Construction and use.

Standard or "low-form" (A) beakers typically have a height about 1.4 times the diameter. The common low form with a spout was devised by John Joseph Griffin and is therefore sometimes called a Griffin beaker. These are the most universal character and are used for various purposes—from preparing solutions and decanting supernatant fluids to holding waste fluids prior to disposal to performing simple reactions. Low form beakers are likely to be used in some way when performing a chemical experiment. "Tall-form" (B) beakers have a height about twice their diameter. These are sometimes called Berzelius beakers and are mostly used for titration. Flat beakers (C) are often called "crystallizers" because most are used to perform crystallization, but they are also often used as a vessel for use in hot-bath heating. These beakers usually do not have a flat scale.  The presence of a spout means that the beaker cannot have a lid. However, when in use, beakers may be covered by a watch glass to prevent contamination or loss of the contents, but allowing venting via the spout. Alternatively, a beaker may be covered with another larger beaker that has been inverted, though a watch glass is preferable.  Beakers are often "graduated", that is, marked on the side with lines indicating the volume contained. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL of volume. These marks are not intended for obtaining a precise measurement of volume (a graduated cylinder or a volumetric flask would be a more appropriate instrument for such a task), but rather an estimation. Most beakers are accurate to within ~10%.

Standards.

DIN EN ISO 3819:2015-12 defines the following types and sizes:

In laboratory equipment, a beaker is generally a cylindrical container with a flat bottom. Most also have a small spout (or "beak") to aid pouring, as shown in the picture. Beakers are available in a wide range of sizes, from one millilitre up to several litres. A beaker is distinguished from a flask by having straight rather than sloping sides. The exception to this definition is a slightly conical-sided beaker called a Philips beaker. The beaker shape in general drinkware is similar.

烧杯是一种常见的实验室玻璃器皿,在绝大多数实验中都会使用到,材质为玻璃或者耐热玻璃,也有用塑料制成的。烧杯呈圆柱形,上方敞口且具有翻边,便于夹持,并且具有散发热量和增加机械程度的作用,顶部的一侧开有一个槽口,便于倾倒液体,底平且烧杯底和烧杯侧面的连接部分为弧形,便于刮取烧杯底部内边缘的物质。大部分烧杯外壁还标有刻度,可以粗略的估计烧杯中液体的体积。烧杯经常用来溶解固体配置溶液、加热液体和作为较大量的试剂的反应容器。


History.

Predecessors.

The heavily armed carrack, first developed in Portugal for either trade or war in the Atlantic Ocean, was the precursor of the "ship of the line". Other maritime European states quickly adopted it in the late 15th and early 16th centuries. These vessels were developed by fusing aspects of the cog of the North Sea and galley of the Mediterranean Sea. The cogs, which traded in the North Sea, in the Baltic Sea and along the Atlantic coasts, had an advantage over galleys in battle because they had raised platforms called "castles" at bow and stern that archers could occupy to fire down on enemy ships or even to drop heavy weights from. Over time these castles became higher and larger, and eventually were built into the structure of the ship, increasing overall strength. This aspect of the cog remained in the newer-style carrack designs and proved its worth in battles like that at Diu in 1509.  The "Mary Rose" was an early 16th-century English carrack or "great ship". She was heavily armed with 78 guns and 91 after an upgrade in the 1530s. Built in Portsmouth in 1510–1512, she was one of the earliest purpose-built men-of-war in the English navy. She was over 500 tons burthen, had a keel of over 32 m (106 ft) and a crew of over 200 sailors, 185 soldiers and 30 gunners. Although the pride of the English fleet, she accidentally sank during the Battle of the Solent, 19 July 1545.  "Henri Grâce à Dieu" (English: "Henry Grace of God"), nicknamed "Great Harry", was another early English carrack. Contemporary with "Mary Rose", "Henri Grâce à Dieu" was 165 feet (50 m) long, weighing 1,000–1,500 tons and having a complement of 700–1,000. It is said that she was ordered by Henry VIII in response to the Scottish ship "Michael", launched in 1511. She was originally built at Woolwich Dockyard from 1512 to 1514 and was one of the first vessels to feature gunports and had twenty of the new heavy bronze cannon, allowing for a broadside. In all, she mounted 43 heavy guns and 141 light guns. She was the first English two-decker, and when launched she was the largest and most powerful warship in Europe, but she saw little action. She was present at the Battle of the Solent against Francis I of France in 1545 (in which "Mary Rose" sank) but appears to have been more of a diplomatic vessel, sailing on occasion with sails of gold cloth. Indeed, the great ships were almost as well known for their ornamental design (some ships, like the "Vasa", were gilded on their stern scrollwork) as they were for the power they possessed.  Carracks fitted for war carried large-calibre guns aboard. Because of their higher freeboard and greater load-bearing ability, this type of vessel was better suited than the galley to gunpowder weapons. Because of their development for conditions in the Atlantic, these ships were more weatherly than galleys and better suited to open waters. The lack of oars meant that large crews were unnecessary, making long journeys more feasible. Their disadvantage was that they were entirely reliant on the wind for mobility. Galleys could still overwhelm great ships, especially when there was little wind and they had a numerical advantage, but as great ships increased in size, galleys became less and less useful.  Another detriment was the high forecastle, which interfered with the sailing qualities of the ship; the bow would be forced low into the water while sailing before the wind. But as guns were introduced and gunfire replaced boarding as the primary means of naval combat during the 16th century, the medieval forecastle was no longer needed, and later ships such as the galleon had only a low, one-deck-high forecastle. By the time of the 1637 launching of England's "Sovereign of the Seas", the forecastle had disappeared altogether.  During the 16th century the galleon evolved from the carrack. It was a longer and more manoeuvrable type of ship with all the advantages of the carrack. The main ships of the English and Spanish fleets in the Battle of Gravelines of 1588 were galleons; all of the English and most of the Spanish galleons survived the battle and the following storm even though the Spanish galleons suffered the heaviest attacks from the English while regrouping their scattered fleet. By the 17th century every major European naval power was building ships like these.  With the growing importance of colonies and exploration and the need to maintain trade routes across stormy oceans, galleys and galleasses (a larger, higher type of galley with side-mounted guns, but lower than a galleon) were used less and less, and only in ever more restricted purposes and areas, so that by about 1750, with a few notable exceptions, they were of little use in naval battles.

Line-of-battle adoption.

King Erik XIV of Sweden initiated construction of the ship "Mars" in 1563; this might have been the first attempt of this battle tactic, roughly 50 years ahead of widespread adoption of the line of battle strategy. "Mars" was likely the largest ship in the world at the time of her build, equipped with 107 guns at a full length of 96 meters. Ironically it became the first ship to be sunk by gunfire from other ships in a naval battle.  In the early to mid-17th century, several navies, particularly those of the Netherlands and England, began to use new fighting techniques. Previously battles had usually been fought by great fleets of ships closing with each other and fighting in whatever arrangement they found themselves in, often boarding enemy vessels as opportunities presented themselves. As the use of broadsides (coordinated fire by the battery of cannon on one side of a warship) became increasingly dominant in battle, tactics changed. The evolving "line-of-battle" tactic, first used in an ad-hoc way, required ships to form single-file lines and close with the enemy fleet on the same tack, battering the enemy fleet until one side had had enough and retreated. Any manoeuvres would be carried out with the ships remaining in line for mutual protection.  In order that this order of battle, this long thin line of guns, may not be injured or broken at some point weaker than the rest, there is at the same time felt the necessity of putting in it only ships which, if not of equal force, have at least equally strong sides. Logically it follows, at the same moment in which the line ahead became definitively the order for battle, there was established the distinction between the ships 'of the line', alone destined for a place therein, and the lighter ships meant for other uses.  The lighter ships were used for various functions, including acting as scouts, and relaying signals between the flagship and the rest of the fleet. This was necessary because from the flagship, only a small part of the line would be in clear sight.  The adoption of line-of-battle tactics had consequences for ship design. The height advantage given by the castles fore and aft was reduced, now that hand-to-hand combat was less essential. The need to manoeuvre in battle made the top weight of the castles more of a disadvantage. So they shrank, making the ship of the line lighter and more manoeuvrable than its forebears for the same combat power. As an added consequence, the hull itself grew larger, allowing the size and number of guns to increase as well.

Evolution of design.

In the 17th century fleets could consist of almost a hundred ships of various sizes, but by the middle of the 18th century, ship-of-the-line design had settled on a few standard types: older two-deckers (i.e., with two complete decks of guns firing through side ports) of 50 guns (which were too weak for the battle line but could be used to escort convoys), two-deckers of between 64 and 90 guns that formed the main part of the fleet, and larger three- or even four-deckers with 98 to 140 guns that served as admirals' command ships. Fleets consisting of perhaps 10 to 25 of these ships, with their attendant supply ships and scouting and messenger frigates, kept control of the sea lanes for major European naval powers whilst restricting the sea-borne trade of enemies.  The most common size of sail ship of the line was the "74" (named for its 74 guns), originally developed by France in the 1730s, and later adopted by all battleship navies. Until this time the British had 6 sizes of ship of the line, and they found that their smaller 50- and 60-gun ships were becoming too small for the battle line, while their 80s and over were three-deckers and therefore unwieldy and unstable in heavy seas. Their best were 70-gun three-deckers of about 46 metres (150 ft) long on the gundeck, while the new French 74s were around 52 metres (170 ft). In 1747 the British captured a few of these French ships during the War of Austrian Succession. In the next decade Thomas Slade (Surveyor of the navy from 1755, along with co-Surveyor William Bately) broke away from the past and designed several new classes of 51- to 52-metre 74s to compete with these French designs, starting with the "Dublin" and "Bellona" classes. Their successors gradually improved handling and size through the 1780s. Other navies ended up building 74s also as they had the right balance between offensive power, cost, and manoeuvrability. Eventually around half of Britain's ships of the line were 74s. Larger vessels were still built, as command ships, but they were more useful only if they could definitely get close to an enemy, rather than in a battle involving chasing or manoeuvring. The 74 remained the favoured ship until 1811, when Seppings's method of construction enabled bigger ships to be built with more stability.  In a few ships the design was altered long after the ship was launched and in service. In the Royal Navy, smaller two-deck 74- or 64-gun ships of the line that could not be used safely in fleet actions had their upper decks removed (or "razeed"), resulting in a very stout, single-gun-deck warship called a "razee". The resulting razeed ship could be classed as a frigate and was still much stronger. The most successful razeed ship in the Royal Navy was HMS "Indefatigable", commanded by Sir Edward Pellew.  "Mahmudiye" (1829), ordered by the Ottoman Sultan Mahmud II and built by the Imperial Naval Arsenal on the Golden Horn in Istanbul, was for many years the largest warship in the world. The ship of the line was armed with 128 cannons on three decks and was manned by 1,280 sailors. She participated in the Siege of Sevastopol (1854–1855) during the Crimean War (1854–1856). She was decommissioned in 1874.  The second largest sailing three-decker ship of the line ever built in the West and the biggest French ship of the line was the "Valmy", launched in 1847. She had right sides, which increased significantly the space available for upper batteries, but reduced the stability of the ship; wooden stabilisers were added under the waterline to address the issue. "Valmy" was thought to be the largest sort of sailing ship possible, as larger dimensions made the manoeuvre of riggings impractical with mere manpower. She participated in the Crimean War, and after her return to France later housed the French Naval Academy under the name "Borda" from 1864 to 1890.

Steam power.

The first major change to the ship-of-the-line concept was the introduction of steam power as an auxiliary propulsion system. The first military uses of steamships came in the 1810s, and in the 1820s a number of navies experimented with paddle steamer warships. Their use spread in the 1830s, with paddle-steamer warships participating in conflicts like the First Opium War alongside ships of the line and frigates.  Paddle steamers, however, had major disadvantages. The paddle wheel above the waterline was exposed to enemy fire, while itself preventing the ship from firing broadsides effectively. During the 1840s, the screw propeller emerged as the most likely method of steam propulsion, with both Britain and the US launching screw-propelled warships in 1843. Through the 1840s, the British and French navies launched ever larger and more powerful screw ships, alongside sail-powered ships of the line. In 1845, Viscount Palmerston gave an indication of the role of the new steamships in tense Anglo-French relations, describing the English Channel as a "steam bridge", rather than a barrier to French invasion. It was partly because of the fear of war with France that the Royal Navy converted several old 74-gun ships of the line into 60-gun steam-powered blockships (following the model of Fulton's "Demologos"), starting in 1845. The blockships were "originally conceived as steam batteries solely for harbour defence, but in September 1845 they were given a reduced [sailing] rig rather than none at all, to make them sea-going ships.... The blockships were to be a cost-effective experiment of great value." They subsequently gave good service in the Crimean War.  The French Navy, however, developed the first purpose-built steam battleship with the 90-gun "Le Napoléon" in 1850. She is also considered the first true steam battleship, and the first screw battleship ever. "Napoleon" was armed as a conventional ship of the line, but her steam engines could give her a speed of 12 knots (22 km/h), regardless of the wind conditions—a potentially decisive advantage in a naval engagement.  Eight sister ships to "Le Napoléon" were built in France over a period of ten years, but the United Kingdom soon took the lead in production, in number of both purpose-built and converted units. Altogether, France built 10 new wooden steam battleships and converted 28 from older battleship units, while the United Kingdom built 18 and converted 41.  In the end, France and Britain were the only two countries to develop fleets of wooden steam screw battleships, although several other navies made some use of a mixture of screw battleships and paddle-steamer frigates. These included Russia, Turkey, Sweden, Naples, Prussia, Denmark, and Austria.

Decline.

In the Crimean War, six line-of-battle ships and two frigates of the Russian Black Sea Fleet destroyed seven Ottoman frigates and three corvettes with explosive shells at the Battle of Sinop in 1853.  In the 1860s unarmoured steam line-of-battle ships were replaced by ironclad warships. In the US civil war, on March 8, 1862, during the first day of the Battle of Hampton Roads, two unarmoured US wooden frigates were sunk and destroyed by the Confederate ironclad CSS "Virginia".  However, the power implied by the ship of the line would find its way into the ironclad, which would develop during the next few decades into the concept of the battleship.  Several navies still use terms equivalent to the "ship of the line" for battleships, such as German Navy ("Linienschiff") and Russian Navy ("lineyniy korabl`" (лине́йный кора́бль) or "linkor" (линкор) in short).

Combat.

In the North Sea and Atlantic Ocean, the fleets of England and later Great Britain, the Netherlands, France, Spain and Portugal fought numerous battles. In the Baltic Sea, Sweden, Denmark, the Netherlands, and Russia did likewise, while in the Mediterranean Sea, the Ottoman Empire, Venice, Spain, France, Britain and Russia battled.  During the Napoleonic Wars, the UK's Royal Navy established itself as the supreme world naval power by defeating a Spanish fleet near Cape St Vincent in 1797, a French fleet at the Bay of Aboukir off the Egyptian coast at the Battle of the Nile in 1798, a combined Franco-Spanish fleet near Cape Trafalgar in Spain at the Battle of Trafalgar in 1805, and the Danish fleet in the bombardment of Copenhagen in the second Battle of Copenhagen (1807). The UK emerged from the Napoleonic Wars in 1815 with the largest and most professional navy in the world, composed of hundreds of wooden, sail-powered ships of all sizes and classes. The Royal Navy demonstrated this naval supremacy again during the Crimean War in the 1850s.  Nonetheless, the Napoleonic Wars, as well as the American War of 1812, had illustrated the shortcomings of ships of the line when an enemy resorted to tactics including the large-scale use of privateers. Both the French and the Americans had demonstrated what a menace small, lightly armed, but fast, nimble, and, most especially, numerous vessels like sloops and schooners could be when they spread across the wide oceans, operating singly or in small groups. They targeted the merchant shipping that was Britain's economic lifeblood, and ships of the line were too few, too slow, and too clumsy to be employed against them.  Overwhelming firepower was of no use if it could not be brought to bear: the Royal Navy's initial response to Napoleon's privateers, which operated from French New World territories, was to buy Bermuda sloops. Similarly, the East India Company's merchant vessels became lightly armed and quite competent in combat during this period, operating a convoy system under an armed merchantman, instead of depending on small numbers of more heavily armed ships.

Restorations and preservation.

The only original ship of the line remaining today is HMS "Victory", preserved as a museum in Portsmouth to appear as she was while under Admiral Horatio Nelson at the Battle of Trafalgar in 1805. Although "Victory" is in drydock, she is still a fully commissioned warship in the Royal Navy and is the oldest commissioned warship in any navy worldwide.  "Regalskeppet Vasa" sank in the Baltic in 1628 and was lost until 1956. She was then raised intact, in remarkably good condition, in 1961 and is presently on display at the Vasa Museum in Stockholm, Sweden. At the time she was the largest Swedish warship ever built. Today the "Vasa" Museum is the most visited museum in Sweden.

A ship of the line was a type of naval warship constructed from the 17th century to the mid-19th century. The ship of the line was designed for the naval tactic known as the line of battle, which depended on the two columns of opposing warships maneuvering to fire with the cannons along their broadsides. In conflicts where opposing ships were both able to fire from their broadsides, the opponent with more cannons—and therefore more firepower—typically had an advantage. Since these engagements were almost invariably won by the heaviest ships carrying the most powerful guns, the natural progression was to build sailing vessels that were the largest and most powerful of their time.

风帆战列舰(英语:ship of the line)是见于17世纪至19世纪中期的一种大型的木质帆船,是风帆时代海军的主力舰。其主要武器,即射程和精度都有限的火炮,主要安装于低层甲板,与龙骨成直角,通过舷侧炮眼向外开火。风向对它的战斗性能有很大的影响,在战斗中,军舰之间的通信也由于噪音和烟雾的影响而相当困难。这些条件和战争实践在17世纪中叶产生的结论是在战斗中,军舰必须始终排成纵列,在通过敌舰附近时侧舷齐射。强大到足以列于这条战列线中的军舰就称为战列舰,风帆战列舰有两层或三层火炮甲板,装有50门以上门甚至上百门各种口径的火炮。最常见的是装有74门火炮的船型。典型的74门炮风帆战列舰排水量达1630吨,长52米,宽14米,吃水7米,有700名船员。19世纪上半叶,蒸汽机和螺旋桨也被应用于风帆战列舰,1850年下水的法国海军拿破仑号()是世界上第一艘使用蒸汽动力的战列舰,同时也保留了风帆。1860年代开始,风帆战列舰被铁甲舰所代替。


History.

Establishment.

Calcutta (now Kolkata) was the capital of India during the British Raj, until December 1911. Calcutta had become the centre of the nationalist movements since the late nineteenth century, which led to the Partition of Bengal by then Viceroy of British India, Lord Curzon. This created massive political and religious upsurge including political assassinations of British officials in Calcutta. The anti-colonial sentiments amongst the public led to complete boycott of British goods, which forced the colonial government to reunite Bengal and immediately shift the capital to New Delhi.  Old Delhi had served as the political and financial centre of several empires of ancient India and the Delhi Sultanate, most notably of the Mughal Empire from 1649 to 1857. During the early 1900s, a proposal was made to the British administration to shift the capital of the British Indian Empire, as India was officially named, from Calcutta on the east coast, to Delhi. The Government of British India felt that it would be logistically easier to administer India from Delhi, which is in the centre of northern India. The land for building the new city of Delhi was acquired under the Land Acquisition Act 1894.  During the Delhi Durbar on 12 December 1911, George V, then Emperor of India, along with Queen Mary, his consort, made the announcement that the capital of the Raj was to be shifted from Calcutta to Delhi, while laying the foundation stone for the viceroy's residence in the Coronation Park, Kingsway Camp. The foundation stone of New Delhi was laid by King George V and Queen Mary at the site of Delhi Durbar of 1911 at Kingsway Camp on 15 December 1911, during their imperial visit. Large parts of New Delhi were planned by Edwin Lutyens, who first visited Delhi in 1912, and Herbert Baker, both leading 20th-century British architects. The contract was given to Sobha Singh. The original plan called for its construction in Tughlaqabad, inside the Tughlaqabad Fort, but this was given up because of the Delhi-Calcutta trunk line that passed through the fort. Construction really began after World War I and was completed by 1931. The city that was later dubbed "Lutyens' Delhi" was inaugurated in ceremonies beginning on 10 February 1931 by Lord Irwin, the Viceroy. Lutyens designed the central administrative area of the city as a testament to Britain's imperial aspirations.  Soon Lutyens started considering other places. Indeed, the Delhi Town Planning Committee, set up to plan the new imperial capital, with George Swinton as chairman, and John A. Brodie and Lutyens as members, submitted reports for both north and south sites. However, it was rejected by the Viceroy when the cost of acquiring the necessary properties was found to be too high. The central axis of New Delhi, which today faces east at India Gate, was previously meant to be a north–south axis linking the Viceroy's House at one end with Paharganj at the other. Eventually, owing to space constraints and the presence of a large number of heritage sites in the north side, the committee settled on the south site. A site atop the Raisina Hill, formerly Raisina Village, a Meo village, was chosen for the Rashtrapati Bhawan, then known as the Viceroy's House. The reason for this choice was that the hill lay directly opposite the Dinapanah citadel, which was also considered the site of Indraprastha, the ancient region of Delhi. Subsequently, the foundation stone was shifted from the site of Delhi Durbar of 1911–1912, where the Coronation Pillar stood, and embedded in the walls of the forecourt of the Secretariat. The Rajpath, also known as King's Way, stretched from the India Gate to the Rashtrapati Bhawan. The Secretariat building, the two blocks of which flank the Rashtrapati Bhawan and houses ministries of the government of India, and the Parliament House, both designed by Baker, are located at the Sansad Marg and run parallel to the Rajpath.  In the south, land up to Safdarjung's Tomb was acquired to create what is today known as Lutyens' Bungalow Zone. Before construction could begin on the rocky ridge of Raisina Hill, a circular railway line around the Council House (now Parliament House), called the "Imperial Delhi Railway", was built to transport construction material and workers for the next twenty years. The last stumbling block was the Agra-Delhi railway line that cut right through the site earmarked for the hexagonal All-India War Memorial (India Gate) and Kingsway (Rajpath), which was a problem because the Old Delhi Railway Station served the entire city at that time. The line was shifted to run along the Yamuna river, and it began operating in 1924. The New Delhi Railway Station opened in 1926, with a single platform at Ajmeri Gate near Paharganj, and was completed in time for the city's inauguration in 1931. As construction of the Viceroy's House (the present Rashtrapati Bhavan), Central Secretariat, Parliament House, and All-India War Memorial (India Gate) was winding down, the building of a shopping district and a new plaza, Connaught Place, began in 1929, and was completed by 1933. Named after Prince Arthur, 1st Duke of Connaught (1850–1942), it was designed by Robert Tor Russell, chief architect to the Public Works Department (PWD).  After the capital of India moved to Delhi, a temporary secretariat building was constructed in a few months in 1912 in North Delhi. Most of the government offices of the new capital moved here from the 'Old secretariat' in Old Delhi (the building now houses the Delhi Legislative Assembly), a decade before the new capital was inaugurated in 1931. Many employees were brought into the new capital from distant parts of India, including the Bengal Presidency and Madras Presidency. Subsequently, housing for them has developed around Gole Market area in the 1920s. Built in the 1940s, to house government employees, with bungalows for senior officials in the nearby Lodhi Estate area, Lodhi colony near historic Lodhi Gardens, was the last residential areas built by the British Raj.

Post-independence.

After India gained independence in 1947, limited autonomy was conferred to New Delhi and was administered by a Chief Commissioner appointed by the Government of India. In 1966, Delhi was converted into a union territory and eventually the Chief Commissioner was replaced by a Lieutenant Governor. The Constitution (Sixty-ninth Amendment) Act, 1991 declared the Union Territory of Delhi to be formally known as National Capital Territory of Delhi. A system was introduced under which the elected government was given wide powers, excluding law and order which remained with the Central Government. The actual enforcement of the legislation came in 1993.  The first major extension of New Delhi outside of Lutyens' Delhi came in the 1950s when the Central Public Works Department (CPWD) developed a large area of land southwest of Lutyens' Delhi to create the diplomatic enclave of Chanakyapuri, where land was allotted for embassies, chanceries, high commissions and residences of ambassadors, around a wide central vista, "Shanti Path".

Geography.

With a total area of, New Delhi forms a small part of the Delhi metropolitan area. Since the city is located on the Indo-Gangetic Plain, there is little difference in elevation across the city. New Delhi and surrounding areas were once a part of the Aravali Range; all that is left of those mountains is the Delhi Ridge, which is also called the Lungs of Delhi. While New Delhi lies on the floodplains of the Yamuna River, it is essentially a landlocked city. East of the river is the urban area of Shahdara. New Delhi falls under the seismic zone-IV, making it vulnerable to earthquakes.

Seismology.

New Delhi lies on several fault lines and thus experiences frequent earthquakes, most of them of mild intensity. There was a spike in the number of earthquakes between 2011 and 2015, most notable being a 5.4 magnitude earthquake in 2015 with its epicentre in Nepal, a 4.7-magnitude earthquake on 25 November 2007, a 4.2-magnitude earthquake on 7 September 2011, a 5.2-magnitude earthquake on 5 March 2012, and a swarm of twelve earthquakes, including four of magnitudes 2.5, 2.8, 3.1, and 3.3, on 12 November 2013.

Climate.

The climate of New Delhi is a hot semi-arid climate (Köppen "BSh") bordering on a dry-winter humid subtropical climate (Köppen "Cwa") with high variation between summer and winter in terms of both temperature and rainfall. The temperature varies from in summers to around in winters. The area's version of a humid subtropical climate is noticeably different from many other cities with this climate classification in that it features long and very hot summers with dust storms, relatively dry and mild winters with wildfire haze, and a monsoonal period. Summers are long, extending from early April to October, with the monsoon season occurring in the middle of the summer. Winter starts in November and peaks in January. The annual mean temperature is around ; monthly daily mean temperatures range from approximately. New Delhi's highest temperature ever recorded is on 26 May 1998 while the lowest temperature ever recorded is on 11 January 1967, both of which are recorded at Indira Gandhi International Airport (formerly known as Palam Airport). The average annual rainfall is, most of which is during the monsoons in July and August.

Air quality.

In Mercer's 2015 annual quality-of-living survey, New Delhi ranks at number 154 out of 230 cities due to bad air quality and pollution. The World Health Organization ranked New Delhi as the world's worst polluted city in 2014 among about 1,600 cities the organisation tracked around the world. In 2016, United States Environmental Protection Agency listed New Delhi as the most polluted city on Earth.  In an attempt to lessen air pollution in New Delhi, which gets worse during the winter, a temporary alternate-day travel scheme for cars using the odd- and even-numbered licence plates system was announced by Delhi government in December 2015. In addition, trucks were to be allowed to enter India's capital only after 11 pm, two hours later than the existing restriction. The driving restriction scheme was planned to be implemented as a trial from 1 January 2016 for an initial period of 15 days. The restriction was in force between 8 am and 8 pm, and traffic was not restricted on Sundays. Public transportation service was increased during the restriction period.  On 16 December 2015, the Supreme Court of India mandated several restrictions on Delhi's transportation system to curb pollution. Among the measures, the court ordered to stop registrations of diesel cars and sport utility vehicles with an engine capacity of 2,000 cc and over until 31 March 2016. The court also ordered all taxis in the Delhi region to switch to compressed natural gas by 1 March 2016. Transportation vehicles that are more than 10 years old were banned from entering the capital.  Analysing real-time vehicle speed data from Uber Delhi revealed that during the odd-even program, average speeds went up by a statistically significant 5.4 per cent (2.8 standard deviation from normal). This means vehicles have lesser idling time in traffic and vehicle engines would run closer to minimum fuel consumption. "In bordering areas, PM 2.5 levels were recorded more than 400 (ug/m3) while in inner areas in Delhi, they were recorded between 150 and 210 on an average." However, the subcity of Dwarka, located in the southwest district, has a substantially low level of air pollution. At the NSIT University campus, located in sector 3 Dwarka, pollution levels were as low as 93 PPM.  On 7 November 2017, the Indian Medical Association declared a public health emergency due to high pollution levels. The highest being in the Punjabi Bagh district with an air quality index of 999 and in the RK Puram district with an index of 852. The lowest index recorded was in the Anand Vihar district with an index of 319. Levels of PM2.5 were recorded at 710 μg/m3, more than 11 times the World Health Organization's safe limit.  In a 2018 study, New Delhi was found to be the most polluted capital out of 61 capital cities around the world.  In December 2019, IIT Bombay, in partnership with the McKelvey School of Engineering of Washington University in St. Louis, launched the Aerosol and Air Quality Research Facility to study air pollution in New Delhi, among other Indian cities.

Demographics.

As of 2011, New Delhi city (the area under NDMC) has a population of 257,803 while New Delhi district has a population of 142,004. Hindi is the most widely spoken language in New Delhi and the lingua franca of the city. English is primarily used as the formal language by business and government institutes. New Delhi has a literacy rate of 89.38% according to 2011 census, which is the highest in Delhi.

Religion.

According to 2011 census, Hinduism is the religion of 89.8% of New Delhi's population. There are also communities of Muslims (4.5%), Christians (2.9%), Sikhs (2.0%), Jains (0.4%). Other religious groups include Parsis, Buddhists and Jews.

Government.

The national capital of India, New Delhi is jointly administered by both the Central Government of India and the local Government of Delhi, it is also the capital of the National Capital Territory (NCT) of Delhi. , the government structure of the New Delhi Municipal Council includes a chairperson, three members of New Delhi's Legislative Assembly, two members nominated by the Chief Minister of the NCT of Delhi and five members nominated by the central government.  The head of state of Delhi is the lieutenant governor of the Union Territory of Delhi, appointed by the president of India on the advice of the Central government and the post is largely ceremonial, as the chief minister of the Union Territory of Delhi is the head of government and is vested with most of the executive powers. According to the Indian constitution, if a law passed by Delhi's legislative assembly is repugnant to any law passed by the Parliament of India, then the law enacted by the parliament will prevail over the law enacted by the assembly.  New Delhi is governed through a municipal government, known as the New Delhi Municipal Council (NDMC). Other urban areas of the metropolis of Delhi are administered by the Municipal Corporation of Delhi (MCD). However, the entire metropolis of Delhi is commonly known as New Delhi in contrast to Old Delhi.

Economy.

New Delhi is the largest commercial city in northern India. It has an estimated net State Domestic Product (FY 2010) of in nominal terms and ~ in PPP terms., the per capita income of Delhi was Rs. 230000, second highest in India after Goa. GSDP in Delhi at the current prices for 2012–13 is estimated at Rs 3.88 trillion (short scale) against Rs 3.11 trillion (short scale) in 2011–12.  Connaught Place, one of North India's largest commercial and financial centres, is located in the northern part of New Delhi. Adjoining areas such as Barakhamba Road, ITO are also major commercial centres. Government and quasi-government sector was the primary employer in New Delhi. The city's service sector has expanded due in part to the large skilled English-speaking workforce that has attracted many multinational companies. Key service industries include information technology, telecommunications, hotels, banking, media, and tourism.  The 2011 World Wealth Report ranks economic activity in New Delhi at 39, but overall the capital is ranked at 37, above cities like Jakarta and Johannesburg. New Delhi with Beijing shares the top position as the most targeted emerging markets retail destination among Asia-Pacific markets.  The government of National Capital Territory of Delhi does not release any economic figures specifically for New Delhi but publishes an official economic report on the whole of Delhi annually. According to the "Economic Survey of Delhi", the metropolis has a net State Domestic Product (SDP) of Rs. 830.85 billion (for the year 2004–05) and a per capita income of Rs. 53,976 ($1,200). In the year 2008–09 New Delhi had a per capita Income of Rs. ($2,595).It grew by 16.2% to reach Rs. ($3,018) in 2009–10 fiscal. New Delhi's per capita GDP (at PPP) was at $6,860 during 2009–10 fiscal, making it one of the richest cities in India. The tertiary sector contributes 78.4% of Delhi's gross SDP followed by secondary and primary sectors with 20.2% and 1.4% contribution respectively.  The gross state domestic product (GSDP) of Delhi at current prices for the year 2011–12 has been estimated at Rs 3.13 trillion (short scale), which is an increase of 18.7 percent over the previous fiscal.

Culture.

New Delhi is a cosmopolitan city due to the multi-ethnic and multi-cultural presence of the vast Indian bureaucracy and political system. The city's capital status has amplified the importance of national events and holidays. National events such as Republic Day, Independence Day and "Gandhi Jayanti" (Gandhi's birthday) are celebrated with great enthusiasm in New Delhi and the rest of India. On India's Independence Day (15 August) the Prime Minister of India addresses the nation from the Red Fort. Most Delhiites celebrate the day by flying kites, which are considered a symbol of freedom. The Republic Day Parade is a large cultural and military parade showcasing India's cultural diversity and military might.  Religious festivals include Diwali (the festival of light), Maha Shivaratri, Teej, Durga Puja, Mahavir Jayanti, Guru Nanak Jayanti, Holi, Lohri, Eid ul-Fitr, Eid ul-Adha, Raksha Bandhan, and Christmas. The Qutub Festival is a cultural event during which performances of musicians and dancers from all over India are showcased at night, with the Qutub Minar as the chosen backdrop of the event. Other events such as Kite Flying Festival, International Mango Festival and "Vasant Panchami" (the Spring Festival) are held every year in Delhi.  In 2007, the Japanese Buddhist organisation Nipponzan Myohoji decided to build a Peace Pagoda in the city containing Buddha relics. It was inaugurated by the current Dalai Lama.

Historic sites, museums and gardens.

New Delhi is home to several historic sites and museums. The National Museum which began with an exhibition of Indian art and artefacts at the Royal Academy in London in the winter of 1947–48 was later at the end was shown at the Rashtrapati Bhawan in 1949. Later it was to form a permanent National Museum. On 15 August 1949, the National Museum was formally inaugurated and currently has 200,000 works of art, both of Indian and foreign origin, covering over 5,000 years.  The India Gate built in 1931 was inspired by the Arc de Triomphe in Paris. It is the national monument of India commemorating the 90,000 soldiers of the Indian Army who lost their lives while fighting for the British Raj in World War I and the Third Anglo-Afghan War. The monument is barricaded now with entry to inside arch restricted.  The Rajpath which was built similar to the Champs-Élysées in Paris is the ceremonial boulevard for the Republic of India located in New Delhi. The annual Republic Day parade takes place here on 26 January. The Beating retreat takes place here two days later. Gandhi Smriti in New Delhi is the location where Mahatma Gandhi spent the last 144 days of his life and was assassinated on 30 January 1948. Rajghat is the place where Mahatma Gandhi was cremated on 31 January 1948 after his assassination and his ashes were buried and make it a final resting place beside the sanctity of the Yamuna River. The Raj Ghat in the shape of large square platform with black marble was designed by architect Vanu Bhuta.  Jantar Mantar located in Connaught Place was built by Maharaja Jai Singh II of Jaipur. It consists of 13 architectural astronomy instruments. The primary purpose of the observatory was to compile astronomical tables, and to predict the times and movements of the sun, moon and planets.  New Delhi is home to Indira Gandhi Memorial Museum, National Gallery of Modern Art, National Museum of Natural History, National Rail Museum, National Handicrafts and Handlooms Museum, National Philatelic Museum, Nehru Planetarium, Shankar's International Dolls Museum. and Supreme Court of India Museum,  In the coming years, a new National War Memorial and Museum will be constructed in New Delhi for.  New Delhi is particularly renowned for its beautifully landscaped gardens that can look quite stunning in spring. The largest of these include Buddha Jayanti Park and the historic Lodi Gardens. In addition, there are the gardens in the Presidential Estate, the gardens along the Rajpath and India Gate, the gardens along Shanti Path, the Rose Garden, Nehru Park and the Railway Garden in Chanakya Puri. Also of note is the garden adjacent to the Jangpura Metro Station near the Defence Colony Flyover, as are the roundabout and neighbourhood gardens throughout the city.  The New Delhi Municipal Council (NDMC) area was declared the cleanest in North India, based on solid waste management, access to sanitation and other parameters of cleanliness, under the zone-wise Swachh Survekshan 2017.

Transport.

Air.

Indira Gandhi International Airport, situated to the southwest of Delhi, is the main gateway for the city's domestic and international civilian air traffic. In 2012–13, the airport was used by more than 35 million passengers, making it one of the busiest airports in South Asia. Terminal 3, which cost to construct between 2007 and 2010, handles an additional 37 million passengers annually.  The Delhi Flying Club, established in 1928 with two de Havilland Moth aircraft named "Delhi" and "Roshanara", was based at "Safdarjung Airport" which started operations in 1929, when it was the Delhi's only airport and the second in India. The airport functioned until 2001, however in January 2002 the government closed the airport for flying activities because of security concerns following the New York attacks in September 2001. Since then, the club only carries out aircraft maintenance courses, and is used for helicopter rides to Indira Gandhi International Airport for VIP including the president and the prime minister.  In 2010, Indira Gandhi International Airport (IGIA) was conferred the fourth best airport award in the world in the 15–25 million category, and "Best Improved Airport" in the Asia-Pacific Region by Airports Council International. The airport was rated as the "Best airport in the world" in the 25–40 million passengers category in 2015, by Airports Council International. Delhi Airport also bags two awards for "The Best Airport in Central Asia/India" and "Best Airport Staff in Central Asia/India" at the Skytrax World Airport Awards 2015.

Road.

New Delhi has one of India's largest bus transport systems. Buses are operated by the state-owned Delhi Transport Corporation (DTC), which owns largest fleet of compressed natural gas (CNG)-fueled buses in the world. Personal vehicles especially cars also form a major chunk of vehicles plying on New Delhi roads. New Delhi has the highest number of registered cars compared to any other metropolitan city in India. Taxis and Auto Rickshaws also ply on New Delhi roads in large numbers. New Delhi has one of the highest road density in India and average vehicle speed is around in peak hours in the city.  Some roads and expressways serve as important pillars of New Delhi's road infrastructure:  National Highways passing through New Delhi  New Delhi is connected by road to the rest of India through National highways:

Railway.

New Delhi is a major junction in the Indian railway network and is the headquarters of the Northern Railway. The five main railway stations are New Delhi railway station, Old Delhi, Nizamuddin Railway Station, Anand Vihar Railway Terminal and Sarai Rohilla. The Delhi Metro, a mass rapid transit system built and operated by Delhi Metro Rail Corporation (DMRC), serves many parts of Delhi and the neighbouring cities Faridabad, Ghaziabad, Gurgaon and Noida. As of December 2016, the metro consists of six operational lines with a total length of and 160 stations. Several other lines are under construction and expected to be commissioned in 2017 adding another 150 km length. It carries almost three million passengers every day. In addition to the Delhi Metro, a suburban railway, the Delhi Suburban Railway exists.

Metro.

The Delhi Metro is a rapid transit system serving Delhi, Faridabad, Ghaziabad, Gurgaon and Noida in the National Capital Region of India. Delhi Metro is the world's 12th largest metro system in terms of length. Delhi Metro was India's first modern public transportation system, which had revolutionised travel by providing a fast, reliable, safe, and comfortable means of transport. Presently, the Delhi Metro network consists of of track, with 160 stations along with six more stations of the Airport Express Link. The network has now crossed the boundaries of Delhi to reach Ghaziabad and Noida in Uttar Pradesh, and Faridabad and Gurgaon in Haryana. All stations have escalators, elevators, and tactile tiles to guide the visually impaired from station entrances to trains. It has a combination of elevated, at-grade, and underground lines, and uses both broad gauge and standard gauge rolling stock. Four types of rolling stock are used: Mitsubishi-ROTEM Broad gauge, Bombardier MOVIA, Mitsubishi-ROTEM Standard gauge, and CAF Beasain Standard gauge. According to a study, Delhi Metro has helped in removing about 390,000 vehicles from the streets of Delhi.  Delhi Metro is being built and operated by the Delhi Metro Rail Corporation Limited (DMRC), a state-owned company with equal equity participation from Government of India and Government of National Capital Territory of Delhi. However, the organisation is under administrative control of Ministry of Urban Development, Government of India. Besides construction and operation of Delhi metro, DMRC is also involved in the planning and implementation of metro rail, monorail and high-speed rail projects in India and providing consultancy services to other metro projects in the country as well as abroad. The Delhi Metro project was spearheaded by Padma Vibhushan E. Sreedharan, the managing director of DMRC and popularly known as the "Metro Man" of India. He famously resigned from DMRC, taking moral responsibility for a metro bridge collapse which took five lives. Sreedharan was awarded with the prestigious Legion of Honour by the French government for his contribution to Delhi Metro.

Cityscape.

Much of New Delhi, planned by the leading 20th-century British architect Edwin Lutyens, was laid out to be the central administrative area of the city as a testament to Britain's imperial ambitions. New Delhi is structured around two central promenades called the Rajpath and the Janpath. The Rajpath, or King's Way, stretches from the Rashtrapati Bhavan to the India Gate. The Janpath (Hindi: "Path of the People"), formerly Queen's Way, begins at Connaught Circus and cuts the Rajpath at right angles. 19 foreign embassies are located on the nearby Shantipath (Hindi: "Path of Peace"), making it the largest diplomatic enclave in India.  At the heart of the city is the magnificent Rashtrapati Bhavan (formerly known as Viceroy's House) which sits atop Raisina Hill. The Secretariat, which houses ministries of the government of India, flanks out of the Rashtrapati Bhavan. The Parliament House, designed by Herbert Baker, is located at the Sansad Marg, which runs parallel to the Rajpath. Connaught Place is a large, circular commercial area in New Delhi, modelled after the Royal Crescent in England. Twelve separate roads lead out of the outer ring of Connaught Place, one of them being the Janpath.

Architecture.

The New Delhi town plan, like its architecture, was chosen with one single chief consideration: to be a symbol of British power and supremacy. All other decisions were subordinate to this, and it was this framework that dictated the choice and application of symbology and influences from both Hindu and Islamic architecture.  It took about 20 years to build the city from 1911. Many elements of New Delhi architecture borrow from indigenous sources; however, they fit into a British Classical/Palladian tradition. The fact that there were any indigenous features in the design were due to the persistence and urging of both the Viceroy Lord Hardinge and historians like E.B. Havell.

Sports.

The city hosted the 2010 Commonwealth Games and annually hosts Delhi Half Marathon foot-race. The city has previously hosted the 1951 Asian Games and the 1982 Asian Games. New Delhi was interested in bidding for the 2019 Asian Games but was turned down by the government on 2 August 2010 amid allegations of corruption in 2010 Commonwealth Games. Major sporting venues in New Delhi include the Jawaharlal Nehru Stadium, Ambedkar Stadium, Indira Gandhi Indoor Stadium, Arun Jaitley Stadium, R.K. Khanna Tennis Complex, Dhyan Chand National Stadium and Siri Fort Sports Complex.

International relations and organisations.

The city is home to numerous international organisations. The Asian and Pacific Centre for Transfer of Technology of the UNESCAP servicing the Asia-Pacific region is headquartered in New Delhi. New Delhi is home to most UN regional offices in India namely the UNDP, UNODC, UNESCO, UNICEF, WFP, UNV, UNCTAD, FAO, UNFPA, WHO, World Bank, ILO, IMF, UNIFEM, IFC and UNAIDS. UNHCR Representation in India is also located in the city.  New Delhi hosts 145 foreign embassies and high commissions.  United Nations Conference on Trade and Development hosted its second meeting conference in the year 1968 at New Delhi.  New Delhi hosted the 7th NAM Summit in 1983, 4th BRICS Summit in 2012 and the IBSA Summit in 2015. It will also host 5th Global Conference on CyberSpace in November 2017. India will also host the G20 summit in 2022 in New Delhi.

New Delhi (, "Naī Dillī") is an urban district located in the city of Delhi. New Delhi serves as the capital of India and the seat of all three branches of the Government of India.

新德里(又名纽德里,;英语:New Delhi)是印度的首都。位于印度西北部,座落在恒河支流亚穆纳河西岸,东北紧连德里旧城(沙贾汉纳巴德)。整个德里国家首都辖区市面积1482平方公里,人口1637万(2011年);其中新德里人口13.37万。2013年4月「世界城市区域研究」(Demographia World Urban Areas)发布第9届调查报告,世界大都市依照人口数排名第4,2282万人。新德里是全国的政治、经济和文化中心。新德里是典型的放射型城市,城市以姆拉斯广场为中心,城市街道成辐射状、蛛网式地伸向四面八方。宏伟的建筑群大多集中于市中心。政府主要机构集中在市区从总统府到印度门之间绵延几公里的宽阔大道两旁。国会大厦为大圆盘式建筑,四周绕以白色大理石高大圆柱,是中亚式的建筑,屋檐和柱头的雕饰又为印度风格。总统府屋顶为巨大的半球形结构,带有莫卧儿王朝的遗风。城市西端的康瑙特市场建筑新巧,呈圆盘形,是新德里的最大商业中心。新德里还是全国交通的中心,有5条国家级公路、6条铁路与各地相通,还建有两座机场。


History.

Archaeological evidence indicates that the use of medicinal plants dates back to the Paleolithic age, approximately 60,000 years ago. Written evidence of herbal remedies dates back over 5,000 years to the Sumerians, who compiled lists of plants. Some ancient cultures wrote about plants and their medical uses in books called "herbals". In ancient Egypt, herbs are mentioned in Egyptian medical papyri, depicted in tomb illustrations, or on rare occasions found in medical jars containing trace amounts of herbs. Among the oldest, lengthiest, and most important medical papyri of ancient Egypt, the Ebers Papyrus dates from about 1550 BC, and covers more than 700 compounds, mainly of plant origin. The earliest known Greek herbals came from Theophrastus of Eresos who, in the 4th century BC, wrote in Greek "Historia Plantarum", from Diocles of Carystus who wrote during the 3rd century BC, and from Krateuas who wrote in the 1st century BC. Only a few fragments of these works have survived intact, but from what remains, scholars noted overlap with the Egyptian herbals. Seeds likely used for herbalism were found in archaeological sites of Bronze Age China dating from the Shang Dynasty (c. 1600–1046 BC). Over a hundred of the 224 compounds mentioned in the "Huangdi Neijing", an early Chinese medical text, are herbs. Herbs also commonly featured in the traditional medicine of ancient India, where the principal treatment for diseases was diet. "De Materia Medica", originally written in Greek by Pedanius Dioscorides (c. 40–90 AD) of Anazarbus, Cilicia, a Greek physician, pharmacologist and botanist, is one example of herbal writing which was used for 1500 years until the 1600s.

Modern herbal medicine.

The World Health Organization (WHO) estimates that 80 percent of the population of some Asian and African countries presently use herbal medicine for some aspect of primary health care. Pharmaceuticals are prohibitively expensive for most of the world's population, half of whom lived on less than $2 U.S. per day in 2002. In comparison, herbal medicines can be grown from seed or gathered from nature for little or no cost.  Many of the pharmaceuticals currently available to physicians have a long history of use as herbal remedies, including artemisinin, opium, aspirin, digitalis, and quinine. According to the World Health Organization, approximately 25% of modern drugs used in the United States have been derived from plants. At least 7,000 medical compounds in the modern pharmacopoeia are derived from plants. Among the 120 active compounds currently isolated from the higher plants and widely used in modern medicine today, 80% show a positive correlation between their modern therapeutic use and the traditional use of the plants from which they are derived.

Clinical tests.

In a 2010 global survey of the most common 1000 plant-derived compounds, 156 had clinical trials published. Preclinical studies (cell culture and animal studies) were reported for about one-half of the plant products, while 120 (12%) of the plants evaluated – although available in the Western market – had no rigorous studies of their properties, and five were toxic or allergenic, a finding that led the authors to conclude "their use ought to be discouraged or forbidden." Nine plants evaluated in human clinical research included "Althaea officinalis" (marshmallow), "Calendula officinalis" (marigold), "Centella asiatica" (centella), "Echinacea purpurea" (echinacea), "Passiflora incarnata" (passionflower), "Punica granatum" (pomegranate), "Vaccinium macrocarpon" (cranberry), "Vaccinium myrtillus" (bilberry), and "Valeriana officinalis" (valerian), although generally there were inconsistent, often negative results, and the studies were of low quality.  In 2015, the Australian Government's Department of Health published the results of a review of alternative therapies that sought to determine if any were suitable for being covered by health insurance; Herbalism was one of 17 topics evaluated for which no clear evidence of effectiveness was found. Establishing guidelines to assess safety and efficacy of herbal products, the European Medicines Agency provides criteria for evaluating and grading the quality of clinical research in preparing monographs about herbal products. In the United States, the National Center for Complementary and Integrative Health of the National Institutes of Health funds clinical trials on herbal compounds, provides fact sheets evaluating the safety, potential effectiveness and side effects of many plant sources, and maintains a registry of clinical research conducted on herbal products.  According to Cancer Research UK as of 2015, "there is currently no strong evidence from studies in people that herbal remedies can treat, prevent or cure cancer".

Prevalence of use.

The use of herbal remedies is more prevalent in patients with chronic diseases such as cancer, diabetes, asthma and end-stage kidney disease. Multiple factors such as gender, age, ethnicity, education and social class are also shown to have association with prevalence of herbal remedies use.  A survey released in May 2004 by the National Center for Complementary and Integrative Health focused on who used complementary and alternative medicines (CAM), what was used, and why it was used. The survey was limited to adults, aged 18 years and over during 2002, living in the United States. According to this survey, herbal therapy, or use of natural products other than vitamins and minerals, was the most commonly used CAM therapy (18.9%) when all use of prayer was excluded.  Herbal remedies are very common in Europe. In Germany, herbal medications are dispensed by apothecaries (e.g., Apotheke). Prescription drugs are sold alongside essential oils, herbal extracts, or herbal teas. Herbal remedies are seen by some as a treatment to be preferred to pure medical compounds that have been industrially produced.  In India the herbal remedy is so popular that the government of India has created a separate department—AYUSH—under the Ministry of Health & Family Welfare. The National Medicinal Plants Board was also established in 2000 by the Indian government in order to deal with the herbal medical system.

Herbal preparations.

There are many forms in which herbs can be administered, the most common of which is in the form of a liquid that is drunk by the patient—either an herbal tea or a (possibly diluted) plant extract.  Several methods of standardization may be determining the amount of herbs used. One is the ratio of raw materials to solvent. However different specimens of even the same plant species may vary in chemical content. For this reason, thin layer chromatography is sometimes used by growers to assess the content of their products before use. Another method is standardization on a signal chemical. Herbal teas, or tisanes, are the resultant liquid of extracting herbs into water, though they are made in a few different ways. Infusions are hot water extracts of herbs, such as chamomile or mint, through steeping. Decoctions are the long-term boiled extracts, usually of harder substances like roots or bark. Maceration is the cold infusion of plants with high mucilage-content, such as sage or thyme. To make macerates, plants are chopped and added to cold water. They are then left to stand for 7 to 12 hours (depending on herb used). For most macerates, 10 hours is used.  Tinctures are alcoholic extracts of herbs, which are generally stronger than herbal teas. Tinctures are usually obtained by combining 100% pure ethanol (or a mixture of 100% ethanol with water) with the herb. A completed tincture has an ethanol percentage of at least 25% (sometimes up to 90%). Non-alcoholic tinctures can be made with glycerin but it is believed to be less absorbed by the body than alcohol based tinctures and has a shorter shelf life. Herbal wine and elixirs are alcoholic extract of herbs, usually with an ethanol percentage of 12–38%. Extracts include liquid extracts, dry extracts, and nebulisates. Liquid extracts are liquids with a lower ethanol percentage than tinctures. They are usually made by vacuum distilling tinctures. Dry extracts are extracts of plant material that are evaporated into a dry mass. They can then be further refined to a capsule or tablet.  The exact composition of an herbal product is influenced by the method of extraction. A tea will be rich in polar components because water is a polar solvent. Oil on the other hand is a non-polar solvent and it will absorb non-polar compounds. Alcohol lies somewhere in between. Many herbs are applied topically to the skin in a variety of forms. Essential oil extracts can be applied to the skin, usually diluted in a carrier oil. Many essential oils can burn the skin or are simply too high dose used straight; diluting them in olive oil or another food grade oil such as almond oil can allow these to be used safely as a topical. Salves, oils, balms, creams and lotions are other forms of topical delivery mechanisms. Most topical applications are oil extractions of herbs. Taking a food grade oil and soaking herbs in it for anywhere from weeks to months allows certain phytochemicals to be extracted into the oil. This oil can then be made into salves, creams, lotions, or simply used as an oil for topical application. Many massage oils, antibacterial salves, and wound healing compounds are made this way.  Inhalation, as in aromatherapy, can be used as a treatment.

Safety.

A number of herbs are thought to be likely to cause adverse effects. Furthermore, "adulteration, inappropriate formulation, or lack of understanding of plant and drug interactions have led to adverse reactions that are sometimes life threatening or lethal." Proper double-blind clinical trials are needed to determine the safety and efficacy of each plant before they can be recommended for medical use. Although many consumers believe that herbal medicines are safe because they are "natural", herbal medicines and synthetic drugs may interact, causing toxicity to the patient. Herbal remedies can also be dangerously contaminated, and herbal medicines without established efficacy, may unknowingly be used to replace medicines that do have corroborated efficacy.  Standardization of purity and dosage is not mandated in the United States, but even products made to the same specification may differ as a result of biochemical variations within a species of plant. Plants have chemical defense mechanisms against predators that can have adverse or lethal effects on humans. Examples of highly toxic herbs include poison hemlock and nightshade. They are not marketed to the public as herbs, because the risks are well known, partly due to a long and colorful history in Europe, associated with "sorcery", "magic" and intrigue. Although not frequent, adverse reactions have been reported for herbs in widespread use. On occasion serious untoward outcomes have been linked to herb consumption. A case of major potassium depletion has been attributed to chronic licorice ingestion., and consequently professional herbalists avoid the use of licorice where they recognize that this may be a risk. Black cohosh has been implicated in a case of liver failure. Few studies are available on the safety of herbs for pregnant women, and one study found that use of complementary and alternative medicines are associated with a 30% lower ongoing pregnancy and live birth rate during fertility treatment. Examples of herbal treatments with likely cause-effect relationships with adverse events include aconite, which is often a legally restricted herb, ayurvedic remedies, broom, chaparral, Chinese herb mixtures, comfrey, herbs containing certain flavonoids, germander, guar gum, liquorice root, and pennyroyal. Examples of herbs where a high degree of confidence of a risk long term adverse effects can be asserted include ginseng, which is unpopular among herbalists for this reason, the endangered herb goldenseal, milk thistle, senna, against which herbalists generally advise and rarely use, aloe vera juice, buckthorn bark and berry, cascara sagrada bark, saw palmetto, valerian, kava, which is banned in the European Union, St. John's wort, Khat, Betel nut, the restricted herb Ephedra, and Guarana.  There is also concern with respect to the numerous well-established interactions of herbs and drugs. In consultation with a physician, usage of herbal remedies should be clarified, as some herbal remedies have the potential to cause adverse drug interactions when used in combination with various prescription and over-the-counter pharmaceuticals, just as a patient should inform a herbalist of their consumption of orthodox prescription and other medication.  For example, dangerously low blood pressure may result from the combination of an herbal remedy that lowers blood pressure together with prescription medicine that has the same effect. Some herbs may amplify the effects of anticoagulants. Certain herbs as well as common fruit interfere with cytochrome P450, an enzyme critical to much drug metabolism.  In a 2018 study, FDA identified active pharmaceutical additives in over 700 of analyzed dietary supplements sold as "herbal", "natural" or "traditional". The undisclosed additives included "unapproved antidepressants and designer steroids", as well as prescription drugs, such as sildenafil or sibutramine.

Labeling accuracy.

A 2013 study found that one-third of herbal supplements sampled contained no trace of the herb listed on the label. The study found products adulterated with contaminants or fillers not listed on the label, including potential allergens such as soy, wheat, or black walnut. One bottle labeled as St. John's Wort was found to actually contain "Alexandrian senna", a laxative.  Researchers at the University of Adelaide found in 2014 that almost 20 per cent of herbal remedies surveyed were not registered with the Therapeutic Goods Administration, despite this being a condition for their sale. They also found that nearly 60 per cent of products surveyed had ingredients that did not match what was on the label. Out of 121 products, only 15 had ingredients that matched their TGA listing and packaging.  In 2015, the New York Attorney General issued cease and desist letters to four major U.S. retailers (GNC, Target, Walgreens, and Walmart) who were accused of selling herbal supplements that were mislabeled and potentially dangerous. Twenty-four products were tested by DNA barcoding as part of the investigation, with all but five containing DNA that did not match the product labels.

Practitioners of herbalism.

Herbalists must learn many skills, including the wildcrafting or cultivation of herbs, diagnosis and treatment of conditions or dispensing herbal medication, and preparations of herbal medications. Education of herbalists varies considerably in different areas of the world. Lay herbalists and traditional indigenous medicine people generally rely upon apprenticeship and recognition from their communities in lieu of formal schooling.  In some countries, formalized training and minimum education standards exist, although these are not necessarily uniform within or between countries. In Australia, for example, the self-regulated status of the profession (as of 2009) resulted in variable standards of training, and numerous loosely-formed associations setting different educational standards. One 2009 review concluded that regulation of herbalists in Australia was needed to reduce the risk of interaction of herbal medicines with prescription drugs, to implement clinical guidelines and prescription of herbal products, and to assure self-regulation for protection of public health and safety. In the United Kingdom, the training of herbalists is done by state funded universities offering Bachelor of Science degrees in herbal medicine.

Government regulations.

The World Health Organization (WHO), the specialized agency of the United Nations (UN) that is concerned with international public health, published "Quality control methods for medicinal plant materials" in 1998 in order to support WHO Member States in establishing quality standards and specifications for herbal materials, within the overall context of quality assurance and control of herbal medicines.  In the European Union (EU), herbal medicines are regulated under the Committee on Herbal Medicinal Products.  In the United States, herbal remedies are regulated dietary supplements by the Food and Drug Administration (FDA) under current good manufacturing practice (cGMP) policy for dietary supplements. Manufacturers of products falling into this category are not required to prove the safety or efficacy of their product so long as they do not make'medical' claims or imply uses other than as a 'dietary supplement', though the FDA may withdraw a product from sale should it prove harmful.  Canadian regulations are described by the Natural and Non-prescription Health Products Directorate which requires an eight-digit Natural Product Number or Homeopathic Medicine Number on the label of licensed herbal medicines or dietary supplements.  Some herbs, such as cannabis and coca, are outright banned in most countries though coca is legal in most of the South American countries where it is grown. The "Cannabis" plant is used as an herbal medicine, and as such is legal in some parts of the world. Since 2004, the sales of ephedra as a dietary supplement is prohibited in the United States by the FDA, and subject to Schedule III restrictions in the United Kingdom.

Scientific criticism.

Herbalism has been criticized as a potential "minefield" of unreliable product quality, safety hazards, and potential for misleading health advice. Globally, there are no standards across various herbal products to authenticate their contents, safety or efficacy, and there is generally an absence of high-quality scientific research on product composition or effectiveness for anti-disease activity. Presumed claims of therapeutic benefit from herbal products, without rigorous evidence of efficacy and safety, receive skeptical views by scientists.  Unethical practices by some herbalists and manufacturers, which may include false advertising about health benefits on product labels or literature, and contamination or use of fillers during product preparation, may erode consumer confidence about services and products.

Paraherbalism.

Paraherbalism is the pseudoscientific use of extracts of plant or animal origin as supposed medicines or health-promoting agents. Phytotherapy differs from plant-derived medicines in standard pharmacology because it does not isolate and standardize the compounds from a given plant believed to be biologically active. It relies on the false belief that preserving the complexity of substances from a given plant with less processing is safer and potentially more effective, for which there is no evidence either condition applies.  Phytochemical researcher Varro Eugene Tyler described paraherbalism as "faulty or inferior herbalism based on pseudoscience", using scientific terminology but lacking scientific evidence for safety and efficacy. Tyler listed ten fallacies that distinguished herbalism from paraherbalism, including claims that there is a conspiracy to suppress safe and effective herbs, herbs can not cause harm, that whole herbs are more effective than molecules isolated from the plants, herbs are superior to drugs, the doctrine of signatures (the belief that the shape of the plant indicates its function) is valid, dilution of substances increases their potency (a doctrine of the pseudoscience of homeopathy), astrological alignments are significant, animal testing is not appropriate to indicate human effects, anecdotal evidence is an effective means of proving a substance works and herbs were created by God to cure disease. Tyler suggests that none of these beliefs have any basis in fact.

Traditional systems.

Africa.

Up to 80% of the population in Africa uses traditional medicine as primary health care.

Americas.

Native Americans medicinally used about 2,500 of the approximately 20,000 plant species that are native to North America.

China.

Some researchers trained in both Western and traditional Chinese medicine have attempted to deconstruct ancient medical texts in the light of modern science. In 1972, Tu Youyou, a pharmaceutical chemist, extracted the anti-malarial drug artemisinin from sweet wormwood, a traditional Chinese treatment for intermittent fevers.

India.

In India, Ayurvedic medicine has quite complex formulas with 30 or more ingredients, including a sizable number of ingredients that have undergone "alchemical processing", chosen to balance dosha. In Ladakh, Lahul-Spiti and Tibet, the Tibetan Medical System is prevalent, also called the 'Amichi Medical System'. Over 337 species of medicinal plants have been documented by C.P. Kala. Those are used by Amchis, the practitioners of this medical system. The Indian book, Vedas, mentions treatment of diseases with plants.

Indonesia.

In Indonesia, especially among the Javanese, the jamu traditional herbal medicine is an age old tradition preserved for centuries. Jamu is thought to have originated in the Mataram Kingdom era, some 1300 years ago. The bas-reliefs on Borobudur depict the image of people grinding herbs with stone mortar and pestle, a drink seller, a physician and masseuse treating their clients. All of these scenes might be interpreted as a traditional herbal medicine and health-related treatments in ancient Java. The Madhawapura inscription from Majapahit period mentioned a specific profession of herbs mixer and combiner (herbalist), called "Acaraki". The medicine book from Mataram dated from circa 1700 contains 3,000 entries of jamu herbal recipes, while Javanese classical literature Serat Centhini (1814) describes some jamu herbal concoction recipes.  Though possibly influenced by Indian Ayurveda systems, Indonesia's vast archipelago holds numerous indigenous plants not to be found in India, including plants similar to those in Australia beyond the Wallace Line. Jamu practices may vary from region to region, and are often not written down, especially in remote areas of the country. Although primarily herbal, some Jamu materials are acquired from animals, such as honey, royal jelly, milk and "ayam kampung" eggs.

Philosophy.

Herbalists tend to use extracts from parts of plants, such as the roots or leaves, believing that plants are subject to environmental pressures and therefore develop resistance to threats such as radiation, reactive oxygen species and microbial attack in order to survive, providing defensive phytochemicals of use in herbalism.

Use of plants by animals.

Indigenous healers often claim to have learned by observing that sick animals change their food preferences to nibble at bitter herbs they would normally reject. Field biologists have provided corroborating evidence based on observation of diverse species, such as chickens, sheep, butterflies, and chimpanzees. The habit of changing diet has been shown to be a physical means of purging intestinal parasites. Lowland gorillas take 90% of their diet from the fruits of "Aframomum melegueta", a relative of the ginger plant, that is a potent antimicrobial and apparently keeps shigellosis and similar infections at bay. Current research focuses on the possibility that this plant also protects gorillas from fibrosing cardiomyopathy, which has a devastating effect on captive animals. Sick animals tend to forage plants rich in secondary metabolites, such as tannins and alkaloids.

Herbal medicine (also herbalism) is the study of botany and the use of medicinal plants. Plants have been the basis for medical treatments through much of human history, and such traditional medicine is still widely practiced today. Modern medicine makes use of many plant-derived compounds as the basis for evidence-based pharmaceutical drugs. Although herbalism may apply modern standards of effectiveness testing to herbs and medicines derived from natural sources, few high-quality clinical trials and standards for purity or dosage exist. The scope of herbal medicine is sometimes extended to include fungal and bee products, as well as minerals, shells and certain animal parts.

草药医学(英语:Herbal medicine,Herbalism),研究与使用植物于医疗用途的学问。它的范围除了植物之外,通常也可扩展到真菌、昆虫、甲壳类、动物及矿物。对所有由自然产生的药物进行研究的学科,称为生药学。


History.

Linus Torvalds developed the Linux kernel and distributed its first version, 0.01, in 1991. Linux was initially distributed as source code only, and later as a pair of downloadable floppy disk images one bootable and containing the Linux kernel itself, and the other with a set of GNU utilities and tools for setting up a file system. Since the installation procedure was complicated, especially in the face of growing amounts of available software, distributions sprang up to simplify this.  Early distributions included the following:  The two oldest and still active distribution projects started in 1993. The SLS distribution was not well maintained, so in July 1993 a new distribution, called Slackware and based on SLS, was released by Patrick Volkerding. Also dissatisfied with SLS, Ian Murdock set to create a free distribution by founding Debian, which had its first release in December 1993.  Users were attracted to Linux distributions as alternatives to the DOS and Microsoft Windows operating systems on IBM PC compatible computers, Mac OS on the Apple Macintosh, and proprietary versions of Unix. Most early adopters were familiar with Unix from work or school. They embraced Linux distributions for their low (if any) cost, and availability of the source code for most or all of the software included.  As of 2017, Linux has become more popular in server and embedded devices markets than in the desktop market. For example, Linux is used on over 50% of web servers, whereas its desktop market share is about 3.7%.

Components.

Many Linux distributions provide an installation system akin to that provided with other modern operating systems. On the other hand, some distributions, including Gentoo Linux, provide only the binaries of a basic kernel, compilation tools, and an installer; the installer compiles all the requested software for the specific architecture of the user's computer, using these tools and the provided source code.

Package management.

Distributions are normally segmented into "packages". Each package contains a specific application or service. Examples of packages are a library for handling the PNG image format, a collection of fonts or a web browser.  The package is typically provided as compiled code, with installation and removal of packages handled by a package management system (PMS) rather than a simple file archiver. Each package intended for such a PMS contains meta-information such as a package description, version, and "dependencies". The package management system can evaluate this meta-information to allow package searches, to perform an automatic upgrade to a newer version, to check that all dependencies of a package are fulfilled, and/or to fulfill them automatically.  Although Linux distributions typically contain much more software than proprietary operating systems, it is normal for local administrators to also install software not included in the distribution. An example would be a newer version of a software application than that supplied with a distribution, or an alternative to that chosen by the distribution (for example, KDE Plasma Workspaces rather than GNOME or vice versa for the user interface layer). If the additional software is distributed in source-only form, this approach requires local compilation. However, if additional software is locally added, the "state" of the local system may fall out of synchronization with the state of the package manager's database. If so, the local administrator will be required to take additional measures to ensure the entire system is kept up to date. The package manager may no longer be able to do so automatically.  Most distributions install packages, including the kernel and other core operating system components, in a predetermined configuration. Few now require or even permit configuration adjustments at first install time. This makes installation less daunting, particularly for new users, but is not always acceptable. For specific requirements, much software must be carefully configured to be useful, to work correctly with other software, or to be secure, and local administrators are often obliged to spend time reviewing and reconfiguring assorted software.  Some distributions go to considerable lengths to specifically adjust and customize most or all of the software included in the distribution. Not all do so. Some distributions provide configuration tools to assist in this process.  By replacing "everything" provided in a distribution, an administrator may reach a "distribution-less" state: everything was retrieved, compiled, configured, and installed locally. It is possible to build such a system from scratch, avoiding a distribution altogether. One needs a way to generate the first binaries until the system is "self-hosting". This can be done via compilation on another system capable of building binaries for the intended target (possibly by cross-compilation). For example, see Linux From Scratch.

Types and trends.

In broad terms, Linux distributions may be:  The diversity of Linux distributions is due to technical, organizational, and philosophical variation among vendors and users. The permissive licensing of free software means that any user with sufficient knowledge and interest can customize an existing distribution or design one to suit his or her own needs.

Rolling distributions.

Rolling Linux distributions are kept updated using small and frequent updates. Software contained in a rolling distribution's software stack is usually standard release, though.  Rolling releases can be either:  The terms "partially rolling" and "partly rolling" (along with synonyms "semi-rolling" and "half-rolling"), "fully rolling", "truly rolling" and "optionally rolling" are all standard terms used by software developers and users.  Repositories of rolling distributions usually contains very recent software releases – often the latest stable software releases available. They have pseudo-releases and installation media that are simply a snapshot of the software distribution at the time of the release of the installation image. Typically, a rolling release operating system installed from an older installation medium can be fully updated post-installation to a current state.  There are pros and cons to both standard release and rolling release software development methodologies.  In terms of the software development process, standard releases require significant development effort being spent on keeping old versions up to date due to propagating bug fixes back to the newest branch, versus focusing more on the newest development branch. Also, unlike rolling releases, standard releases require more than one code branch to be developed and maintained, which increases the software development and software maintenance workload of the software developers and software maintainers.  On the other hand, software features and technology planning are easier in standard releases due to a better understanding of upcoming features in the next version(s) rather than simply the whim of the developers at any given time. Software release cycles can also be synchronized with those of major upstream software projects, such as desktop environments.  As far as the user experience, standard releases are often viewed as more stable and bug-free since software conflicts can be more easily addressed and the software stack more thoroughly tested and evaluated, during the software development cycle. For this reason, they tend to be the preferred choice in enterprise environments and mission-critical tasks.  However, rolling releases offer more current software which can also provide increased stability and fewer software bugs along with the additional benefits of new features, greater functionality, faster running speeds, and improved system and application security. Regarding software security, the rolling release model can have advantages in timely security updates, fixing system or application security bugs and vulnerabilities, that standard releases may have to wait till the next release for or patch in various versions. In a rolling release distribution, where the user has "chosen" to run it as a highly dynamic system, the constant flux of software packages can introduce new unintended vulnerabilities.

Installation-free distributions (live CD/USB).

A "live" distribution is a Linux distribution that can be booted from removable storage media such as optical discs or USB flash drives, instead of being installed on and booted from a hard disk drive. The portability of installation-free distributions makes them advantageous for applications such as demonstrations, borrowing someone else's computer, rescue operations, or as installation media for a standard distribution.  When the operating system is booted from a read-only medium such as a CD or DVD, any user data that needs to be retained between sessions cannot be stored on the boot device but must be written to another storage device, such as a USB flash drive or a hard disk drive.  Many Linux distributions provide a "live" form in addition to their conventional form, which is a network-based or removable-media image intended to be used only for installation; such distributions include SUSE, Ubuntu, Linux Mint, MEPIS and Fedora. Some distributions, including Knoppix, Puppy Linux, Devil-Linux, SuperGamer, SliTaz GNU/Linux and, are designed primarily for live use. Additionally, some minimal distributions can be run directly from as little space as one floppy disk without the need to change the contents of the system's hard disk drive.

Examples.

The website DistroWatch lists many Linux distributions, and displays some of the ones that have the most web traffic on the site. The Wikimedia Foundation released an analysis of the browser User Agents of visitors to WMF websites until 2015, which includes details of the most popular Operating System identifiers, including some Linux distributions. Many of the popular distributions are listed below.

Lightweight distributions.

Lightweight Linux distributions are those that have been designed with support for older hardware in mind, allowing older hardware to still be used productively, or, for maximum possible speed in newer hardware by leaving more resources available for use by applications. Examples include Tiny Core Linux, Puppy Linux and Slitaz.

Niche distributions.

Other distributions target specific niches, such as:

Android and non-GNU distributions.

Whether Google's Android counts as a Linux distribution is a matter of definition. It uses the Linux kernel, so the Linux Foundation and Chris DiBona, Google's open source chief, agree that Android is a Linux distribution; others, such as Google engineer Patrick Brady, disagree by noting the lack of support for many GNU tools in Android, including glibc.  Other non-GNU distributions include Cyanogenmod, its fork LineageOS, Android-x86 and recently Tizen and Mer/Sailfish OS.

Interdistribution issues.

The Free Standards Group is an organization formed by major software and hardware vendors that aims to improve interoperability between different distributions. Among their proposed standards are the Linux Standard Base, which defines a common ABI and packaging system for Linux, and the Filesystem Hierarchy Standard which recommends a standard filenaming chart, notably the basic directory names found on the root of the tree of any Linux filesystem. Those standards, however, see limited use, even among the distributions developed by members of the organization.  The diversity of Linux distributions means that not all software runs on all distributions, depending on what libraries and other system attributes are required. Packaged software and software repositories are usually specific to a particular distribution, though cross-installation is sometimes possible on closely related distributions.

Tools for choosing a distribution.

The process of constantly switching between distributions is often referred to as "distro hopping". Virtual machines such as VirtualBox and VMware Workstation virtualize hardware allowing users to test live media on a virtual machine. Some websites like DistroWatch offer lists of popular distributions, and link to screenshots of operating systems as a way to get a first impression of various distributions.  There are tools available to help people select an appropriate distribution, such as several versions of the Linux Distribution Chooser, and the universal package search tool "whohas". There are easy ways to try out several Linux distributions before deciding on one: Multi Distro is a Live CD that contains nine space-saving distributions.

Installation.

There are several ways to install a Linux distribution. Nowadays, the most common method of installing Linux is by booting from a live USB memory stick, which can be created by using an USB image writer application and the ISO image, which can be downloaded from the various Linux distribution websites. DVD disks, CD disks, network installations and even other hard drives can also be used as "installation media".  Early Linux distributions were installed using sets of floppies but this has been abandoned by all major distributions. Nowadays most distributions offer CD and DVD sets with the vital packages on the first disc and less important packages on later ones. They usually also allow installation over a network after booting from either a set of floppies or a CD with only a small amount of data on it.  New users tend to begin by partitioning a hard drive in order to keep their previously installed operating system. The Linux distribution can then be installed on its own separate partition without affecting previously saved data.  In a Live CD setup, the computer boots the entire operating system from CD without first installing it on the computer's hard disk. Some distributions have a Live CD "installer", where the computer boots the operating system from the disk, and then proceeds to install it onto the computer's hard disk, providing a seamless transition from the OS running from the CD to the OS running from the hard disk.  Both servers and personal computers that come with Linux already installed are available from vendors including Hewlett-Packard, Dell and System76.  On embedded devices, Linux is typically held in the device's firmware and may or may not be consumer-accessible.  Anaconda, one of the more popular installers, is used by Red Hat Enterprise Linux, Fedora (which uses the Fedora Media Writer) and other distributions to simplify the installation process. Debian, Ubuntu and many others use Debian-Installer.

Installation via an existing operating system.

Some distributions let the user install Linux on top of their current system, such as WinLinux or coLinux. Linux is installed to the Windows hard disk partition, and can be started from inside Windows itself.  Virtual machines (such as VirtualBox or VMware) also make it possible for Linux to be run inside another OS. The VM software simulates a separate computer onto which the Linux system is installed. After installation, the virtual machine can be booted as if it were an independent computer.  Various tools are also available to perform full dual-boot installations from existing platforms without a CD, most notably:

Proprietary software.

Some specific proprietary software products are not available in any form for Linux. As of September 2015, the Steam gaming service has 1,500 games available on Linux, compared to 2,323 games for Mac and 6,500 Windows games. Emulation and API-translation projects like Wine and CrossOver make it possible to run non-Linux-based software on Linux systems, either by emulating a proprietary operating system or by translating proprietary API calls (e.g., calls to Microsoft's Win32 or DirectX APIs) into native Linux API calls. A virtual machine can also be used to run a proprietary OS (like Microsoft Windows) on top of Linux.

OEM contracts.

Computer hardware is usually sold with an operating system other than Linux already installed by the original equipment manufacturer (OEM). In the case of IBM PC compatibles the OS is usually Microsoft Windows; in the case of Apple Macintosh computers it has always been a version of Apple's OS, currently macOS; Sun Microsystems sold SPARC hardware with the Solaris installed; video game consoles such as the Xbox, PlayStation, and Wii each have their own proprietary OS. This limits Linux's market share: consumers are unaware that an alternative exists, they must make a conscious effort to use a different operating system, and they must either perform the actual installation themselves, or depend on support from a friend, relative, or computer professional.  However, it is possible to buy hardware with Linux already installed. Lenovo, Hewlett-Packard, Dell, Affordy, Purism, and System76 all sell general-purpose Linux laptops, and custom-order PC manufacturers will also build Linux systems (but possibly with the Windows key on the keyboard). Fixstars Solutions (formerly Terra Soft) sells Macintosh computers and PlayStation 3 consoles with Yellow Dog Linux installed.  It is more common to find embedded devices sold with Linux as the default manufacturer-supported OS, including the Linksys NSLU2 NAS device, TiVo's line of personal video recorders, and Linux-based cellphones (including Android smartphones), PDAs, and portable music players.  The current Microsoft Windows license lets the manufacturer determine the refund policy. With previous versions of Windows, it was possible to obtain a refund if the manufacturer failed to provide the refund by litigation in the small claims courts. On 15 February 1999, a group of Linux users in Orange County, California held a "Windows Refund Day" protest in an attempt to pressure Microsoft into issuing them refunds. In France, the Linuxfrench and AFUL (French speaking Libre Software Users' Association) organizations along with free software activist Roberto Di Cosmo started a "Windows Detax" movement, which led to a 2006 petition against "racketiciels" (translation: Racketware) with 39,415 signatories and the DGCCRF branch of the French government filing several complaints against bundled software. On March 24, 2014, a new international petition was launched by AFUL on the Avaaz platform, translated into several languages and supported by many organizations around the world.

Statistics.

There are no official figures on popularity, adoption, downloads or installed base of Linux distributions.  There are also no official figures for the total number of Linux systems, partly due to the difficulty of quantifying the number of PCs running Linux (see Desktop Linux#Measuring adoption), since many users download Linux distributions. Hence, the sales figures for Linux systems and commercial Linux distributions indicate a much lower number of Linux systems and level of Linux adoption than is the case; this is mainly due to Linux being free and open source software that can be downloaded free of charge. A Linux Counter Project had kept track of a running guesstimate of the number of Linux systems, but did not distinguish between rolling release and standard release distributions. It ceased operation in August of 2018, though a few related blog posts were created through October 2018.  Desktop usage statistical reports for particular Linux distributions have been collected and published in January of 2020 by the Linux Hardware Project.

A Linux distribution (often abbreviated as distro) is an operating system made from a software collection that is based upon the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading one of the Linux distributions, which are available for a wide variety of systems ranging from embedded devices (for example, OpenWrt) and personal computers (for example, Linux Mint) to powerful supercomputers (for example, Rocks Cluster Distribution).

Linux 发行版(英语:Linux distribution,也被叫做GNU/Linux 发行版),为一般使用者预先整合好的Linux操作系统及各种应用软件。一般使用者不需要重新编译,在直接安装之后,只需要小幅度更改设定就可以使用,通常以软件包管理系统来进行应用软件的管理。Linux发行版通常包含了包括桌面环境、办公套件、媒体播放器、数据库等应用软件。这些操作系统通常由Linux内核、以及来自GNU计划的大量的函式库,和基于X Window的图形界面。有些发行版考虑到容量大小而没有预装 X Window,而使用更加轻量级的软件,如:busybox, UClibc 或 dietlibc。现在有超过300个Linux发行版(Linux发行版列表)。大部分都正处于活跃的开发中,不断地改进。 由于大多数软件包是自由软件和开源软件,所以Linux发行版的形式多种多样——从功能齐全的桌面系统以及服务器系统到小型系统(通常在嵌入式设备,或者启动软盘)。除了一些定制软件(如安装和配置工具),发行版通常只是将特定的应用软件安装在一堆函式库和内核上,以满足特定使用者的需求。