Scheele achieved astonishingly prolific and important results without the expensive laboratory equipment to which his Parisian contemporary Antoine-Laurent Lavoisier was accustomed. Through the studies of Lavoisier, Joseph Priestley, Scheele, and others, chemistry was made a standardized field with consistent procedures. Although Scheele was unable to grasp the significance of his discovery of the substance that Lavoisier later named oxygen, his work was essential for the abandonment of the long-held theory of phlogiston. Scheele's study of the gas not yet named oxygen was prompted by a complaint by Torbern Olof Bergman, a professor at Uppsala University who would eventually become Scheele's friend.
The theory of phlogiston
Carl Wilhelm Scheele
Carl Wilhelm Scheele | The theory of phlogiston
Theory of phlogiston Theory of phlogiston Theory of phlogiston. The theory of phlogiston.
oxygen (o2) is formed in photosynthesis as a direct result of
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Light-driven splitting of water during oxygenic photosynthesis
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how does lavoisier contribute?
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He conducted the first adequate quantitative experiments on oxidation and gave the first correct explanation of how combustion works
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what are its isotopes?
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They are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number
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what are its allotropes?
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Sorry. I cannot find the answer based on the context.
assistant
how is it stored?
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Sorry. I cannot find the answer based on the context.
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is it toxic?
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No it is not toxic
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what are its industrial uses?
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Sorry. I cannot find the answer based on the context.
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which scientist was involved in early experiments related to it?
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It was solated by Michael Sendivogius before 1604, but it is commonly believed that the element was discovered independently by Carl Wilhelm Scheele
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which theory was proposed by the second scientist?
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He ultimately obtained oxygen by heating mercuric oxide, silver carbonate, magnesium nitrate, and other nitrate salts. Scheele wrote about his findings to Lavoisier who was able to see the significance of the results. His discovery of oxygen (ca. 1771) was chronologically earlier than the corresponding work of Priestley and Lavoisier, but he did not publish this discovery until 1777, after both of his rivals had published.
Carl Wilhelm Scheele | The theory of phlogiston
By the time he was a teenager, Scheele had learned the dominant theory of gases which in the 1770s was the phlogiston theory. Phlogiston, classified as "matter of fire", was supposed to be released from any burning material, and when it was exhausted, combustion would stop. When Scheele discovered oxygen he called it "fire air" as it supported combustion. Scheele explained oxygen using phlogistical terms because he did not believe that his discovery disproved the phlogiston theory. Before Scheele made his discovery of oxygen, he studied air. Air was thought to be an element that made up the environment in which chemical reactions took place but did not interfere with the reactions.
Carl Wilhelm Scheele | Existing theories before Scheele
Scheele's investigation of air enabled him to conclude that air was a mixture of "fire air" and "foul air;" in other words, a mixture of two gases. Scheele performed numerous experiments in which he heated substances such as saltpetre (potassium nitrate), manganese dioxide, heavy metal nitrates, silver carbonate and mercuric oxide. In all of these experiments, he isolated the same gas: his "fire air," which he believed combined with phlogiston in materials to be released during heat-releasing reactions. However, his first publication, "Chemische Abhandlung von der Luft und dem Feuer", was delivered to the printer Swederus in 1775, but not published until 1777, at which time both Joseph Priestley and Lavoisier had already published their experimental data and conclusions concerning oxygen and the phlogiston theory.
Carl Wilhelm Scheele | Existing theories before Scheele
Bergman informed Scheele that the saltpeter he had purchased from Scheele's employer, after long heating, produced red vapors (now known to be nitrogen dioxide) when it came into contact with acetic acid. Scheele's quick explanation was that the saltpeter had absorbed phlogiston with the heat (had been reduced to nitrite, in modern terms) and gave off a new phlogisticated gas as an active principle when combined with an acid (even a weak acid). Bergman next suggested that Scheele analyze the properties of manganese (IV) oxide. It was through his studies of manganese (IV) oxide that Scheele developed his concept of "fire air" (his name for oxygen).
Carl Wilhelm Scheele | The theory of phlogiston
The phlogiston theory was proposed in 1667 by Johann Joachim Becher. It postulated the existence of a fire-like element called "phlogiston", which was contained within combustible bodies and released during combustion. This proved to be false in 1785 by Antoine Lavoisier who found the correct explanation of the combustion as reaction with oxygen from the air.
Chemical reaction | History
Scheele achieved astonishingly prolific and important results without the expensive laboratory equipment to which his Parisian contemporary Antoine-Laurent Lavoisier was accustomed. Through the studies of Lavoisier, Joseph Priestley, Scheele, and others, chemistry was made a standardized field with consistent procedures. Although Scheele was unable to grasp the significance of his discovery of the substance that Lavoisier later named oxygen, his work was essential for the abandonment of the long-held theory of phlogiston. Scheele's study of the gas not yet named oxygen was prompted by a complaint by Torbern Olof Bergman, a professor at Uppsala University who would eventually become Scheele's friend.
Carl Wilhelm Scheele | The theory of phlogiston
Carl was credited for finding oxygen with two other people, Joseph Priestley and Antoine Lavoisier. The first English edition, "Chemical Observation and Experiments on Air and Fire" was published in 1780, with an introduction "Chemical Treatise on Air and Fire".
Carl Wilhelm Scheele | Existing theories before Scheele
Becher's main contribution was the start of the theory itself, however much it was changed after him. Becher's idea was that combustible substances contain an ignitable matter, the "terra pinguis."
Phlogiston theory | Johann Joachim Becher
The phlogiston theory is a superseded scientific theory that postulated the existence of a fire-like element called phlogiston () contained within combustible bodies and released during combustion. The name comes from the Ancient Greek φλογιστόν "phlogistón" ("burning up"), from φλόξ "phlóx" ("flame"). The idea was first proposed in 1667 by Johann Joachim Becher and later put together more formally by Georg Ernst Stahl. Phlogiston theory attempted to explain processes such as combustion and rusting, now collectively known as oxidation, and was abandoned before the end of the 18th century following experiments by Antoine Lavoisier and others. Phlogiston theory led to experiments which ultimately concluded with the discovery of Oxygen.
Phlogiston theory | Introduction
J. Becher was the theory of phlogiston. This theory did not have any experimental basis before Stahl. He was able to make the theory applicable to chemistry. Becher's theories attempted in explaining chemistry as comprehensively as seemingly possible through classifying different earths according to specific reactions. "Terra pinguis" was a substance that escaped during combustion reactions, according to Becher. Stahl, influenced by Becher's work, developed his theory of phlogiston. Phlogiston theory did not have any experimental basis before Stahl worked with metals and various other substances in order separate phlogiston from them. Stahl proposed that metals were made of calx, or ash, and phlogiston and that once a metal is heated, the phlogiston leaves only the calx within the substance.
Georg Ernst Stahl | Chemistry
In the early 20th century, Henry Norris Russell proposed that rather than being a new element, the line at 500.7 nm was due to a familiar element in unfamiliar conditions.
H II region | Observations
Empedocles had formulated the classical theory that there were four elements: water, earth, fire and air and Aristotle reinforced this idea by characterising them as moist, dry, hot and cold. Fire was thus thought of as a substance and burning was seen as a process of decomposition which applied only to compounds. Experience had shown that burning was not always accompanied by a loss of material and a better theory was needed to account for this.
Phlogiston theory | History of phlogiston theory
In 1667, Johann Joachim Becher published his book "Physica subterranea", which contained the first instance of what would become the phlogiston theory. In his book, Becher eliminated fire and air from the classical element model and replaced them with three forms of earth: "terra lapidea", "terra fluida", and "terra pinguis". "Terra pinguis" was the element that imparted oily, sulphurous, or combustible properties. Becher believed that "terra pinguis" was a key feature of combustion and was released when combustible substances were burned. Becher did not have much to do with phlogiston theory as we know it now, but he had a large influence on his student Stahl.
Phlogiston theory | Johann Joachim Becher
In addition to his joint recognition for the discovery of oxygen, Scheele is argued to have been the first to discover other chemical elements such as barium (1772), manganese (1774), molybdenum (1778), and tungsten (1781), as well as several chemical compounds, including citric acid, lactic acid, glycerol, hydrogen cyanide (also known, in aqueous solution, as prussic acid), hydrogen fluoride, and hydrogen sulfide (1777). In addition, he discovered a process similar to pasteurization, along with a means of mass-producing phosphorus (1769), leading Sweden to become one of the world's leading producers of matches. Scheele made one other very important scientific discovery in 1774, arguably more revolutionary than his isolation of oxygen.
Carl Wilhelm Scheele | New elements and compounds
Soot was almost pure phlogiston, which is why heating it with a metallic calx transforms the calx into the metal and Stahl attempted to prove that the phlogiston in soot and sulphur were identical by converting sulphates to liver of sulphur using charcoal. He did not account for the increase in weight on combustion of tin and lead that were known at the time.
Phlogiston theory | Georg Ernst Stahl
Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the "phlogiston theory", which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, and modified by the chemist Georg Ernst Stahl by 1731, phlogiston theory stated that all combustible materials were made of two parts. One part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx.
Oxygen | Phlogiston theory
He identified lime, silica, and iron in a specimen of pyrolusite (impure manganese dioxide) given to him by his friend, Johann Gottlieb Gahn, but could not identify an additional component (this was the manganese, which Scheele recognized was present as a new element, but could not isolate). When he treated the pyrolusite with hydrochloric acid over a warm sand bath, a yellow-green gas with a strong odor was produced. He found that the gas sank to the bottom of an open bottle and was denser than ordinary air. He also noted that the gas was not soluble in water. It turned corks a yellow color and removed all color from wet, blue litmus paper and some flowers.
Carl Wilhelm Scheele | New elements and compounds
In 2004 CERRIE rejected the SET by a 10 to 2 majority consensus (Busby and non-scientist Richard Bramhall, dissented). The rejection was made for following reasons:
Christopher Busby | Second event theory and photoelectric effect controversy
Johann Juncker also created a very complete picture of phlogiston. When reading Stahl's work, he assumed that phlogiston was in fact very material. He therefore came to the conclusion that phlogiston has the property of levity, or that it makes the compound that it is in much lighter than it would be without the phlogiston. He also showed that air was needed for combustion by putting substances in a sealed flask and trying to burn them. Guillaume-Francois Rouelle brought the theory of phlogiston to France, and he was a very influential scientist and teacher so it gained quite a strong foothold very quickly.
Phlogiston theory | Others
Flames were considered to be a mix of phlogiston and water, while a phlogiston-and-earthy mixture could not burn properly. Phlogiston permeating everything in the universe, it could be released as heat when combined with acid. Pott proposed the following properties: Pott's formulations proposed little new theory; he merely supplied further details and rendered existing theory more approachable to the common man.
Phlogiston theory | J. H. Pott
Johann Heinrich Pott, a student of one of Stahl's students, expanded the theory and attempted to make it much more understandable to a general audience. He compared phlogiston to light or fire, saying that all three were substances whose natures were widely understood but not easily defined. He thought that phlogiston should not be considered as a particle but as an essence that permeates substances, arguing that in a pound of any substance one could not simply pick out the particles of phlogiston. Pott also observed the fact that when certain substances are burned they increase in mass instead of losing the mass of the phlogiston as it escapes; according to him, phlogiston was the basic fire principle and could not be obtained by itself.
Phlogiston theory | J. H. Pott
Heavier elements beyond the actinides were first proposed to exist as early as 1895, when the Danish chemist Hans Peter Jørgen Julius Thomsen predicted that thorium and uranium formed part of a 32-element period which would end at a chemically inactive element with atomic weight 292 (not far from the 294 known today for the first and only discovered isotope of oganesson). In 1913, the Swedish physicist Johannes Rydberg similarly predicted that the next noble gas after radon would have atomic number 118, and purely formally derived even heavier congeners of radon at "Z" = 168, 218, 290, 362, and 460, exactly where the Aufbau principle would predict them to be.
Extended periodic table | History
Eventually, quantitative experiments revealed problems, including the fact that some metals gained mass when they burned, even though they were supposed to have lost phlogiston. Some phlogiston proponents explained this by concluding that phlogiston had negative weight; others, such as Louis-Bernard Guyton de Morveau, gave the more conventional argument that it was lighter than air. However, a more detailed analysis based on Archimedes' principle, the densities of magnesium and its combustion product showed that just being lighter than air could not account for the increase in mass. Stahl himself did not address the problem of the metals that burn gaining weight, but those who followed his ideas and did not question his ideas were the ones that worked on this problem.
Phlogiston theory | Challenge and demise
The theory originally proposed that "all" atomic nuclei are produced by the successive capture of neutrons, one mass unit at a time. However, later study challenged the universality of the successive capture theory. No element was found to have a stable isotope with an atomic mass of five or eight. Physicists soon noticed that these "mass gaps" would hinder the production of elements beyond helium. Just as it's impossible to climb a staircase one step at a time when one of the steps is missing, this discovery meant that the successive capture theory could not account for higher elements. It was eventually recognized that most of the heavy elements observed in the present universe are the result of stellar nucleosynthesis in stars, a theory first suggested by Arthur Stanley Eddington, given credence by Hans Bethe, and quantitatively developed by Fred Hoyle and a number of other scientists.
Alpher–Bethe–Gamow paper | Main shortcoming of the theory
Much of Scheele's later theoretical speculations were based upon Stahl. In 1765 Scheele worked under the progressive and well informed apothecary, C. M. Kjellström in Malmö, and became acquainted with Anders Jahan Retzius who was a lecturer at the University of Lund and later a professor of chemistry at Stockholm. Scheele arrived in Stockholm between 1767 and 1769 and worked as a pharmacist. During this period he discovered tartaric acid and with his friend, Retzius, studied the relation of quicklime to calcium carbonate. While in the capital, he also became acquainted with many luminaries, such as: Abraham Bäck, Peter Jonas Bergius, Bengt Bergius and Carl Friedreich von Schultzenheim.
Carl Wilhelm Scheele | Biography
In 1667 the German scientist Johann Becker proposed that fire was caused by an ethereal, odourless, tasteless, colourless, weightless entity called phlogiston. The idea was that phlogiston causes things to burn, reducing them to their pure form. For example, burning wood releases phlogiston, leaving the pure form of wood – ash, therefore wood is composed of ash (pure wood) and phlogiston. Phlogiston was accepted as scientific truth, paralysing the scientific community's ability to discover more, true elements. One scientist even claimed to have isolated phlogiston.
Chemistry: A Volatile History | Johann Becher and phlogiston
In 1703 Georg Ernst Stahl, professor of medicine and chemistry at Halle, proposed a variant of the theory in which he renamed Becher's "terra pinguis" to "phlogiston", and it was in this form that the theory probably had its greatest influence. The term phlogiston itself was not something that Stahl invented. There is evidence that the word was used as early as 1606, and in a way that was very similar to what Stahl was using it for. The term was derived from a Greek word meaning to inflame. The following paragraph describes Stahl's view of phlogiston:To Stahl, metals were compounds containing phlogiston in combination with metallic oxides (calces); on ignition the phlogiston was freed from the metal leaving the oxide behind.
Phlogiston theory | Georg Ernst Stahl
Nalin de Silva who is influenced by Paul Feyerabend rejected the existence of scientific method and propose proliferation of sciences on various chinthanayas. He proposes theories are stories constructed by abductive reasoning to explain phenomenas . He refuses ideas that science is truth or science is advancing towards the truth.
Nalin de Silva | Philoosphy of science
At first, he continued his work on crystals on his own but when Bohr's student became ill, he was assigned the urgent task of working on the helium problem. Hylleraas modified the first attempt in two important ways: he replaced the incomplete bound-state hydrogenic functions by the complete Laguerre functions and reduced the number of co-ordinates from 6 to 3, namely the distances of the two electrons from the nucleus and the angle between the position vectors of the two electrons. Then, with the aid of a mechanical desk calculator obtained result in much better agreement with experiment. The result was well received but the discrepancy of 0.12 eV continued to bother him.
Egil Hylleraas | The Golden Age of Atomic Physics
A number of chemists, including Claude Berthollet, suggested that Scheele's "dephlogisticated muriatic acid air" must be a combination of oxygen and the yet undiscovered element, and Scheele named the supposed new element within this oxide as "muriaticum". The suggestion that this newly discovered gas was a simple element was made in 1809 by Joseph Louis Gay-Lussac and Louis-Jacques. This was confirmed in 1810 by Sir Humphry Davy, who named it chlorine, from the Greek word "χλωρός" (chlōros), meaning "green-yellow". Chlorine is a component of many other compounds. It is the second most abundant halogen and 21st most abundant chemical element in Earth's crust.
Period 3 element | Chlorine
His study established that any particular droplet's electrical charge is a multiple of a definite, fundamental value — the electron's charge — and thus a confirmation that all electrons have the same charge and mass. Beginning in 1912, he spent several years investigating and finally proving Albert Einstein's proposed linear relationship between energy and frequency, and providing the first direct photoelectric support for Planck's constant. In 1923 Millikan was awarded the Nobel Prize for Physics. In 1909, S. P. L. Sørensen invented the pH concept and develops methods for measuring acidity. In 1911, Antonius Van den Broek proposed the idea that the elements on the periodic table are more properly organized by positive nuclear charge rather than atomic weight.
20th century in science | Chemistry
The source of the second muon was argued to be due to the decay of pions and kaons. Cline and others provided evidence against this by observing “(i) the rate of dimuon events, (ii) the opposite signs of their electric charges, (iii) the different densities of the target materials in which they were produced, and (iv) the distributions in muon momentum and transverse momentum.”
David B. Cline | Investigation of Dimuon Events
However, in 1812, Bernard Courtois proved that the isoelectronic substance iodine is an element. This finding resolved Berzelius's disagreement. Berzelius continued his investigations into the chemistry of chlorine during his stay in Claude Louis Berthollet's laboratory.
Jöns Jacob Berzelius | Relations with other scientists
Crell stopped publishing the journal in 1804 after the concurrence of the chemical journal of Alexander Nicolaus Scherer and Adolph Ferdinand Gehlen, today published as "Journal für praktische Chemie" became too strong. Crell was involved in the sometimes harsh discussion about the phlogiston theory. The experiments of Antoine-Laurent Lavoisier showed that the up to that point accepted theory was probably wrong. Von Crell translated some articles of Richard Kirwan, a supporter of the phlogiston theory. Von Crell defended the theory until 1799 and never openly accepted that it was wrong. Crell was elected into the German Academy of Sciences Leopoldina in 1778.
Lorenz Florenz Friedrich von Crell | Life and work
Niels Bohr predicted in 1922 the electronic structure of this next noble gas at "Z" = 118, and suggested that the reason why elements beyond uranium were not seen in nature was because they were too unstable. The German physicist and engineer Richard Swinne published a review paper in 1926 containing predictions on the transuranic elements (he may have coined the term) in which he anticipated modern predictions of an island of stability: he had hypothesised since 1914 that half-lives should not decrease strictly with atomic number, but suggested instead that there might be some longer-lived elements at "Z" = 98–102 and "Z" = 108–110, and speculated that such elements might exist in the Earth's core, in iron meteorites, or in the ice caps of Greenland where they had been locked up from their supposed cosmic origin.
Extended periodic table | History
Developed under Johann Joachim Becher and Georg Ernst Stahl, phlogiston theory was an attempt to account for products of combustion. According to the theory, a substance called phlogiston was released from flammable materials through burning. The resulting product was termed "calx", which was considered a 'dephlogisticated' substance in its 'true' form. The first strong evidence against phlogiston theory came from pneumatic chemists in Britain during the later half of the 18th century. Joseph Black, Joseph Priestley and Henry Cavendish all identified different gases that composed air; however, it was not until Antoine Lavoisier discovered in the fall of 1772 that, when burned, sulphur and phosphorus “gain[ed] in weight” that the phlogiston theory began to unravel.
Science in the Age of Enlightenment | Chemistry
In his second "prolegomena" paper, R. Aris mentioned the work of N.Z. Shapiro, L.S. Shapley (1965), where an important part of his scientific program was realized.
Chemical reaction network theory | History
Influenced by such leading figures as Liebig and Dumas, by 1856 Wurtz became a powerful advocate of a reform in chemical theory then being led by Charles Gerhardt and Alexander Williamson. This new chemistry of the 1850s took the idea of chemical atoms seriously, adopted atomic weights for the elements that strongly resemble the modern ones, and proposed a unitary schematic plan that opposed the dualistic theory derived from the work of Jons Jacob Berzelius. Soon thereafter, Wurtz also adopted the new structural theory that was developing from the work of younger chemists such as August Kekulé. However, a kind of skeptical positivism was influential in France during the second half of the nineteenth century, and Wurtz's efforts to gain a favorable hearing for atomism and structuralism in his homeland were largely frustrated.
Charles Adolphe Wurtz | Scientific and academic work
Olbers discovered and named the asteroid (2) Pallas, a second object in roughly the same orbit as (1) Ceres. Olbers proposed that these two discoveries were the fragments of a disrupted planet that had formerly orbited the Sun, and predicted that more of these pieces would be found. The discovery of the asteroid (3) Juno by Karl Ludwig Harding and (4) Vesta by Olbers, buttressed his hypothesis. In 1823, German linguist and retired teacher J.G. Radlof called Olbers' destroyed planet "Phaëthon", linking it to the Greek myths and legends about Phaethon and others. The idea was similar to those later advocated by Immanuel Velikovsky but only in that the catastrophe was in recent times.
Phaeton (hypothetical planet) | Phaeton hypothesis
In 1756, Lomonosov tried to replicate Robert Boyle's experiment of 1673. He concluded that the commonly accepted phlogiston theory was false. Anticipating the discoveries of Antoine Lavoisier, he wrote in his diary: "Today I made an experiment in hermetic glass vessels in order to determine whether the mass of metals increases from the action of pure heat. The experiments – of which I append the record in 13 pages – demonstrated that the famous Robert Boyle was deluded, for without access of air from outside the mass of the burnt metal remains the same". That is the Law of Mass Conservation in chemical reaction, which was well-known today as "in a chemical reaction, the mass of reactants is equal to the mass of the products." Lomonosov, together with Lavoisier, is regarded as the one who discovered the law of mass conservation.
Mikhail Lomonosov | Physicist
He called this gas with bleaching abilities, "dephlogisticated muriatic acid" (dephlogisticated hydrochloric acid, or oxidized hydrochloric acid). Eventually, Sir Humphry Davy named the gas chlorine, with reference to its pale green colour. Chlorine's bleaching properties were eventually turned into an industry by Berzelius, and became the foundation of a second industry of disinfection and deodorization of putrefied tissue and wounds (including wounds in living humans) in the hands of Labarraque, by 1824.
Carl Wilhelm Scheele | New elements and compounds
He did maintain the later-discredited phlogiston hypothesis, but wasn't doctrinaire about it. In 1786 he was elected a Fellow of the Royal Society of London. In 1787 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were John Playfair, James Hutton, and James Gregory.
Adair Crawford | Life
In 1661, Robert Boyle proposed his theory of corpuscularism which favoured the analysis of matter as constituted by irreducible units of matter (atoms) and, choosing to side with neither Aristotle's view of the four elements nor Paracelsus' view of three fundamental elements, left open the question of the number of elements. The first modern list of chemical elements was given in Antoine Lavoisier's 1789 "Elements of Chemistry", which contained thirty-three elements, including light and caloric. By 1818, Jöns Jakob Berzelius had determined atomic weights for forty-five of the forty-nine then-accepted elements. Dmitri Mendeleev had sixty-six elements in his periodic table of 1869.
Chemical element | Chemical definitions
As a second application of the proposed hypothesis, Ishiwara considered the problem of the photoelectric effect, obtaining a linear relationship between the electron energy and the radiation frequency in accordance with the Einstein formula. Later in the same year Ishiwara put forward another hypothesis, according to which the product of the energy of the atom and the period of electron motion in the stationary state should be equal to the integer number of Planck constants. In 1918, he linked the postulate proposed three years earlier to the theory of adiabatic invariants. Around the same time, analogous rules for quantizing systems of many degrees of freedom were independently obtained by William Wilson and Sommerfeld and are usually called the Sommerfeld quantum conditions.
Jun Ishiwara | Quantum physics
During the eighteenth century, as it became clear that metals gained mass when they were oxidized, phlogiston was increasingly regarded as a "principle" rather than a material substance. By the end of the eighteenth century, for the few chemists who still used the term phlogiston, the concept was linked to hydrogen. Joseph Priestley, for example, in referring to the reaction of steam on iron, while fully acknowledging that the iron gains mass as it binds with oxygen to form a calx, iron oxide, iron also loses "the basis of inflammable air (hydrogen), and this is the substance or principle, to which we give the name phlogiston." Following Lavoisier’s description of oxygen as the "oxidizing principle" (hence its name, from Ancient Greek: oksús, “sharp;” génos, “birth,” referring to oxygen's supposed role in the formation of acids), Priestley described phlogiston as the "alkaline principle." Phlogiston remained the dominant theory until the 1770s when Antoine-Laurent de Lavoisier showed that combustion requires a gas that has mass (specifically, oxygen) and could be measured by means of weighing closed vessels.
Phlogiston theory | Challenge and demise
His study established that any particular droplet's electrical charge is a multiple of a definite, fundamental value — the electron's charge — and thus a confirmation that all electrons have the same charge and mass. Beginning in 1912, he spent several years investigating and finally proving Albert Einstein's proposed linear relationship between energy and frequency, and providing the first direct photoelectric support for Planck's constant. In 1923 Millikan was awarded the Nobel Prize for Physics. In 1909, S. P. L. Sørensen invented the pH concept and developed methods for measuring acidity. In 1911, Antonius Van den Broek proposed the idea that the elements on the periodic table are more properly organized by positive nuclear charge rather than atomic weight.
History of chemistry | 20th century
In 1815, William Prout reported on his observation that the atomic weights of the elements were whole multiples of the atomic weight of hydrogen. He then hypothesized that the hydrogen atom was the fundamental object and that the other elements were a combination of different numbers of hydrogen atoms.
Whole number rule | Prout's hypothesis
For this seemingly astonishing result, he was awarded the Copley Medal. Wollaston, again anonymously, offered a reward to anyone who could confirm Chenevix's claims experimentally. On his part, Chenevix published a second paper supporting his result in 1805, by which time he'd made Paris his permanent home. Henry Cavendish, an admirer of Wollaston, was the sole Society objector in the vote for the publication. Later that year, Wollaston publicly revealed his authorship (although he had communicated as much to the Royal Society before Chenevix's second paper) and details of how he had, correctly, isolated the element palladium. Chenevix bore no apparent animus in later meetings between the two.
Richard Chenevix (chemist) | Career
Wilhelm Hisinger (23 December 1766 – 28 June 1852) was a Swedish physicist and chemist who in 1807, working in coordination with Jöns Jakob Berzelius, noted that in electrolysis any given substance always went to the same pole, and that substances attracted to the same pole had other properties in common. This showed that there was at least a qualitative correlation between the chemical and electrical natures of bodies. In 1803, in separate laboratories, Martin Heinrich Klaproth in one, and Berzelius and Hisinger in another, the element Cerium was discovered, which was named after the newly discovered asteroid, Ceres. It was discovered nearly simultaneously by both laboratories, though it was later shown that Berzelius and Hisinger's cerium was actually a mixture of cerium, lanthanum and so-called didymium.
Wilhelm Hisinger | Introduction
Clapeyron's analysis of Carnot was more broadly disseminated in 1843 when Johann Poggendorff translated it into German. In 1842 Clapeyron published his findings on the "optimal position for the piston at which the various valves should be opened or closed." In 1843, Clapeyron further developed the idea of a reversible process, already suggested by Carnot and made a definitive statement of "Carnot's principle", what is now known as the second law of thermodynamics.
Benoît Paul Émile Clapeyron | Work
Berzelius was a prolific correspondent with leading scientists of his time, such as Gerardus Johannes Mulder, Claude Louis Berthollet, Humphry Davy, Friedrich Wöhler and Eilhard Mitscherlich. In 1812, Berzelius traveled to London, England, including Greenwich to meet with prominent British scientists of the time. These included Humphry Davy, chemist William Wollaston, physician-scientist Thomas Young, astronomer William Herschel, chemist Smithson Tennant, and inventor James Watt, among others. Berzelius also visited Davy's laboratory. After his visit to Davy's laboratory, Berzelius remarked, "A tidy laboratory is a sign of a lazy chemist." Humphry Davy in 1810 proposed that chlorine is an element. Berzelius refuted this claim because of his belief that all acids were based on oxygen, and HCl contains no oxygen and so could not be an element, in Berzelius's perception.
Jöns Jacob Berzelius | Relations with other scientists
Pokorny suggested that Illyrian elements were to be found in much of the continental Europe and also in the British Isles. Pokorny's "Illyromania" derived in part from archaeological "Germanomania" and was supported by contemporary place-name specialists such as Max Vasmer and Hans Krahe.
Pan-Illyrian theories | First attempt
The following year, Pelletier was master apothecary, married Marguerite Sedillot and bought Rouelle's pharmacy. From 1783, Pelletier was a student at the Paris Faculty of Medicine, where he made but no degree. In 1784, on a suggestion from crystallographer Jean-Baptiste Romé de L’Isle, Pelletier produced strongly soluble salt crystals through slow evaporation and inoculation. A year later, he confirmed Carl Wilhelm Scheele's discovery that chlorine can be produced from hydrochloric acid and manganese. Like Claude Louis Berthollet, Pelletier arrived to the false conclusion that the resulting gas was a combination of hydrochloric acid and oxygen. An adherent to Carl Wilhelm Scheele's phlogiston theory, Pelletier followed Lavoisier's more modern approaches only after 1787.
Bertrand Pelletier | Biography
In 1773, Swedish chemist Carl Wilhelm Scheele discovered oxygen, which he called "fire air", but did not immediately publish his achievement. In 1774, English chemist Joseph Priestley independently isolated oxygen in its gaseous state, calling it "dephlogisticated air", and published his work before Scheele. During his lifetime, Priestley's considerable scientific reputation rested on his invention of soda water, his writings on electricity, and his discovery of several "airs" (gases), the most famous being what Priestley dubbed "dephlogisticated air" (oxygen). However, Priestley's determination to defend phlogiston theory and to reject what would become the chemical revolution eventually left him isolated within the scientific community.
History of chemistry | Development and dismantling of phlogiston
In 1896, the mathematician Ernst Zermelo advanced a theory that the second law of thermodynamics was absolute rather than statistical. Zermelo bolstered his theory by pointing out that the Poincaré recurrence theorem shows statistical entropy in a closed system must eventually be a periodic function; therefore, the Second Law, which is always observed to increase entropy, is unlikely to be statistical. To counter Zermelo's argument, the Austrian physicist Ludwig Boltzmann advanced two theories. The first theory, now believed to be the correct one, is that the Universe started for some unknown reason in a low-entropy state. The second and alternative theory, published in 1896 but attributed in 1895 to Boltzmann's assistant Ignaz Schütz, is the "Boltzmann universe" scenario.
Boltzmann brain | Boltzmann universe
According to Aristotle, Democritus and Leucippus, and many other physicists, proposed the atomic theory, which supposes that everything in the universe is either atoms or voids, specifically to contradict Parmenides' argument. Karl Popper wrote: So what was really new in Parmenides was his axiomatic-deductive method, which Leucippus and Democritus turned into a hypothetical-deductive method, and thus made part of scientific methodology.
Parmenides | Legacy
This idea was subsequently proposed independently by Wundt.
George Henry Lewes | Science
When the oxide was heated with a substance rich in phlogiston, such as charcoal, the calx again took up phlogiston and regenerated the metal. Phlogiston was a definite substance, the same in all its combinations.Stahl's first definition of phlogiston first appeared in his "Zymotechnia fundamentalis", published in 1697. His most quoted definition was found in the treatise on chemistry entitled "Fundamenta chymiae" in 1723. According to Stahl, phlogiston was a substance that was not able to be put into a bottle, but could be transferred nonetheless. To him, wood was just a combination of ash and phlogiston, and making a metal was as simple as getting a metal calx and adding phlogiston.
Phlogiston theory | Georg Ernst Stahl
The purer elements could then be utilized in other applications. Later in his career he continued published and spoke about the numerical relations between the atomic masses of analogous elements. His theories were early in the development of the Periodic Table. He rejected the current theory of triads and expanded the connections between the elements to larger groupings. He argued that the weights of different elements in a group were separated by multiples of a certain number that varied based upon the group. His work in this area was later cited by Dmitri Mendeleev in his construction of the Periodic Table of Elements.
Max Joseph von Pettenkofer | Career as chemist
Prout's hypothesis was an early 19th-century attempt to explain the existence of the various chemical elements through a hypothesis regarding the internal structure of the atom. In 1815 and 1816, the English chemist William Prout published two papers in which he observed that the atomic weights that had been measured for the elements known at that time appeared to be whole multiples of the atomic weight of hydrogen. He then hypothesized that the hydrogen atom was the only truly fundamental object, which he called protyle, and that the atoms of other elements were actually groupings of various numbers of hydrogen atoms.
Prout's hypothesis | Introduction
It is possible, that the of was needed to change again into diatonic genus. According to the New Method (since 1814) was always chromatic and based on the of , memorised as . This was Chrysanthos' way to understand Manuel Chrysaphes—probably a contemporary way, since the 17th-century Papadike introduced a seventh for .
Nenano | Phthora nenano and the plagal second echos
Carl Wilhelm Scheele (, ; 9 December 1742 – 21 May 1786) was a German and Swedish Pomeranian pharmaceutical chemist. Isaac Asimov called him "hard-luck Scheele" because he made a number of chemical discoveries before others who are generally given the credit. For example, Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, hydrogen, and chlorine before Humphry Davy, among others. Scheele discovered organic acids tartaric, oxalic, uric, lactic, and citric, as well as hydrofluoric, hydrocyanic, and arsenic acids. He preferred speaking German to Swedish his whole life, as German was commonly spoken among Swedish pharmacists.
Carl Wilhelm Scheele | Introduction
In the fall of 1785, Scheele began to suffer from symptoms described as kidney disease. In early 1786, he also contracted a disease of the skin, which, combined with kidney problems, so enfeebled him that he could foresee an early death. With this in mind, he married the widow of his predecessor, Pohl, two days before he died, so that he could pass undisputed title to his pharmacy and his possessions to her. While Scheele's experiments generated substances which have long since been found to be hazardous, the compounds and elements he used to start his experiments were dangerous to begin with, especially heavy metals.
Carl Wilhelm Scheele | Death
The resulting helical curve, which de Chancourtois called a square circle triangle, brought similar elements onto corresponding points above or below one another on the cylinder. Thus, he suggested that "the properties of the elements are the properties of numbers." He was the first scientist to see the periodicity of elements when they were arranged in order of their atomic weights. He saw that the similar elements occurred at regular atomic weight intervals. Despite de Chancourtois' work, his publication attracted little attention from chemists around the world. He presented the paper to the French Academy of Sciences which published it in "Comptes Rendus", the academy's journal.
Alexandre-Émile Béguyer de Chancourtois | Organizing the elements
A study of Dalton's laboratory notebooks, discovered in the rooms of the Manchester Literary and Philosophical Society, concluded that so far from Dalton being led by his search for an explanation of the law of multiple proportions to the idea that chemical combination consists in the interaction of atoms of definite and characteristic weight, the idea of atoms arose in his mind as a purely physical concept, forced on him by study of the physical properties of the atmosphere and other gases. The first published indications of this idea are to be found at the end of his paper "On the Absorption of Gases by Water and other Liquids" already mentioned.
John Dalton | Atomic theory
Noddack's idea of nuclear fission was not confirmed until much later. Experiments along a similar line to Fermi's, by Irène Joliot-Curie, Frédéric Joliot-Curie and Pavle Savić in 1938 raised what they called "interpretational difficulties" when the supposed transuranics exhibited the properties of rare earths rather than those of adjacent elements. Ultimately on December 17, 1938, Otto Hahn and Fritz Strassmann provided chemical proof that the previously presumed transuranic elements were isotopes of barium, and Hahn wrote these exciting results to his exiled colleague Lise Meitner, explaining the process as a 'bursting' of the uranium nucleus into lighter elements. Meitner and Otto Frisch utilized Fritz Kalckar and Niels Bohr's liquid drop hypothesis (first proposed by George Gamow in 1935) to provide a first theoretical model and mathematical proof of what Frisch coined nuclear fission.
Ida Noddack | Nuclear fission
The second controversy came when the 1983 prize went in part to William Alfred Fowler "for his theoretical and experimental studies of the nuclear reactions of importance in the formation of the chemical elements in the universe." The controversy arose because Hoyle had been the inventor of the theory of nucleosynthesis in the stars with two research papers published shortly after WWII. So some suspicion arose that Hoyle was denied the third share of this prize because of his earlier public disagreement with the 1974 award. British scientist Harry Kroto later said that the Nobel Prize is not just an award for a piece of work, but a recognition of a scientist's overall reputation and Hoyle's championing many disreputable and disproven ideas may have invalidated him.
Fred Hoyle | Nobel Physics Prizes
The third experiment, which started in 1969, published its final results in 1979, confirming the theory with a precision of 0.0007%. The United States took over the "g"−2 experiment in 1984.
Muon g-2 | Muon "g"−2 at CERN
The first part attempts to refute Lavoisier's challenges to his work on oxygen; the second part describes how steam is "converted" into air. After several variations of the experiment, with different substances as fuel and several different collecting apparatuses (which produced different results), he concluded that air could travel through more substances than previously surmised, a conclusion "contrary to all the known principles of hydrostatics". This discovery, along with his earlier work on what would later be recognised as gaseous diffusion, would eventually lead John Dalton and Thomas Graham to formulate the kinetic theory of gases. In 1777, Antoine Lavoisier had written "Mémoire sur la combustion en général", the first of what proved to be a series of attacks on phlogiston theory; it was against these attacks that Priestley responded in 1783.
Joseph Priestley | Chemical Revolution
In order to get agreement with experimental results, Fresnel found that the individual contributions from the secondary waves on the sphere had to be multiplied by a constant, −"i"/λ, and by an additional inclination factor, "K"(χ). The first assumption means that the secondary waves oscillate at a quarter of a cycle out of phase with respect to the primary wave, and that the magnitude of the secondary waves are in a ratio of 1:λ to the primary wave. He also assumed that "K"(χ) had a maximum value when χ = 0, and was equal to zero when χ = π/2, where χ is the angle between the normal of the primary wave front and the normal of the secondary wave front.
Huygens–Fresnel principle | Mathematical expression of the principle
Experiments at Berkeley were unsuccessful, but eventually elements 110-112 (110, darmstadtium; 111, roentgenium and 112, copernicium) were identified at the Darmstadt laboratory. Subsequent work at the JINR laboratory at Dubna, led by Yuri Oganessian and a Russian-American team of scientists, was successful in identifying elements 113-118 (113, nihonium; 114, flerovium; 115, moscovium; 116, livermorium; 117, tennessine and 118, oganesson), thereby completing the seventh row of the periodic table of the elements.
Albert Ghiorso | New elements
The fundamental reason for this is that if the first atom is measured to be in formula_57, then there is a single mode of the electromagnetic field within the cavity that will subsequently affect the measurement outcome of the second atom.
Ramsey interferometry | Experiments of Serge Haroche
Problems were submitted to the group without information about the source but included the automatic tracking of targets, radio propagation, underwater explosions, heat flow in steel, and the diffusion equation later found to be for isotope separation. The second group was the magnetron research group of Phyllis Lockett Nicolson, David Copely, and Oscar Buneman. The work was done for the Committee for the Co-ordination of the Valve Development assisting the development of radar. A differential analyser could have been used if more integrators had been available, so Hartree set up his group as three "CPUs" to work on mechanical desk calculators in parallel.
Douglas Hartree | Second World War
Around 1945, Alfred Tarski asked whether the free groups on two or more generators have the same first order theory, and whether this theory is decidable. answered the first question by showing that any two nonabelian free groups have the same first order theory, and answered both questions, showing that this theory is decidable. A similar unsolved (as of 2011) question in free probability theory asks whether the von Neumann group algebras of any two non-abelian finitely generated free groups are isomorphic.
Free group | Tarski's problems
The element was first isolated by Carl Gustaf Mosander in 1838. Hisinger was elected a member of the Royal Swedish Academy of Sciences in 1804.
Wilhelm Hisinger | Introduction
In the language of Heisenberg's matrix mechanics, the hydrogen atom was first solved by Wolfgang Pauli using a rotational symmetry in four dimensions [O(4)-symmetry] generated by the angular momentum and the Laplace–Runge–Lenz vector. By extending the symmetry group O(4) to the dynamical group O(4,2), the entire spectrum and all transitions were embedded in a single irreducible group representation. In 1979 the (non-relativistic) hydrogen atom was solved for the first time within Feynman's path integral formulation of quantum mechanics by Duru and Kleinert. This work greatly extended the range of applicability of Feynman's method.
Hydrogen atom | Alternatives to the Schrödinger theory
Christian Hülsen proposed a theory that the diribitorium was a second story atop the Saepta.
Diribitorium | Introduction
This chain theory was superseded in 1893, almost 25 years later, when Alfred Werner proposed his coordination theory.
Christian Wilhelm Blomstrand | Chemical structure
This demonstration established water as a compound of oxygen and hydrogen with great certainty for those who viewed it. The dissemination of the experiment, however, proved subpar, as it lacked the details to properly display the amount of precision taken in the measurements. The paper ended with a hasty statement that the experiment was "more than sufficient to lay hold of the certainty of the proposition" of the composition of water and stated that the methods used in the experiment would unite chemistry with the other physical sciences and advance discoveries.
Antoine Lavoisier | Dismantling phlogiston theory
du Fay observed that the “leaf-gold is first attracted by the tube; and acquires an electricity be approaching it; and of consequence is immediately repell’d by it.” This seemed to confirm for du Fay that the leaf was being pushed as a ‘current’ of electricity flowed around and through it. Through further testing, du Fray determined that an object could hold one of two types of electricity, either vitreous or resinous electricity. He found that an object with vitreous electricity would repel another vitreous object, but would be attracted to an object with resinous electricity
Fluid theory of electricity | Two-fluid theory
After this he traveled around Peru, searching for suitable places to construct hydro-electric central power stations. In the Third Pan-American Scientific Congress held in Lima, Antúnez de Mayolo presented the work "Hipótesis sobre la constitución de la materia," proposing the existence of a "neutral element" in the atom. Eight years later, Englishman James Chadwick confirmed this theory. In 1934, he proposed the existence of the positron in his article "Los tres elementos constitutivos de la materia." In 1936, David Anderson received the Nobel prize for its discovery. He died in 1967.
Santiago Antúnez de Mayolo | Early years
Peter Jacob Hjelm successfully isolated molybdenum by using carbon and linseed oil in 1781. Regarding tungsten, in 1781 Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite (at the time named tungsten). Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid. In 1783, José and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, in Spain, the brothers succeeded in isolating tungsten by reduction of this acid with charcoal, and they are credited with the discovery of the element.
Group 6 element | Discoveries
In 1886, he proposed the name "austrium" for what he believed was a new chemical element.
Eduard Linnemann | Introduction
The first two reactions that the Berlin group had observed were light elements created by the breakup of uranium nuclei; the third, the 23-minute one, was a decay into the real element 93. On returning to Copenhagen, Frisch informed Bohr, who slapped his forehead and exclaimed "What idiots we have been!" Bohr promised not to say anything until they had a paper ready for publication. To speed the process, they decided to submit a one-page note to "Nature". At this point, the only evidence that they had was the barium. Logically, if barium was formed, the other element must be krypton, although Hahn mistakenly believed that the atomic masses had to add up to 239 rather than the atomic numbers adding up to 92, and thought it was masurium (technetium), and so did not check for it: Over a series of long-distance phone calls, Meitner and Frisch came up with a simple experiment to bolster their claim: to measure the recoil of the fission fragments, using a Geiger counter with the threshold set above that of the alpha particles.
Lise Meitner | Nuclear fission
In establishing the coordinate axes to evaluate the derivation, Darken refers back to Smigelskas and Kirkendall’s experiment which the inert wires were designated as the origin. In respect to the derivation of the second equation, Darken referenced W. A. Johnson’s experiment on a gold–silver system, which was performed to determine the chemical diffusivity. In this experiment radioactive gold and silver isotopes were used to measure the diffusivity of gold and silver, because it was assumed that the radioactive isotopes have relatively the same mobility as the non-radioactive elements. If the gold–silver solution is assumed to behave ideally, it would be expected the diffusivities would also be equivalent.
Darken's equations | Experimental methods
All of the following papers were published by Scheele within a span of fifteen years. Scheele's papers appeared first in the "Transactions" of the Swedish Academy of Sciences, and in various periodicals such as Lorenz Florenz Friedrich von Crell's "Chemische Annalen". Scheele's work was collected and published in four languages beginning with "Mémoires de Chymie" by Mme. Claudine Picardet in 1785 and "Chemical Essays" by Thomas Beddoes in 1786, followed by Latin and German. Another English translation was published by Dr Leonard Dobbin, in 1931.
Carl Wilhelm Scheele | Published papers
So there are lower limits for "Sv" and v, and an upper limit for "S" and with those values one can calculate the produced heat, which is proportional to "Sρv". The calculation shows that earth's temperature would rise by 10 degrees per second. Poincaré noticed, ""that the earth could not long stand such a regime."" Poincaré also analyzed some wave models (Tommasina and Lorentz), remarking that they suffered the same problems as the particle models. To reduce drag, superluminal wave velocities were necessary, and they would still be subject to the heating problem. After describing a similar re-radiation model like Thomson, he concluded: ""Such are the complicated hypotheses to which we are led when we seek to make Le Sage's theory tenable"".
Le Sage's theory of gravitation | Later assessments
The first muon "g"−2 experiments were born at CERN in 1959 under the initiative of Leon Lederman. A group of six physicists formed the first experiment, using the Synchrocyclotron at CERN. The first results were published in 1961, with a 2% precision with respect to the theoretical value, and then the second ones with this time a 0.4% precision, hence validating the quantum electrodynamics theory. A second experiment started in 1966 with a new group, working this time with the Proton-Synchrotron, still at CERN. The results were then 25 times more precise than the previous ones and showed a quantitative discrepancy between the experimental values and the theoretical ones, thus required the physicists to recalculate their theoretical model.
Muon g-2 | Muon "g"−2 at CERN
He was the first to propose the correct formula for indole in 1869, after publishing the first synthesis three years earlier. His contributions to theoretical chemistry include the 'strain' ("Spannung") theory of triple bonds and strain theory in small carbon rings. In 1871 he discovered the synthesis of phenolphthalein by condensation of phthalic anhydride with two equivalents of phenol under acidic conditions (hence the name). That same year he was the first to obtain synthetic fluorescein, a fluorophore pigment which is similar to naturally occurring pyoverdin that is synthesised by microorganisms (e.g., by some fluorescent strains of "Pseudomonas"). Baeyer named his finding "resorcinphthalein" as he had synthesised it from phthalic anhydride and resorcinol.
Adolf von Baeyer | Academic career and achievements
Gadolinite, a mineral (from Ytterby, a village in Sweden), consists of several compounds (oxides or earths): yttria, erbia (sub-component as ytterbia) and terbia. In 1878, Jean Charles Galissard de Marignac assumed that ytterbia consisted of a new element he called ytterbium (but actually there were two new elements). In 1907, Georges Urbain isolated element 70 and element 71 from ytterbia. He called element 70 neoytterbium ("new ytterbium") and called element 71 lutecium. At about the same time, Carl Auer von Welsbach also independently isolated these and proposed the names aldebaranium (Ad), after the star Aldebaran (in the constellation of Taurus), for element 70 (ytterbium), and cassiopeium (Cp), after the constellation Cassiopeia, for element 71 (lutetium), but both proposals were rejected.
List of chemical elements naming controversies | Elements 70 (<a href="Ytterbium">Ytterbium</a> Yb) and 71 (<a href="Lutetium">Lutetium</a> Lu)
Chlorine: In 1774, Scheele obtained chlorine from hydrochloric acid but thought it was an oxide. Only in 1808 did Humphry Davy recognize it as an element.
Nonmetal | 18th century: H, O, N, (Te), Cl
In his 1891 novel "The Doings of Raffles Haw", Arthur Conan Doyle talks about turning elements into other elements of decreasing atomic number, until a gray matter is reached. In his 1959 novel "Life and Fate", Vasily Grossman's principal character, the physicist Viktor Shtrum, reflects on Prout's hypothesis about hydrogen being the origin of other elements (and the felicitous fact that Prout's incorrect data led to an essentially correct conclusion), as he worries about his inability to formulate his own thesis.
Prout's hypothesis | Literary allusions
The domain of neutrino physics was in rapid expansion in the 60's. Neutrino experiments using bubble chambers were already running at the first synchrotron at CERN, the PS, and the question of the next generation of bubble chambers had been on the agenda for some time. André Lagarrigue, an esteemed physicist at the École Polytechnique in Paris, and some of his colleagues, wrote the first published report, dated 10 February 1964, proposing the construction of a heavy liquid chamber to be built under the supervision of CERN. He formed a collaboration consisting of seven laboratories: École Polytechnique Paris, RWTH Aachen, ULB Bruxelles, Istituto di Fisica dell'Università di Milano, , University College London and CERN.
Gargamelle | Conception and construction
The researchers reported that they had performed the reaction In 2001, they published a retraction after researchers at other laboratories were unable to duplicate the results and the Berkeley lab could not duplicate them either. In June 2002, the director of the lab announced that the original claim of the discovery of these two elements had been based on data fabricated by principal author Victor Ninov. Newer experimental results and theoretical predictions have confirmed the exponential decrease in cross sections with lead and bismuth targets as the atomic number of the resulting nuclide increases.
Oganesson | Unconfirmed discovery claims
Witten's proposal was based on the observation that the five string theories can be mapped to one another by certain rules called dualities and are identified by these dualities. Witten's announcement led to a flurry of work now known as the second superstring revolution.
Edward Witten | M-theory
Following his degree, Di Lella continued his work with Marcello Conversi, now at the University of Rome. He was commuting between Rome and CERN, using the Synchrocyclotron at CERN as an accelerator for his experiments, before he in 1961 secured a two-year position as a Fellow at CERN. In the 1950s physicist had started to wonder why processes like the decay of a positive muon to a positron and a photon, , or electron emission from nuclear capture of a negative muon, , were not observed. Given the knowledge of that time, there was no reason why these reactions could not exist – energy, charge and spin are conserved.
Luigi Di Lella | Career and Research
Although incorrect in their details, Astbury's models were correct in essence and correspond to modern elements of secondary structure, the α-helix and the β-strand (Astbury's nomenclature was kept), which were developed twenty years later by Linus Pauling and Robert Corey in 1951. Hans Neurath was the first to show that Astbury's models could not be correct in detail, because they involved clashes of atoms. Neurath's paper and Astbury's data inspired H. S. Taylor (1941,1942) and Maurice Huggins (1943) to propose models of keratin that are very close to the modern α-helix. In 1931, Astbury was also the first to propose that mainchain-mainchain hydrogen bonds (i.e., hydrogen bonds between the backbone amide groups) contributed to stabilizing protein structures.
William Astbury | X-ray diffraction studies of fibrous proteins
Based on the electrodynamic laws of Wilhelm Eduard Weber, Carl Friedrich Gauß, and Bernhard Riemann, between 1870-1900 many scientists tried to combine gravitation with a finite propagation speed and tried to derive the correct value for the perihelion shift of Mercury's orbit. In 1890 Maurice Lévy succeeded in doing so by combining the laws of Weber and Riemann, whereby the speed of gravity is equal to the speed of light in his theory. However, because the basic laws of Weber and others were wrong (for example, Weber's law was superseded by Maxwell's equations), those hypotheses were rejected. A variation of those superseded theories (albeit not directly based on Weber's theory) was the one of Gerber, which he developed in 1898 and 1902.
Paul Gerber | Basic concept
Irving Langmuir was the first to propose in his 1919 article "The Arrangement of Electrons in Atoms and Molecules" in which, building on Gilbert N. Lewis's cubical atom theory and Walther Kossel's chemical bonding theory, he outlined his "concentric theory of atomic structure". Langmuir had developed his work on electron atomic structure from other chemists as is shown in the development of the History of the periodic table and the Octet rule. Niels Bohr (1923) incorporated Langmuir’s model that the periodicity in the properties of the elements might be explained by the electronic structure of the atom. His proposals were based on the then current Bohr model of the atom, in which the electron shells were orbits at a fixed distance from the nucleus.
Electron configuration | History
Busby initially proposed the Second Event Theory (SET) in 1995, in his self-published book "Wings of Death: Nuclear Pollution and Human Health" claiming that isotopes which decay sequentially, emitting two or more particles in a short decay chain, have far greater genotoxic effects than predicted by the LNT model. According to this theory, the Sr-Y decay chain would be ~30 times more carcinogenic than predicted by LNT. According to SET, primary exposure to a beta particle alters a cell to the G Phase, which Busby claims would render the cell highly radio-sensitive and more prone to malignant changes when exposed to a second particle.
Christopher Busby | Second event theory and photoelectric effect controversy