Editors note: This is a work of the author, and not of the Student Health Physics Society of The Idaho State University. The breakdown of the time frame index is a way of breaking up the information for the WWW and not part of the original Chronology written by the author.
Permission is given to copy this but not for sale or as part of any "for profit" transaction. For an updated version contact the author at JEW1@PGE.COM or phone (805)545-3029
Is it right to probe so deeply into Nature's secrets?
The question must here be raised whether it will benefit mankind, or whether the knowledge will be harmful. Radium could be very dangerous in criminal hands. Alfred Nobel's discoveries are characteristic; powerful explosives can help men perform admirable tasks. They are also a means to terrible destruction in the hands of the great criminals who lead peoples to war... -- Pierre Curie in his Nobel Prize Oration, June 6,1905
1,800,000 BC First "reactor accident." Concentration of enriched uranium forms natural nuclear reactor at Oklo, Gabon and becomes critical; core burns for 200,000 years.
500 BC Democritus and Leucippus of Greece postulate that all matter is made of indivisible units they call "atomos." "For by convention color exist, by convention bitter, by convention sweet, but in reality atoms and void." -- Galen quoting one of Democritus' 72 lost works.
450 BC Greek philosopher Anaxagoras states that matter cannot be created nor destroyed.
79 AD First known use of uranium. Roman artisans produce yellow colored glass in mosaic mural near Naples.
1400 AD Mysterious malady kills miners at an early age in mountains around Schneeberg (Saxony) and Joachimsthal (Jachymov) in the Sudetenland (now Czechoslovakia). Called "mountain sickness."
1669 Phosphorous discovered by Hennig Brand (Germany).
1704 "It seems probable to me that God in the beginning formed matter in solid, massy, hard, impenetrable, movable particles, of such sizes and figures, and with such other properties, and in such proportion to space, as most conduced to the end to which he formed them." --Sir Isaac Newton.
1735 Platinum discovered by Julius Scaliger (Italy).
1737 Cobalt discovered by George Brandt (Sweden).
1746 Zinc discovered by Andreas Marggraf (Germany).
1751 Nickel discovered by Axel Cronstedt (Sweden).
1766 Hydrogen discovered by Henry Cavendish (England).
1772 Nitrogen discovered by Daniel Rutherford (Scotland).
1774 Oxygen discovered by Joseph Priestly (England) and Carl Wilhelm Scheele (Sweden).
1774 Chlorine discovered by Carl Wilhelm Scheele (Sweden).
1774 Manganese discovered by Johann Gahn (Sweden).
1778 Molybdenum discovered by Carl Wilhelm Scheele (Sweden).
1782 Tellurium discovered by Franz Mueller von Reichenstein (Romania).
1783 Tungsten discovered by Fausto and Juan Jose de Elhuyar (Spain).
1784 William Morgan unknowingly produces X-rays in experiment witnessed by Ben Franklin.
1789 (Sept 24) Martin Klaproth announces his discovery of a new element, uranium.
1789 Zirconium discovered by Martin Klaproth (Germany).
1790 Strontium discovered by A. Crawford (Scotland).
1791 Titanium discovered by William Gregor (England).
1794 Yttrium discovered by Johann Gadolin (Finland).
1797 Chromium discovered by Louis Vauquelin (France).
1798 Beryllium discovered by Fredrich Woehler (Germany) and A. A. Bussy (France).
1800 William Herschel (Germany-USA) discovers a point below the frequency of red light which he terms infrared.
1801 Johann Wilhelm Ritter (Germany) discovers light beyond the violet end of the spectrum which he terms ultraviolet.
1801 Niobium discovered by Charles Hatchet (England).
1802 Tantalum discovered by Anders Ekeberg (Sweden)
1803 "Thou knowest no man can split the atom."--John Dalton
1803 Palladium discovered by William Wollaston (England).
1803 Cerium discovered by W. von Hisinger, J. Berzelius, M. Kaproth (Sweden / Germany).
1804 Rhodium discovered by William Wollaston (England).
1804 Iodine discovered by Bernard Courtois (France).
1804 Osmium discovered by Smithson Tenant (England).
1804 Iridium discovered by S. Tenant, A.F. Fourcory, L.N. Vauquelin, and H.V. Collet-Descoltils (England / France).
1807 Sodium discovered by Sir Humphrey Davy (England).
1807 Potassium discovered by Sir Humphrey Davy (England).
1808 Magnesium discovered by Sir Humphrey Davy (England).
1808 Calcium discovered by Sir Humphrey Davy (England).
1808 Barium discovered by Sir Humphrey Davy (England).
1808 John Dalton (England) formulates the Chemical Atomic Theory which states that elements combine in fixed proportions of their masses.
1811 Amedeo Avogadro (Italy) states equal volumes of all gases contain equal number of molecules under conditions of fixed temperature and pressure.
1816 William Prout (England) postulates that all atoms are made of multiples of the hydrogen atom. His work, although published anonymously, becomes known as "Prout's Hypothesis."
1817 Lithium discovered by Johann Arfvedson (Sweden).
1817 Selenium discovered by Jons Berzelius (Sweden).
1817 Cadmium discovered by Fredrich Stromeyer (Germany).
1823 Silicon discovered by Jons Berzelius (Sweden).
1824 Uranium described in Gmelin's Handbook. Much animal toxicity studies done thereafter.
1825 Aluminum discovered by Hans Christian Oersted (Denmark).
1825 Oersted observes that some undefinable magnetic effect is associated with charged particles in motion.
1826 Bromine discovered by Antoine J. Balard (France).
1828 Boron discovered by H. Day (England), J.L. Gay-Lussac and L.J. Thenard (France.)
1828 Thorium discovered by Jons Berzelius (Sweden).
1830 Vanadium discovered by Nils Stefstrom (Sweden).
1830 Michael Faraday (England) claims that moving charges (current) may be generated by moving magnetic fields.
1839 M. Daguerre discovers photography which later becomes the basis for personnel dosimetry and discovery of radioactivity in uranium.
1839 Lanthanum discovered by Carl Mosander (Sweden).
1843 Terbium discovered by Carl Mosander (Sweden).
1843 Erbium discovered by Carl Mosander (Sweden).
1844 Ruthenium discovered by Karl Klaus (Russia).
1847 H. von Helmholz states that energy may be converted to other forms but may not be destroyed or lost.
1850 First commercial use of uranium in glass by Lloyd & Summerfield of Birmingham, England.
1860 Uranium is first used in homeopathic medicine for treatment of diabetes.
1860 Cesium discovered by Gustov Kirchoff and Robert Bunsen (Germany).
1861 Rubidium discovered by Gustov Kirchoff and Robert Bunsen (Germany).
1861 Thallium discovered by Sir William Crookes (England).
1863 Indium discovered by Ferdinand Reich and H. Richter (Germany).
1865 H. Geissler and J. Plucker observe fluorescence in evacuated tubes containing electrodes.
1869 E. Goldstein coins phrase "cathode rays."
1869 Hittorf shows cathode emanation stopped by solid object.
1869 William Crookes notes fogging in photographic plates in his laboratory and complains of defective packaging. The fogging is actually caused by an unknown at the time radiation, x-rays, produced in Crookes' tubes.
1870 James Maxwell puts forth an extension of the theories of Michael Faraday and Orsted in a rigorous mathematical form: charge and the electric field; the magnetic field; magnetic effect of a charging electric field or moving charge; and the electric effect of a changing magnetic field.
1872 (July) Dmitri Ivanovitch Mendeleev, an unknown Siberian supervisor of weights and measures, presents paper in St. Petersburg detailing his Periodic Table of the Elements.
1875 Gallium discovered by Paul Emile Lecoq de Boisbaudron (France).
1876 Eugen Goldstein (Germany) coins the phrase "cathode rays."
1878 Holmium discovered by J.L. Soret (Switzerland).
1878 Ytterbium discovered by Jean de Marignac (Switzerland).
1879 W. Crookes shows cathode rays are solid matter with sufficient energy to drive a small wheel.
1879 Identification of the malady in Schneeberg mines as lung cancer. Thought to be lymphosarcomata, the causation remains murky.
1879 Scandium discovered by Lars Nilson (Sweden).
1879 Samarium discovered by Paul Emile Lecoq de Boisbaudron (France).
1879 Thulium discovered by Per Theodor Cleve (Sweden).
1880 Gadolinium discovered by Jean de Marignac (Switzerland).
1881 George Johnstone Stoney (Ireland) names the indivisible unit of electricity the electron.
1884 Balmer (Switzerland), a high school teacher, finds that gases bombarded by electrons will emit electromagnetic waves of only certain wavelengths which he measures with a grating spectroscope.
1885 Praseodymium discovered by C.F. Aver von Welsbach (Austria).
1886 H. Hertz characterizes long wave electromagnetic radiation.
1886 Goldstein notices rays going the opposite way from cathode rays channeling through a hole in the cathode. He names them "channel rays." These are later found to be the positive ions of the wisps of gas in the tube or parts of the cathode.
1886 Fluorine discovered by Henri Moissan (France).
1886 Germanium discovered by Clemens Winkler (Germany).
1886 Dysprosium discovered by Paul Emile Lecoq de Boisbaudron (France).
1891 H. Hertz, assisted by P. Lenard, studies the penetrating power of cathode rays.
1894 Argon discovered by Sir William Ramsey and Baron Rayleigh (Scotland).
1895 Helium discovered by William Ramsey, Nilo Langet, and P.T. Cleve (Scotland and Sweden).
1895 Rutherford shows that "uranium emanation" has a spectral line of helium.
1895 (Nov 8) Roentgen discovers X-rays.
1895-1900 Photographic emulsions and electroscopes are primary instruments used when radiation is discovered.
1896 (Feb 3) First diagnostic X-ray in US (E. Frost).
1896 (Feb) First x-ray picture of a fetus in utero.
1896 (Mar) First application of X-rays in dentistry (C. Kells and W. Rollins).
1896 (Mar 3) Becquerel demonstrates the radioactivity of uranium.
1896 (Mar) Thomas Edison reports eye injuries from X-rays.
1896 (June) N. Tesla cautions experimenters not to get too close to X-ray tubes.
1896 First therapeutic applications of X-rays (Grubbe, Voigt, Despeignes)
1896 Dr. D. W. Gage (McCook, NB.) writing in New York's "Medical Record," notes cases of hair loss, reddened skin, skin sloughing off, and lesions. "I wish to suggest that more be understood regarding the action of the x rays before the general practitioner adopts them in his daily work."
1897 J.J. Thomson demonstrates corpuscular nature of cathode rays. He theorizes that these electrons might be a constituent part of all matter.
1898 (Mar) Discovery of radioactivity of thorium by G. Schmidt.
1898 (Apr 12) Marie Sklodovska Curie announces the probable presence in pitchblende ores of a new element endowed with powerful radioactivity.
1898 (July 13) Polonium isolated from pitchblende by Marie & Pierre Curie.
1898 (July) Marie & Pierre Curie coin word "radioactivity."
1898 (Dec 26) Radium-226 isolated from pitchblende by Marie & Pierre Curie.
1898 Discovery of gamma rays by P. Villard.
1898 Becquerel receives skin burn from radium given to him by the Curies that he keeps in his vest pocket. He declares, "I love this radium but I have a grudge against it!"
1898 Neon discovered by Sir William Ramsey and M.W. Travers (England).
1898 Krypton discovered by Sir William Ramsey and M.W. Travers (England).
1898 Xenon discovered by Sir William Ramsey and M.W. Travers (England).
1899 Radioactive gaseous emanation from thorium is described by Rutherford.
1899 Andre Louis Debiere (France) discovers actinium, a radioactive element (atomic number 89.)
1900 Crookes shows that purified uranium has almost no radioactivity. He suggests that uranium was not the origin of the radiation but some impurity in the uranium.
1900 Thorium-234 discovered by Crookes.
1900 Friedrich Ernst Dorn discovers radon (atomic number 86), a radioactive daughter of uranium.
1900 Thorium beginning of use in gas mantles.
1900 Marie Curie explains natural transmutation as a decay of an unstable atom to one of a lower atomic weight.
1900-1924 Gradual development of mechanical electrometers.
1901 Becquerel confirms Crookes' statement about uranium not being the origins of the radiation but also shows that if uranium is left standing, its radioactivity increases.
1901 Europium discovered by Eugene Demarcay (France).
1901 Max Planck proposes that atoms could gain and lose energy only in discrete quantities (quantum).
1902 (Apr) Radioactive spontaneous disintegration, the unaided transmutation of elements, observed and named by Soddy and Rutherford.
1902 Radium-224 (thorium X) discovered by Soddy and Rutherford.
1902 Rollins experimentally shows X-rays can kill higher life forms.
1902 Existence of radium verified by Curies by chemical methods.
1903 (June 25) Marie Curie accorded the title of doctor of physical science, with the mention of très honorable from the University of Paris, Sorbonne
1903 (Nov 12) Marie and Pierre Curie awarded the Nobel Prize for Physics.
1903 Sir William Crookes and, independently, Elster and Geitel discover that crystals of zinc sulfide emit tiny flashes of visible light (scintillations) when struck with alpha particles. Rutherford quickly adopts this detector for his work.
1904 (Oct) Clarence Madison Dally, a glass blower at Thomas Edison's Menlo Park lab, is first person known to have been killed by x-ray exposure. Severely burned in 1896, he still works with x-rays until 1898. His death causes Edison to discontinue radiation work in his lab.
1904 Rutherford shows that alpha particles are helium atoms and works out the natural decay series.
1904 Radon and daughters identified as part of the uranium series. Work with animals begins, especially in Russia and France.
1904 Colormetric dosimetry system devised by Saboroud and Noire.
1904 Marie Curie publishes an observation that diamonds when exposed to radiation and later heated glow proportional to exposure. This is published in Research on Radioactive Substances . This is the basis for thermoluminescent dosimetry which waits until 1950 to be further developed.
1904 "If it were ever possible to control at will the rate of disintegration of radio elements, an enormous amount of energy could be obtained from a small amount of matter." --Ernest Rutherford.
1904 H. Nagaoka (Japan) publishes planetary hypothesis of atomic structure.
1904 Rutherford coins the term "half-life."
1905 (June 6) "Is it right to probe so deeply into Nature's secrets? The question must here be raised whether it will benefit mankind, or whether the knowledge will be harmful. Radium could be very dangerous in criminal hands. Alfred Nobel's discoveries are characteristic; powerful explosives can help men perform admirable tasks. They are also a means to terrible destruction in the hands of the great criminals who lead peoples to war..." Pierre Curie in his Nobel Prize Oration delayed from 1903.
1905 Einstein publishes Theory of Relativity which explains the phenomenon called the Photoelectric Effect.
1905 Thorium-228 discovered by Hahn.
1905 Ionization unit proposed by M. Franklin.
1905 Boltwood calls attention that lead is found with uranium and suggests that lead might be the end product of uranium.
1906 (April 19) Pierre Curie killed by a horse-drawn wagon filled with military uniforms driven by Louis Manin on the streets of Paris, France.
1906 Ernest Rutherford conducts experiments where he bombards gold foil with alpha particles. Most of the alphas pass through. He theorizes that atoms are mostly space.
1907 Ionium (Th-230) discovered by Boltwood.
1907 Lutetium discovered by Georg Urbain (France).
1907 H. N. McCoy and W. H. Ross at the University of Chicago show that two different radioelements might be chemically identical.
1910 Curie unit defined as activity of 1 gram of radium.
1910 Animal work on distribution and excretion of radium (mostly in Europe). Radium begun to be used as nostrum.
1910 Jesuit Father Theodor Wulf measures radiation at ground level and at top of Eiffel Tower. Radiation increases at higher elevation. Suspects extraterrestrial origins of this radiation. Suggests balloonists measure dose rates.
1911 (Aug) Rutherford and Geiger discover that atoms are mostly space using alpha particles to bounce off thin gold foil.
1911 Marie Curie awarded the Nobel Prize for Chemistry for the separation of radium from pitchblende.
1911 Robert Andrews Millikan using oil droplets measures the charge of an electron.
1911 Soddy suggests that "the expulsion of the alpha particle causes the radioelement to change its position on the periodic table..."
1911 Charles Glover Barkla (England) shows certain x-rays predominate; these are termed characteristic x-rays.
1911 Microscope is used to count grain densities in photographic film.
1911 Charles Thomas Rees Wilson (Scotland) invents the cloud chamber which shows tracks of radiation in a supersaturated atmosphere.
1911 Georg von Hevesy conceives the idea of using radioactive tracers. Leads to Nobel Prize in 1943.
1911-1912 Victor Hess (Austrian) takes balloon rides to measure radiation at heights up to 5000 meters. Discovers cosmic radiation which he names "Hoehenstrahlung" (high altitude rays.)
1912 (July 16) Patent granted to the Radium Ore Revigorator Co., 260 California St., San Francisco, CA for a device, the Revigorator, that charges water with radon, ushering in a 20-year craze in radioactive health crocks. Instructions read: "Fill jar every night, use hydrant or any good water, drink freely when thirsty and upon rising and retiring. Average six or more glasses daily. Scrub with stiff brush and scald monthly."
1912 Arthritis patient dies because of Ra-226 injections.
1912 T. Christen puts forth concept of half value layer for shielding x or gamma radiation, i.e., only half the incident radiation will be stopped by each successive shielding layer.
1912 Max von Laue (Germany) uses the crystals of zinc sulfide to diffract x-rays and measure their wavelength. He thereby proves the wavelike nature of x-rays.
WW I Exposure of hundreds of girls to luminous paint compound for instrument dials in New York and Illinois.
WW I Henry Gwyn-Jeffries Mosley killed at Gallipoli. Mosley, a student of Rutherford, had bombarded each of the known elements with a beam of electrons to show the number of electric charges in each nucleus was increased in regular steps between each element in the periodic table.
1913 (Jan 31) A. S. Russell put forward that in beta decay the position of the element in the periodic table changes by one place.
1913 Hans Geiger unveils his prototype gas-filled radiation detector.
1913 Niels Bohr (Denmark) applies the newly invented quantum theory to atomic electron orbitals. These stationary orbitals would allow an electron to orbit a nucleus without emitting energy.
1913 Soddy proposes the term "isotope" for atoms with the same number of protons and differing only in number of neutrons.
1914 H.G. Wells publishes The World Set Free set in 1956 predicts an alliance of England, France, and America against Germany and Austria. All the major cities of the world are destroyed by atomic bombs.
1914 Ernest Marsden, Rutherford's assistant, reports an odd result when he bombards nitrogen gas with alpha particles -- something is thrown back with much greater velocity. This is the first report of nuclei fissioning.
1915 (June) British Roentgen Society proposes standards for radiation protection workers; includes shielding, restricted work hours, medical exams; no limits because of lack of units for dose or dosimeters; voluntary controls.
1915 (Aug) Robert Rich Sharp discovers the Shinkolobwe uranium deposit in the Congo. Mine averages 68% uranium; richest find in history and is on the surface.
1916 A. Sommerfeld (Germany) modifies Bohr's model of electron orbitals to allow elliptical orbits.
1917 Otto Hahn and Lise Meitner discover protactinium.
1919 First artificial transformation of an element by performed by Rutherford; alpha particle on nitrogen causes the expulsion of oxygen and hydrogen.
1920 Luminous dial painting expanded to clock factories.
1920 Rutherford suggests additional neutral nuclear particle (later called a neutron). "Such an atom would have very novel properties. Its external field would be practically zero, except close to the nucleus, and, in consequence, it should be able to move freely through matter."
1920 James Chadwick in Rutherford's lab uses alpha particle scattering to determine the charges on the nucleus of copper, silver, and platinum.
1920-1930s Much use of radon generators in hospitals for preparation of radon seeds.
1921 Suggestion that radium and radium emanation might be causative agent in cancer in miners taken seriously but not proven.
1921 British X-ray and Radium Protection Committee present its first radiation protection standards.
1922 American Roentgen Ray Society adopts radiation protection rules.
1922 American Registry of X-ray Technicians founded.
1922 G. Pfahler recommends personnel monitoring with film.
1922 P. Auger and F. Perrin determine the charge on the nucleus of argon.
1922-1924 Suspicions develop around dial painter's jaw lesions.
1923 A.H. Compton reports wavelengths lengthened for bounced x-rays and gammas. Leads to Nobel prize for the "Compton Effect".
1923 A. Mutscheller puts forth first "tolerance dose" (0.2R/day).
1923 "There is no likelihood man can ever tap the power of the atom... Nature has introduced a few foolproof devices into the great majority of elements that constitute the bulk of the world, and they have no energy to give up in the process of disintegration."--Dr. Robert Andrews Millikan
1923 Hafnium discovered by Dirk Coster and Georg von Hevesy (Denmark).
1924 Description of jaw necrosis by dentist, Blum; attributed to radiation from deposited luminous paint.
1924 DeBroglie states that an electron has wave properties and assigns a wavelength to an electron much the same way Einstein assigns a mass to an electromagnetic wave in 1905. This standing wave allows an electron to exist a some distance from the nucleus without gaining or losing energy.
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