           BYRON LUTHER HAVENS (USA, b. 1914) employed maser beams in the most precise 
              ether-drift experiment yet performed.  The results showed that if the effect exists, it is less 
              than one-thousandth of the earth's orbital speed or less than one ten-millionth of the speed 
              of light.  The precision in the comparison of the frequencies of the masers was about one 
              part in a million million. 
1958    RUDOLPH L. MOSSBAUER (Germany, b. 1929) predicted and found an extremely small 
               frequency spread in the emission of low-energy gamma rays from nuclei bound in a crystal
               lattice.  This effect results from giving the gamma-ray recoil momentum to the whole 
               lattice instead of to an individual nucleus.  The effect provides a very high-precision 
               frequency standard suitable for testing several predictions of the special and general 
               theories of relativity. He was awarded the Nobel prize for physics jointly with 
               R. HOFSTADTER in 1961.
1959    JAMES ALFRED VAN ALLEN (USA, b. 1914) showed from the data obtained from 
                 instruments carried by artificial satellites that the earth is encircled by two zones, called 
                 VAN ALLEN radiation belts, of high-energy charged particles which are trapped by the 
                 earth's magnetic field.


1960        Drury HS, No. Adams, MA           Graduates over 200,  inc.  AJD 


1960    THEODORE HAROLD MAIMAN (USA, b. 1927) made the first ruby laser.
1960    ALI JAVAN (Iran, USA, b. 1926) made the first helium-neon laser.
1960   VERNON WILLARD HUGHES (USA, b. 1921), 
           D. W. McCOLM, KLAUS OTTO Ziock (Germany, USA, b. 1925) and 
           R. PREPOST made and studied muonium,a short-lived atom having a positive mu-meson 
              nucleus and an orbiting electron.
1962    B. D. JOSEPHSON (England) discovered and theoretically analyzed a number of 
               unexpected phenomena occurring at a "Josephson junction," an arrangement consisting 
               of two superconductors separated by a very thin layer of insulating material. 


1964       MA State College at No. Adams unleashes .LT. 30 Sci-Math's,  inc. AJD 


1965    JEROME V. V. KASPER and GEORGE CLAUDE PIMENTEL (USA, b. 1922) made the
               first chemical laser, a device in which pumping energy is supplied by chemical reactions 
               instead of by an external source of power.