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Linus Pauling

Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. New Scientist called him one of the 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have won more than one Nobel Prize (the others being Marie Curie, John Bardeen, Frederick Sanger, and Karl Barry Sharpless). Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie.

Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativities of the elements. Pauling also worked on the structures of biological molecules, and showed the importance of the alpha helix and beta sheet in protein secondary structure. Pauling's approach combined methods and results from X-ray crystallography, molecular model building, and quantum chemistry. His discoveries inspired the work of Rosalind Franklin, James Watson, Francis Crick, and Maurice Wilkins on the structure of DNA, which in turn made it possible for geneticists to crack the DNA code of all organisms.

In his later years, he promoted nuclear disarmament, as well as orthomolecular medicine, megavitamin therapy, and dietary supplements, especially ascorbic acid (commonly known as Vitamin C). None of his ideas concerning the medical usefulness of large doses of vitamins have gained much acceptance in the mainstream scientific community. He was married to the American human rights activist Ava Helen Pauling.

Early life and education

Linus Carl Pauling was born on February 28, 1901, in Portland, Oregon, the firstborn child of Herman Henry William Pauling (1876–1910) and Lucy Isabelle "Belle" Darling (1881–1926). He was named "Linus Carl", in honor of Lucy's father, Linus, and Herman's father, Carl. His ancestry included German and English.

In 1902, after his sister Pauline was born, Pauling's parents decided to move out of Portland to find more affordable and spacious living quarters than their one-room apartment. Lucy stayed with her husband's parents in Oswego until Herman brought the family to Salem, where he worked briefly as a traveling salesman for the Skidmore Drug Company. Within a year of Lucile's birth in 1904, Herman Pauling moved his family to Oswego, Oregon where he opened his own drugstore. He moved his family to Condon, Oregon, in 1905. By 1906, Herman Pauling was suffering from recurrent abdominal pain. He died of a perforated ulcer on June 11, 1910, leaving Lucy to care for Linus, Lucile and Pauline.

Pauling attributes his interest in becoming a chemist to being amazed by experiments conducted by a friend, Lloyd A. Jeffress, who had a small chemistry lab kit. He later wrote: "I was simply entranced by chemical phenomena, by the reactions in which substances, often with strikingly different properties, appear; and I hoped to learn more and more about this aspect of the world."

In high school, Pauling conducted chemistry experiments by scavenging equipment and material from an abandoned steel plant. With an older friend, Lloyd Simon, Pauling set up Palmon Laboratories in Simon's basement. They approached local dairies offering to perform butterfat samplings at cheap prices but dairymen were wary of trusting two boys with the task, and the business ended in failure.

At age 15, the high school senior had enough credits to enter Oregon State University (OSU), known then as Oregon Agricultural College. Lacking two American history courses required for his high school diploma, Pauling asked the school principal if he could take the courses concurrently during the spring semester. Denied, he left Washington High School in June without a diploma. The school awarded him an honorary diploma 45 years later, after he was awarded two Nobel Prizes.

Pauling held a number of jobs to earn money for his future college expenses, including working part-time at a grocery store for US$8 per week (equivalent to US$ in ). His mother arranged an interview with the owner of a number of manufacturing plants in Portland, Mr. Schwietzerhoff, who hired him as an apprentice machinist at a salary of US$40 per month (equivalent to US$ in ). This was soon raised to US$50 per month. Pauling also set up a photography laboratory with two friends. In September 1917, Pauling was finally admitted by Oregon State University. He immediately resigned from the machinist's job and informed his mother, who saw no point in a university education, of his plans.

Higher education

In his first semester, Pauling registered for two courses in chemistry, two in mathematics, mechanical drawing, introduction to mining and use of explosives, modern English prose, gymnastics and military drill. His roommate was childhood pal and lifelong best friend Lloyd Jeffress. He was active in campus life and founded the school's chapter of the Delta Upsilon fraternity. After his second year, he planned to take a job in Portland to help support his mother. The college offered him a position teaching quantitative analysis, a course he had just finished taking himself. He worked forty hours a week in the laboratory and classroom and earned US$100 a month (equivalent to US$ in ), enabling him to continue his studies.

In his last two years at school, Pauling became aware of the work of Gilbert N. Lewis and Irving Langmuir on the electronic structure of atoms and their bonding to form molecules. He decided to focus his research on how the physical and chemical properties of substances are related to the structure of the atoms of which they are composed, becoming one of the founders of the new science of quantum chemistry.

Engineering professor Samuel Graf selected Pauling to be his teaching assistant in a mechanics and materials course. During the winter of his senior year, Pauling taught a chemistry course for home economics majors. It was in one of these classes that Pauling met his future wife, Ava Helen Miller.

In 1922, Pauling graduated with a degree in chemical engineering. He went on to graduate school at the California Institute of Technology (Caltech) in Pasadena, California, under the guidance of Roscoe Dickinson and Richard Tolman. His graduate research involved the use of X-ray diffraction to determine the structure of crystals. He published seven papers on the crystal structure of minerals while he was at Caltech. He received his PhD in physical chemistry and mathematical physics, summa cum laude, in 1925.

Career
In 1926, Pauling was awarded a Guggenheim Fellowship to travel to Europe, to study under German physicist Arnold Sommerfeld in Munich, Danish physicist Niels Bohr in Copenhagen and Austrian physicist Erwin Schrödinger in Zürich. All three were experts in the new field of quantum mechanics and other branches of physics. Pauling became interested in how quantum mechanics might be applied in his chosen field of interest, the electronic structure of atoms and molecules. In Zürich, Pauling was also exposed to one of the first quantum mechanical analyses of bonding in the hydrogen molecule, done by Walter Heitler and Fritz London. Pauling devoted the two years of his European trip to this work and decided to make it the focus of his future research. He became one of the first scientists in the field of quantum chemistry and a pioneer in the application of quantum theory to the structure of molecules.

In 1927, Pauling took a new position as an assistant professor at Caltech in theoretical chemistry. He launched his faculty career with a very productive five years, continuing with his X-ray crystal studies and also performing quantum mechanical calculations on atoms and molecules. He published approximately fifty papers in those five years, and created the five rules now known as Pauling's rules. By 1929, he was promoted to associate professor, and by 1930, to full professor. In 1931, the American Chemical Society awarded Pauling the Langmuir Prize for the most significant work in pure science by a person 30 years of age or younger. The following year, Pauling published what he regarded as his most important paper, in which he first laid out the concept of hybridization of atomic orbitals and analyzed the tetravalency of the carbon atom.

At Caltech, Pauling struck up a close friendship with theoretical physicist Robert Oppenheimer at the University of California, Berkeley, who spent part of his research and teaching schedule as a visitor at Caltech each year. Pauling was also affiliated with Berkeley, serving as a visiting lecturer in physics and chemistry from 1929 to 1934. Oppenheimer even gave Pauling a stunning personal collection of minerals. The two men planned to mount a joint attack on the nature of the chemical bond: apparently Oppenheimer would supply the mathematics and Pauling would interpret the results. Their relationship soured when Oppenheimer tried to pursue Pauling's wife, Ava Helen. When Pauling was at work, Oppenheimer came to their home and blurted out an invitation to Ava Helen to join him on a tryst in Mexico. She flatly refused, and reported the incident to Pauling. He immediately cut off his relationship with Oppenheimer.

In the summer of 1930, Pauling made another European trip, during which he learned about gas-phase electron diffraction from Herman Francis Mark. After returning, he built an electron diffraction instrument at Caltech with a student of his, Lawrence Olin Brockway, and used it to study the molecular structure of a large number of chemical substances.

Pauling introduced the concept of electronegativity in 1932. Using the various properties of molecules, such as the energy required to break bonds and the dipole moments of molecules, he established a scale and an associated numerical value for most of the elementsthe Pauling Electronegativity Scalewhich is useful in predicting the nature of bonds between atoms in molecules.

In 1936, Pauling was promoted to chairman of the division of chemistry and chemical engineering at Caltech, and to the position of director of the Gates and Crellin Laboratories of Chemistry. He would hold both positions until 1958. Pauling also spent a year in 1948 at the University of Oxford as George Eastman Visiting Professor and Fellow of Balliol.

Nature of the chemical bond

In the late 1920s, Pauling began publishing papers on the nature of the chemical bond. Between 1937 and 1938, he took a position as George Fischer Baker Non-Resident Lecturer in Chemistry at Cornell University. While at Cornell, he delivered a series of nineteen lectures and completed the bulk of his famous textbook The Nature of the Chemical Bond. It is based primarily on his work in this area that he received the Nobel Prize in Chemistry in 1954 "for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances". Pauling's book has been considered "chemistry's most influential book of this century and its effective bible". In the 30 years after its first edition was published in 1939, the book was cited more than 16,000 times. Even today, many modern scientific papers and articles in important journals cite this work, more than seventy years after the first publication.

Part of Pauling's work on the nature of the chemical bond led to his introduction of the concept of orbital hybridization. While it is normal to think of the electrons in an atom as being described by orbitals of types such as s and p, it turns out that in describing the bonding in molecules, it is better to construct functions that partake of some of the properties of each. Thus the one 2s and three 2p orbitals in a carbon atom can be (mathematically) 'mixed' or combined to make four equivalent orbitals (called sp3 hybrid orbitals), which would be the appropriate orbitals to describe carbon compounds such as methane, or the 2s orbital may be combined with two of the 2p orbitals to make three equivalent orbitals (called sp$2$ hybrid orbitals), with the remaining 2p orbital unhybridized, which would be the appropriate orbitals to describe certain unsaturated carbon compounds such as ethylene. Other hybridization schemes are also found in other types of molecules. Another area which he explored was the relationship between ionic bonding, where electrons are transferred between atoms, and covalent bonding, where electrons are shared between atoms on an equal basis. Pauling showed that these were merely extremes, and that for most actual cases of bonding, the quantum-mechanical wave function for a polar molecule AB is a combination of wave functions for covalent and ionic molecules. Here Pauling's electronegativity concept is particularly useful; the electronegativity difference between a pair of atoms will be the surest predictor of the degree of ionicity of the bond.

The third of the topics that Pauling attacked under the overall heading of "the nature of the chemical bond" was the accounting of the structure of aromatic hydrocarbons, particularly the prototype, benzene. The best description of benzene had been made by the German chemist Friedrich Kekulé. He had treated it as a rapid interconversion between two structures, each with alternating single and double bonds, but with the double bonds of one structure in the locations where the single bonds were in the other. Pauling showed that a proper description based on quantum mechanics was an intermediate structure which was a blend of each. The structure was a superposition of structures rather than a rapid interconversion between them. The name "resonance" was later applied to this phenomenon. In a sense, this phenomenon resembles those of hybridization and also polar bonding, both described above, because all three phenomena involve combining more than one electronic structure to achieve an intermediate result.

Ionic crystal structures
In 1929, Pauling published five rules which help to predict and explain crystal structures of ionic compounds. These rules concern (1) the ratio of cation radius to anion radius, (2) the electrostatic bond strength, (3) the sharing of polyhedron corners, edges and faces, (4) crystals containing different cations, and (5) the rule of parsimony.

Biological molecules

In the mid-1930s, Pauling, strongly influenced by the biologically oriented funding priorities of the Rockefeller Foundation's Warren Weaver, decided to strike out into new areas of interest. Although Pauling's early interest had focused almost exclusively on inorganic molecular structures, he had occasionally thought about molecules of biological importance, in part because of Caltech's growing strength in biology. Pauling interacted with such great biologists as Thomas Hunt Morgan, Theodosius Dobzhanski, Calvin Bridges and Alfred Sturtevant. His early work in this area included studies of the structure of hemoglobin with his student Charles D. Coryell. He demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen molecule. As a result of this observation, he decided to conduct a more thorough study of protein structure in general. He returned to his earlier use of X-ray diffraction analysis. But protein structures were far less amenable to this technique than the crystalline minerals of his former work. The best X-ray pictures of proteins in the 1930s had been made by the British crystallographer William Astbury, but when Pauling tried, in 1937, to account for Astbury's observations quantum mechanically, he could not.

It took eleven years for Pauling to explain the problem: his mathematical analysis was correct, but Astbury's pictures were taken in such a way that the protein molecules were tilted from their expected positions. Pauling had formulated a model for the structure of hemoglobin in which atoms were arranged in a helical pattern, and applied this idea to proteins in general.

In 1951, based on the structures of amino acids and peptides and the planar nature of the peptide bond, Pauling, Robert Corey and Herman Branson correctly proposed the alpha helix and beta sheet as the primary structural motifs in protein secondary structure. This work exemplified Pauling's ability to think unconventionally; central to the structure was the unorthodox assumption that one turn of the helix may well contain a non-integer number of amino acid residues; for the alpha helix it is 3.7 amino acid residues per turn.

Pauling then proposed that deoxyribonucleic acid (DNA) was a triple helix; his model contained several basic mistakes, including a proposal of neutral phosphate groups, an idea that conflicted with the acidity of DNA. Sir Lawrence Bragg had been disappointed that Pauling had won the race to find the alpha helix structure of proteins. Bragg's team had made a fundamental error in making their models of protein by not recognizing the planar nature of the peptide bond. When it was learned at the Cavendish Laboratory that Pauling was working on molecular models of the structure of DNA, James Watson and Francis Crick were allowed to make a molecular model of DNA. They later benefited from unpublished data from Maurice Wilkins and Rosalind Franklin at King's College which showed evidence for a helix and planar base stacking along the helix axis. Early in 1953 Watson and Crick proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. Pauling described this situation as "the biggest disappointment in his life".

During the time Pauling was researching the problem, Rosalind Franklin in England was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert Corey did see at least some of them, while taking Pauling's place at a summer 1952 protein conference in England. Pauling had been prevented from attending because his passport was withheld by the State Department on suspicion that he had Communist sympathies. This led to the legend that Pauling missed the structure of DNA because of the politics of the day (this was at the start of the McCarthy period in the United States). Politics did not play a critical role. Not only did Corey see the images at the time, but Pauling himself regained his passport within a few weeks and toured English laboratories well before writing his DNA paper. He had ample opportunity to visit Franklin's lab and see her work, but chose not to. Despite these times, Pauling chose to move on from them and be thankful for the discoveries that he had already found.

Pauling also studied enzyme reactions and was among the first to point out that enzymes bring about reactions by stabilizing the transition state of the reaction, a view which is central to understanding their mechanism of action. He was also among the first scientists to postulate that the binding of antibodies to antigens would be due to a complementarity between their structures. Along the same lines, with the physicist turned biologist Max Delbrück, he wrote an early paper arguing that DNA replication was likely to be due to complementarity, rather than similarity, as suggested by a few researchers. This was made clear in the model of the structure of DNA that Watson and Crick discovered.

Molecular genetics

In November 1949, Pauling, Harvey Itano, S. J. Singer and Ibert Wells published "Sickle Cell Anemia, a Molecular Disease" in the journal Science. It was the first proof of a human disease being caused by an abnormal protein, and sickle cell anemia became the first disease understood at the molecular level. (It was not, however, the first demonstration that variant forms of hemoglobin could be distinguished by electrophoresis, which had been shown several years earlier by Maud Menten and collaborators). Using electrophoresis, they demonstrated that individuals with sickle cell disease have a modified form of hemoglobin in their red blood cells, and that individuals with sickle cell trait have both the normal and abnormal forms of hemoglobin. This was the first demonstration causally linking an abnormal protein to a disease, and also the first demonstration that Mendelian inheritance determines the specific physical properties of proteins, not simply their presence or absence – the dawn of molecular genetics.

His success with sickle cell anemia led Pauling to speculate that a number of other diseases, including mental illnesses such as schizophrenia, might result from flawed genetics. As chairman of the Division of Chemistry and Chemical Engineering and director of the Gates and Crellin Chemical Laboratories, he encouraged the hiring of researchers with a chemical-biomedical approach to mental illness, a direction not always popular with established Caltech chemists.

In 1951, Pauling gave a lecture entitled "Molecular Medicine". In the late 1950s, he studied the role of enzymes in brain function, believing that mental illness may be partly caused by enzyme dysfunction. In the 1960s, as part of his interest in the effects of nuclear weapons, he investigated the role of mutations in evolution, proposing with his student Emile Zuckerkandl, the molecular evolutionary clock, the idea that mutations in proteins and DNA accumulate at a constant rate over time.

Structure of the atomic nucleus

On September 16, 1952, Pauling opened a new research notebook with the words "I have decided to attack the problem of the structure of nuclei." On October 15, 1965, Pauling published his Close-Packed Spheron Model of the atomic nucleus in two well respected journals, Science and the Proceedings of the National Academy of Sciences. For nearly three decades, until his death in 1994, Pauling published numerous papers on his spheron cluster model.

The basic idea behind Pauling's spheron model is that a nucleus can be viewed as a set of "clusters of nucleons". The basic nucleon clusters include the deuteron [np], helion [pnp], and triton [npn]. Even–even nuclei are described as being composed of clusters of alpha particles, as has often been done for light nuclei. Pauling attempted to derive the shell structure of nuclei from pure geometrical considerations related to Platonic solids rather than starting from an independent particle model as in the usual shell model. In an interview given in 1990 Pauling commented on his model:

"Now recently, I have been trying to determine detailed structures of atomic nuclei by analyzing the ground state and excited state vibrational bends, as observed experimentally. From reading the physics literature, Physical Review Letters and other journals, I know that many physicists are interested in atomic nuclei, but none of them, so far as I have been able to discover, has been attacking the problem in the same way that I attack it. So I just move along at my own speed, making calculations ..."

Wartime work
Pauling had been practically apolitical until World War II. At the beginning of the Manhattan Project, Robert Oppenheimer invited him to be in charge of the Chemistry division of the project. He declined, not wanting to uproot his family.

Pauling did, however, work on research for the military. He was a principal investigator on 14 OSRD contracts. The National Defense Research Committee called a meeting on October 3, 1940, wanting an instrument that could reliably measure oxygen content in a mixture of gases, so that they could measure oxygen conditions in submarines and airplanes. In response Pauling designed the Pauling oxygen meter, which was developed and manufactured by Arnold O. Beckman, Inc. After the war, Beckman adapted the oxygen analyzers for use in incubators for premature babies.

In 1942, Pauling successfully submitted a proposal on "The Chemical Treatment of Protein Solutions in the Attempt to Find a Substitute for Human Serum for Transfusions". His project group, which included Joseph B. Koepfli and Dan H. Campbell, developed a possible replacement for human blood plasma in transfusions: polyoxy gelatin (Oxypolygelatin).

Other wartime projects with more direct military applications included work on explosives, rocket propellants and the patent for an armor-piercing shell. In October 1948, Pauling, along with Lee A. DuBridge, William A. Fowler, Max Mason, and Bruce H. Sage, was awarded a Presidential Medal for Merit by President Harry S. Truman. The citation credits him for his "imaginative mind", "brilliant success", and "exceptionally meritorious conduct in the performance of outstanding services". In 1949, he served as president of the American Chemical Society.

Nuclear activism
The aftermath of the Manhattan Project and his wife Ava's pacifism changed Pauling's life profoundly, and he became a peace activist.

In June 1945, a "May-Johnson Bill" began  that would become the Atomic Energy Act of 1946 (signed August 1, 1946). In November 1945, Pauling spoke to the Independent Citizens Committee of the Arts, Sciences and Professions (ICCASP) on atomic weapons; shortly after, wife Ava and he accepted membership. On January 21, 1946, the group met to discuss academic freedom, during which Pauling said, "There is, of course, always a threat to academic freedom – as there is to the other aspects of the freedom and rights of the individual, in the continued attacks which are made on this freedom, these rights, by the selfish, the overly ambitious, the misguided, the unscrupulous, who seek to oppress the great body of mankind in order that they themselves may profit – and we must always be on the alert against this threat, and must fight it with vigor when it becomes dangerous."

In 1946, he joined the Emergency Committee of Atomic Scientists, chaired by Albert Einstein. Its mission was to warn the public of the dangers associated with the development of nuclear weapons. His political activism prompted the US State Department to deny him a passport in 1952, when he was invited to speak at a scientific conference in London. In a speech before the US Senate on June 6 of the same year, Senator Wayne Morse publicly denounced the action of the State Department, and urged the Passport Division to reverse its decision. Pauling and his wife Ava were then issued a "limited passport" to attend the conference. His full passport was restored in 1954, shortly before the ceremony in Stockholm where he received his first Nobel Prize.

Joining Einstein, Bertrand Russell and eight other leading scientists and intellectuals, he signed the Russell-Einstein Manifesto issued July 9, 1955. He also supported the Mainau Declaration of July 15, 1955, signed by 52 Nobel Prize laureates.

In May 1957, working with Washington University in St. Louis professor Barry Commoner, Pauling began to circulate a petition among scientists to stop nuclear testing. On January 15, 1958, Pauling and his wife presented a petition to United Nations Secretary General Dag Hammarskjöld calling for an end to the testing of nuclear weapons. It was signed by 11,021 scientists representing fifty countries.

In February 1958, Pauling participated in a publicly televised debate with the atomic physicist Edward Teller about the actual probability of fallout causing mutations. Later in 1958, Pauling published No more war!, in which he not only called for an end to the testing of nuclear weapons but also an end to war itself. He proposed that a World Peace Research Organization be set up as part of the United Nations to "attack the problem of preserving the peace".

Pauling also supported the work of the St. Louis Citizen's Committee for Nuclear Information (CNI). This group, headed by Barry Commoner, Eric Reiss, M. W. Friedlander and John Fowler, organized a longitudinal study to measure radioactive strontium-90 in the baby teeth of children across North America. The "Baby Tooth Survey", published by Louise Reiss, demonstrated conclusively in 1961 that above-ground nuclear testing posed significant public health risks in the form of radioactive fallout spread primarily via milk from cows that had ingested contaminated grass. The Committee for Nuclear Information is frequently credited for its significant contribution to supporting the test ban, as is the ground-breaking research conducted by Reiss and the "Baby Tooth Survey".

Public pressure and the frightening results of the CNI research led to a moratorium on above-ground nuclear weapons testing, followed by the Partial Test Ban Treaty, signed in 1963 by John F. Kennedy and Nikita Khrushchev. On the day that the treaty went into force, October 10, 1963, the Nobel Prize Committee awarded Pauling the Nobel Peace Prize for 1962. (No prize had previously been awarded for that year.) They described him as "Linus Carl Pauling, who ever since 1946 has campaigned ceaselessly, not only against nuclear weapons tests, not only against the spread of these armaments, not only against their very use, but against all warfare as a means of solving international conflicts." Pauling himself acknowledged his wife Ava's deep involvement in peace work, and regretted that she was not awarded the Nobel Peace Prize with him.

Political criticism
Many of Pauling's critics, including scientists who appreciated the contributions that he had made in chemistry, disagreed with his political positions and saw him as a naïve spokesman for Soviet communism. In 1960, he was ordered to appear before the Senate Internal Security Subcommittee, which termed him "the number one scientific name in virtually every major activity of the Communist peace offensive in this country". A headline in Life magazine characterized his 1962 Nobel Prize as "A Weird Insult from Norway".

Pauling was a frequent target of the National Review magazine. In an article entitled "The Collaborators" in the magazine's July 17, 1962, issue, Pauling was referred to not only as a collaborator, but as a "fellow traveler" of proponents of Soviet-style communism. In 1963, Pauling sued the magazine, its publisher William Rusher, and its editor William F. Buckley, Jr for $1 million. He lost both his libel suits and the 1968 appeal (unlike his earlier 1963 libel case against the Hearst Corporation), because in the meantime the landmark case New York Times Co. v. Sullivan had established the actual malice standard for libel lawsuits by public figures, requiring that not only falsehood but deliberate lying should be proved by the plaintiff in such cases.

His peace activism, his frequent travels, and his enthusiastic expansion into chemical-biomedical research all aroused opposition at Caltech. In 1958, the Caltech Board of Trustees demanded that Pauling step down as chairman of the Chemistry and Chemical Engineering Division. Although he had retained tenure as a full professor, Pauling chose to resign from Caltech after he received the Nobel peace prize money. He spent the next three years at the Center for the Study of Democratic Institutions (1963–1967). In 1967, he moved to the University of California at San Diego, but remained there only briefly, leaving in 1969 in part because of political tensions with the Reagan-era board of regents. From 1969 to 1974, he accepted a position as professor of chemistry at Stanford University.

Vietnam war activism
During the 1960s, President Lyndon Johnson's policy of increasing America's involvement in the Vietnam War caused an anti-war movement that the Paulings joined with enthusiasm. Pauling denounced the war as unnecessary and unconstitutional. He made speeches, signed protest letters and communicated personally with the North Vietnamese leader, Ho Chi Minh, and gave the lengthy written response to President Johnson. His efforts were ignored by the American government.

Pauling was awarded the International Lenin Peace Prize by the USSR in 1970. He continued his peace activism in the following years. He and his wife Ava helped to found the International League of Humanists in 1974. He was president of the scientific advisory board of the World Union for Protection of Life and also one of the signatories of the Dubrovnik–Philadelphia statement of 1974/1976. Linus Carl Pauling was an honorary president and member of the International Academy of Science, Munich, until the end of his life.

Global activism
He was one of the signatories of the agreement to convene a convention for drafting a world constitution. As a result, for the first time in human history, a World Constituent Assembly convened to draft and adopt a Constitution for the Federation of Earth.

Eugenics
Pauling supported a limited form of eugenics by suggesting that human carriers of defective genes be given a compulsory visible mark – such as a forehead tattoo – to discourage potential mates with the same defect, in order to reduce the number of babies with diseases such as sickle cell anemia.

Medical research and vitamin C advocacy

In 1941, at age 40, Pauling was diagnosed with Bright's disease, a renal disease. Following the recommendations of Thomas Addis, who actively recruited Ava Helen Pauling as "nutritionist, cook, and eventually as deputy 'doctor'", Pauling believed he was able to control the disease with Addis's then-unusual low-protein salt-free diet and vitamin supplements. Thus Pauling's initial – and intensely personal – exposure to the idea of treating disease with vitamin supplements was positive.

In 1965, Pauling read Niacin Therapy in Psychiatry by Abram Hoffer and theorized vitamins might have important biochemical effects unrelated to their prevention of associated deficiency diseases. In 1968, Pauling published a brief paper in Science entitled "Orthomolecular psychiatry", giving a name to the popular but controversial megavitamin therapy movement of the 1970s, and advocating that "orthomolecular therapy, the provision for the individual person of the optimum concentrations of important normal constituents of the brain, may be the preferred treatment for many mentally ill patients." Pauling coined the term "orthomolecular" to refer to the practice of varying the concentration of substances normally present in the body to prevent and treat disease. His ideas formed the basis of orthomolecular medicine, which is not generally practiced by conventional medical professionals and has been strongly criticized.

In 1973, with Arthur B. Robinson and another colleague, Pauling founded the Institute of Orthomolecular Medicine in Menlo Park, California, which was soon renamed the Linus Pauling Institute of Science and Medicine. Pauling directed research on vitamin C, but also continued his theoretical work in chemistry and physics until his death. In his last years, he became especially interested in the possible role of vitamin C in preventing atherosclerosis and published three case reports on the use of lysine and vitamin C to relieve angina pectoris. During the 1990s, Pauling put forward a comprehensive plan for the treatment of heart disease using lysine and vitamin C. In 1996, a website was created expounding Pauling's treatment which it referred to as Pauling Therapy. Proponents of Pauling Therapy believe that heart disease can be treated and even cured using only lysine and Vitamin C and without drugs or heart operations.

Pauling's work on vitamin C in his later years generated much controversy. He was first introduced to the concept of high-dose vitamin C by biochemist Irwin Stone in 1966. After becoming convinced of its worth, Pauling took 3 grams of vitamin C every day to prevent colds. Excited by his own perceived results, he researched the clinical literature and published Vitamin C and the Common Cold in 1970. He began a long clinical collaboration with the British cancer surgeon Ewan Cameron in 1971 on the use of intravenous and oral vitamin C as cancer therapy for terminal patients. Cameron and Pauling wrote many technical papers and a popular book, Cancer and Vitamin C, that discussed their observations. Pauling made vitamin C popular with the public and eventually published two studies of a group of 100 allegedly terminal patients that claimed vitamin C increased survival by as much as four times compared to untreated patients.

A re-evaluation of the claims in 1982 found that the patient groups were not actually comparable, with the vitamin C group being less sick on entry to the study, and judged to be "terminal" much earlier than the comparison group. Later clinical trials conducted by the Mayo Clinic led by oncologist Dr. Edward T. Creagan also concluded that high-dose (10,000 mg) vitamin C was no better than placebo at treating cancer and that there was no benefit to high-dose vitamin C.  The failure of the clinical trials to demonstrate any benefit resulted in the conclusion that vitamin C was not effective in treating cancer; the medical establishment concluded that his claims that vitamin C could prevent colds or treat cancer were quackery. Pauling denounced the conclusions of these studies and handling of the final study as "fraud and deliberate misrepresentation", and criticized the studies for using oral, rather than intravenous vitamin C (which was the dosing method used for the first ten days of Pauling's original study ). Pauling also criticised the Mayo Clinic studies because the controls were taking vitamin C during the trial, and because the duration of the treatment with vitamin C was short; Pauling advocated continued high-dose vitamin C for the rest of the cancer patient's life whereas the Mayo Clinic patients in the second trial were treated with vitamin C for a median of 2.5 months.

Ultimately the negative findings of the Mayo Clinic studies ended general interest in vitamin C as a treatment for cancer. Despite this, Pauling continued to promote vitamin C for treating cancer and the common cold, working with The Institutes for the Achievement of Human Potential to use vitamin C in the treatment of brain-injured children. He later collaborated with the Canadian physician Abram Hoffer on a micronutrient regime, including high-dose vitamin C, as adjunctive cancer therapy. A 2009 review also noted differences between the studies, such as the Mayo Clinic not using intravenous Vitamin C, and suggested further studies into the role of vitamin C when given intravenously. Results from most clinical trials suggest that modest vitamin C supplementation alone or with other nutrients offers no benefit in the prevention of cancer.

Personal life
Pauling married Ava Helen Miller on June 17, 1923. The marriage lasted until her death in 1981. They had four children. Linus Carl Jr. (1925–2023) became a psychiatrist; Peter (1931–2003) a crystallographer at University College London; Edward Crellin (1937–1997) a biologist; and Linda Helen (born 1932) married noted Caltech geologist and glaciologist Barclay Kamb.

Pauling was raised as a member of the Lutheran Church, but later joined the Unitarian Universalist Church. Two years before his death, in a published dialogue with Buddhist philosopher Daisaku Ikeda, Pauling publicly declared his atheism.

On January 30, 1960, Pauling and his wife were using a cabin about 80 mi south of Monterey, California, and he decided to go for a walk on a coastal trail. He got lost and tried to climb the rocky cliff, but reached a large overhanging rock about 300 ft above the ocean. He decided it was safest to stay there, and meanwhile he was reported missing. He spent a sleepless night on the cliff before being found after almost 24 hours.

Death and legacy
Pauling died of prostate cancer on August 19, 1994, at 19:20 at home in Big Sur, California. He was 93 years old. A grave marker for Pauling was placed in Oswego Pioneer Cemetery in Lake Oswego, Oregon by his sister Pauline, but Pauling's ashes, along with those of his wife, were not buried there until 2005.

Pauling's discoveries led to decisive contributions in a diverse array of areas including around 350 publications in the fields of quantum mechanics, inorganic chemistry, organic chemistry, protein structure, molecular biology, and medicine.

His work on chemical bonding marks him as one of the founders of modern quantum chemistry. The Nature of the Chemical Bond was the standard work for many years, and concepts like hybridization and electronegativity remain part of standard chemistry textbooks. While his Valence bond approach fell short of accounting quantitatively for some of the characteristics of molecules, such as the color of organometallic complexes, and would later be eclipsed by the molecular orbital theory of Robert Mulliken, Valence Bond Theory still competes, in its modern form, with Molecular Orbital Theory and density functional theory (DFT) as a way of describing chemical phenomena. Pauling's work on crystal structure contributed significantly to the prediction and elucidation of the structures of complex minerals and compounds. His discovery of the alpha helix and beta sheet is a fundamental foundation for the study of protein structure.

Francis Crick acknowledged Pauling as the "father of molecular biology". His discovery of sickle cell anemia as a "molecular disease" opened the way toward examining genetically acquired mutations at a molecular level.

Pauling's 1951 publication with Robert B. Corey and H. R. Branson, "The Structure of Proteins: Two Hydrogen-Bonded Helical Configurations of the Polypeptide Chain," was a key early finding in the then newly emerging field of molecular biology. This publication was honored by a Citation for Chemical Breakthrough Award from the Division of History of Chemistry of the American Chemical Society presented to the department of chemistry, Caltech, in 2017.

Commemorations
Oregon State University completed construction of the $77 million, 100,000 sqft Linus Pauling Science Center in the late 2000s, now housing the bulk of Oregon State's chemistry classrooms, labs, and instruments.

On March 6, 2008, the United States Postal Service released a 41 cent stamp honoring Pauling designed by artist Victor Stabin. His description reads: "A remarkably versatile scientist, structural chemist Linus Pauling (1901–1994) won the 1954 Nobel Prize in Chemistry for determining the nature of the chemical bond linking atoms into molecules. His work in establishing the field of molecular biology; his studies of hemoglobin led to the classification of sickle cell anemia as a molecular disease." The other scientists on this sheet of stamps included Gerty Cori, biochemist, Edwin Hubble, astronomer, and John Bardeen, physicist.

California Governor Arnold Schwarzenegger and First Lady Maria Shriver announced on May 28, 2008, that Pauling would be inducted into the California Hall of Fame, located at The California Museum for History, Women and the Arts. The induction ceremony took place December 15, 2008. Pauling's son was asked to accept the honor in his place.

By proclamation of Gov. John Kitzhaber in the state of Oregon, February 28 has been named "Linus Pauling Day". The Linus Pauling Institute still exists, but moved in 1996 from Palo Alto, California, to Corvallis, Oregon, where it is part of the Linus Pauling Science Center at Oregon State University. The Valley Library Special Collections at Oregon State University contain the Ava Helen and Linus Pauling Papers, including digitized versions of Pauling's forty-six research notebooks.

In 1986, Caltech commemorated Linus Pauling with a symposium and lectureship. The Pauling Lecture series at Caltech began in 1989 with a lecture by Pauling himself. The Caltech Chemistry Department renamed room 22 of Gates Hall the Linus Pauling Lecture Hall, since Pauling spent so much time there.

Other places named after Pauling include Pauling Street in Foothill Ranch, California; Linus Pauling Drive in Hercules, California; Linus and Ava Helen Pauling Hall at Soka University of America in Aliso Viejo, California; Linus Pauling Middle School in Corvallis, Oregon; and Pauling Field, a small airfield located in Condon, Oregon, where Pauling spent his youth. There is a psychedelic rock band in Houston, Texas, named The Linus Pauling Quartet.

The asteroid 4674 Pauling in the inner asteroid belt, discovered by Eleanor F. Helin, was named after Linus Pauling in 1991, on his 90th birthday.

Linus Torvalds, developer of the Linux kernel, is named after Pauling.

Nobel laureate Peter Agre has said that Linus Pauling inspired him.

In 2010, Pacific Northwest National Laboratory named its distinguished postdoctoral program in his honor, as the Linus Pauling Distinguished Postdoctoral Fellowship Program.

Honors and awards
Pauling received numerous awards and honors during his career, including the following:

 * 1931 ACS Award in Pure Chemistry
 * 1931 Irving Langmuir Award, American Chemical Society.
 * 1933 Elected Member of the United States National Academy of Sciences
 * 1936 Elected Member of the United States American Philosophical Society
 * 1940 Alpha Chi Sigma, professional chemistry fraternity.
 * 1941 Nichols Medal, New York Section, American Chemical Society.
 * 1944 Elected Member of the American Academy of Arts and Sciences
 * 1946 Willard Gibbs Award, Chicago section of the American Chemical Society.
 * 1947 Davy Medal, Royal Society.
 * 1947 T. W. Richards Medal, Northeastern Section of the American Chemical Society.
 * 1948 Presidential Medal for Merit by President Harry S. Truman of the United States.
 * 1948 Elected a Foreign Member of the Royal Society of London (ForMemRS)
 * 1951 Gilbert N. Lewis medal, California section of the American Chemical Society.
 * 1952 Pasteur Medal, Biochemical Society of France.
 * 1954 Nobel Prize in Chemistry.
 * 1955 Addis Medal, National Nephrosis Foundation.
 * 1955 John Phillips Memorial Award, American College of Physicians.
 * 1956 Avogadro Medal, Italian Academy of Science.
 * 1957 Paul Sabatier Medal.
 * 1957 Pierre Fermat Medal in Mathematics (awarded for only the sixth time in three centuries).
 * 1957 International Grotius Medal.
 * 1959 Messenger Lectureship
 * 1960 Fellow, Royal Society of Arts
 * 1961 Humanist of the Year, American Humanist Association.
 * 1961 Gandhi Peace Award by Promoting Enduring Peace.
 * 1962 Nobel Peace Prize.
 * 1965 Medal, Academy of the Rumanian People's Republic.
 * 1966 Linus Pauling Award.
 * 1966 Silver Medal, Institute of France.
 * 1966 Supreme Peace Sponsor, World Fellowship of Religion.
 * 1967 Washington A. Roebling Medal, Mineralogical Society of America.
 * 1972 Lenin Peace Prize.
 * 1974 National Medal of Science by President Gerald R. Ford of the United States.
 * 1978 Lomonosov Gold Medal, Presidium of the Academy of the USSR.
 * 1979 Gold Medal Honoree, National Institute of Social Sciences.
 * 1979 NAS Award in Chemical Sciences, National Academy of Sciences.
 * 1979 Golden Plate Award, American Academy of Achievement
 * 1981 John K. Lattimer Award, American Urological Association.
 * 1984 Priestley Medal, American Chemical Society.
 * 1984 Award for Chemistry, Arthur M. Sackler Foundation.
 * 1986 Lavoisier Medal by Fondation de la Maison de la Chimie.
 * 1987 Award in Chemical Education, American Chemical Society.
 * 1989 Vannevar Bush Award, National Science Board.
 * 1990 Richard C. Tolman Medal, American Chemical Society Southern California Section.
 * 1992 Daisaku Ikeda Medal, Soka Gakkai International
 * 2008 "American Scientists" U.S. postage stamp series, $0.41, for his sickle cell disease work.

Books

 * Greatly revised and expanded in 1947, 1953, and 1970. Reprinted by Dover Publications in 1988.
 * Manuscript notes and typescripts (clear images)
 * Greatly revised and expanded in 1947, 1953, and 1970. Reprinted by Dover Publications in 1988.
 * Manuscript notes and typescripts (clear images)
 * Manuscript notes and typescripts (clear images)
 * Manuscript notes and typescripts (clear images)

General and cited references

 * online
 * Pauling, Linus.  Selected Scientific Papers Vol. II online
 * Pauling, Linus.  Selected Scientific Papers Vol. II online

title: Linus Pauling


text:
Shrapnel shell

Shrapnel shells were anti-personnel artillery munitions which carried many individual bullets close to a target area and then ejected them to allow them to continue along the shell's trajectory and strike targets individually. They relied almost entirely on the shell's velocity for their lethality. The munition has been obsolete since the end of World War I for anti-personnel use; high-explosive shells superseded it for that role. The functioning and principles behind shrapnel shells are fundamentally different from high-explosive shell fragmentation. Shrapnel is named after Lieutenant-General Henry Shrapnel (1761–1842), a British artillery officer, whose experiments, initially conducted on his own time and at his own expense, culminated in the design and development of a new type of artillery shell.

Usage of the term "shrapnel" has changed over time to also refer to fragmentation of the casing of shells and bombs. This is its most common modern usage, which strays from the original meaning.

Development
In 1784, Lieutenant Shrapnel of the Royal Artillery began developing an anti-personnel weapon. At the time artillery could use "canister shot" to defend themselves from infantry or cavalry attack, which involved loading a tin or canvas container filled with small iron or lead balls instead of the usual cannonball. When fired, the container burst open during passage through the bore or at the muzzle, giving the effect of an oversized shotgun shell. At ranges of up to 300 m canister shot was still highly lethal, though at this range the shots’ density was much lower, making a hit on a human body less likely. At longer ranges, solid shot or the common shell—a hollow cast-iron sphere filled with black powder—was used, although with more of a concussive than a fragmentation effect, as the pieces of the shell were very large and sparse in number.

Shrapnel's innovation was to combine the multi-projectile shotgun effect of canister shot, with a time fuse to open the canister and disperse the bullets it contained at some distance along the canister's trajectory from the gun. His shell was a hollow cast-iron sphere filled with a mixture of balls and powder, with a crude time fuse. If the fuse was set correctly then the shell would break open, either in front of or above the intended human objective, releasing its contents (of musket balls). The shrapnel balls would carry on with the "remaining velocity" of the shell. In addition to a denser pattern of musket balls, the retained velocity could be higher as well, since the shrapnel shell as a whole would likely have a higher ballistic coefficient than the individual musket balls (see external ballistics).

The explosive charge in the shell was to be just enough to break the casing rather than scatter the shot in all directions. As such his invention increased the effective range of canister shot from 300 m to about 1,100 m.

He called his device 'spherical case shot', but in time it came to be called after him; a nomenclature formalised in 1852 by the British Government.

Initial designs suffered from the potentially catastrophic problem that friction between the shot and black powder during the high acceleration down the gun bore could sometimes cause premature ignition of the powder. Various solutions were tried, with limited if any success. However, in 1852 Colonel Boxer proposed using a diaphragm to separate the bullets from the bursting charge; this proved successful and was adopted the following year. As a buffer to prevent lead shot deforming, a resin was used as a packing material between the shot. A useful side effect of using the resin was that the combustion also gave a visual reference upon the shell bursting, as the resin shattered into a cloud of dust.

British artillery adoption
It took until 1803 for the British artillery to adopt (albeit with great enthusiasm) the shrapnel shell (as "spherical case"). Henry Shrapnel was promoted to major in the same year. The first recorded use of shrapnel by the British was in 1804 against the Dutch at Fort Nieuw-Amsterdam in Suriname. The Duke of Wellington's armies used it from 1808 in the Peninsular War and at the Battle of Waterloo, and he wrote admiringly of its effectiveness.

The design was improved by Captain E. M. Boxer of the Royal Arsenal around 1852 and crossed over when cylindrical shells for rifled guns were introduced. Lieutenant-Colonel Boxer adapted his design in 1864 to produce shrapnel shells for the new rifled muzzle-loader (RML) guns: the walls were of thick cast iron, but the gunpowder charge was now in the shell base with a tube running through the centre of the shell to convey the ignition flash from the time fuse in the nose to the gunpowder charge in the base. The powder charge both shattered the cast iron shell wall and liberated the bullets. The broken shell wall continued mainly forward but had little destructive effect. The system had major limitations: the thickness of the iron shell walls limited the available carrying capacity for bullets but provided little destructive capability, and the tube through the centre similarly reduced available space for bullets.

In the 1870s William Armstrong provided a design with the bursting charge in the head and the shell wall made of steel and hence much thinner than previous cast-iron shrapnel shell walls. While the thinner shell wall and absence of a central tube allowed the shell to carry far more bullets, it had the disadvantage that the bursting charge separated the bullets from the shell casing by firing the case forward and at the same time slowing the bullets down as they were ejected through the base of the shell casing, rather than increasing their velocity. Britain adopted this solution for several smaller calibres (below 6-inch) but by World War I few if any such shells remained.

The final shrapnel shell design, adopted in the 1880s, bore little similarity to Henry Shrapnel's original design other than its spherical bullets and time fuse. It used a much thinner forged steel shell case with a timer fuse in the nose and a tube running through the centre to convey the ignition flash to a gunpowder bursting charge in the shell base. The use of steel allowed a thinner shell wall, allowing space for many more bullets. It also withstood the force of the powder charge without shattering, so that the bullets were fired forward out of the shell case with increased velocity, much like a shotgun. This design came to be adopted by all countries and was in standard use when World War I began in 1914. During the 1880s, when both the old cast-iron and modern forged-steel shrapnel shell designs were in British service, British ordnance manuals referred to the older cast-iron design as "Boxer shrapnel", apparently to differentiate it from the modern steel design.

The modern thin-walled forged-steel design made feasible shrapnel shells for howitzers, which had a much lower velocity than field guns, by using a larger gunpowder charge to accelerate the bullets forward on bursting. The ideal shrapnel design would have had a timer fuse in the shell base to avoid the need for a central tube, but this was not technically feasible due to the need to manually adjust the fuse before firing, and was in any case rejected from an early date by the British due to risk of premature ignition and irregular action.

Technical considerations
The size of shrapnel balls in World War I was based on two considerations. One was the premise that a projectile energy of about 60 ftlbf was required to disable an enemy soldier. A typical World War I 3 in field gun shell at its maximum possible range traveling at a velocity of 250 feet/second, plus the additional velocity from the shrapnel bursting charge (about 150 feet per second), would give individual shrapnel bullets a velocity of 400 feet per second and an energy of 60 foot-pounds (81 joules): this was the minimum energy of a single half-inch lead-antimony ball of approximately 170 gr, or 41-42 balls = 1 pound. Hence this was a typical field gun shrapnel bullet size.

The maximum possible range, typically beyond 7,000 yards, was beyond useful shrapnel combat ranges for normal field guns due to loss of accuracy and the fact that at extreme range the projectiles descended relatively steeply and hence the "cone" of bullets covered a relatively small area.

At a more typical combat range of 3,000 yards, giving a fairly flat trajectory and hence a long "beaten zone" for the bullets, a typical 3-inch or 75-mm field gun shrapnel shell would have a velocity of approximately 900 feet/second. The bursting charge would add a possible 150 feet/second, giving a bullet velocity of 1,050 feet/second. This would give each bullet approximately 418 foot-pounds: seven times the assumed energy required to disable a man.
 * $$1/41 \times 1050^2/64.32 = 418 \text{ foot-pounds}$$

For larger guns which had lower velocities, correspondingly larger balls were used so that each individual ball carried enough energy to be lethal.

Most engagements using guns in this size range used direct fire at enemy from 1,500 yards to 3,000 yards distant, at which ranges the residual shell velocity was correspondingly higher, as in the table - at least in the earlier stages of World War 1.

The other factor was the trajectory. The shrapnel bullets were typically lethal for about 300 yards from normal field guns after bursting and over 400 yards from heavy field guns. To make maximum use of these distances a flat-trajectory and hence high-velocity gun was required. The pattern in Europe was that the armies with higher-velocity guns tended to use heavier bullets because they could afford to have fewer bullets per shell.

The important points to note about shrapnel shells and bullets in their final stage of development in World War I are:
 * They used the property of carrying power, whereby if two projectiles are fired with the same velocity, then the heavier one goes farther. Bullets packed into a heavier carrier shell went farther than they would individually.
 * The shell body itself was not designed to be lethal: its sole function was to transport the bullets close to the target, and it fell to the ground intact after the bullets were released. A battlefield where a shrapnel barrage had been fired was afterwards typically littered with intact empty shell bodies, fuses and central tubes. Troops under a shrapnel barrage would attempt to convey any of these intact fuses they found to their own artillery units, as the time setting on the fuse could be used to calculate the shell's range and hence identify the firing gun's position, allowing it to be targeted in a counter-barrage.
 * They depended almost entirely on the shell's velocity for their lethality: there was no lateral explosive effect.

A firsthand description of successful British deployment of shrapnel in a defensive barrage during the Third Battle of Ypres, 1917: "... the air is full of yellow spurts of smoke that burst about 30 feet up and shoot towards the earth – just ahead of each of these yellow puffs the earth rises in a lashed-up cloud – shrapnel – and how beautifully placed – long sweeps of it fly along that slope lashing up a good 200 yards of earth at each burst."

Tactical use
During the initial stages of World War I, shrapnel was widely used by all sides as an anti-personnel weapon. It was the only type of shell available for British field guns (13-pounder, 15 pounder and 18-pounder) until October 1914. Shrapnel was effective against troops in the open, particularly massed infantry (advancing or withdrawing). However, the onset of trench warfare from late 1914 led to most armies decreasing their use of shrapnel in favour of high-explosive. Britain continued to use a high percentage of shrapnel shells. New tactical roles included cutting barbed wire and providing "creeping barrages" to both screen its own attacking troops and suppressing the enemy defenders to prevent them from shooting at their attackers.

In a creeping barrage fire was 'lifted' from one 'line' to the next as the attackers advanced. These lines were typically 100 yard apart and the lifts were typically 4 minutes apart. Lifting meant that time fuses settings had to be changed. The attackers tried to keep as close as possible (as little as 25 yards sometimes) to the bursting shrapnel so as to be on top of the enemy trenches when fire lifted beyond them, and before the enemy could get back to their parapets.

Advantages
While shrapnel made no impression on trenches and other earthworks, it remained the favoured weapon of the British (at least) to support their infantry assaults by suppressing the enemy infantry and preventing them from manning their trench parapets. This was called 'neutralization' and by the second half of 1915 had become the primary task of artillery supporting an attack. Shrapnel was less hazardous to the assaulting British infantry than high-explosives – as long as their own shrapnel burst above or ahead of them, attackers were safe from its effects, whereas high-explosive shells bursting short are potentially lethal within 100 yards or more in any direction. Shrapnel was also useful against counter-attacks, working parties and any other troops in the open.

British Expeditionary Force "GHQ Artillery Notes No. 5 Wire-cutting" was issued in June 1916. It prescribed the use of shrapnel for wirecutting, with HE used to scatter the posts and wire when cut. However, there were constraints: the best ranges for 18-pdrs were 1,800–2,400 yards. Shorter ranges meant the flat trajectories might not clear the firers' own parapets, and fuses could not be set for less than 1,000 yards. The guns had to be overhauled by artificers and carefully calibrated. Furthermore, they needed good platforms with trail and wheels anchored with sandbags, and an observing officer had to monitor the effects on the wire continuously and make any necessary adjustments to range and fuse settings. These instructions were repeated in "GHQ Artillery Notes No. 3 Artillery in Offensive Operations", issued in February 1917 with added detail including the amount of ammunition required per yard of wire frontage. The use of shrapnel for wire-cutting was also highlighted in RA "Training Memoranda No. 2 1939".

Shrapnel provided a useful "screening" effect from the smoke of the black-powder bursting charges when the British used it in "creeping barrages".

Disadvantages
One of the key factors that contributed to the heavy casualties sustained by the British at the Battle of the Somme was the perceived belief that shrapnel would be effective at cutting the barbed wire entanglements in no man's land (although it has been suggested that the reason for the use of shrapnel as a wire-cutter at the Somme was because Britain lacked the capacity to manufacture enough HE shell ). This perception was reinforced by the successful deployment of shrapnel shells against Germany's barbed wire entanglements in the 1915 Battle of Neuve Chapelle, but the Germans thickened their barbed wire strands after that battle. As a result, shrapnel was later only effective in killing enemy personnel; even if the conditions were correct, with the angle of descent being flat to maximise the number of bullets going through the entanglements, the probability of a shrapnel ball hitting a thin line of barbed wire and successfully cutting it was extremely low. The bullets also had limited destructive effect and were stopped by sandbags, so troops behind protection or in bunkers were generally safe. Additionally, steel helmets, including both the German Stahlhelm and the British Brodie helmet, could resist shrapnel bullets and protect the wearer from head injury: "... suddenly, with a great clanging thud, I was hit on the forehead and knocked flying onto the floor of the trench... a shrapnel bullet had hit my helmet with great violence, without piercing it, but sufficiently hard to dent it. If I had, as had been usual up until a few days previously, been wearing a cap, then the Regiment would have had one more man killed."

A shrapnel shell was more expensive than a high-explosive one and required higher-grade steel for the shell body. They were also harder to use correctly because getting the correct fuse running time was critical in order to burst the shell in the right place. This required considerable skill by the observation officer when engaging moving targets.

An added complication was that the actual fuse running time was affected by the meteorological conditions, with the variation in gun muzzle velocity being an added complication. However, the British used fuse indicators at each gun that determined the correct fuse running time (length) corrected for muzzle velocity.

Replacement by high-explosive shell
With the advent of relatively insensitive high explosives which could be used as the filling for shells, it was found that the casing of a properly designed high-explosive shell fragmented effectively. For example, the detonation of an average 105 mm shell produces several thousand high-velocity (1,000 to 1,500 m/s) fragments, a lethal (at very close range) blast overpressure and, if a surface or sub-surface burst, a useful cratering and anti-materiel effect – all in a munition much less complex than the later versions of the shrapnel shell. However, this fragmentation was often lost when shells penetrated soft ground, and because some fragments went in all directions it was a hazard to assaulting troops.

Variations
One item of note is the "universal shell", a type of field gun shell developed by Krupp of Germany in the early 1900s. This shell could function as either a shrapnel shell or high-explosive projectile. The shell had a modified fuse, and, instead of resin as the packing between the shrapnel balls, TNT was used. When a timed fuse was set the shell functioned as a shrapnel round, ejecting the balls and igniting (not detonating) the TNT, giving a visible puff of black smoke. When allowed to impact, the TNT filling would detonate, becoming a high-explosive shell with a very large amount of low-velocity fragmentation and a milder blast. Due to its complexity it was dropped in favour of a simple high-explosive shell.

During World War I the UK also used shrapnel pattern shells to carry "pots" instead of "bullets". These were incendiary shells with seven pots using a thermite compound.

When World War I began the United States also had what it referred to as the "Ehrhardt high-explosive shrapnel" in its inventory. It appears to be similar to the German design, with bullets embedded in TNT rather than resin, together with a quantity of explosive in the shell nose. Douglas Hamilton mentions this shell type in passing, as "not as common as other types" in his comprehensive treatises on manufacturing shrapnel and high-explosive shells of 1915 and 1916, but gives no manufacturing details. Nor does Ethan Viall in 1917. Hence the US appears to have ceased its manufacture early in the war, presumably based on the experience of other combatants.

World War II era
A new British streamlined shrapnel shell, Mk 3D, had been developed for BL 60 pounder gun in the early 1930s, containing 760 bullets. There was some use of shrapnel by the British in the campaigns in East and North East Africa at the beginning of the war, where 18-pdr and 4.5-in (114 mm) howitzers were used. By World War II shrapnel shells, in the strict sense of the word, fell out of use, the last recorded use of shrapnel being 60 pdr shells fired in Burma in 1943. In 1945 the British conducted successful trials with shrapnel shells fused with VT. However, shrapnel was not developed as munitions for any new British artillery models after World War I.

Vietnam War era
Although not strictly shrapnel, a 1960s weapons project produced splintex shells for 90 and 106 mm recoilless rifles and 105 mm howitzers, where it was called a "beehive" round. Unlike the shrapnel shells’ balls, the splintex shells contained flechettes. The result was the 105 mm M546 APERS-T (anti-personnel-tracer) round, first used in the Vietnam War in 1966. The shell consisted of approximately 8,000 one-half-gram flechettes arranged in five tiers, a time fuse, body-shearing detonators, a central flash tube, a smokeless propellant charge with a dye marker contained in the base and a tracer element. The shell functioned as follows: the time fuse fired, the flash traveled down the flash tube, the shearing detonators fired, and the forward body split into four pieces. The body and first four tiers were dispersed by the projectile's spin, the last tier and visual marker by the powder charge itself. The flechettes spread, mainly due to spin, from the point of burst in an ever-widening cone along the projectile's previous trajectory prior to bursting. The round was complex to make, but is a highly effective anti-personnel weapon – soldiers reported that after beehive rounds were fired during an overrun attack, many enemy dead had their hands nailed to the wooden stocks of their rifles, and these dead could be dragged to mass graves by the rifle. It is said that the name beehive was given to the munition type due to the noise of the flechettes moving through the air resembling that of a swarm of bees.

Modern era
Though shrapnel rounds are now rarely used, apart from the beehive munitions, there are other modern rounds, that use, or have used, the shrapnel principle. The DM 111 20 mm cannon round used for close-range air defense, the flechette-filled 40 mm HVCC (40 x 53 mm HV grenade), the 35 mm cannon (35 × 228 mm) AHEAD ammunition (152 × 3.3g tungsten cylinders), RWM Schweiz 30 × 173 mm air-bursting munition, five-inch (127 mm) shotgun projectile (KE-ET) and possibly more. Also, many modern armies have canister shot ammunition for tank and artillery guns, the XM1028 round for the 120 mm M256 tank gun being one example (approx 1150 tungsten balls at 1,400 m/s).

Some anti-ballistic missiles (ABMs) use shrapnel-like warheads instead of the more common blast-fragmentation types. As with a blast-frag warhead, the use of this type of warhead does not require a direct body-on-body impact, so greatly reduces tracking and steering accuracy requirements. At a predetermined distance from the incoming re-entry vehicle (RV) the warhead releases, in the case of the ABM warhead by an explosive expulsion charge, an array of mainly rod-like sub-projectiles into the RV's flight path. Unlike a blast-frag warhead, the expulsion charge is only needed to release the sub-projectiles from the main warhead, not to accelerate them to high velocity. The velocity required to penetrate the RV's casing comes from the high terminal velocity of the warhead, similar to the shrapnel shell's principle. The reason for the use of this type of warhead and not a blast-frag is that the fragments produced by a blast-frag warhead cannot guarantee penetration of the RV's casing. By using rod-like sub-projectiles, a much greater thickness of material can be penetrated, greatly increasing the potential for disruption of the incoming RV.

The Starstreak missile uses a similar system, with three metal darts splitting from the missile prior to impact, although in the case of Starstreak these darts are guided and contain an explosive charge.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Shrapnel shell


text:
Henry Shrapnel

Lieutenant-General Henry Scrope Shrapnel (3 June 1761 – 13 March 1842) was a British Army officer whose name has entered the English language as the inventor of the shrapnel shell.

Biography
Henry Shrapnel was born at Midway Manor in Bradford-on-Avon, Wiltshire, England, the ninth child of Zachariah Shrapnel and his wife Lydia.

In 1784, while a lieutenant in the Royal Artillery, he perfected, with his own resources, an invention of what he called "spherical case" ammunition: a hollow cannonball filled with lead shot that burst in mid-air. He successfully demonstrated this in 1787 at Gibraltar. He intended the device as an anti-personnel weapon.

In 1803, the British Army adopted a similar but elongated explosive shell which immediately acquired the inventor's name. It has lent the term "shrapnel" to fragmentation from artillery shells and fragmentation in general ever since, long after it was replaced by high-explosive rounds. Until the end of World War I, the shells were still manufactured according to his original principles.

Shrapnel served in Flanders, where he was wounded in 1793. He was promoted to major on 1 November 1803 after eight years as a captain. After his invention's success in battle at Fort Nieuw-Amsterdam, Surinam, on 30 April 1804, Shrapnel was promoted to lieutenant colonel on 20 July 1804, less than nine months later.

In 1814, the British Government recognized Shrapnel's contribution by awarding him £1,200 (equivalent to £0 in 2021) a year for life. Bureaucracy, however, prevented him from receiving the full benefit of this award. He was appointed to the office of colonel-commandant, Royal Artillery, on 6 March 1827. He rose to the rank of lieutenant general on 10 January 1837.

Shrapnel lived at Peartree House, near Peartree Green, Southampton, from about 1835 until his death.

title: Henry Shrapnel


text:
Dominus Iesus

Dominus Iesus (The Lord Jesus) is a declaration by the Congregation for the Doctrine of the Faith (previously known as the "Holy Office"), approved in a plenary meeting of the Congregation and signed by its then prefect, Joseph Cardinal Ratzinger (later Pope Benedict XVI), and its then-secretary, Archbishop Tarcisio Bertone. The declaration was approved by Pope John Paul II and was published on August 6, 2000.

It is known for its elaboration of the Catholic dogma that the Catholic Church is the sole true Church founded by Jesus Christ.

Background
The Catholic dogma extra ecclesiam nulla salus (lit. '"no salvation outside the Church"') has sometimes been interpreted as denying salvation to non-Catholic Christians as well as non-Christians, though Catholic teaching has long stressed the possibility of salvation for persons invincibly ignorant (through no fault of their own) of the Catholic Church's necessity and thus not culpable for lacking communion with the Church.

The Second Vatican Council document Lumen gentium further affirmed that salvation could be available to people who had not even heard of Christ. However, all who gain salvation do so only by membership in the Catholic Church, whether that membership is ordinary (explicit) or by extraordinary means (implicit), such that any person who, despite "knowing that the Catholic Church was made necessary by Christ, would refuse to enter or to remain in it, [cannot] be saved."

Role of other religious communities
While affirming the teaching of Lumen gentium that the Catholic Church "is the single Church of Christ" and that "[t]his Church, constituted and organized as a society in the present world, subsists in the Catholic Church", Dominus Iesus offers further comments on what it means for the true Church to "subsist in" the Catholic Church. The document states that, "[w]ith the expression subsistit in, the Second Vatican Council sought to harmonize two doctrinal statements: on the one hand, that the Church of Christ, despite the divisions which exist among Christians, continues to exist fully only in the Catholic Church, and on the other hand, that 'outside of her structure, many elements can be found of sanctification and truth.'"

Non-Catholic Christians
The document reserves the word "Church" for bodies that have preserved a "valid episcopate and the genuine and integral substance of the Eucharistic mystery". Such bodies, which include the Eastern Orthodox, Oriental Orthodox and the Old Catholic Churches, "are true particular Churches", and the document affirms that "the Church of Christ is present and operative also in these Churches, even though they lack full communion with the Catholic Church, since they do not accept the Catholic doctrine of Primacy."

The document uses the term "ecclesial community" (from the Greek word ecclesia, meaning "church") rather than "Church" for those Christian bodies not named in the preceding paragraph, most notably including all Protestants. The document states that, although such Christian communities "are not Churches in the proper sense; however, those who are baptized in these communities are, by Baptism, incorporated in Christ and thus are in a certain communion, albeit imperfect, with the Church." It further states that such Christian communities, "though we believe they suffer from defects, have by no means been deprived of significance and importance in the mystery of salvation. For the spirit of Christ has not refrained from using them as means of salvation."

Non-Christian religions
The document declares that, although the Catholic Church is intended by God to be "the instrument for the salvation of humanity," such beliefs do not "lessen the sincere respect which the Church has for the religions of the world." It does, however, "rule out, in a radical way... a religious relativism which leads to the belief that 'one religion is as good as another'" which characterizes "indifferentism".

The document goes on to affirm the possibility that those who subscribe to non-Christian religions may eventually be saved while insisting that the means of such salvation must be by Christ through his Church, and not through the religion to which such a person subscribes: "If it is true that the followers of other religions can receive divine grace, it is also certain that they are in a gravely deficient situation in comparison with those who, in the Church, have the fullness of the means of salvation." The document then immediately reminds Christians that their more direct enjoyment of the means of salvation comes "not from their own merits, but from the grace of Christ. If they fail to respond in thought, word, and deed to that grace, not only shall they not be saved, but they shall be more severely judged." Thus, the document ultimately views such non-Catholic religions as non-salvific, since "all salvation comes from Christ the Head through the Church, His body", as the Second Vatican Council stated.

John Paul II
On 1 October 2000, during one of his angelus, Pope John Paul II stated he had approved Dominus Iesus "in a special way". He added: "This confession does not deny salvation to non-Christians, but points to its ultimate source in Christ, in whom man and God are united."

title: Dominus Iesus


text:
Liberation theology

Liberation theology is a theological approach emphasizing the "liberation of the oppressed". It engages in socio-economic analyses, with social concern for the poor and political liberation for oppressed peoples and addresses other forms of perceived inequality. Liberation theology was influential in Latin America, especially within Catholicism in the 1960s after the Second Vatican Council, where it became the political praxis of theologians such as Frei Betto, Gustavo Gutiérrez, Leonardo Boff, and Jesuits Juan Luis Segundo and Jon Sobrino, who popularized the phrase "preferential option for the poor".

"The option for the poor is simply the idea that, as reflected in canon law, 'The Christian faithful are also obliged to promote social justice and, mindful of the precept of the Lord, to assist the poor.' It indicates an obligation, on the part of those who would call themselves Christian, first and foremost to care for the poor and vulnerable."

This expression was used first by Jesuit Fr. General Pedro Arrupe in 1968 and soon after the World Synod of Catholic Bishops in 1971 chose as its theme "Justice in the World".

Latin America also produced Protestant advocates of liberation theology, such as Rubem Alves, José Míguez Bonino, and C. René Padilla, who in the 1970s called for integral mission, emphasizing evangelism and social responsibility.

Theologies of liberation have also developed in other parts of the world such as black theology in the United States and South Africa, Palestinian liberation theology, Dalit theology in India, Minjung theology in South Korea, as well as liberation theology in Ireland.

Latin American liberation theology
Liberation theology developed within the Catholic Church in Latin America in the 1960s, as a reaction to the poverty and social injustice in the region, which CEPAL deemed the most unequal in the world. The term was coined in 1971 by the Peruvian priest Gustavo Gutiérrez, who wrote one of the movement's defining books, A Theology of Liberation. Other exponents include Leonardo Boff of Brazil, and Jesuits Jon Sobrino of El Salvador and Juan Luis Segundo of Uruguay.

Latin American liberation theology influenced parts of the evangelical movement and Catholic bishops in the United States. Its reliance on "Marxism" led in the mid-1980s to an admonition by the Vatican's Congregation for the Doctrine of the Faith (CDF). While stating that "in itself, the expression 'theology of liberation' is a thoroughly valid term", the prefect Cardinal Ratzinger rejected certain forms of Latin American liberation theology for focusing on institutionalized or systemic sin and for identifying Catholic Church hierarchy in South America as members of the same privileged class that had long been oppressing Indigenous populations from the arrival of Pizarro onward.

Black theology
More or less at the same time as the initial publications of Latin American liberation theology are also found voices of Black liberation theology and feminist liberation theology. Black theology refers to a theological perspective which originated in some black churches in the United States and later in other parts of the world, which contextualizes Christianity in an attempt to help those of African descent overcome oppression. It especially focuses on the injustices committed against African Americans and black South Africans during American segregation and apartheid, respectively.

Black theology seeks to liberate people of colour from multiple forms of political, social, economic, and religious subjugation and views Christian theology as a theology of liberation—"a rational study of the being of God in the world in light of the existential situation of an oppressed community, relating the forces of liberation to the essence of the Gospel, which is Jesus Christ," writes James Hal Cone, one of the original advocates of the perspective. Black theology mixes Christianity with questions of civil rights, particularly as raised by the Black Power movement and the Black Consciousness Movement.

Dalit theology
Dalit theology is a branch of Christian theology that emerged among the Dalit castes in the Indian subcontinent in the 1980s. It shares a number of themes with Latin American liberation theology, which arose two decades earlier, including a self-identity as a people undergoing Exodus. Dalit theology sees hope in the "Nazareth Manifesto" of Luke 4, where Jesus speaks of preaching "good news to the poor ... freedom for the prisoners and recovery of sight for the blind" and of releasing "the oppressed".

Palestinian liberation theology
Palestinian liberation theology is an expression of political theology and a contextual theology that represents an attempt by a number of independently working Palestinian theologians from various denominations—mostly Protestant mainline churches—to articulate the gospel message in such a way as to make that liberating gospel relevant to the perceived needs of their Indigenous flocks. As a rule, this articulation involves a theological underpinning of Palestinian resistance to Israel as well as Palestinian national aspirations, and an intense valorization of Palestinian ethnic and cultural identity as guarantors of a truer grasp of the gospel by virtue of the fact that they are inhabitants of the land of Jesus and the Bible. The principal figure in Palestinian liberation theology is the Anglican cleric Naim Ateek, founder of the Sabeel Ecumenical Liberation Theology Center in Jerusalem.

The Northern Ireland Troubles and armed struggle
In Ireland, liberation theology has been associated with the ideas and praxis of the Belfast Roman Catholic priest Des Wilson. Following the onset of the Northern Ireland Troubles, Wilson defended the right of communities systematically failed by the state, the churches and other institutions to create "alternative education, alternative welfare, alternative theatre, broadcasting, theological and political discussion, public inquiries and much else". More controversially, citing the example of Brazilian archbishop Hélder Câmara, he argued that this right extended to "alternative police and alternative armies".

During the military dictatorship in Brazil, Câmara, who called on clergy to engage in the struggle for justice without fear of identification with the revolutionary left ("When I give food to the poor, they call me a saint. When I ask why they are poor, they call me a communist"), refused to condemn armed resistance. In a famous interview with Italian journalist Oriana Fallaci, he explained that while it was not his choice ("not my road, not my way to apply the Gospels"), he would never say "to use weapons against an oppressor is immoral or anti-Christian".

Wilson argued that a church, not itself pacifist (as a schoolchild he recalls being taught to revere General Franco as a soldier of Christ), needed to develop a new "theology of pacifism". Acknowledging the predicament of those who had "a duty to protect others--their families their homes", this would need to do more than satisfy the needs of "an oppressive government or of people seeking undemanding respectability".

Peace movement
The Christian peace movement has been associated with liberation theology in many ways. Participating theologians have been in all continents and countries, including countries with Christian minorities. A central theme has been peace as a way of redemption and liberation.

title: Liberation theology