Nitrogen is the chemical element with the symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772. Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is accorded the credit because his work was published first; the name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790, when it was found that nitrogen was present in nitric acid and nitrates. Antoine Lavoisier suggested instead the name azote, from the Greek ἀζωτικός "no life", as it is an asphyxiant gas. Nitrogen is the lightest member of group 15 of the periodic table called the pnictogens; the name comes from the Greek πνίγειν "to choke", directly referencing nitrogen's asphyxiating properties. It is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2.

Dinitrogen forms about 78 % of Earth's atmosphere. Nitrogen occurs in all organisms in amino acids, in the nucleic acids and in the energy transfer molecule adenosine triphosphate; the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds back into the atmosphere. Many industrially important compounds, such as ammonia, nitric acid, organic nitrates, cyanides, contain nitrogen; the strong triple bond in elemental nitrogen, the second strongest bond in any diatomic molecule after carbon monoxide, dominates nitrogen chemistry. This causes difficulty for both organisms and industry in converting N2 into useful compounds, but at the same time means that burning, exploding, or decomposing nitrogen compounds to form nitrogen gas releases large amounts of useful energy. Synthetically produced ammonia and nitrates are key industrial fertilisers, fertiliser nitrates are key pollutants in the eutrophication of water systems.

Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric and cyanoacrylate used in superglue. Nitrogen is a constituent including antibiotics. Many drugs are mimics or prodrugs of natural nitrogen-containing signal molecules: for example, the organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolizing into nitric oxide. Many notable nitrogen-containing drugs, such as the natural caffeine and morphine or the synthetic amphetamines, act on receptors of animal neurotransmitters. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus, they were well known by the Middle Ages. Alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts; the mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the king of metals. The discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air.

Though he did not recognise it as an different chemical substance, he distinguished it from Joseph Black's "fixed air", or carbon dioxide. The fact that there was a component of air that does not support combustion was clear to Rutherford, although he was not aware that it was an element. Nitrogen was studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as "mephitic air" or azote, from the Greek word άζωτικός, "no life". In an atmosphere of pure nitrogen, animals died and flames were extinguished. Though Lavoisier's name was not accepted in English, since it was pointed out that all gases are mephitic, it is used in many languages and still remains in English in the common names of many nitrogen compounds, such as hydrazine and compounds of the azide ion, it led to the name "pnictogens" for the group headed by nitrogen, from the Greek πνίγειν "to choke".

The English word nitrogen entered the language from the French nitrogène, coined in 1790 by French chemist Jean-Antoine Chaptal, from the French nitre and the French suffix -gène, "producing", from the Greek -γενής. Chaptal's meaning was that nitrogen is the essential part of nitric acid, which in turn was produced from nitre. In earlier times, niter had been confused with Egyptian "natron" – called νίτρον in Greek – which, despite the name, contained no nitrate; the earliest military and agricultural applications of nitrogen compounds used saltpeter, most notably in gunpowder, as fertiliser. In 1910, Lord Rayleigh discovered that an electrical discharge in nitrogen gas produced "active nitrogen", a monatomic allotrope of nitrogen; the "whirling cloud of brilliant yell

Michael Ellam

Michael James Ellam is a British banker and former civil servant. Ellam was educated at Forest Hill School, before studying economics at Peterhouse, Cambridge from 1987 to 1990 and at the London School of Economics from 1990 to 1991. A career Civil Servant, he joined HM Treasury in 1993, he held a succession of posts including Private Secretary to Chancellor Kenneth Clarke, Head of Debt and Reserves Management and Director of Policy. He was appointed Director of Communications at 10 Downing Street under Gordon Brown from 2007 to 2009. In 2009, he returned to HM Treasury as Director General International Finance continuing into the premiership of David Cameron, he was appointed Chairman of the EU Financial Services Committee in 2011. He joined HSBC in 2013 and is Co-Head of Public Sector Banking in the Global Banking and Markets Division, he was awarded a Companion of the Order of the Bath by Her Majesty Queen Elizabeth II in 2014 for services to international finance policy. Michael Ellam on IMDb

Lu Tang

Lu Tang, courtesy name Ziming, was an army officer of the Ming dynasty in China. He participated in the suppression of the Jiajing wokou raids from 1547 to 1562, during which he fought the Portuguese smugglers who settled in pirate havens on the outlying islands of the Chinese coast; the Portuguese called him Luthissi, a combination of his surname Lu and the position he held, "dusi", or regional military commander. As a seasoned general, Lu Tang was a skilled strategist but suffered many setbacks on the battlefield, his career was not only affected by his military fortunes, but the fates of the numerous commanders that he served. A native of Runing, Henan, Lu Tang began his career by inheriting a minor military position from his father. By 1548, he rose to the post of Regional Military Commander of Fujian, where he gained the confidence of the Zhejiang grand coordinator Zhu Wan. On 15 April 1548, Zhu Wan ordered Lu Tang and Ke Qiao to lead a fleet from Wenzhou to attack the pirate haven Shuangyu, being used as a trading post by Chinese pirates and merchants from Japan and Portugal.

The fleet descended onto Shuangyu one night under the cover of thick weather. Fifty-five to a few hundred smugglers perished, but the lieutenants such as Li Guangtou and Wang Zhi were able to escape. Lu Tang razed the town and rendered the harbour permanently unusable by filling it in with stones under Zhu Wan's orders. Zhu Wan and his generals were rewarded in silver for the victory, but they drew the ire of his political enemies among the gentry, whose profits were directly affected by the destruction of Shuangyu. After the loss of Shuangyu, the smugglers scattered along the coast of Zhejiang and Fujian to find good hideouts to trade; the deep water inlet of Zoumaxi by the Dongshan Peninsula near the Fujian-Guangdong border was found to be a suitable place for trade since the terrain sheltered the ships from the winds. On 19 March 1549, Lu Tang and Ke Qiao ambushed two junks in Zoumaxi while the smugglers were trading with the Portuguese aboard. Lu and Ke lured the Portuguese guards away from the junks by feigning to attack from the shore set upon the junks the Ming fleet hidden behind a promontory.

The junks were captured after a brief and feeble resistance, resulting in 33 deaths and 206 smugglers captured. Among the captured were Li Guangtou and a number of Portuguese men, Lu Tang had four of the more good-looking Portuguese pretend to be kings of Malacca in order to make the victory seem more complete. Fearing that the captives might bribe their way out, Zhu Wan executed 96 of the Chinese smugglers using his discretionary powers; the Portuguese record of this incident by the crewman Galeote Pereira allege that Lu Tang, Ke Qiao, Zhu Wan exaggerated their victory in hopes of being rewarded with the goods they found on the junks, killed the Chinese crew to prevent the ruse of the "Malaccan" kings from being exposed. On April 27, Zhu Wan was impeached for exceeding his authority since executions had to be sanctioned by the emperor; the Jiajing Emperor ordered a full investigation on the matter. Seeing that the odds were against him, Zhu Wan committed suicide by drinking poison in January 1550.

The investigation uncovered the ruse of the "Malaccan" kings, so Lu Tang and Ke Qiao were put in prison and condemned to death for their part in the affair, while the Portuguese smugglers were exiled to Guizhou. The death of Zhu Wan was followed by the wholesale reversion of his policies. For three years the position held by Zhu Wan remained vacant, the wokou raiders took full advantage of the military vacuum. In 1552, the Grand Coordinator of Shandong Wang Yu was summoned to take Zhu Wan's old grand coordinator position in Zhejiang in the face of the escalating wokou crisis; as grand coordinator, Wang Yu released Lu Tang and Ke Qiao from prison to make use of their experience against the wokou. However, Wang Yu's armies suffered repeated defeats during his tenure, while Lu Tang suffered military defeats against the pirates off the coast of Zhejiang in 1554. For this, Wang Yu and Lu Tang were sacked from office for their failure. A short time Lu Tang was recalled to serve under Zhang Jing, the new supreme commander of the six coastal provinces from Shandong to Guangxi.

He was put in charge of the Miao troops from Baojing, won a spectacular victory at Wangjiangjing in May 1555 with the generals Yu Dayou and Tang Kekuan. In September that year he captured the pirate chief Lin Bichuan, he continued fighting in the field despite his superiors being replaced three times over two years, came to serve under a supreme commander stable in his position, Hu Zongxian. Under Hu Zongxian, Lu Tang participated in the suppression of the raid of 1556, where he won a decisive victory in Taizhou south of Ningbo and helped defeat and kill the ringleader Xu Hai at the Shen Family Estate in late September, he took an active part in Hu's plan to capture the most powerful pirate lord Wang Zhi, cooking up schemes such as using the offer of free trade to induce Wang to surrender, attempting to turn Wang's Japanese collaborators against him. Wang Zhi surrendered in 1557 and was executed in 1559. However, Lu Tang was impeached for chasing the pirates away from the coast instead of annihilating them.

He was demoted, but was reinstated in his post of regional commander of the Southern Metropolitan Region and Zhejiang through the influence of Tang Shunzhi, the vice director of the bureau of operations. In addition, Lu Tang was recognized for his role in the capture of Wang Zhi, was promoted in rank to vice commissioner-in-ch