hpprc/enwiki-paragraphs · Datasets at Hugging Face

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Agnosticism	894	History	Raised in a religious environment, Charles Darwin (1809–1882) studied to be an Anglican clergyman. While eventually doubting parts of his faith, Darwin continued to help in church affairs, even while avoiding church attendance. Darwin stated that it would be "absurd to doubt that a man might be an ardent theist and an evolutionist". Although reticent about his religious views, in 1879 he wrote that "I have never been an atheist in the sense of denying the existence of a God. – I think that generally ... an agnostic would be the most correct description of my state of mind."
Agnosticism	894	History	Agnostic views are as old as philosophical skepticism, but the terms agnostic and agnosticism were created by Huxley (1825–1895) to sum up his thoughts on contemporary developments of metaphysics about the "unconditioned" (William Hamilton) and the "unknowable" (Herbert Spencer). Though Huxley began to use the term agnostic in 1869, his opinions had taken shape some time before that date. In a letter of September 23, 1860, to Charles Kingsley, Huxley discussed his views extensively:
Agnosticism	894	History	I neither affirm nor deny the immortality of man. I see no reason for believing it, but, on the other hand, I have no means of disproving it. I have no a priori objections to the doctrine. No man who has to deal daily and hourly with nature can trouble himself about a priori difficulties. Give me such evidence as would justify me in believing in anything else, and I will believe that. Why should I not? It is not half so wonderful as the conservation of force or the indestructibility of matter ...
Agnosticism	894	History	It is no use to talk to me of analogies and probabilities. I know what I mean when I say I believe in the law of the inverse squares, and I will not rest my life and my hopes upon weaker convictions ...
Agnosticism	894	History	That my personality is the surest thing I know may be true. But the attempt to conceive what it is leads me into mere verbal subtleties. I have champed up all that chaff about the ego and the non-ego, noumena and phenomena, and all the rest of it, too often not to know that in attempting even to think of these questions, the human intellect flounders at once out of its depth.
Agnosticism	894	History	And again, to the same correspondent, May 6, 1863:
Agnosticism	894	History	I have never had the least sympathy with the a priori reasons against orthodoxy, and I have by nature and disposition the greatest possible antipathy to all the atheistic and infidel school. Nevertheless I know that I am, in spite of myself, exactly what the Christian would call, and, so far as I can see, is justified in calling, atheist and infidel. I cannot see one shadow or tittle of evidence that the great unknown underlying the phenomenon of the universe stands to us in the relation of a Father [who] loves us and cares for us as Christianity asserts. So with regard to the other great Christian dogmas, immortality of soul and future state of rewards and punishments, what possible objection can I—who am compelled perforce to believe in the immortality of what we call Matter and Force, and in a very unmistakable present state of rewards and punishments for our deeds—have to these doctrines? Give me a scintilla of evidence, and I am ready to jump at them.
Agnosticism	894	History	Of the origin of the name agnostic to describe this attitude, Huxley gave the following account:
Agnosticism	894	History	When I reached intellectual maturity and began to ask myself whether I was an atheist, a theist, or a pantheist; a materialist or an idealist; Christian or a freethinker; I found that the more I learned and reflected, the less ready was the answer; until, at last, I came to the conclusion that I had neither art nor part with any of these denominations, except the last. The one thing in which most of these good people were agreed was the one thing in which I differed from them. They were quite sure they had attained a certain "gnosis"—had, more or less successfully, solved the problem of existence; while I was quite sure I had not, and had a pretty strong conviction that the problem was insoluble. And, with Hume and Kant on my side, I could not think myself presumptuous in holding fast by that opinion ... So I took thought, and invented what I conceived to be the appropriate title of "agnostic". It came into my head as suggestively antithetic to the "gnostic" of Church history, who professed to know so much about the very things of which I was ignorant. ... To my great satisfaction the term took.
Agnosticism	894	History	In 1889, Huxley wrote:
Agnosticism	894	History	Therefore, although it be, as I believe, demonstrable that we have no real knowledge of the authorship, or of the date of composition of the Gospels, as they have come down to us, and that nothing better than more or less probable guesses can be arrived at on that subject.
Agnosticism	894	History	William Stewart Ross (1844–1906) wrote under the name of Saladin. He was associated with Victorian Freethinkers and the organization the British Secular Union. He edited the Secular Review from 1882; it was renamed Agnostic Journal and Eclectic Review and closed in 1907. Ross championed agnosticism in opposition to the atheism of Charles Bradlaugh as an open-ended spiritual exploration.
Agnosticism	894	History	In Why I am an Agnostic (c. 1889) he claims that agnosticism is "the very reverse of atheism".
Agnosticism	894	History	Bertrand Russell (1872–1970) declared Why I Am Not a Christian in 1927, a classic statement of agnosticism. He calls upon his readers to "stand on their own two feet and look fair and square at the world with a fearless attitude and a free intelligence".
Agnosticism	894	History	In 1939, Russell gave a lecture on The existence and nature of God, in which he characterized himself as an atheist. He said:
Agnosticism	894	History	The existence and nature of God is a subject of which I can discuss only half. If one arrives at a negative conclusion concerning the first part of the question, the second part of the question does not arise; and my position, as you may have gathered, is a negative one on this matter.
Agnosticism	894	History	However, later in the same lecture, discussing modern non-anthropomorphic concepts of God, Russell states:
Agnosticism	894	History	That sort of God is, I think, not one that can actually be disproved, as I think the omnipotent and benevolent creator can.
Agnosticism	894	History	In Russell's 1947 pamphlet, Am I An Atheist or an Agnostic? (subtitled A Plea For Tolerance in the Face of New Dogmas), he ruminates on the problem of what to call himself:
Agnosticism	894	History	As a philosopher, if I were speaking to a purely philosophic audience I should say that I ought to describe myself as an Agnostic, because I do not think that there is a conclusive argument by which one can prove that there is not a God. On the other hand, if I am to convey the right impression to the ordinary man in the street I think I ought to say that I am an Atheist, because when I say that I cannot prove that there is not a God, I ought to add equally that I cannot prove that there are not the Homeric gods.
Agnosticism	894	History	In his 1953 essay, What Is An Agnostic? Russell states:
Agnosticism	894	History	An agnostic thinks it impossible to know the truth in matters such as God and the future life with which Christianity and other religions are concerned. Or, if not impossible, at least impossible at the present time.
Agnosticism	894	History	Are Agnostics Atheists?
Agnosticism	894	History	No. An atheist, like a Christian, holds that we can know whether or not there is a God. The Christian holds that we can know there is a God; the atheist, that we can know there is not. The Agnostic suspends judgment, saying that there are not sufficient grounds either for affirmation or for denial.
Agnosticism	894	History	Later in the essay, Russell adds:
Agnosticism	894	History	I think that if I heard a voice from the sky predicting all that was going to happen to me during the next twenty-four hours, including events that would have seemed highly improbable, and if all these events then produced to happen, I might perhaps be convinced at least of the existence of some superhuman intelligence.
Agnosticism	894	History	In 1965, Christian theologian Leslie Weatherhead (1893–1976) published The Christian Agnostic, in which he argues:
Agnosticism	894	History	... many professing agnostics are nearer belief in the true God than are many conventional church-goers who believe in a body that does not exist whom they miscall God.
Agnosticism	894	History	Although radical and unpalatable to conventional theologians, Weatherhead's agnosticism falls far short of Huxley's, and short even of weak agnosticism:
Agnosticism	894	History	Of course, the human soul will always have the power to reject God, for choice is essential to its nature, but I cannot believe that anyone will finally do this.
Agnosticism	894	History	Robert G. Ingersoll (1833–1899), an Illinois lawyer and politician who evolved into a well-known and sought-after orator in 19th-century America, has been referred to as the "Great Agnostic".
Agnosticism	894	History	In an 1896 lecture titled Why I Am An Agnostic, Ingersoll related why he was an agnostic:
Agnosticism	894	History	Is there a supernatural power—an arbitrary mind—an enthroned God—a supreme will that sways the tides and currents of the world—to which all causes bow? I do not deny. I do not know—but I do not believe. I believe that the natural is supreme—that from the infinite chain no link can be lost or broken—that there is no supernatural power that can answer prayer—no power that worship can persuade or change—no power that cares for man.
Agnosticism	894	History	I believe that with infinite arms Nature embraces the all—that there is no interference—no chance—that behind every event are the necessary and countless causes, and that beyond every event will be and must be the necessary and countless effects.
Agnosticism	894	History	Is there a God? I do not know. Is man immortal? I do not know. One thing I do know, and that is, that neither hope, nor fear, belief, nor denial, can change the fact. It is as it is, and it will be as it must be.
Agnosticism	894	History	In the conclusion of the speech he simply sums up the agnostic position as:
Agnosticism	894	History	We can be as honest as we are ignorant. If we are, when asked what is beyond the horizon of the known, we must say that we do not know.
Agnosticism	894	History	In 1885, Ingersoll explained his comparative view of agnosticism and atheism as follows:
Agnosticism	894	History	The Agnostic is an Atheist. The Atheist is an Agnostic. The Agnostic says, 'I do not know, but I do not believe there is any God.' The Atheist says the same.
Agnosticism	894	History	Canon Bernard Iddings Bell (1886–1958), a popular cultural commentator, Episcopal priest, and author, lauded the necessity of agnosticism in Beyond Agnosticism: A Book for Tired Mechanists, calling it the foundation of "all intelligent Christianity". Agnosticism was a temporary mindset in which one rigorously questioned the truths of the age, including the way in which one believed God. His view of Robert Ingersoll and Thomas Paine was that they were not denouncing true Christianity but rather "a gross perversion of it". Part of the misunderstanding stemmed from ignorance of the concepts of God and religion. Historically, a god was any real, perceivable force that ruled the lives of humans and inspired admiration, love, fear, and homage; religion was the practice of it. Ancient peoples worshiped gods with real counterparts, such as Mammon (money and material things), Nabu (rationality), or Ba'al (violent weather); Bell argued that modern peoples were still paying homage—with their lives and their children's lives—to these old gods of wealth, physical appetites, and self-deification. Thus, if one attempted to be agnostic passively, he or she would incidentally join the worship of the world's gods.
Agnosticism	894	History	In Unfashionable Convictions (1931), he criticized the Enlightenment's complete faith in human sensory perception, augmented by scientific instruments, as a means of accurately grasping Reality. Firstly, it was fairly new, an innovation of the Western World, which Aristotle invented and Thomas Aquinas revived among the scientific community. Secondly, the divorce of "pure" science from human experience, as manifested in American Industrialization, had completely altered the environment, often disfiguring it, so as to suggest its insufficiency to human needs. Thirdly, because scientists were constantly producing more data—to the point where no single human could grasp it all at once—it followed that human intelligence was incapable of attaining a complete understanding of universe; therefore, to admit the mysteries of the unobserved universe was to be actually scientific.
Agnosticism	894	History	Bell believed that there were two other ways that humans could perceive and interact with the world. Artistic experience was how one expressed meaning through speaking, writing, painting, gesturing—any sort of communication which shared insight into a human's inner reality. Mystical experience was how one could "read" people and harmonize with them, being what we commonly call love. In summary, man was a scientist, artist, and lover. Without exercising all three, a person became "lopsided".
Agnosticism	894	History	Bell considered a humanist to be a person who cannot rightly ignore the other ways of knowing. However, humanism, like agnosticism, was also temporal, and would eventually lead to either scientific materialism or theism. He lays out the following thesis:
Agnosticism	894	Demographics	Demographic research services normally do not differentiate between various types of non-religious respondents, so agnostics are often classified in the same category as atheists or other non-religious people.
Agnosticism	894	Demographics	A 2010 survey published in Encyclopædia Britannica found that the non-religious people or the agnostics made up about 9.6% of the world's population. A November–December 2006 poll published in the Financial Times gives rates for the United States and five European countries. The rates of agnosticism in the United States were at 14%, while the rates of agnosticism in the European countries surveyed were considerably higher: Italy (20%), Spain (30%), Great Britain (35%), Germany (25%), and France (32%).
Agnosticism	894	Demographics	A study conducted by the Pew Research Center found that about 16% of the world's people, the third largest group after Christianity and Islam, have no religious affiliation. According to a 2012 report by the Pew Research Center, agnostics made up 3.3% of the US adult population. In the U.S. Religious Landscape Survey, conducted by the Pew Research Center, 55% of agnostic respondents expressed "a belief in God or a universal spirit", whereas 41% stated that they thought that they felt a tension "being non-religious in a society where most people are religious".
Agnosticism	894	Demographics	According to the 2021 Australian Bureau of Statistics, 38.9% of Australians have "no religion", a category that includes agnostics. Between 64% and 65% of Japanese and up to 81% of Vietnamese are atheists, agnostics, or do not believe in a god. An official European Union survey reported that 3% of the EU population is unsure about their belief in a god or spirit.
Agnosticism	894	Criticism	Agnosticism is criticized from a variety of standpoints. Some atheists criticize the use of the term agnosticism as functionally indistinguishable from atheism; this results in frequent criticisms of those who adopt the term as avoiding the atheist label.
Agnosticism	894	Criticism	Theistic critics claim that agnosticism is impossible in practice, since a person can live only either as if God did not exist (etsi deus non-daretur), or as if God did exist (etsi deus daretur).
Agnosticism	894	Criticism	According to Pope Benedict XVI, strong agnosticism in particular contradicts itself in affirming the power of reason to know scientific truth. He blames the exclusion of reasoning from religion and ethics for dangerous pathologies such as crimes against humanity and ecological disasters. "Agnosticism", said Benedict, "is always the fruit of a refusal of that knowledge which is in fact offered to man ... The knowledge of God has always existed". He asserted that agnosticism is a choice of comfort, pride, dominion, and utility over truth, and is opposed by the following attitudes: the keenest self-criticism, humble listening to the whole of existence, the persistent patience and self-correction of the scientific method, a readiness to be purified by the truth.
Agnosticism	894	Criticism	The Catholic Church sees merit in examining what it calls "partial agnosticism", specifically those systems that "do not aim at constructing a complete philosophy of the unknowable, but at excluding special kinds of truth, notably religious, from the domain of knowledge". However, the Church is historically opposed to a full denial of the capacity of human reason to know God. The Council of the Vatican declares, "God, the beginning and end of all, can, by the natural light of human reason, be known with certainty from the works of creation".
Agnosticism	894	Criticism	Blaise Pascal argued that even if there were truly no evidence for God, agnostics should consider what is now known as Pascal's Wager: the infinite expected value of acknowledging God is always greater than the finite expected value of not acknowledging his existence, and thus it is a safer "bet" to choose God.
Agnosticism	894	Criticism	According to Richard Dawkins, a distinction between agnosticism and atheism is unwieldy and depends on how close to zero a person is willing to rate the probability of existence for any given god-like entity. About himself, Dawkins continues, "I am agnostic only to the extent that I am agnostic about fairies at the bottom of the garden." Dawkins also identifies two categories of agnostics; "Temporary Agnostics in Practice" (TAPs), and "Permanent Agnostics in Principle" (PAPs). He states that "agnosticism about the existence of God belongs firmly in the temporary or TAP category. Either he exists or he doesn't. It is a scientific question; one day we may know the answer, and meanwhile we can say something pretty strong about the probability" and considers PAP a "deeply inescapable kind of fence-sitting".
Agnosticism	894	Ignosticism	A related concept is ignosticism, the view that a coherent definition of a deity must be put forward before the question of the existence of a deity can be meaningfully discussed. If the chosen definition is not coherent, the ignostic holds the noncognitivist view that the existence of a deity is meaningless or empirically untestable. A. J. Ayer, Theodore Drange, and other philosophers see both atheism and agnosticism as incompatible with ignosticism on the grounds that atheism and agnosticism accept the statement "a deity exists" as a meaningful proposition that can be argued for or against.
Argon	896		Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust.
Argon	896		Nearly all of the argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in supernovas.
Argon	896		The name "argon" is derived from the Greek word ἀργόν, neuter singular form of ἀργός meaning 'lazy' or 'inactive', as a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83.8058 K is a defining fixed point in the International Temperature Scale of 1990.
Argon	896		Argon is extracted industrially by the fractional distillation of liquid air. It is mostly used as an inert shielding gas in welding and other high-temperature industrial processes where ordinarily unreactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. It is also used in incandescent, fluorescent lighting, and other gas-discharge tubes. It makes a distinctive blue-green gas laser. It is also used in fluorescent glow starters.
Argon	896	Characteristics	Argon has approximately the same solubility in water as oxygen and is 2.5 times more soluble in water than nitrogen. Argon is colorless, odorless, nonflammable and nontoxic as a solid, liquid or gas. Argon is chemically inert under most conditions and forms no confirmed stable compounds at room temperature.
Argon	896	Characteristics	Although argon is a noble gas, it can form some compounds under various extreme conditions. Argon fluorohydride (HArF), a compound of argon with fluorine and hydrogen that is stable below 17 K (−256.1 °C; −429.1 °F), has been demonstrated. Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form clathrates with water when atoms of argon are trapped in a lattice of water molecules. Ions, such as ArH, and excited-state complexes, such as ArF, have been demonstrated. Theoretical calculation predicts several more argon compounds that should be stable but have not yet been synthesized.
Argon	896	History	Argon (Greek ἀργόν, neuter singular form of ἀργός meaning "lazy" or "inactive") is named in reference to its chemical inactivity. This chemical property of this first noble gas to be discovered impressed the namers. An unreactive gas was suspected to be a component of air by Henry Cavendish in 1785.
Argon	896	History	Argon was first isolated from air in 1894 by Lord Rayleigh and Sir William Ramsay at University College London by removing oxygen, carbon dioxide, water, and nitrogen from a sample of clean air. They first accomplished this by replicating an experiment of Henry Cavendish's. They trapped a mixture of atmospheric air with additional oxygen in a test-tube (A) upside-down over a large quantity of dilute alkali solution (B), which in Cavendish's original experiment was potassium hydroxide, and conveyed a current through wires insulated by U-shaped glass tubes (CC) which sealed around the platinum wire electrodes, leaving the ends of the wires (DD) exposed to the gas and insulated from the alkali solution. The arc was powered by a battery of five Grove cells and a Ruhmkorff coil of medium size. The alkali absorbed the oxides of nitrogen produced by the arc and also carbon dioxide. They operated the arc until no more reduction of volume of the gas could be seen for at least an hour or two and the spectral lines of nitrogen disappeared when the gas was examined. The remaining oxygen was reacted with alkaline pyrogallate to leave behind an apparently non-reactive gas which they called argon.
Argon	896	History	Before isolating the gas, they had determined that nitrogen produced from chemical compounds was 0.5% lighter than nitrogen from the atmosphere. The difference was slight, but it was important enough to attract their attention for many months. They concluded that there was another gas in the air mixed in with the nitrogen. Argon was also encountered in 1882 through independent research of H. F. Newall and W. N. Hartley. Each observed new lines in the emission spectrum of air that did not match known elements.
Argon	896	History	Until 1957, the symbol for argon was "A", but now it is "Ar".
Argon	896	Occurrence	Argon constitutes 0.934% by volume and 1.288% by mass of Earth's atmosphere. Air is the primary industrial source of purified argon products. Argon is isolated from air by fractionation, most commonly by cryogenic fractional distillation, a process that also produces purified nitrogen, oxygen, neon, krypton and xenon. Earth's crust and seawater contain 1.2 ppm and 0.45 ppm of argon, respectively.
Argon	896	Isotopes	The main isotopes of argon found on Earth are Ar (99.6%), Ar (0.34%), and Ar (0.06%). Naturally occurring K, with a half-life of 1.25×10 years, decays to stable Ar (11.2%) by electron capture or positron emission, and also to stable Ca (88.8%) by beta decay. These properties and ratios are used to determine the age of rocks by K–Ar dating.
Argon	896	Isotopes	In Earth's atmosphere, Ar is made by cosmic ray activity, primarily by neutron capture of Ar followed by two-neutron emission. In the subsurface environment, it is also produced through neutron capture by K, followed by proton emission. Ar is created from the neutron capture by Ca followed by an alpha particle emission as a result of subsurface nuclear explosions. It has a half-life of 35 days.
Argon	896	Isotopes	Between locations in the Solar System, the isotopic composition of argon varies greatly. Where the major source of argon is the decay of K in rocks, Ar will be the dominant isotope, as it is on Earth. Argon produced directly by stellar nucleosynthesis is dominated by the alpha-process nuclide Ar. Correspondingly, solar argon contains 84.6% Ar (according to solar wind measurements), and the ratio of the three isotopes Ar : Ar : Ar in the atmospheres of the outer planets is 8400 : 1600 : 1. This contrasts with the low abundance of primordial Ar in Earth's atmosphere, which is only 31.5 ppmv (= 9340 ppmv × 0.337%), comparable with that of neon (18.18 ppmv) on Earth and with interplanetary gasses, measured by probes.
Argon	896	Isotopes	The atmospheres of Mars, Mercury and Titan (the largest moon of Saturn) contain argon, predominantly as Ar, and its content may be as high as 1.93% (Mars).
Argon	896	Isotopes	The predominance of radiogenic Ar is the reason the standard atomic weight of terrestrial argon is greater than that of the next element, potassium, a fact that was puzzling when argon was discovered. Mendeleev positioned the elements on his periodic table in order of atomic weight, but the inertness of argon suggested a placement before the reactive alkali metal. Henry Moseley later solved this problem by showing that the periodic table is actually arranged in order of atomic number (see History of the periodic table).
Argon	896	Compounds	Argon's complete octet of electrons indicates full s and p subshells. This full valence shell makes argon very stable and extremely resistant to bonding with other elements. Before 1962, argon and the other noble gases were considered to be chemically inert and unable to form compounds; however, compounds of the heavier noble gases have since been synthesized. The first argon compound with tungsten pentacarbonyl, W(CO)5Ar, was isolated in 1975. However, it was not widely recognised at that time. In August 2000, another argon compound, argon fluorohydride (HArF), was formed by researchers at the University of Helsinki, by shining ultraviolet light onto frozen argon containing a small amount of hydrogen fluoride with caesium iodide. This discovery caused the recognition that argon could form weakly bound compounds, even though it was not the first. It is stable up to 17 kelvins (−256 °C). The metastable ArCF2 dication, which is valence-isoelectronic with carbonyl fluoride and phosgene, was observed in 2010. Argon-36, in the form of argon hydride (argonium) ions, has been detected in interstellar medium associated with the Crab Nebula supernova; this was the first noble-gas molecule detected in outer space.
Argon	896	Compounds	Solid argon hydride (Ar(H2)2) has the same crystal structure as the MgZn2 Laves phase. It forms at pressures between 4.3 and 220 GPa, though Raman measurements suggest that the H2 molecules in Ar(H2)2 dissociate above 175 GPa.
Argon	896	Production	Argon is extracted industrially by the fractional distillation of liquid air in a cryogenic air separation unit; a process that separates liquid nitrogen, which boils at 77.3 K, from argon, which boils at 87.3 K, and liquid oxygen, which boils at 90.2 K. About 700,000 tonnes of argon are produced worldwide every year.
Argon	896	Applications	Argon has several desirable properties:
Argon	896	Applications	Other noble gases would be equally suitable for most of these applications, but argon is by far the cheapest. It is inexpensive, since it occurs naturally in air and is readily obtained as a byproduct of cryogenic air separation in the production of liquid oxygen and liquid nitrogen: the primary constituents of air are used on a large industrial scale. The other noble gases (except helium) are produced this way as well, but argon is the most plentiful by far. The bulk of its applications arise simply because it is inert and relatively cheap.
Argon	896	Applications	Argon is used in some high-temperature industrial processes where ordinarily non-reactive substances become reactive. For example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning.
Argon	896	Applications	For some of these processes, the presence of nitrogen or oxygen gases might cause defects within the material. Argon is used in some types of arc welding such as gas metal arc welding and gas tungsten arc welding, as well as in the processing of titanium and other reactive elements. An argon atmosphere is also used for growing crystals of silicon and germanium.
Argon	896	Applications	Argon is used in the poultry industry to asphyxiate birds, either for mass culling following disease outbreaks, or as a means of slaughter more humane than electric stunning. Argon is denser than air and displaces oxygen close to the ground during inert gas asphyxiation. Its non-reactive nature makes it suitable in a food product, and since it replaces oxygen within the dead bird, argon also enhances shelf life.
Argon	896	Applications	Argon is sometimes used for extinguishing fires where valuable equipment may be damaged by water or foam.
Argon	896	Applications	Liquid argon is used as the target for neutrino experiments and direct dark matter searches. The interaction between the hypothetical WIMPs and an argon nucleus produces scintillation light that is detected by photomultiplier tubes. Two-phase detectors containing argon gas are used to detect the ionized electrons produced during the WIMP–nucleus scattering. As with most other liquefied noble gases, argon has a high scintillation light yield (about 51 photons/keV), is transparent to its own scintillation light, and is relatively easy to purify. Compared to xenon, argon is cheaper and has a distinct scintillation time profile, which allows the separation of electronic recoils from nuclear recoils. On the other hand, its intrinsic beta-ray background is larger due to Ar contamination, unless one uses argon from underground sources, which has much less Ar contamination. Most of the argon in Earth's atmosphere was produced by electron capture of long-lived K (K + e → Ar + ν) present in natural potassium within Earth. The Ar activity in the atmosphere is maintained by cosmogenic production through the knockout reaction Ar(n,2n)Ar and similar reactions. The half-life of Ar is only 269 years. As a result, the underground Ar, shielded by rock and water, has much less Ar contamination. Dark-matter detectors currently operating with liquid argon include DarkSide, WArP, ArDM, microCLEAN and DEAP. Neutrino experiments include ICARUS and MicroBooNE, both of which use high-purity liquid argon in a time projection chamber for fine grained three-dimensional imaging of neutrino interactions.
Argon	896	Applications	At Linköping University, Sweden, the inert gas is being utilized in a vacuum chamber in which plasma is introduced to ionize metallic films. This process results in a film usable for manufacturing computer processors. The new process would eliminate the need for chemical baths and use of expensive, dangerous and rare materials.
Argon	896	Applications	Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the European food additive code E938). Aerial oxidation, hydrolysis, and other chemical reactions that degrade the products are retarded or prevented entirely. High-purity chemicals and pharmaceuticals are sometimes packed and sealed in argon.
Argon	896	Applications	In winemaking, argon is used in a variety of activities to provide a barrier against oxygen at the liquid surface, which can spoil wine by fueling both microbial metabolism (as with acetic acid bacteria) and standard redox chemistry.
Argon	896	Applications	Argon is sometimes used as the propellant in aerosol cans.
Argon	896	Applications	Argon is also used as a preservative for such products as varnish, polyurethane, and paint, by displacing air to prepare a container for storage.
Argon	896	Applications	Since 2002, the American National Archives stores important national documents such as the Declaration of Independence and the Constitution within argon-filled cases to inhibit their degradation. Argon is preferable to the helium that had been used in the preceding five decades, because helium gas escapes through the intermolecular pores in most containers and must be regularly replaced.
Argon	896	Applications	Argon may be used as the inert gas within Schlenk lines and gloveboxes. Argon is preferred to less expensive nitrogen in cases where nitrogen may react with the reagents or apparatus.
Argon	896	Applications	Argon may be used as the carrier gas in gas chromatography and in electrospray ionization mass spectrometry; it is the gas of choice for the plasma used in ICP spectroscopy. Argon is preferred for the sputter coating of specimens for scanning electron microscopy. Argon gas is also commonly used for sputter deposition of thin films as in microelectronics and for wafer cleaning in microfabrication.
Argon	896	Applications	Cryosurgery procedures such as cryoablation use liquid argon to destroy tissue such as cancer cells. It is used in a procedure called "argon-enhanced coagulation", a form of argon plasma beam electrosurgery. The procedure carries a risk of producing gas embolism and has resulted in the death of at least one patient.
Argon	896	Applications	Blue argon lasers are used in surgery to weld arteries, destroy tumors, and correct eye defects.
Argon	896	Applications	Argon has also been used experimentally to replace nitrogen in the breathing or decompression mix known as Argox, to speed the elimination of dissolved nitrogen from the blood.
Argon	896	Applications	Incandescent lights are filled with argon, to preserve the filaments at high temperature from oxidation. It is used for the specific way it ionizes and emits light, such as in plasma globes and calorimetry in experimental particle physics. Gas-discharge lamps filled with pure argon provide lilac/violet light; with argon and some mercury, blue light. Argon is also used for blue and green argon-ion lasers.
Argon	896	Applications	Argon is used for thermal insulation in energy-efficient windows. Argon is also used in technical scuba diving to inflate a dry suit because it is inert and has low thermal conductivity.
Argon	896	Applications	Argon is used as a propellant in the development of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). Compressed argon gas is allowed to expand, to cool the seeker heads of some versions of the AIM-9 Sidewinder missile and other missiles that use cooled thermal seeker heads. The gas is stored at high pressure.
Argon	896	Applications	Argon-39, with a half-life of 269 years, has been used for a number of applications, primarily ice core and ground water dating. Also, potassium–argon dating and related argon-argon dating are used to date sedimentary, metamorphic, and igneous rocks.
Argon	896	Applications	Argon has been used by athletes as a doping agent to simulate hypoxic conditions. In 2014, the World Anti-Doping Agency (WADA) added argon and xenon to the list of prohibited substances and methods, although at this time there is no reliable test for abuse.
Argon	896	Safety	Although argon is non-toxic, it is 38% more dense than air and therefore considered a dangerous asphyxiant in closed areas. It is difficult to detect because it is colorless, odorless, and tasteless. A 1994 incident, in which a man was asphyxiated after entering an argon-filled section of oil pipe under construction in Alaska, highlights the dangers of argon tank leakage in confined spaces and emphasizes the need for proper use, storage and handling.
Arsenic	897		Arsenic is a chemical element; it has symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the grey form, which has a metallic appearance, is important to industry.
Arsenic	897		The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III–V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the increasing recognition of the toxicity of arsenic and its compounds.
Arsenic	897		A few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are an essential dietary element in rats, hamsters, goats, chickens, and presumably other species. A role in human metabolism is not known. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed. Arsenic contamination of groundwater is a problem that affects millions of people across the world.

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History

Raised in a religious environment, Charles Darwin (1809–1882) studied to be an Anglican clergyman. While eventually doubting parts of his faith, Darwin continued to help in church affairs, even while avoiding church attendance. Darwin stated that it would be "absurd to doubt that a man might be an ardent theist and an evolutionist". Although reticent about his religious views, in 1879 he wrote that "I have never been an atheist in the sense of denying the existence of a God. – I think that generally ... an agnostic would be the most correct description of my state of mind."

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History

Agnostic views are as old as philosophical skepticism, but the terms agnostic and agnosticism were created by Huxley (1825–1895) to sum up his thoughts on contemporary developments of metaphysics about the "unconditioned" (William Hamilton) and the "unknowable" (Herbert Spencer). Though Huxley began to use the term agnostic in 1869, his opinions had taken shape some time before that date. In a letter of September 23, 1860, to Charles Kingsley, Huxley discussed his views extensively:

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History

I neither affirm nor deny the immortality of man. I see no reason for believing it, but, on the other hand, I have no means of disproving it. I have no a priori objections to the doctrine. No man who has to deal daily and hourly with nature can trouble himself about a priori difficulties. Give me such evidence as would justify me in believing in anything else, and I will believe that. Why should I not? It is not half so wonderful as the conservation of force or the indestructibility of matter ...

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History

It is no use to talk to me of analogies and probabilities. I know what I mean when I say I believe in the law of the inverse squares, and I will not rest my life and my hopes upon weaker convictions ...

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History

That my personality is the surest thing I know may be true. But the attempt to conceive what it is leads me into mere verbal subtleties. I have champed up all that chaff about the ego and the non-ego, noumena and phenomena, and all the rest of it, too often not to know that in attempting even to think of these questions, the human intellect flounders at once out of its depth.

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History

And again, to the same correspondent, May 6, 1863:

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History

I have never had the least sympathy with the a priori reasons against orthodoxy, and I have by nature and disposition the greatest possible antipathy to all the atheistic and infidel school. Nevertheless I know that I am, in spite of myself, exactly what the Christian would call, and, so far as I can see, is justified in calling, atheist and infidel. I cannot see one shadow or tittle of evidence that the great unknown underlying the phenomenon of the universe stands to us in the relation of a Father [who] loves us and cares for us as Christianity asserts. So with regard to the other great Christian dogmas, immortality of soul and future state of rewards and punishments, what possible objection can I—who am compelled perforce to believe in the immortality of what we call Matter and Force, and in a very unmistakable present state of rewards and punishments for our deeds—have to these doctrines? Give me a scintilla of evidence, and I am ready to jump at them.

Agnosticism

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History

Of the origin of the name agnostic to describe this attitude, Huxley gave the following account:

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History

When I reached intellectual maturity and began to ask myself whether I was an atheist, a theist, or a pantheist; a materialist or an idealist; Christian or a freethinker; I found that the more I learned and reflected, the less ready was the answer; until, at last, I came to the conclusion that I had neither art nor part with any of these denominations, except the last. The one thing in which most of these good people were agreed was the one thing in which I differed from them. They were quite sure they had attained a certain "gnosis"—had, more or less successfully, solved the problem of existence; while I was quite sure I had not, and had a pretty strong conviction that the problem was insoluble. And, with Hume and Kant on my side, I could not think myself presumptuous in holding fast by that opinion ... So I took thought, and invented what I conceived to be the appropriate title of "agnostic". It came into my head as suggestively antithetic to the "gnostic" of Church history, who professed to know so much about the very things of which I was ignorant. ... To my great satisfaction the term took.

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History

In 1889, Huxley wrote:

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History

Therefore, although it be, as I believe, demonstrable that we have no real knowledge of the authorship, or of the date of composition of the Gospels, as they have come down to us, and that nothing better than more or less probable guesses can be arrived at on that subject.

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894

History

William Stewart Ross (1844–1906) wrote under the name of Saladin. He was associated with Victorian Freethinkers and the organization the British Secular Union. He edited the Secular Review from 1882; it was renamed Agnostic Journal and Eclectic Review and closed in 1907. Ross championed agnosticism in opposition to the atheism of Charles Bradlaugh as an open-ended spiritual exploration.

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History

In Why I am an Agnostic (c. 1889) he claims that agnosticism is "the very reverse of atheism".

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History

Bertrand Russell (1872–1970) declared Why I Am Not a Christian in 1927, a classic statement of agnosticism. He calls upon his readers to "stand on their own two feet and look fair and square at the world with a fearless attitude and a free intelligence".

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History

In 1939, Russell gave a lecture on The existence and nature of God, in which he characterized himself as an atheist. He said:

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History

The existence and nature of God is a subject of which I can discuss only half. If one arrives at a negative conclusion concerning the first part of the question, the second part of the question does not arise; and my position, as you may have gathered, is a negative one on this matter.

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History

However, later in the same lecture, discussing modern non-anthropomorphic concepts of God, Russell states:

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History

That sort of God is, I think, not one that can actually be disproved, as I think the omnipotent and benevolent creator can.

Agnosticism

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History

In Russell's 1947 pamphlet, Am I An Atheist or an Agnostic? (subtitled A Plea For Tolerance in the Face of New Dogmas), he ruminates on the problem of what to call himself:

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History

As a philosopher, if I were speaking to a purely philosophic audience I should say that I ought to describe myself as an Agnostic, because I do not think that there is a conclusive argument by which one can prove that there is not a God. On the other hand, if I am to convey the right impression to the ordinary man in the street I think I ought to say that I am an Atheist, because when I say that I cannot prove that there is not a God, I ought to add equally that I cannot prove that there are not the Homeric gods.

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History

In his 1953 essay, What Is An Agnostic? Russell states:

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History

An agnostic thinks it impossible to know the truth in matters such as God and the future life with which Christianity and other religions are concerned. Or, if not impossible, at least impossible at the present time.

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History

Are Agnostics Atheists?

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History

No. An atheist, like a Christian, holds that we can know whether or not there is a God. The Christian holds that we can know there is a God; the atheist, that we can know there is not. The Agnostic suspends judgment, saying that there are not sufficient grounds either for affirmation or for denial.

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History

Later in the essay, Russell adds:

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History

I think that if I heard a voice from the sky predicting all that was going to happen to me during the next twenty-four hours, including events that would have seemed highly improbable, and if all these events then produced to happen, I might perhaps be convinced at least of the existence of some superhuman intelligence.

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History

In 1965, Christian theologian Leslie Weatherhead (1893–1976) published The Christian Agnostic, in which he argues:

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History

... many professing agnostics are nearer belief in the true God than are many conventional church-goers who believe in a body that does not exist whom they miscall God.

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History

Although radical and unpalatable to conventional theologians, Weatherhead's agnosticism falls far short of Huxley's, and short even of weak agnosticism:

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History

Of course, the human soul will always have the power to reject God, for choice is essential to its nature, but I cannot believe that anyone will finally do this.

Agnosticism

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History

Robert G. Ingersoll (1833–1899), an Illinois lawyer and politician who evolved into a well-known and sought-after orator in 19th-century America, has been referred to as the "Great Agnostic".

Agnosticism

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History

In an 1896 lecture titled Why I Am An Agnostic, Ingersoll related why he was an agnostic:

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History

Is there a supernatural power—an arbitrary mind—an enthroned God—a supreme will that sways the tides and currents of the world—to which all causes bow? I do not deny. I do not know—but I do not believe. I believe that the natural is supreme—that from the infinite chain no link can be lost or broken—that there is no supernatural power that can answer prayer—no power that worship can persuade or change—no power that cares for man.

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History

I believe that with infinite arms Nature embraces the all—that there is no interference—no chance—that behind every event are the necessary and countless causes, and that beyond every event will be and must be the necessary and countless effects.

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History

Is there a God? I do not know. Is man immortal? I do not know. One thing I do know, and that is, that neither hope, nor fear, belief, nor denial, can change the fact. It is as it is, and it will be as it must be.

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History

In the conclusion of the speech he simply sums up the agnostic position as:

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History

We can be as honest as we are ignorant. If we are, when asked what is beyond the horizon of the known, we must say that we do not know.

Agnosticism

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History

In 1885, Ingersoll explained his comparative view of agnosticism and atheism as follows:

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History

The Agnostic is an Atheist. The Atheist is an Agnostic. The Agnostic says, 'I do not know, but I do not believe there is any God.' The Atheist says the same.

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History

Canon Bernard Iddings Bell (1886–1958), a popular cultural commentator, Episcopal priest, and author, lauded the necessity of agnosticism in Beyond Agnosticism: A Book for Tired Mechanists, calling it the foundation of "all intelligent Christianity". Agnosticism was a temporary mindset in which one rigorously questioned the truths of the age, including the way in which one believed God. His view of Robert Ingersoll and Thomas Paine was that they were not denouncing true Christianity but rather "a gross perversion of it". Part of the misunderstanding stemmed from ignorance of the concepts of God and religion. Historically, a god was any real, perceivable force that ruled the lives of humans and inspired admiration, love, fear, and homage; religion was the practice of it. Ancient peoples worshiped gods with real counterparts, such as Mammon (money and material things), Nabu (rationality), or Ba'al (violent weather); Bell argued that modern peoples were still paying homage—with their lives and their children's lives—to these old gods of wealth, physical appetites, and self-deification. Thus, if one attempted to be agnostic passively, he or she would incidentally join the worship of the world's gods.

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History

In Unfashionable Convictions (1931), he criticized the Enlightenment's complete faith in human sensory perception, augmented by scientific instruments, as a means of accurately grasping Reality. Firstly, it was fairly new, an innovation of the Western World, which Aristotle invented and Thomas Aquinas revived among the scientific community. Secondly, the divorce of "pure" science from human experience, as manifested in American Industrialization, had completely altered the environment, often disfiguring it, so as to suggest its insufficiency to human needs. Thirdly, because scientists were constantly producing more data—to the point where no single human could grasp it all at once—it followed that human intelligence was incapable of attaining a complete understanding of universe; therefore, to admit the mysteries of the unobserved universe was to be actually scientific.

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History

Bell believed that there were two other ways that humans could perceive and interact with the world. Artistic experience was how one expressed meaning through speaking, writing, painting, gesturing—any sort of communication which shared insight into a human's inner reality. Mystical experience was how one could "read" people and harmonize with them, being what we commonly call love. In summary, man was a scientist, artist, and lover. Without exercising all three, a person became "lopsided".

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History

Bell considered a humanist to be a person who cannot rightly ignore the other ways of knowing. However, humanism, like agnosticism, was also temporal, and would eventually lead to either scientific materialism or theism. He lays out the following thesis:

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894

Demographics

Demographic research services normally do not differentiate between various types of non-religious respondents, so agnostics are often classified in the same category as atheists or other non-religious people.

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Demographics

A 2010 survey published in Encyclopædia Britannica found that the non-religious people or the agnostics made up about 9.6% of the world's population. A November–December 2006 poll published in the Financial Times gives rates for the United States and five European countries. The rates of agnosticism in the United States were at 14%, while the rates of agnosticism in the European countries surveyed were considerably higher: Italy (20%), Spain (30%), Great Britain (35%), Germany (25%), and France (32%).

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Demographics

A study conducted by the Pew Research Center found that about 16% of the world's people, the third largest group after Christianity and Islam, have no religious affiliation. According to a 2012 report by the Pew Research Center, agnostics made up 3.3% of the US adult population. In the U.S. Religious Landscape Survey, conducted by the Pew Research Center, 55% of agnostic respondents expressed "a belief in God or a universal spirit", whereas 41% stated that they thought that they felt a tension "being non-religious in a society where most people are religious".

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Demographics

According to the 2021 Australian Bureau of Statistics, 38.9% of Australians have "no religion", a category that includes agnostics. Between 64% and 65% of Japanese and up to 81% of Vietnamese are atheists, agnostics, or do not believe in a god. An official European Union survey reported that 3% of the EU population is unsure about their belief in a god or spirit.

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Criticism

Agnosticism is criticized from a variety of standpoints. Some atheists criticize the use of the term agnosticism as functionally indistinguishable from atheism; this results in frequent criticisms of those who adopt the term as avoiding the atheist label.

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Criticism

Theistic critics claim that agnosticism is impossible in practice, since a person can live only either as if God did not exist (etsi deus non-daretur), or as if God did exist (etsi deus daretur).

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Criticism

According to Pope Benedict XVI, strong agnosticism in particular contradicts itself in affirming the power of reason to know scientific truth. He blames the exclusion of reasoning from religion and ethics for dangerous pathologies such as crimes against humanity and ecological disasters. "Agnosticism", said Benedict, "is always the fruit of a refusal of that knowledge which is in fact offered to man ... The knowledge of God has always existed". He asserted that agnosticism is a choice of comfort, pride, dominion, and utility over truth, and is opposed by the following attitudes: the keenest self-criticism, humble listening to the whole of existence, the persistent patience and self-correction of the scientific method, a readiness to be purified by the truth.

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Criticism

The Catholic Church sees merit in examining what it calls "partial agnosticism", specifically those systems that "do not aim at constructing a complete philosophy of the unknowable, but at excluding special kinds of truth, notably religious, from the domain of knowledge". However, the Church is historically opposed to a full denial of the capacity of human reason to know God. The Council of the Vatican declares, "God, the beginning and end of all, can, by the natural light of human reason, be known with certainty from the works of creation".

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Criticism

Blaise Pascal argued that even if there were truly no evidence for God, agnostics should consider what is now known as Pascal's Wager: the infinite expected value of acknowledging God is always greater than the finite expected value of not acknowledging his existence, and thus it is a safer "bet" to choose God.

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Criticism

According to Richard Dawkins, a distinction between agnosticism and atheism is unwieldy and depends on how close to zero a person is willing to rate the probability of existence for any given god-like entity. About himself, Dawkins continues, "I am agnostic only to the extent that I am agnostic about fairies at the bottom of the garden." Dawkins also identifies two categories of agnostics; "Temporary Agnostics in Practice" (TAPs), and "Permanent Agnostics in Principle" (PAPs). He states that "agnosticism about the existence of God belongs firmly in the temporary or TAP category. Either he exists or he doesn't. It is a scientific question; one day we may know the answer, and meanwhile we can say something pretty strong about the probability" and considers PAP a "deeply inescapable kind of fence-sitting".

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Ignosticism

A related concept is ignosticism, the view that a coherent definition of a deity must be put forward before the question of the existence of a deity can be meaningfully discussed. If the chosen definition is not coherent, the ignostic holds the noncognitivist view that the existence of a deity is meaningless or empirically untestable. A. J. Ayer, Theodore Drange, and other philosophers see both atheism and agnosticism as incompatible with ignosticism on the grounds that atheism and agnosticism accept the statement "a deity exists" as a meaningful proposition that can be argued for or against.

Argon

896

Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust.

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Nearly all of the argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in supernovas.

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The name "argon" is derived from the Greek word ἀργόν, neuter singular form of ἀργός meaning 'lazy' or 'inactive', as a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83.8058 K is a defining fixed point in the International Temperature Scale of 1990.

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Argon is extracted industrially by the fractional distillation of liquid air. It is mostly used as an inert shielding gas in welding and other high-temperature industrial processes where ordinarily unreactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. It is also used in incandescent, fluorescent lighting, and other gas-discharge tubes. It makes a distinctive blue-green gas laser. It is also used in fluorescent glow starters.

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Characteristics

Argon has approximately the same solubility in water as oxygen and is 2.5 times more soluble in water than nitrogen. Argon is colorless, odorless, nonflammable and nontoxic as a solid, liquid or gas. Argon is chemically inert under most conditions and forms no confirmed stable compounds at room temperature.

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Characteristics

Although argon is a noble gas, it can form some compounds under various extreme conditions. Argon fluorohydride (HArF), a compound of argon with fluorine and hydrogen that is stable below 17 K (−256.1 °C; −429.1 °F), has been demonstrated. Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form clathrates with water when atoms of argon are trapped in a lattice of water molecules. Ions, such as ArH, and excited-state complexes, such as ArF, have been demonstrated. Theoretical calculation predicts several more argon compounds that should be stable but have not yet been synthesized.

Argon

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History

Argon (Greek ἀργόν, neuter singular form of ἀργός meaning "lazy" or "inactive") is named in reference to its chemical inactivity. This chemical property of this first noble gas to be discovered impressed the namers. An unreactive gas was suspected to be a component of air by Henry Cavendish in 1785.

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History

Argon was first isolated from air in 1894 by Lord Rayleigh and Sir William Ramsay at University College London by removing oxygen, carbon dioxide, water, and nitrogen from a sample of clean air. They first accomplished this by replicating an experiment of Henry Cavendish's. They trapped a mixture of atmospheric air with additional oxygen in a test-tube (A) upside-down over a large quantity of dilute alkali solution (B), which in Cavendish's original experiment was potassium hydroxide, and conveyed a current through wires insulated by U-shaped glass tubes (CC) which sealed around the platinum wire electrodes, leaving the ends of the wires (DD) exposed to the gas and insulated from the alkali solution. The arc was powered by a battery of five Grove cells and a Ruhmkorff coil of medium size. The alkali absorbed the oxides of nitrogen produced by the arc and also carbon dioxide. They operated the arc until no more reduction of volume of the gas could be seen for at least an hour or two and the spectral lines of nitrogen disappeared when the gas was examined. The remaining oxygen was reacted with alkaline pyrogallate to leave behind an apparently non-reactive gas which they called argon.

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History

Before isolating the gas, they had determined that nitrogen produced from chemical compounds was 0.5% lighter than nitrogen from the atmosphere. The difference was slight, but it was important enough to attract their attention for many months. They concluded that there was another gas in the air mixed in with the nitrogen. Argon was also encountered in 1882 through independent research of H. F. Newall and W. N. Hartley. Each observed new lines in the emission spectrum of air that did not match known elements.

Argon

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History

Until 1957, the symbol for argon was "A", but now it is "Ar".

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896

Occurrence

Argon constitutes 0.934% by volume and 1.288% by mass of Earth's atmosphere. Air is the primary industrial source of purified argon products. Argon is isolated from air by fractionation, most commonly by cryogenic fractional distillation, a process that also produces purified nitrogen, oxygen, neon, krypton and xenon. Earth's crust and seawater contain 1.2 ppm and 0.45 ppm of argon, respectively.

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Isotopes

The main isotopes of argon found on Earth are Ar (99.6%), Ar (0.34%), and Ar (0.06%). Naturally occurring K, with a half-life of 1.25×10 years, decays to stable Ar (11.2%) by electron capture or positron emission, and also to stable Ca (88.8%) by beta decay. These properties and ratios are used to determine the age of rocks by K–Ar dating.

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Isotopes

In Earth's atmosphere, Ar is made by cosmic ray activity, primarily by neutron capture of Ar followed by two-neutron emission. In the subsurface environment, it is also produced through neutron capture by K, followed by proton emission. Ar is created from the neutron capture by Ca followed by an alpha particle emission as a result of subsurface nuclear explosions. It has a half-life of 35 days.

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Isotopes

Between locations in the Solar System, the isotopic composition of argon varies greatly. Where the major source of argon is the decay of K in rocks, Ar will be the dominant isotope, as it is on Earth. Argon produced directly by stellar nucleosynthesis is dominated by the alpha-process nuclide Ar. Correspondingly, solar argon contains 84.6% Ar (according to solar wind measurements), and the ratio of the three isotopes Ar : Ar : Ar in the atmospheres of the outer planets is 8400 : 1600 : 1. This contrasts with the low abundance of primordial Ar in Earth's atmosphere, which is only 31.5 ppmv (= 9340 ppmv × 0.337%), comparable with that of neon (18.18 ppmv) on Earth and with interplanetary gasses, measured by probes.

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896

Isotopes

The atmospheres of Mars, Mercury and Titan (the largest moon of Saturn) contain argon, predominantly as Ar, and its content may be as high as 1.93% (Mars).

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Isotopes

The predominance of radiogenic Ar is the reason the standard atomic weight of terrestrial argon is greater than that of the next element, potassium, a fact that was puzzling when argon was discovered. Mendeleev positioned the elements on his periodic table in order of atomic weight, but the inertness of argon suggested a placement before the reactive alkali metal. Henry Moseley later solved this problem by showing that the periodic table is actually arranged in order of atomic number (see History of the periodic table).

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Compounds

Argon's complete octet of electrons indicates full s and p subshells. This full valence shell makes argon very stable and extremely resistant to bonding with other elements. Before 1962, argon and the other noble gases were considered to be chemically inert and unable to form compounds; however, compounds of the heavier noble gases have since been synthesized. The first argon compound with tungsten pentacarbonyl, W(CO)5Ar, was isolated in 1975. However, it was not widely recognised at that time. In August 2000, another argon compound, argon fluorohydride (HArF), was formed by researchers at the University of Helsinki, by shining ultraviolet light onto frozen argon containing a small amount of hydrogen fluoride with caesium iodide. This discovery caused the recognition that argon could form weakly bound compounds, even though it was not the first. It is stable up to 17 kelvins (−256 °C). The metastable ArCF2 dication, which is valence-isoelectronic with carbonyl fluoride and phosgene, was observed in 2010. Argon-36, in the form of argon hydride (argonium) ions, has been detected in interstellar medium associated with the Crab Nebula supernova; this was the first noble-gas molecule detected in outer space.

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Compounds

Solid argon hydride (Ar(H2)2) has the same crystal structure as the MgZn2 Laves phase. It forms at pressures between 4.3 and 220 GPa, though Raman measurements suggest that the H2 molecules in Ar(H2)2 dissociate above 175 GPa.

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Production

Argon is extracted industrially by the fractional distillation of liquid air in a cryogenic air separation unit; a process that separates liquid nitrogen, which boils at 77.3 K, from argon, which boils at 87.3 K, and liquid oxygen, which boils at 90.2 K. About 700,000 tonnes of argon are produced worldwide every year.

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Applications

Argon has several desirable properties:

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896

Applications

Other noble gases would be equally suitable for most of these applications, but argon is by far the cheapest. It is inexpensive, since it occurs naturally in air and is readily obtained as a byproduct of cryogenic air separation in the production of liquid oxygen and liquid nitrogen: the primary constituents of air are used on a large industrial scale. The other noble gases (except helium) are produced this way as well, but argon is the most plentiful by far. The bulk of its applications arise simply because it is inert and relatively cheap.

Argon

896

Applications

Argon is used in some high-temperature industrial processes where ordinarily non-reactive substances become reactive. For example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning.

Argon

896

Applications

For some of these processes, the presence of nitrogen or oxygen gases might cause defects within the material. Argon is used in some types of arc welding such as gas metal arc welding and gas tungsten arc welding, as well as in the processing of titanium and other reactive elements. An argon atmosphere is also used for growing crystals of silicon and germanium.

Argon

896

Applications

Argon is used in the poultry industry to asphyxiate birds, either for mass culling following disease outbreaks, or as a means of slaughter more humane than electric stunning. Argon is denser than air and displaces oxygen close to the ground during inert gas asphyxiation. Its non-reactive nature makes it suitable in a food product, and since it replaces oxygen within the dead bird, argon also enhances shelf life.

Argon

896

Applications

Argon is sometimes used for extinguishing fires where valuable equipment may be damaged by water or foam.

Argon

896

Applications

Liquid argon is used as the target for neutrino experiments and direct dark matter searches. The interaction between the hypothetical WIMPs and an argon nucleus produces scintillation light that is detected by photomultiplier tubes. Two-phase detectors containing argon gas are used to detect the ionized electrons produced during the WIMP–nucleus scattering. As with most other liquefied noble gases, argon has a high scintillation light yield (about 51 photons/keV), is transparent to its own scintillation light, and is relatively easy to purify. Compared to xenon, argon is cheaper and has a distinct scintillation time profile, which allows the separation of electronic recoils from nuclear recoils. On the other hand, its intrinsic beta-ray background is larger due to Ar contamination, unless one uses argon from underground sources, which has much less Ar contamination. Most of the argon in Earth's atmosphere was produced by electron capture of long-lived K (K + e → Ar + ν) present in natural potassium within Earth. The Ar activity in the atmosphere is maintained by cosmogenic production through the knockout reaction Ar(n,2n)Ar and similar reactions. The half-life of Ar is only 269 years. As a result, the underground Ar, shielded by rock and water, has much less Ar contamination. Dark-matter detectors currently operating with liquid argon include DarkSide, WArP, ArDM, microCLEAN and DEAP. Neutrino experiments include ICARUS and MicroBooNE, both of which use high-purity liquid argon in a time projection chamber for fine grained three-dimensional imaging of neutrino interactions.

Argon

896

Applications

At Linköping University, Sweden, the inert gas is being utilized in a vacuum chamber in which plasma is introduced to ionize metallic films. This process results in a film usable for manufacturing computer processors. The new process would eliminate the need for chemical baths and use of expensive, dangerous and rare materials.

Argon

896

Applications

Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the European food additive code E938). Aerial oxidation, hydrolysis, and other chemical reactions that degrade the products are retarded or prevented entirely. High-purity chemicals and pharmaceuticals are sometimes packed and sealed in argon.

Argon

896

Applications

In winemaking, argon is used in a variety of activities to provide a barrier against oxygen at the liquid surface, which can spoil wine by fueling both microbial metabolism (as with acetic acid bacteria) and standard redox chemistry.

Argon

896

Applications

Argon is sometimes used as the propellant in aerosol cans.

Argon

896

Applications

Argon is also used as a preservative for such products as varnish, polyurethane, and paint, by displacing air to prepare a container for storage.

Argon

896

Applications

Since 2002, the American National Archives stores important national documents such as the Declaration of Independence and the Constitution within argon-filled cases to inhibit their degradation. Argon is preferable to the helium that had been used in the preceding five decades, because helium gas escapes through the intermolecular pores in most containers and must be regularly replaced.

Argon

896

Applications

Argon may be used as the inert gas within Schlenk lines and gloveboxes. Argon is preferred to less expensive nitrogen in cases where nitrogen may react with the reagents or apparatus.

Argon

896

Applications

Argon may be used as the carrier gas in gas chromatography and in electrospray ionization mass spectrometry; it is the gas of choice for the plasma used in ICP spectroscopy. Argon is preferred for the sputter coating of specimens for scanning electron microscopy. Argon gas is also commonly used for sputter deposition of thin films as in microelectronics and for wafer cleaning in microfabrication.

Argon

896

Applications

Cryosurgery procedures such as cryoablation use liquid argon to destroy tissue such as cancer cells. It is used in a procedure called "argon-enhanced coagulation", a form of argon plasma beam electrosurgery. The procedure carries a risk of producing gas embolism and has resulted in the death of at least one patient.

Argon

896

Applications

Blue argon lasers are used in surgery to weld arteries, destroy tumors, and correct eye defects.

Argon

896

Applications

Argon has also been used experimentally to replace nitrogen in the breathing or decompression mix known as Argox, to speed the elimination of dissolved nitrogen from the blood.

Argon

896

Applications

Incandescent lights are filled with argon, to preserve the filaments at high temperature from oxidation. It is used for the specific way it ionizes and emits light, such as in plasma globes and calorimetry in experimental particle physics. Gas-discharge lamps filled with pure argon provide lilac/violet light; with argon and some mercury, blue light. Argon is also used for blue and green argon-ion lasers.

Argon

896

Applications

Argon is used for thermal insulation in energy-efficient windows. Argon is also used in technical scuba diving to inflate a dry suit because it is inert and has low thermal conductivity.

Argon

896

Applications

Argon is used as a propellant in the development of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). Compressed argon gas is allowed to expand, to cool the seeker heads of some versions of the AIM-9 Sidewinder missile and other missiles that use cooled thermal seeker heads. The gas is stored at high pressure.

Argon

896

Applications

Argon-39, with a half-life of 269 years, has been used for a number of applications, primarily ice core and ground water dating. Also, potassium–argon dating and related argon-argon dating are used to date sedimentary, metamorphic, and igneous rocks.

Argon

896

Applications

Argon has been used by athletes as a doping agent to simulate hypoxic conditions. In 2014, the World Anti-Doping Agency (WADA) added argon and xenon to the list of prohibited substances and methods, although at this time there is no reliable test for abuse.

Argon

896

Safety

Although argon is non-toxic, it is 38% more dense than air and therefore considered a dangerous asphyxiant in closed areas. It is difficult to detect because it is colorless, odorless, and tasteless. A 1994 incident, in which a man was asphyxiated after entering an argon-filled section of oil pipe under construction in Alaska, highlights the dangers of argon tank leakage in confined spaces and emphasizes the need for proper use, storage and handling.

Arsenic

897

Arsenic is a chemical element; it has symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the grey form, which has a metallic appearance, is important to industry.

Arsenic

897

The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III–V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the increasing recognition of the toxicity of arsenic and its compounds.

Arsenic

897

A few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are an essential dietary element in rats, hamsters, goats, chickens, and presumably other species. A role in human metabolism is not known. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed. Arsenic contamination of groundwater is a problem that affects millions of people across the world.