Etymology and meanings.

First attested in English in the early 14th century, the word "navy" came via Old French "navie", "fleet of ships", from the Latin "navigium", "a vessel, a ship, bark, boat", from "navis", "ship". The word "naval" came from Latin "navalis", "pertaining to ship"; cf. Greek ("naus"), "ship", ("nautes"), "seaman, sailor". The earliest attested form of the word is in the Mycenaean Greek compound word, "na-u-do-mo" (*), "shipbuilders", written in Linear B syllabic script.  The word formerly denoted fleets of both commercial and military nature. In modern usage "navy" used alone always denotes a military fleet, although the term "merchant navy" for a commercial fleet still incorporates the non-military word sense. This overlap in word senses between commercial and military fleets grew out of the inherently dual-use nature of fleets; centuries ago, nationality was a trait that unified a fleet across both civilian and military uses. Although nationality of commercial vessels has little importance in peacetime trade other than for tax avoidance, it can have greater meaning during wartime, when supply chains become matters of patriotic attack and defense, and when in some cases private vessels are even temporarily converted to military vessels. The latter was especially important, and common, before 20th-century military technology existed, when merely adding artillery and naval infantry to any sailing vessel could render it fully as martial as any military-owned vessel. Such privateering has been rendered obsolete in blue-water strategy since modern missile and aircraft systems grew to leapfrog over artillery and infantry in many respects; but privateering nevertheless remains potentially relevant in littoral warfare of a limited and asymmetric nature.

History.

Naval warfare developed when humans first fought from water-borne vessels. Prior to the introduction of the cannon and ships with sufficient capacity to carry the large guns, navy warfare primarily involved ramming and boarding actions. In the time of ancient Greece and the Roman Empire, naval warfare centered on long, narrow vessels powered by banks of oarsmen (such as triremes and quinqueremes) designed to ram and sink enemy vessels or come alongside the enemy vessel so its occupants could be attacked hand-to-hand. Naval warfare continued in this vein through the Middle Ages until the cannon became commonplace and capable of being reloaded quickly enough to be reused in the same battle. The Chola Dynasty of medieval Tamil Nadu was known as one of the greatest naval powers of its time from 300 BC to 1279 AD. The Chola Navy, Chola kadarpadai comprised the naval forces of the Chola Empire along with several other Naval-arms of the country. The Chola navy played a vital role in the expansion of the Chola Tamil kingdom, including the conquest of the Sri Lanka islands, Kadaaram (Present day Burma), Sri Vijaya (present day Southeast Asia), the spread of Hinduism, Tamil architecture and Tamil culture to Southeast Asia and in curbing the piracy in Southeast Asia in 900 CE. In ancient China, large naval battles were known since the Qin dynasty ("also see" Battle of Red Cliffs, 208), employing the war junk during the Han dynasty. However, China's first official standing navy was not established until the Southern Song dynasty in the 12th century, a time when gunpowder was a revolutionary new application to warfare.  Nusantaran thalassocracies made extensive use of naval power and technologies. This enabled the seafaring Malay people to attack as far as the coast of Tanganyika and Mozambique with 1000 boats and attempted to take the citadel of Qanbaloh, about 7,000 km to their West, in 945-946 AD. In 1350 AD Majapahit launched its largest military expedition, the invasion of Pasai, with 400 large jong and innumerable smaller vessels. The second largest military expedition, invasion of Singapura in 1398, Majapahit deployed 300 jong with no less than 200,000 men.  The mass and deck space required to carry a large number of cannon made oar-based propulsion impossible, and ships came to rely primarily on sails. Warships were designed to carry increasing numbers of cannon and naval tactics evolved to bring a ship's firepower to bear in a broadside, with ships-of-the-line arranged in a line of battle.  The development of large capacity, sail-powered ships carrying cannon led to a rapid expansion of European navies, especially the Spanish and Portuguese navies which dominated in the 16th and early 17th centuries, and helped propel the age of exploration and colonialism. The repulsion of the Spanish Armada (1588) by the English fleet revolutionized naval warfare by the success of a guns-only strategy and caused a major overhaul of the Spanish Navy, partly along English lines, which resulted in even greater dominance by the Spanish. From the beginning of the 17th century the Dutch cannibalized the Portuguese Empire in the East and, with the immense wealth gained, challenged Spanish hegemony at sea. From the 1620s, Dutch raiders seriously troubled Spanish shipping and, after a number of battles which went both ways, the Dutch Navy finally broke the long dominance of the Spanish Navy in the Battle of the Downs (1639). England emerged as a major naval power in the mid-17th century in the first Anglo-Dutch war with a technical victory. Successive decisive Dutch victories in the second and third Anglo-Dutch Wars confirmed the Dutch mastery of the seas during the Dutch Golden Age, financed by the expansion of the Dutch Empire. The French Navy won some important victories near the end of the 17th century but a focus upon land forces led to the French Navy's relative neglect, which allowed the Royal Navy to emerge with an ever-growing advantage in size and quality, especially in tactics and experience, from 1695. As a response to growing naval influence of the navies of Portuguese, the warrior king of the Marathas, Chhatrapati Shivaji Maharaj laid the foundation of the Maratha navy in 1654.  Throughout the 18th century the Royal Navy gradually gained ascendancy over the French Navy, with victories in the War of Spanish Succession (1701–1714), inconclusive battles in the War of Austrian Succession (1740–1748), victories in the Seven Years' War (1754–1763), a partial reversal during the American War of Independence (1775–1783), and consolidation into uncontested supremacy during the 19th century from the Battle of Trafalgar in 1805. These conflicts saw the development and refinement of tactics which came to be called the line of battle.  The next stage in the evolution of naval warfare was the introduction of metal plating along the hull sides. The increased mass required steam-powered engines, resulting in an arms race between armor and weapon thickness and firepower. The first armored vessels, the French and British, made wooden vessels obsolete. Another significant improvement came with the invention of the rotating turrets, which allowed the guns to be aimed independently of ship movement. The battle between and during the American Civil War (1861–1865) is often cited as the beginning of this age of maritime conflict. The Russian Navy was considered the third strongest in the world on the eve of the Russo-Japanese War, which turned to be a catastrophe for the Russian military in general and the Russian Navy in particular. Although neither party lacked courage, the Russians were defeated by the Japanese in the Battle of Port Arthur, which was the first time in warfare that mines were used for offensive purposes. The warships of the Baltic Fleet sent to the Far East were lost in the Battle of Tsushima. A further step change in naval firepower occurred when the United Kingdom launched in 1906, but naval tactics still emphasized the line of battle.  The first practical military submarines were developed in the late 19th century and by the end of World War I had proven to be a powerful arm of naval warfare. During World War II, Nazi Germany's submarine fleet of U-boats almost starved the United Kingdom into submission and inflicted tremendous losses on U.S. coastal shipping. The, a sister ship of, was almost put out of action by miniature submarines known as X-Craft. The X-Craft severely damaged her and kept her in port for some months.  A major paradigm shift in naval warfare occurred with the introduction of the aircraft carrier. First at Taranto in 1940 and then at Pearl Harbor in 1941, the carrier demonstrated its ability to strike decisively at enemy ships out of sight and range of surface vessels. The Battle of Leyte Gulf (1944) was arguably the largest naval battle in history; it was also the last battle in which battleships played a significant role. By the end of World War II, the carrier had become the dominant force of naval warfare.  World War II also saw the United States become by far the largest Naval power in the world. In the late 20th and early 21st centuries, the United States Navy possessed over 70% of the world's total numbers and total tonnage of naval vessels of 1,000 tons or greater. Throughout the rest of the 20th century, the United States Navy would maintain a tonnage greater than that of the next 17 largest navies combined. During the Cold War, the Soviet Navy became a significant armed force, with large numbers of large, heavily armed ballistic missile submarines and extensive use of heavy, long-ranged antisurface missiles to counter the numerous United States carrier battle groups. Only three nations (United States, France, and Brazil) presently operate CATOBAR carriers of any size, while Russia, China and India operate sizeable STOBAR carriers (although all three are originally of Russian design). The United Kingdom is also currently constructing two carriers, which will be the largest STOVL vessels in service, and India is currently building one aircraft carrier,, and considering another. France is also looking at a new carrier, probably using a CATOBAR system and possibly based on the British "Queen Elizabeth" design.

Operations.

A navy typically operates from one or more naval bases. The base is a port that is specialized in naval operations, and often includes housing, a munitions depot, docks for the vessels, and various repair facilities. During times of war temporary bases may be constructed in closer proximity to strategic locations, as it is advantageous in terms of patrols and station-keeping. Nations with historically strong naval forces have found it advantageous to obtain basing rights in other countries in areas of strategic interest.  Navy ships can operate independently or with a group, which may be a small squadron of comparable ships, or a larger naval fleet of various specialized ships. The commander of a fleet travels in the flagship, which is usually the most powerful vessel in the group. Prior to the invention of radio, commands from the flagship were communicated by means of flags. At night signal lamps could be used for a similar purpose. Later these were replaced by the radio transmitter, or the flashing light when radio silence was needed.  A "blue water navy" is designed to operate far from the coastal waters of its home nation. These are ships capable of maintaining station for long periods of time in deep ocean, and will have a long logistical tail for their support. Many are also nuclear powered to save having to refuel. By contrast a "brown water navy" operates in the coastal periphery and along inland waterways, where larger ocean-going naval vessels can not readily enter. Regional powers may maintain a "green water navy" as a means of localized force projection. Blue water fleets may require specialized vessels, such as minesweepers, when operating in the littoral regions along the coast.

Traditions.

A basic tradition is that all ships commissioned in a navy are referred to as ships rather than vessels, with the exception of destroyers and submarines, which are known as boats. The prefix on a ship's name indicates that it is a commissioned ship.  An important tradition on board naval vessels of some nations has been the ship's bell. This was historically used to mark the passage of time, as warning devices in heavy fog, and for alarms and ceremonies.  The ship's captain, and more senior officers are "piped" aboard the ship using a Boatswain's call.  In the United States, the First Navy Jack is a flag that has the words, "Don't Tread on Me" on the flag.  By English tradition, ships have been referred to as a "she". However, it was long considered bad luck to permit women to sail on board naval vessels. To do so would invite a terrible storm that would wreck the ship. The only women that were welcomed on board were figureheads mounted on the prow of the ship.  Firing a cannon salute partially disarms the ship, so firing a cannon for no combat reason showed respect and trust. As the tradition evolved, the number of cannon fired became an indication of the rank of the official being saluted.

Naval organization.

Ships.

Historically, navy ships were primarily intended for warfare. They were designed to withstand damage and to inflict the same, but only carried munitions and supplies for the voyage (rather than merchant cargo). Often, other ships which were not built specifically for warfare, such as the galleon or the armed merchant ships in World War II, did carry armaments. In more recent times, navy ships have become more specialized and have included supply ships, troop transports, repair ships, oil tankers and other logistics support ships as well as combat ships.  Modern navy combat ships are generally divided into seven main categories: aircraft carriers, cruisers, destroyers, frigates, corvettes, submarines, and amphibious assault ships. There are also support and auxiliary ships, including the oiler, minesweeper, patrol boat, hydrographic and oceanographic survey ship and tender. During the age of sail, the ship categories were divided into the ship of the line, frigate, and sloop-of-war.  Naval ship names are typically prefixed by an abbreviation indicating the national navy in which they serve. For a list of the prefixes used with ship names (HMS, USS, LÉ, etc.) see ship prefix.  Today ships are significantly faster than in former times, thanks to much improved propulsion systems. Also, the efficiency of the engines has improved, in terms of fuel, and of how many sailors it takes to operate them. In World War II, ships needed to refuel very often. However, today ships can go on very long journeys without refueling. Also, in World War II, the engine room needed about a dozen sailors to work the many engines, however, today, only about 4–5 are needed (depending on the class of the ship). Today, naval strike groups on longer missions are always followed by a range of support and replenishment ships supplying them with anything from fuel and munitions, to medical treatment and postal services. This allows strike groups and combat ships to remain at sea for several months at a time.

Boats.

The term "boat" refers to small craft limited in their use by size and usually not capable of making lengthy independent voyages at sea. The old navy adage to differentiate between ships and boats is that boats are capable of being carried by ships. (Submarines by this rule are ships rather than boats, but are customarily referred to as boats reflecting their previous smaller size.)  Navies use many types of boat, ranging from dinghies to landing craft. They are powered by either diesel engines, out-board gasoline engines, or waterjets. Most boats are built of aluminum, fiberglass, or steel. Rigid-hulled inflatable boats are also used.  Patrol boats are used for patrols of coastal areas, lakes and large rivers. Landing craft are designed to carry troops, vehicles, or cargo from ship to shore under combat conditions, to unload, to withdraw from the beach, and to return to the ship. They are rugged, with powerful engines, and usually armed. There are many types in today's navies including hovercraft. They will typically have a power-operated bow ramp, a cargo well and after structures that house engine rooms, pilot houses, and stowage compartments. These boats are sometimes carried by larger ships.  Special operations craft are high-speed craft used for insertion and extraction of special forces personnel and some may be transportable (and deployed) by air.  Boats used in non-combat roles include lifeboats, mail boats, line handling boats, buoy boats, aircraft rescue boats, torpedo retrievers, explosive ordnance disposal craft, utility boats, dive boats, targets, and work boats. Boats are also used for survey work, tending divers, and minesweeping operations. Boats for carrying cargo and personnel are sometimes known as launches, gigs, barges or shore party boats.

Units.

Naval forces are typically arranged into units based on the number of ships included, a single ship being the smallest operational unit. Ships may be combined into squadrons or flotillas, which may be formed into fleets. The largest unit size may be the whole Navy or Admiralty.  A task force can be assembled using ships from different fleets for an operational task.

Personnel.

Despite their acceptance in many areas of naval service, female sailors were not permitted to serve on board U.S. submarines until the U.S. Navy lifted the ban in April 2010. The major reasons historically cited by the U.S. Navy were the extended duty tours and close conditions which afford almost no privacy. The United Kingdom's Royal Navy has had similar restrictions. Australia, Canada, Norway, and Spain previously opened submarine service to women sailors.

Ranks.

A navy will typically have two sets of ranks, one for enlisted personnel and one for officers.  Typical ranks for commissioned officers include the following, in ascending order (Commonwealth ranks are listed first on each line; USA ranks are listed second in those instances where they differ from Commonwealth ranks):  "Flag officers" include any rank that includes the word "admiral" (or commodore in services other than the US Navy), and are generally in command of a battle group, strike group or similar flotilla of ships, rather than a single ship or aspect of a ship. However, commodores can also be temporary or honorary positions. For example, during World War II, a Navy captain was assigned duty as a convoy commodore, which meant that he was still a captain, but in charge of all the merchant vessels in the convoy.  The most senior rank employed by a navy will tend to vary depending on the size of the navy and whether it is wartime or peacetime, for example, few people have ever held the rank of Fleet Admiral in the U.S. Navy, the chief of the Royal Australian Navy holds the rank of Vice Admiral, and the chief of the Irish Naval Service holds the rank of Commodore.

Naval infantry.

Naval infantry, commonly known as marines, are a category of infantry that form part of a state's naval forces and perform roles on land and at sea, including amphibious operations, as well as other, naval roles. They also perform other tasks, including land warfare, separate from naval operations.  During the era of the Roman empire, naval forces included marine legionaries for maritime boarding actions. These were troops primarily trained in land warfare, and did not need to be skilled at handling a ship. Much later during the age of sail, a component of marines served a similar role, being ship-borne soldiers who were used either during boarding actions, as sharp-shooters, or in raids along shorelines.  The Spanish "Infantería de Marina" was formed in 1537, making it the oldest, current marine force in the world. The British Royal Marines combine being both a ship-based force and also being specially trained in commando-style operations and tactics, operating in some cases separately from the rest of the Royal Navy. The Royal Marines also have their own special forces unit.  In the majority of countries, the marine force is an integral part of the navy. The United States Marine Corps is a separate armed service within the United States Department of the Navy, with its own leadership structure.

Naval aviation.

Naval aviation is the application of military air power by navies, whether from warships that embark aircraft, or land bases.  In World War I several navies used floatplanes and flying boats - mainly for scouting. By World War II, aircraft carriers could carry bomber aircraft capable of attacking naval and land targets, as well as fighter aircraft for defence. Since World War II helicopters have been embarked on smaller ships in roles such as anti-submarine warfare and transport. Some navies have also operated land-based aircraft in roles such as maritime patrol and training.  Naval aviation forces primarily perform naval roles at sea. However, they are also used in a variety of other roles.

A navy or sea force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It includes anything conducted by surface ships, amphibious ships, submarines, and seaborne aviation, as well as ancillary support, communications, training, and other fields. The strategic offensive role of a navy is projection of force into areas beyond a country's shores (for example, to protect sea-lanes, deter or confront piracy, ferry troops, or attack other navies, ports, or shore installations). The strategic defensive purpose of a navy is to frustrate seaborne projection-of-force by enemies. The strategic task of the navy also may incorporate nuclear deterrence by use of submarine-launched ballistic missiles. Naval operations can be broadly divided between riverine and littoral applications (brown-water navy), open-ocean applications (blue-water navy), and something in between (green-water navy), although these distinctions are more about strategic scope than tactical or operational division.

Válečné loďstvo (tzv. námořnictvo) je součástí ozbrojených sil přímořských států. Primárně působí na moři, ale jeho součástí mohou být i složky působící na zemi (námořní pěchota) a ve vzduchu (námořní nebo palubní letectvo). Námořnictvo používá řadu druhů plavidel, největší z nich jsou letadlové lodě a v minulosti i lodě bitevní. Vzhledem k jejich pořizovacím a provozním nákladům si je ale může dovolit pouze několik zemí a ostatní státy opírají svoji námořní sílu o menší jednotky. Na současných lodích jsou umístěny protiletadlové a protilodní rakety, které mohou být schopné zasáhnout cíl vzdálený i přes 100 km.


History.

The classical tradition was slow to use capital letters for initials at all; in surviving Roman texts it often is difficult even to separate the words as spacing was not used either. In the Late Antique period both came into common use in Italy, the initials usually were set in the left margin (as in the third example below), as though to cut them off from the rest of the text, and about twice as tall as the other letters. The radical innovation of insular manuscripts was to make initials much larger, not indented, and for the letters immediately following the initial also to be larger, but diminishing in size (called the "diminuendo" effect, after the musical notation). Subsequently, they became larger still, coloured, and penetrated farther and farther into the rest of the text, until the whole page might be taken over. The decoration of insular initials, especially large ones, was generally abstract and geometrical, or featured animals in patterns. Historiated initials were an Insular invention, but did not come into their own until the later developments of Ottonian art, Anglo-Saxon art, and the Romanesque style in particular. After this period, in Gothic art large paintings of scenes tended to go in rectangular framed spaces, and the initial, although often still historiated, tended to become smaller again.  In the very early history of printing the typesetters would leave blank the necessary space, so that the initials could be added later by a scribe or miniature painter. Later initials were printed using separate blocks in woodcut or metalcut techniques.  Since 2003, the W3C is working for initial letter modules for CSS Inline Layout Module Level 3, which standardized the output of initial letters for web pages.

Types of initial.

The initials are morphologically classified: "the rubricated" letter (red); the "epigraphic" letter, imitating ancient Roman majuscules; the "figurated" initial (usually in miniatures); the "historiated" initial, that gives spatial support to scenes of a narrative character; etc.  The initial may sit on the same baseline as the first line of text, at the same margin, as it does here. This is the easiest to typeset on a computer, including in HTML. An example follows:  Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.  Alternatively, the initial may be in the left margin, with the text indented, as shown here. In word processors and HTML, this may be implemented using a table with two cells, one for the initial and one for the rest of the text. The difference between this and a true drop cap may be seen when the text extends below the initial. For example:  With a drop cap, the initial sits within the margins and runs several lines deep into the paragraph, indenting some normal-sized text in these lines. This keeps the left and top margins of the paragraph flush.  In modern computer browsers, this may be achieved with a combination of HTML and CSS by using the float: left; setting. A CSS-only solution alternatively can use the :first-letter pseudo-element. An example of this format is the following paragraph: orem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.  In some older manuscripts, the first letter of normal sized text after a drop cap also would be capitalized, as may be seen in the Mainz Psalter above, and in the original 1609 printing of Shakespeare's sonnets. This evoked the handwritten "diminuendo" style of gradually reducing the text size over the course of the first line. This style now is rare, except in newspapers.

In a written or published work, an initial or drop cap is a letter at the beginning of a word, a chapter, or a paragraph that is larger than the rest of the text. The word is derived from the Latin "initialis", which means "standing at the beginning". An initial is often several lines in height and in older books or manuscripts, sometimes ornately decorated.

Iniciála (z latinského "initium" „začátek“, ze slovesa "in-ire", „vejít, vstoupit“) je první písmeno slova, které je výrazně odlišeno od ostatního textu velikostí, barvou nebo tvarem, někdy (hlavně v rukopisech, ale i ve starších tiscích) vybaveno i iluminací. Obvykle bývá na začátku stránky, kapitoly nebo odstavce.


Name and etymology.

The English word "Jew" continues Middle English '. These terms were loaned via the Old French ', which itself evolved from the earlier ', which in turn derived from'which through elision had dropped the letter "d" from the Medieval Latin "Iudaeus", which, like the New Testament Greek term "Ioudaios", meant both "Jew" and "Judean" / "of Judea". The Greek term was a loan from Aramaic "", corresponding to Hebrew, originally the term for a member of the tribe of Judah or the people of the kingdom of Judah. According to the Hebrew Bible, the name of both the tribe and kingdom derive from Judah, the fourth son of Jacob. Genesis 29:35 and 49:8 connect the name "Judah" with the verb, meaning "praise", but scholars generally agree that the name of both the patriarch and the kingdom instead have a geographic origin—possibly referring to the gorges and ravines of the region.  The Hebrew word for "Jew" is

Who is a Jew?

Judaism shares some of the characteristics of a nation, an ethnicity, a religion, and a culture, making the definition of who is a Jew vary slightly depending on whether a religious or national approach to identity is used. Generally, in modern secular usage Jews include three groups: people who were born to a Jewish family regardless of whether or not they follow the religion, those who have some Jewish ancestral background or lineage (sometimes including those who do not have strictly matrilineal descent), and people without any Jewish ancestral background or lineage who have formally converted to Judaism and therefore are followers of the religion.  Historical definitions of Jewish identity have traditionally been based on "halakhic" definitions of matrilineal descent, and halakhic conversions. These definitions of who is a Jew date back to the codification of the Oral Torah into the Babylonian Talmud, around 200 CE. Interpretations of sections of the Tanakh, such as Deuteronomy 7:1–5, by Jewish sages, are used as a warning against intermarriage between Jews and Canaanites because "[the non-Jewish husband] will cause your child to turn away from Me

History.

Origins.

A factual reconstruction for the origin of the Jews is a difficult and complex endeavor. It requires examining at least 3,000 years of ancient human history using documents in vast quantities and variety written in at least ten near Eastern languages. As archaeological discovery relies upon researchers and scholars from diverse disciplines, the goal is to interpret all of the factual data, focusing on the most consistent theory. The prehistory and ethnogenesis of the Jews are closely intertwined with archaeology, biology, and historical textual records, as well as religious literature and mythology. The ethnic stock to which Jews originally trace their ancestry was a confederation of Iron Age Semitic-speaking tribes known as the Israelites that inhabited a part of Canaan during the tribal and monarchic periods. Modern Jews are named after and also descended from the southern Israelite Kingdom of Judah.  According to the Hebrew Bible narrative, Jewish ancestry is traced back to the Biblical patriarchs such as Abraham, his son Isaac, Isaac's son Jacob, and

Babylon and Rome.

After the destruction of the Second Temple, Judaism lost much of its sectarian nature.  Without a Temple, Greek-speaking Jews no longer looked to Jerusalem in the way they had before. Judaism separated into a linguistically Greek and a Hebrew / Aramaic sphere. The theology and religious texts of each community were distinctively different. Hellenized Judaism never developed yeshivas to study the Oral Law. Rabbinic Judaism (centered in the Land of Israel and Babylon) almost entirely ignores the Hellenized Diaspora in its writings. Hellenized Judaism eventually disappeared as its practitioners assimilated into Greco-Roman culture, leaving a strong Rabbinic eastern Diaspora with large centers of learning in Babylon.  By the first century, the Jewish community in Babylonia, to which Jews were exiled after the Babylonian conquest as well as after the Bar Kokhba revolt in 135 CE, already held a speedily growing population of an estimated one million Jews, which increased to an estimated two million between the years 200 CE and 500 CE, both by natural growth and by immigration of more Jews from the Land of Israel, making up

Culture.

Religion.

The Jewish people and the religion of Judaism are strongly interrelated. Converts to Judaism typically have a status within the Jewish "ethnos" equal to those born into it. However, several converts to Judaism, as well as ex-Jews, have claimed that converts are treated as second-class Jews by many born Jews. Conversion is not encouraged by mainstream Judaism, and it is considered a difficult task. A significant portion of conversions are undertaken by children of mixed marriages, or would-be or current spouses of Jews.  The Hebrew Bible, a religious interpretation of the traditions and early history of the Jews, established the first of the Abrahamic religions, which are now

Languages.

Hebrew is the liturgical language of Judaism (termed "lashon ha-kodesh", "the holy tongue"), the language in which most of the Hebrew scriptures (Tanakh) were composed, and the daily speech of the Jewish people for centuries. By the 5th century BCE, Aramaic, a closely related tongue, joined Hebrew as the spoken language in Judea. By the 3rd century BCE, some Jews of the diaspora were speaking Greek. Others, such as in the Jewish communities of Babylonia, were speaking Hebrew and Aramaic, the languages of the Babylonian Talmud. These languages were also used by the Jews of Israel

Leadership.

There is no single governing body for the Jewish community, nor a single authority with responsibility for religious doctrine. Instead, a variety of secular and religious institutions at the local, national, and international levels lead various parts of the Jewish

Demographics.

Ethnic divisions.

Within the world's Jewish population there are distinct ethnic divisions, most of which are primarily the result of geographic branching from an originating Israelite population, and subsequent independent evolutions. An array of Jewish communities was established by Jewish settlers in various places around the Old World, often at great distances from one another, resulting in effective and often long-term isolation. During the millennia of the Jewish diaspora the communities would develop under the influence of their local environments: political, cultural, natural, and populational. Today, manifestations of these differences among the Jews can be observed in

Genetic studies.

Y DNA studies tend to imply a small number of founders in an old population whose members parted and followed different migration paths. In most Jewish populations, these male line ancestors appear to have been mainly Middle Eastern. For example, Ashkenazi Jews share more common paternal lineages with other Jewish and Middle Eastern groups than with non-Jewish populations in areas where Jews lived in Eastern Europe, Germany and the French Rhine Valley. This is consistent with Jewish traditions in placing most Jewish paternal origins in the region of the Middle East. Conversely, the maternal lineages of Jewish populations, studied by looking

Population centers.

Although historically, Jews have been found all over the world, in the decades since World War II and the establishment of Israel, they have increasingly concentrated in a small number of countries. In 2013, the United States and Israel were collectively home to more than 80 percent of the global Jewish population, each country having approximately 41 percent of the world's Jews.  According to the Israel Central Bureau of Statistics there were 13,421,000 Jews worldwide in 2009, roughly 0.19 percent of the world's population at the time.  According to the 2007 estimates of The Jewish People Policy Planning Institute, the world's Jewish population is 13.2 million. Adherents.com cites figures ranging from 12 to 18 million. These statistics incorporate both practicing Jews affiliated with synagogues and the Jewish community, and approximately 4.5 million unaffiliated and secular Jews.  According to Sergio Della Pergola, a demographer of the Jewish population, in 2015 there were about 6.3 million Jews in Israel, 5.7 million in the United States, and 2.3 million in the rest of the world.

Israel.

Israel, the Jewish nation-state, is the only country in which Jews make up a majority of the citizens. Israel was established as an independent democratic and Jewish state on 14 May 1948. Of the 120 members in its parliament, the Knesset,, 14 members of the Knesset are Arab citizens of Israel (not including the Druze), most representing Arab political parties. One of Israel's Supreme Court judges is also an Arab citizen of Israel.  Between 1948 and 1958, the Jewish population rose from 800,000 to two million. Currently, Jews account for 75.4 percent of the Israeli population, or 6 million people. The

Diaspora (outside Israel).

The waves of immigration to the United States and elsewhere at the turn of the 19th century, the founding of Zionism and later events, including pogroms in Russia, the massacre of European Jewry during the Holocaust, and the founding of the state of Israel, with the subsequent Jewish exodus from Arab lands, all resulted in substantial shifts in the population centers of world Jewry by the end of the 20th century.  More than half of the Jews live in the Diaspora (see Population table). Currently, the largest Jewish community outside Israel, and either the largest or second-largest Jewish community in the world, is located in the United States, with 5.2 million to 6.4 million Jews by various estimates. Elsewhere in the Americas, there are also large Jewish populations in Canada (315,000), Argentina (180,000–300,000), and Brazil (196,000–600,000), and smaller populations in Mexico, Uruguay, Venezuela, Chile, Colombia and several other countries (see History of the Jews in Latin America). According to a 2010 Pew Research Center study, about 470,000 people of Jewish heritage live in Latin-America and the Caribbean. Demographers disagree on whether the United States has a larger Jewish population than Israel, with many maintaining that Israel surpassed the United States in Jewish population during the 2000s, while others maintain that the United States still has the largest Jewish population in the world. Currently, a major national Jewish population survey is planned to ascertain whether or not Israel has overtaken the United States in Jewish population.  Western Europe's largest Jewish community, and the third-largest Jewish community in the world, can be found in France, home to between 483,000 and 500,000 Jews, the majority of whom are immigrants or refugees from North African countries such

Demographic changes.

Assimilation.

Since at least the time of the Ancient Greeks, a proportion of Jews have assimilated into the wider non-Jewish society around them, by either choice or force, ceasing to practice Judaism and losing their Jewish identity. Assimilation took place in all areas, and during all time periods, with some Jewish communities, for example the Kaifeng Jews of China, disappearing entirely. The advent of the Jewish Enlightenment of the 18th century (see Haskalah) and the subsequent emancipation of the Jewish populations of Europe and America

War and persecution.

The Jewish people and Judaism have experienced various persecutions throughout Jewish history. During Late Antiquity and the Early Middle Ages the Roman Empire (in its later phases known as the Byzantine Empire) repeatedly repressed the Jewish population, first by ejecting them from their homelands during the pagan Roman era and later by officially establishing them as second-class citizens during the Christian Roman era.  According to James Carroll, "Jews accounted for 10% of the total population of the Roman Empire. By that ratio, if other factors had not intervened, there would be 200 million Jews in the world today, instead of something like 13 million."  Later in medieval Western Europe, further persecutions of Jews by Christians occurred, notably during the Crusades—when Jews all over Germany were massacred—and a series of

Migrations.

Throughout Jewish history, Jews have repeatedly been directly or indirectly expelled from both their original homeland, the Land of Israel, and many of the areas in which they have settled. This experience as refugees has shaped Jewish identity and religious practice in many ways, and is thus a major element of Jewish history. The patriarch Abraham is described as a migrant to the land of Canaan from Ur of the Chaldees after an attempt on his life by King Nimrod. His descendants, the Children of Israel, in the Biblical story (whose historicity is uncertain) undertook the Exodus (meaning "departure"

Growth.

Israel is the only country with a Jewish population that is consistently growing through natural population growth, although the Jewish populations of other countries, in Europe and North America, have recently increased through immigration. In the Diaspora, in almost every country the Jewish population in general is either declining or steady, but Orthodox and Haredi Jewish communities, whose members often shun birth control for religious reasons, have experienced rapid population growth.  Orthodox and Conservative Judaism discourage proselytism to non-Jews, but many Jewish groups have tried to reach out to the assimilated Jewish communities of the Diaspora in

Contributions.

Jews have made many contributions to humanity in a broad and diverse range of fields, including the sciences, arts, politics, and business. For example, although Jews comprise only 0.2 percent of the world's population, over 20 percent of Nobel Prize laureates have been Jewish or of Jewish descent, with multiple winners in each category.

Jews (, ) or Jewish people are an ethnoreligious group and a nation, originating from the Israelites and Hebrews of historical Israel and Judah. Jewish ethnicity, nationhood, and religion are strongly interrelated, as Judaism is the ethnic religion of the Jewish people, while its observance varies from strict observance to complete nonobservance.

Židé (hebrejsky יְהוּדִים, "Jehudim", sg. יְהוּדִי, "Jehudi") jsou semitským národem pocházejícím z oblasti Blízkého východu. Kromě označení "Židé" jsou nazýváni též jako Izrael (hebrejsky "Jisra’el") nebo Synové Izraele, Izraelité (hebrejsky "Bnej Jisra’el"). Občas se pro Židy používá i označení Hebrejové či Hebrejci (hebrejsky עברי, "Ivri" (sg.), עברים, "Ivrim" (pl.); rusky "Jevrej"). Nejstarší záznamy o existenci izraelského národa spadají do 2. tisíciletí př. n. l. Během 3 000 let se Židé ze své pravlasti – Izraele – rozšířili do celého světa. Kromě národnostně-etnické skupiny tvoří Židé i skupinu náboženskou.


Naming.

The names of earlier versions of the language through FORTRAN 77 were conventionally spelled in all-capitals (FORTRAN 77 was the last version in which the

History.

In late 1953, John W. Backus submitted a proposal to his superiors at IBM to develop a more practical alternative to assembly language for programming their IBM 704 mainframe computer. Backus' historic FORTRAN team consisted of programmers Richard Goldberg, Sheldon F. Best, Harlan Herrick, Peter Sheridan, Roy Nutt, Robert Nelson, Irving Ziller, Harold Stern, Lois Haibt, and David Sayre. Its concepts included easier entry of equations into a computer, an idea developed by J. Halcombe Laning and demonstrated in the Laning and Zierler system of 1952. Some of these programmers were chess players and were chosen to work at IBM with the thought being they had logical minds.  A draft specification for "The IBM Mathematical Formula Translating System" was completed by November 1954. The first manual for FORTRAN appeared in October 1956, with the first FORTRAN compiler delivered in April 1957. This was the first optimizing compiler, because customers were reluctant to use a high-level programming language unless its compiler could generate code with performance approaching that of hand-coded assembly language.  While the community was skeptical that this new method could possibly outperform hand-coding, it reduced the number of programming statements necessary to operate a machine by a factor of 20, and quickly gained acceptance. John Backus said during a 1979 interview with "Think", the IBM employee magazine, "Much of my work has come from being lazy. I didn't like writing programs, and so, when I was working on the IBM 701, writing programs for computing missile trajectories, I started work on a programming system to make it easier to write programs."  The language was widely adopted by scientists for writing numerically intensive programs, which encouraged compiler writers to produce compilers that could generate faster and more efficient code. The inclusion of a complex number data type in the language made Fortran especially suited to technical applications such as electrical engineering.  By 1960, versions of FORTRAN were available for the IBM 709, 650, 1620, and 7090 computers. Significantly, the increasing popularity of FORTRAN spurred competing computer manufacturers to provide FORTRAN compilers for their machines, so that by 1963 over 40 FORTRAN compilers existed. For these reasons, FORTRAN is considered to be the first widely used cross-platform programming language.  The development of Fortran paralleled the early evolution of compiler technology, and many advances in the theory and design of compilers were specifically motivated by the need to generate efficient code for Fortran programs.  The most comprehensive account of Fortran history in a single document is given by Lorenzo in the book listed below.

Science and engineering.

Although a 1968 journal article by the authors of BASIC already described FORTRAN as "old-fashioned", Fortran has now been in use for several decades and there is a vast body of Fortran software in daily use throughout the scientific and engineering communities. Jay Pasachoff wrote in 1984 that "physics and astronomy students simply have to learn FORTRAN. So much exists in FORTRAN that it seems unlikely that scientists will change to Pascal, Modula-2, or whatever." In 1993, Cecil E. Leith called FORTRAN the "mother tongue of scientific computing", adding that its replacement by any other possible language "may remain a forlorn hope".  It is the primary language for some of the most intensive super-computing tasks, such as in astronomy, climate modeling, computational chemistry, computational economics, computational fluid dynamics, computational physics, data analysis, hydrological modeling, numerical linear algebra and numerical libraries (LAPACK,

Language features.

The precise characteristics and syntax of

Portability.

Portability was a problem in the early days because there was no agreed upon standard—not even IBM's reference manual—and computer companies vied to differentiate their offerings from others by providing incompatible features. Standards have improved portability. The 1966 standard provided a reference syntax and semantics, but vendors continued to provide incompatible extensions. Although careful programmers were coming to realize that use of incompatible extensions caused expensive portability problems, and were therefore using programs such as "The PFORT Verifier," it was not until after the 1977 standard, when the National Bureau of Standards (now NIST) published "FIPS PUB 69", that processors purchased by the U.S. Government were required to diagnose extensions of the standard. Rather than offer two processors, essentially every compiler eventually had at least

Variants.

Fortran 5.

Fortran 5 was marketed by Data General Corp in the late 1970s and early 1980s, for the Nova,

FORTRAN V.

FORTRAN V was distributed by Control Data Corporation in 1968 for the CDC 6600 series. The language was

Fortran 6.

Fortran 6 or Visual Fortran 2001 was licensed to Compaq by Microsoft. They

Specific variants.

Vendors of high-performance scientific computers ("e.g.," Burroughs, Control Data Corporation (CDC), Cray, Honeywell, IBM, Texas Instruments, and UNIVAC) added extensions to Fortran to take advantage of special hardware features such as instruction cache, CPU pipelines, and vector arrays. For example, one of IBM's FORTRAN compilers ("H Extended IUP") had a level of optimization which reordered the machine code instructions to keep multiple internal arithmetic units busy simultaneously. Another example is "CFD", a special variant of FORTRAN designed specifically for the ILLIAC IV supercomputer, running at NASA's Ames Research Center. IBM Research Labs also developed an extended FORTRAN-based language called "VECTRAN" for processing vectors and matrices.  Object-Oriented Fortran was an object-oriented extension of Fortran, in which data items can be grouped into objects, which can be instantiated and executed in parallel. It was available for Sun, Iris, iPSC, and nCUBE, but is no longer supported.  Such machine-specific extensions have either disappeared over time or have had elements incorporated into the main standards. The major remaining extension is OpenMP, which is a cross-platform extension for shared memory programming. One new extension, Coarray Fortran, is intended to support parallel programming.

FOR TRANSIT for the IBM 650.

"FOR TRANSIT" was the name of a reduced version of the IBM 704 FORTRAN language, which was implemented for the IBM 650, using a translator program developed at Carnegie in the late 1950s. The following comment appears in the IBM Reference Manual ("FOR TRANSIT Automatic Coding System" C28-4038, Copyright 1957, 1959 by IBM): The FORTRAN system was designed for a more complex machine than the 650, and consequently some of the 32 statements found in the FORTRAN Programmer's Reference Manual are not acceptable to the FOR TRANSIT system. In addition, certain restrictions to the FORTRAN language have been added. However, none of these restrictions make a

Fortran-based languages.

Prior to FORTRAN 77, a number of preprocessors were commonly used to provide a friendlier language, with the advantage that the preprocessed code could be compiled on any machine with a standard FORTRAN compiler. These preprocessors would typically support structured programming, variable names longer than six characters, additional data types, conditional compilation, and even macro capabilities. Popular preprocessors included FLECS, iftran, MORTRAN, SFtran, S-Fortran, Ratfor, and Ratfiv. Ratfor and Ratfiv, for example, implemented a C-like language, outputting preprocessed code in standard FORTRAN 66. Despite advances in the Fortran language, preprocessors continue to be used for conditional compilation and macro substitution.  One of the earliest versions of FORTRAN, introduced in the '60s, was popularly used in colleges and universities. Developed, supported, and distributed by the University of Waterloo, WATFOR was based largely on FORTRAN IV. A student using WATFOR could submit their batch FORTRAN job and, if there were no syntax errors, the program would move straight to execution. This simplification allowed students to concentrate on their program's syntax and semantics,

Code examples.

The following program illustrates dynamic memory allocation and array-based operations, two features introduced with Fortran 90. Particularly noteworthy is the absence of loops and / statements in manipulating the

Humor.

During the same FORTRAN standards committee meeting at which the name "FORTRAN 77" was chosen, a satirical technical proposal was incorporated into the official distribution bearing the title "Letter O Considered Harmful". This proposal purported to address the confusion that sometimes arises between the letter "O" and the numeral zero, by eliminating the letter from allowable variable names. However, the method proposed was to eliminate the letter from the character set entirely (thereby retaining 48 as the number of lexical characters, which the colon had increased to 49). This was considered beneficial in that it would promote structured programming, by making it impossible to use the notorious statement as before. (Troublesome statements would also be eliminated.) It was noted that this "might invalidate some existing programs" but that most of these "probably were non-conforming, anyway".  When X3J3 debated whether the minimum trip count for a DO loop should be zero or one in Fortran 77, Loren Meissner suggested a minimum trip count of two—reasoning "(tongue-in-cheek)" that if it was less than two then there would be no reason for a loop!  When assumed-length arrays were being added, there was a dispute as to the appropriate character to separate upper and lower bounds. In a comment examining these arguments, Dr. Walt Brainerd penned an article entitled "Astronomy vs. Gastroenterology" because some proponents had suggested using the star or asterisk ("*"), while others favored the colon (":").  In FORTRAN 77 (and most earlier versions), variable names beginning with the letters I–N had a default type of integer, while variables starting with any other letters defaulted to real, although programmers could override the defaults with an explicit declaration. This led to the joke: "In Fortran, GOD is REAL (unless declared LOGICAL)."

Fortran (; formerly FORTRAN, derived from "Formula Translation") is a general-purpose, compiled imperative programming language that is especially suited to numeric computation and scientific computing.

Fortran (akronymická zkratka z anglického FORmula a TRANslator – překladač vzorců) je v informatice imperativní programovací jazyk, který v 50. letech 20. století navrhla firma IBM pro vědecké výpočty a numerické aplikace. Zpočátku byl označován jako FORTRAN (verzálami), ale od verze Fortran 90 se přešlo na označení Fortran. Kolem roku 1960 firma IBM doporučovala Fortran zapisovat jako FØRTRAN. V současné době se především používá pro: výpočty drah raket, turbulencí ve 3D, Fourierův rozvoj, Fourierovu transformaci, vývoj počasí, elektroinženýrství, fyzikální chemii a částicovou fyziku.


Purpose.

In building applications, an API (application programming interface) simplifies programming by abstracting the underlying implementation and only exposing objects or actions the developer needs. While a graphical interface for an email client might provide a user with a button that performs all the steps for fetching and highlighting new emails, an API for file input/output might give the developer a function that copies a file from one location to another without requiring that the developer understand the file system operations occurring behind the scenes.

Usage.

Libraries and frameworks.

An API usually is related to a software library. The API describes and prescribes the "expected behavior" (a specification) while the library is an "actual implementation" of this set of rules.  A single API can have multiple implementations (or none, being abstract) in the form of different libraries that share the same programming interface.  The separation of the API from its implementation can allow programs written in one language to use a library written in another. For example, because Scala and Java compile to compatible bytecode, Scala developers can take advantage of any Java API.  API use can vary depending on the type of programming language involved. An API for a procedural language such as Lua could consist primarily of basic routines to execute code, manipulate data or handle errors while an API for an object-oriented language, such as Java, would provide a specification of classes and its class methods.  Language bindings are also APIs. By mapping the features and capabilities of one language to an interface implemented in another language, a language binding allows a library or service written in one language to be used when developing in another language. Tools such as SWIG and F2PY, a Fortran-to-Python interface generator, facilitate the creation of such interfaces.  An API can also be related to a software framework: a framework can be based on several libraries implementing several APIs, but unlike the normal use of an API, the access to the behavior built into the framework is mediated by extending its content with new classes plugged into the framework itself.  Moreover, the overall program flow of control can be out of the control of the caller and in the hands of the framework by inversion of control or a similar mechanism.

Operating systems.

An API can specify the interface between an application and the operating system. POSIX, for example, specifies a set of common APIs that aim to enable an application written for a POSIX conformant operating system to be compiled for another POSIX conformant operating system.  Linux and Berkeley Software Distribution are examples of operating systems that implement the POSIX APIs.  Microsoft has shown a strong commitment to a backward-compatible API, particularly within its Windows API (Win32) library, so older applications may run on newer versions of Windows using an executable-specific setting called "Compatibility Mode".  An API differs from an application binary interface (ABI) in that an API is source code based while an ABI is binary based. For instance, POSIX provides APIs while the Linux Standard Base provides an ABI.

Remote APIs.

Remote APIs allow developers to manipulate remote resources through protocols, specific standards for communication that allow different technologies to work together, regardless of language or platform. For example, the Java Database Connectivity API allows developers to query many different types of databases with the same set of functions, while the Java remote method invocation API uses the Java Remote Method Protocol to allow invocation of functions that operate remotely, but appear local to the developer.  Therefore, remote APIs are useful in maintaining the object abstraction in object-oriented programming; a method call, executed locally on a proxy object, invokes the corresponding method on the remote object, using the remoting protocol, and acquires the result to be used locally as a return value.  A modification on the proxy object also will result in a corresponding modification on the remote object.

Web APIs.

Web APIs are the defined interfaces through which interactions happen between an enterprise and applications that use its assets, which also is a Service Level Agreement (SLA) to specify the functional provider and expose the service path or URL for its API users. An API approach is an architectural approach that revolves around providing a program interface to a set of services to different applications serving different types of consumers.  When used in the context of web development, an API is typically defined as a set of specifications, such as Hypertext Transfer Protocol (HTTP) request messages, along with a definition of the structure of response messages, usually in an Extensible Markup Language (XML) or JavaScript Object Notation (JSON) format. An example might be a shipping company API that can be added to an eCommerce-focused website to facilitate ordering shipping services and automatically include current shipping rates, without the site developer having to enter the shipper's rate table into a web database. While "web API" historically has been virtually synonymous with web service, the recent trend (so-called Web 2.0) has been moving away from Simple Object Access Protocol (SOAP) based web services and service-oriented architecture (SOA) towards more direct representational state transfer (REST) style web resources and resource-oriented architecture (ROA). Part of this trend is related to the Semantic Web movement toward Resource Description Framework (RDF), a concept to promote web-based ontology engineering technologies. Web APIs allow the combination of multiple APIs into new applications known as mashups. In the social media space, web APIs have allowed web communities to facilitate sharing content and data between communities and applications. In this way, content that is created in one place dynamically can be posted and updated to multiple locations on the web. For example, Twitter's REST API allows developers to access core Twitter data and the Search API provides methods for developers to interact with Twitter Search and trends data.

Design.

The design of an API has significant impact on its usage. The principle of information hiding describes the role of programming interfaces as enabling modular programming by hiding the implementation details of the modules so that users of modules need not understand the complexities inside the modules. Thus, the design of an API attempts to provide only the tools a user would expect. The design of programming interfaces represents an important part of software architecture, the organization of a complex piece of software.  Several authors have created recommendations for how to design APIs, such as Joshua Bloch, Kin Lane, and Michi Henning. Patterns for the design and evolution of remote APIs are covered in a series of EuroPLoP papers.

Release policies.

APIs are one of the more common ways technology companies integrate with each other. Those that provide and use APIs are considered as being members of a business ecosystem.  The main policies for releasing an API are:

Public API implications.

An important factor when an API becomes public is its "interface stability". Changes to the API —for example adding new parameters to a function call—could break compatibility with the clients that depend on that API.  When parts of a publicly presented API are subject to change and thus not stable, such parts of a particular API should be documented explicitly as "unstable". For example, in the Google Guava library, the parts that are considered unstable, and that might change in the near future, are marked with the Java annotation codice_1.  A public API can sometimes declare parts of itself as "deprecated" or rescinded. This usually means that part of the API should be considered a candidate for being removed, or modified in a backward incompatible way. Therefore, these changes allows developers to transition away from parts of the API that will be removed or not supported in the future.  Client code may contain innovative or opportunistic usages that were not intended by the API designers. In other words, for a library with a significant user base, when an element becomes part of the public API, it may be used in diverse ways. On February 19, 2020, Akamai published their annual “State of the Internet” report, showcasing the growing trend of cybercriminals targeting public API platforms at financial services worldwide. From December 2017 through November 2019, Akamai witnessed 85.42 billion credential violation attacks. About 20%, or 16.55 billion, were against hostnames defined as API endpoints. Of these, 473.5 million have targeted financial services sector organizations.

Documentation.

API documentation describes what services an API offers and how to use those services, aiming to cover everything a client would need to know for practical purposes.  Documentation is crucial for the development and maintenance of applications using the API. API documentation is traditionally found in documentation files but can also be found in social media such as blogs, forums, and Q&A websites.  Traditional documentation files are often presented via a documentation system, such as Javadoc or Pydoc, that has a consistent appearance and structure. However, the types of content included in the documentation differs from API to API.  In the interest of clarity, API documentation may include a description of classes and methods in the API as well as "typical usage scenarios, code snippets, design rationales, performance discussions, and contracts", but implementation details of the API services themselves are usually omitted.  Restrictions and limitations on how the API can be used are also covered by the documentation. For instance, documentation for an API function could note that its parameters cannot be null, that the function itself is not thread safe, or that a decrement and cancel protocol averts self-trading. Because API documentation tends to be comprehensive, it is a challenge for writers to keep the documentation updated and for users to read it carefully, potentially yielding bugs.  API documentation can be enriched with metadata information like Java annotations. This metadata can be used by the compiler, tools, and by the "run-time" environment to implement custom behaviors or custom handling.  It is possible to generate API documentation in a data-driven manner. By observing many programs that use a given API, it is possible to infer the typical usages, as well the required contracts and directives. Then, templates can be used to generate natural language from the mined data.

Copyright controversy.

In 2010, Oracle Corporation sued Google for having distributed a new implementation of Java embedded in the Android operating system. Google had not acquired any permission to reproduce the Java API, although permission had been given to the similar OpenJDK project. Judge William Alsup ruled in the "Oracle v. Google" case that APIs cannot be copyrighted in the U.S, and that a victory for Oracle would have widely expanded copyright protection and allowed the copyrighting of simple software commands:  In 2014, however, Alsup's ruling was overturned on appeal to the Court of Appeals for the Federal Circuit, though the question of whether such use of APIs constitutes fair use was left unresolved.  In 2016, following a two-week trial, a jury determined that Google's reimplementation of the Java API constituted fair use, but Oracle vowed to appeal the decision. Oracle won on its appeal, with the Court of Appeals for the Federal Circuit ruling that Google's use of the APIs did not qualify for fair use. In 2019, Google appealed to the Supreme Court of the United States over both the copyrightability and fair use rulings, and the Supreme Court granted review.

An application programming interface (API) is a computing interface which defines interactions between multiple software intermediaries. It defines the kinds of calls or requests that can be made, how to make them, the data formats that should be used, the conventions to follow, etc. It can also provide extension mechanisms so that users can extend existing functionality in various ways and to varying degrees. An API can be entirely custom, specific to a component, or it can be designed based on an industry standard to ensure interoperability. Some APIs have to be documented, others are designed so that they can be "interrogated" to determine supported functionality. Since other components/systems rely only on the API, the system that provides the API can (ideally) change its internal details "behind" that API without affecting its users.

API (zkratka pro Application Programming Interface) označuje v informatice rozhraní pro programování aplikací. Tento termín používá softwarové inženýrství. Jde o sbírku procedur, funkcí, tříd či protokolů nějaké knihovny (ale třeba i jiného programu nebo jádra operačního systému), které může programátor využívat. API určuje, jakým způsobem jsou funkce knihovny volány ze zdrojového kódu programu. Rozhraní, které se vytváří při kompilaci a je využíváno při běhu programu, se nazývá ABI.


Early life.

Fielding was born at Sharpham, Somerset, and educated at Eton College, where he established a lifelong friendship with William Pitt the Elder. His mother died when he was 11. A suit for custody was brought by his grandmother against his charming but irresponsible father, Lt Gen. Edmund Fielding. The settlement placed Henry in his grandmother's care, although he continued to see his father in London. In 1725, Henry tried to abduct his cousin, Sarah Andrews, while she was on her way to church. He fled to avoid prosecution. In 1728, he travelled to Leiden to study classics and law at the university. However, lack of money obliged him to return to London and he began writing for the theatre. Some of his work was savagely critical of the government of Prime Minister Sir Robert Walpole.

Dramatist and novelist.

The Theatrical Licensing Act of 1737 is said to be a direct response to his activities in writing for the theatre. Although the play that triggered the act was the unproduced, anonymously authored "The Golden Rump", Fielding's dramatic satires had set the tone. Once it was passed, political satire on the stage became virtually impossible. Fielding retired from the theatre and resumed his career in law to support his wife Charlotte Craddock and two children by becoming a barrister.  Fielding's lack of financial acumen meant he and his family often endured periods of poverty, but he was helped by Ralph Allen, a wealthy benefactor, on whom Squire Allworthy in "Tom Jones" would be based. Allen went on to provide for the education and support of Fielding's children after the writer's death. Fielding never stopped writing political satire and satires of current arts and letters. "The Tragedy of Tragedies" (for which Hogarth designed the frontispiece) was, for example, quite successful as a printed play. Based on his earlier "Tom Thumb", this was another of Fielding's "irregular" plays published under the name of H. Scriblerus Secundus, a pseudonym intended to link himself ideally with the Scriblerus Club of literary satirists founded by Jonathan Swift, Alexander Pope and John Gay. He also contributed a number of works to journals of the time.  From 1734 until 1739 he wrote anonymously for the leading Tory periodical, "The Craftsman", against the Prime Minister, Sir Robert Walpole. Fielding's patron was the opposition Whig MP George Lyttelton, a boyhood friend from Eton. Lyttelton followed his leader Lord Cobham in forming a Whig opposition to Walpole's government called the Cobhamites (which included another of Fielding's Eton friends, William Pitt). In the "Craftsman", Fielding voiced the opposition attack on bribery and corruption in British politics. Although writing for the opposition to Walpole, which included Tories as well as Whigs, Fielding was "unshakably a Whig" and often praised Whig heroes such as the Duke of Marlborough and Gilbert Burnet.  Fielding dedicated his play "Don Quixote in England" to the opposition Whig leader Lord Chesterfield. It was published on 17 April 1734, the same day writs were issued for the general election. He dedicated his 1735 play "The Universal Gallant" to Charles Spencer, 3rd Duke of Marlborough, a political follower of Chesterfield. The other prominent opposition newspaper, "Common Sense", founded by Chesterfield and Lyttelton, was named after a character in Fielding's "Pasquin" (1736). Fielding wrote at least two articles for it in 1737 and 1738.  Fielding continued to air his political views in satirical articles and newspapers in the late 1730s and early 1740s. He was the main writer and editor from 1739 to 1740 for the satirical paper "The Champion", which was heavily critical of Walpole's government and of pro-government literary and political writers. He sought to avoid charges of libel by making its political attacks so funny or embarrassing to the victim that a publicized court case would seem even worse. He later became chief writer for the Whig government of Henry Pelham.  Fielding took to novel writing in 1741, angered by Samuel Richardson's success with "Pamela; or, Virtue Rewarded". His first success was an anonymous parody of that: "Shamela". This follows the model of Tory satirists of the previous generation, notably Swift and Gay.  Fielding followed this with "Joseph Andrews" (1742), an original work supposedly dealing with Pamela's brother, Joseph. His purpose, however, was more than parody, for as announced in the preface, he intended a "kind of writing which I do not remember to have seen hitherto attempted in our language." In what Fielding called a "comic epic poem in prouse," he blended two classical traditions: that of the epic, which had been poetic, and that of the drama, but emphasizing the comic rather than the tragic. Another distinction of "Joseph Andrews" and of the novels to come was the use of everyday reality of character and action as opposed to the fables of the past. Although begun as a parody, it developed into an accomplished novel in its own right and is considered to mark Fielding's debut as a serious novelist. In 1743, he published a novel in the "Miscellanies" volume III (which was the first volume of the Miscellanies): "The Life and Death of Jonathan Wild, the Great", which is sometimes counted as his first, as he almost certainly began it before he wrote "Shamela" and "Joseph Andrews". It is a satire of Walpole equating him and Jonathan Wild, the gang leader and highwayman. He implicitly compares the Whig party in Parliament with a gang of thieves run by Walpole, whose constant desire to be a "Great Man" (a common epithet with Walpole) ought to culminate in the antithesis of greatness: hanging.  His anonymous "The Female Husband" (1746) fictionalizes a case in which a female transvestite was tried for duping another woman into marriage; this was one of several small pamphlets costing sixpence. Though a minor piece of Fielding's œuvre, it reflects his preoccupation with fraud, shamming and masks.  His greatest work was "Tom Jones" (1749), a meticulously constructed comic novel with elements of the picaresque novel and the Bildungsroman, telling the convoluted and hilarious tale of how a foundling came into a fortune. The plot of "Tom Jones" is too ingenious for simple summary; its basis is Tom's alienation from his foster father, Squire Allworthy, and his sweetheart, Sophia Western, and his reconciliation with them after lively and dangerous adventures on the road and in London. The triumph is its presentation of English life and character in the mid-18th century. Every social type is represented, and through them every shade of moral behaviour. Fielding's varied style tempers the basic seriousness of the novel and his authorial comment before each chapter adds a marked dimension to a conventionally straightforward narrative.

Sister.

Fielding's younger sister, Sarah, also became a successful writer. Her novel "The Governess, or The Little Female Academy" (1749) is thought to be the first novel in English aimed expressly at children.

Marriages.

Fielding married Charlotte Craddock in 1734 at the Church of St Mary in Charlcombe, Somerset. She died in 1744, and he later modelled the heroines of "Tom Jones" and of "Amelia" on her. They had five children; their only daughter Henrietta died at the age of 23, having already been "in deep decline" when she married a military engineer, James Gabriel Montresor, some months before. Three years after Charlotte's death, Fielding disregarded public opinion by marrying her former maid Mary Daniel, who was pregnant. Mary bore five children: three daughters who died young, and two sons, William and Allen.

Jurist and magistrate.

Despite this scandal, Fielding's consistent anti-Jacobitism and support for the Church of England led to his being appointed a year later as London's chief magistrate, while his literary career went from strength to strength. Most of his work concerned London's criminal population of thieves, informers, gamblers and prostitutes. Though living in a corrupt and callous society, he became noted for impartial judgements, incorruptibility and compassion for those whom social inequities forced into crime. The income from his office ("the dirtiest money upon earth") dwindled as he refused to take money from the very poor. Joined by his younger half-brother John, he helped found what some call London's first police force, the Bow Street Runners, in 1749.  According to the historian G. M. Trevelyan, the Fieldings were two of the best magistrates in 18th-century London, who did much to enhance judicial reform and improve prison conditions. Fielding's influential pamphlets and enquiries included a proposal for abolishing public hangings. This did not, however, imply opposition to capital punishment as such – as is evident, for example, in his presiding in 1751 over the trial of the notorious criminal James Field, finding him guilty in a robbery and sentencing him to hang. John Fielding, despite being blind by then, succeeded his older brother as chief magistrate, becoming known as the "Blind Beak of Bow Street" for his ability to recognise criminals by their voices alone. In January 1752 Fielding started a fortnightly, "The Covent-Garden Journal", which he published under the pseudonym "Sir Alexander Drawcansir, Knt., Censor of Great Britain" until November of that year. Here Fielding challenged the "armies of Grub Street" and periodical writers of the day in a conflict that became the Paper War of 1752–1753.  Fielding then published "Examples of the Interposition of Providence in the Detection and Punishment of Murder" (1752), a treatise rejecting deistic and materialistic visions of the world in favour of belief in God's presence and divine judgement, arguing that the murder rate was rising due to neglect of the Christian religion. In 1753 he wrote "Proposals for Making an Effectual Provision for the Poor".  Fielding's humanitarian commitment to justice in the 1750s (for instance in support of Elizabeth Canning) coincided with rapid deterioration in his health. Gout, asthma and cirrhosis of the liver left him on crutches, and with other afflictions sent him to Portugal in 1754 to seek a cure, only to die two months later in Lisbon, reportedly in pain and mental distress. His tomb there is in the English Cemetery ("Cemitério Inglês"), now the graveyard of St. George's Church, Lisbon.

Henry Fielding (22 April 1707 – 8 October 1754) was an English novelist and dramatist known for his earthy humour and satire, and as the author of the comic novel "Tom Jones". He also holds a place in the history of law enforcement, having used his authority as a magistrate to found the Bow Street Runners, which some have called London's first police force.

Henry Fielding [Fildyng] (22. dubna 1707 Sharpham Park – 8. října 1754 Lisabon) byl anglický spisovatel, publicista a právník, představitel realismu.


Etymology.

Hydrochloric acid was known to European alchemists as "spirits of salt" or "acidum salis" (salt acid). Both names are still used, especially in other languages, such as,,,,, Bulgarian: солна киселина, Russian: соляная кислота,, Korean: 염산, and Japanese: 塩酸. Gaseous HCl was called "marine acid air".  The old (pre-systematic) name "muriatic acid" has the same origin ("muriatic" means "pertaining to brine or salt", hence "muriate" means hydrochloride), and this name is still sometimes used. The name "hydrochloric acid" was coined by the French chemist Joseph Louis Gay-Lussac in 1814.

History.

Hydrochloric acid has been an important and frequently used chemical from early history and was discovered by the alchemist Jabir ibn Hayyan around the year 800 AD.  Aqua regia, a mixture consisting of hydrochloric and nitric acids, prepared by dissolving sal ammoniac in nitric acid, was described in the works of Pseudo-Geber, a 13th-century European alchemist. Other references suggest that the first mention of aqua regia is in Byzantine manuscripts dating to the end of the 13th century.  Free hydrochloric acid was first formally described in the 16th century by Libavius, who prepared it by heating salt in clay crucibles. Other authors claim that pure hydrochloric acid was first discovered by the German Benedictine monk Basil Valentine in the 15th century, when he heated common salt and green vitriol, whereas others argue that there is no clear reference to the preparation of pure hydrochloric acid until the end of the 16th century.  In the 17th century, Johann Rudolf Glauber from Karlstadt am Main, Germany used sodium chloride salt and sulfuric acid for the preparation of sodium sulfate in the Mannheim process, releasing hydrogen chloride gas. Joseph Priestley of Leeds, England prepared pure hydrogen chloride in 1772, and by 1808 Humphry Davy of Penzance, England had proved that the chemical composition included hydrogen and chlorine.  During the Industrial Revolution in Europe, demand for alkaline substances increased. A new industrial process developed by Nicolas Leblanc of Issoudun, France enabled cheap large-scale production of sodium carbonate (soda ash). In this Leblanc process, common salt is converted to soda ash, using sulfuric acid, limestone, and coal, releasing hydrogen chloride as a by-product. Until the British Alkali Act 1863 and similar legislation in other countries, the excess HCl was vented into the air. After the passage of the act, soda ash producers were obliged to absorb the waste gas in water, producing hydrochloric acid on an industrial scale.  In the 20th century, the Leblanc process was effectively replaced by the Solvay process without a hydrochloric acid by-product. Since hydrochloric acid was already fully settled as an important chemical in numerous applications, the commercial interest initiated other production methods, some of which are still used today. After the year 2000, hydrochloric acid is mostly made by absorbing by-product hydrogen chloride from industrial organic compounds production.  Since 1988, hydrochloric acid has been listed as a Table II precursor under the 1988 United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances because of its use in the production of heroin, cocaine, and methamphetamine.

Structure and reactions.

Hydrochloric acid is the salt of the hydronium ion, HO and chloride. It is usually prepared by treating HCl with water.  However, the speciation of hydrochloric acid is more complicated than this simple equation implies. The structure of bulk water is infamously complex, and likewise, the formula HO is also a gross oversimplification of the true nature of the solvated proton, H, present in hydrochloric acid. A combined IR, Raman, X-ray and neutron diffraction study of concentrated solutions of hydrochloric acid revealed that the primary form of H in these solutions is HO, which, along with the chloride anion, is hydrogen-bonded to neighboring water molecules in several different ways. (In HO, the proton is sandwiched midway between two water molecules at 180°). The author suggests that HO may become more important in dilute HCl solutions. (See Hydronium for further discussion of this issue.)  Hydrochloric acid is a strong acid, since it is completely dissociated in water. It can therefore be used to prepare salts containing the Cl anion called "chlorides".  As a strong acid, hydrogen chloride has a large "K". Theoretical attempts to assign the p"K" of hydrogen chloride have been made, with the most recent estimate being −5.9. However, it is important to distinguish between hydrogen chloride gas and hydrochloric acid. Due to the leveling effect, except when highly concentrated and behavior deviates from ideality, "hydrochloric acid" (aqueous HCl) is only as acidic as the strongest proton donor available in water, the aquated proton (popularly known as "hydronium ion"). When chloride salts such as NaCl are added to aqueous HCl, they have only a minor effect on pH, indicating that Cl is a very weak conjugate base and that HCl is fully dissociated in aqueous solution. Dilute solutions of HCl have a pH close to that predicted by assuming full dissociation into hydrated H and Cl.  Of the six common strong mineral acids in chemistry, hydrochloric acid is the monoprotic acid least likely to undergo an interfering oxidation-reduction reaction. It is one of the least hazardous strong acids to handle; despite its acidity, it consists of the non-reactive and non-toxic chloride ion. Intermediate-strength hydrochloric acid solutions are quite stable upon storage, maintaining their concentrations over time. These attributes, plus the fact that it is available as a pure reagent, make hydrochloric acid an excellent acidifying reagent.  Hydrochloric acid is the preferred acid in titration for determining the amount of bases. Strong acid titrants give more precise results due to a more distinct endpoint. Azeotropic, or "constant-boiling", hydrochloric acid (roughly 20.2%) can be used as a primary standard in quantitative analysis, although its exact concentration depends on the atmospheric pressure when it is prepared.  Hydrochloric acid is frequently used in chemical analysis to prepare ("digest") samples for analysis. Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas. It also reacts with basic compounds such as calcium carbonate or copper(II) oxide, forming the dissolved chlorides that can be analyzed.

Physical properties.

Physical properties of hydrochloric acid, such as boiling and melting points, density, and pH, depend on the concentration or molarity of HCl in the aqueous solution. They range from those of water at very low concentrations approaching 0% HCl to values for fuming hydrochloric acid at over 40% HCl.  Hydrochloric acid as the binary (two-component) mixture of HCl and HO has a constant-boiling azeotrope at 20.2% HCl and 108.6 °C (227 °F). There are four constant-crystallization eutectic points for hydrochloric acid, between the crystal form of HCl·HO (68% HCl), HCl·2HO (51% HCl), HCl·3HO (41% HCl), HCl·6HO (25% HCl), and ice (0% HCl). There is also a metastable eutectic point at 24.8% between ice and the HCl·3HO crystallization.

Production.

Hydrochloric acid is prepared by dissolving hydrogen chloride in water. Hydrogen chloride can be generated in many ways, and thus several precursors to hydrochloric acid exist. The large-scale production of hydrochloric acid is almost always integrated with the industrial scale production of other chemicals.

Industrial market.

Hydrochloric acid is produced in solutions up to 38% HCl (concentrated grade). Higher concentrations up to just over 40% are chemically possible, but the evaporation rate is then so high that storage and handling require extra precautions, such as pressurization and cooling. Bulk industrial-grade is therefore 30% to 35%, optimized to balance transport efficiency and product loss through evaporation. In the United States, solutions of between 20% and 32% are sold as muriatic acid. Solutions for household purposes in the US, mostly cleaning, are typically 10% to 12%, with strong recommendations to dilute before use. In the United Kingdom, where it is sold as "Spirits of Salt" for domestic cleaning, the potency is the same as the US industrial grade. In other countries, such as Italy, hydrochloric acid for domestic or industrial cleaning is sold as "Acido Muriatico", and its concentration ranges from 5% to 32%.  Major producers worldwide include Dow Chemical at 2 million metric tons annually (2 Mt/year), calculated as HCl gas, Georgia Gulf Corporation, Tosoh Corporation, Akzo Nobel, and Tessenderlo at 0.5 to 1.5 Mt/year each. Total world production, for comparison purposes expressed as HCl, is estimated at 20 Mt/year, with 3 Mt/year from direct synthesis, and the rest as secondary product from organic and similar syntheses. By far, most hydrochloric acid is consumed captively by the producer. The open world market size is estimated at 5 Mt/year.

Applications.

Hydrochloric acid is a strong inorganic acid that is used in many industrial processes such as refining metal. The application often determines the required product quality.

Pickling of steel.

One of the most important applications of hydrochloric acid is in the pickling of steel, to remove rust or iron oxide scale from iron or steel before subsequent processing, such as extrusion, rolling, galvanizing, and other techniques. Technical quality HCl at typically 18% concentration is the most commonly used pickling agent for the pickling of carbon steel grades.  The spent acid has long been reused as iron(II) chloride (also known as ferrous chloride) solutions, but high heavy-metal levels in the pickling liquor have decreased this practice.  The steel pickling industry has developed hydrochloric acid regeneration processes, such as the spray roaster or the fluidized bed HCl regeneration process, which allow the recovery of HCl from spent pickling liquor. The most common regeneration process is the pyrohydrolysis process, applying the following formula:  By recuperation of the spent acid, a closed acid loop is established. The iron(III) oxide by-product of the regeneration process is valuable, used in a variety of secondary industries.

Production of organic compounds.

Another major use of hydrochloric acid is in the production of organic compounds, such as vinyl chloride and dichloroethane for PVC. This is often captive use, consuming locally produced hydrochloric acid that never actually reaches the open market. Other organic compounds produced with hydrochloric acid include bisphenol A for polycarbonate, activated carbon, and ascorbic acid, as well as numerous pharmaceutical products.

Production of inorganic compounds.

Numerous products can be produced with hydrochloric acid in normal acid-base reactions, resulting in inorganic compounds. These include water treatment chemicals such as iron(III) chloride and polyaluminium chloride (PAC).  Both iron(III) chloride and PAC are used as flocculation and coagulation agents in sewage treatment, drinking water production, and paper production.  Other inorganic compounds produced with hydrochloric acid include road application salt calcium chloride, nickel(II) chloride for electroplating, and zinc chloride for the galvanizing industry and battery production.

pH control and neutralization.

Hydrochloric acid can be used to regulate the acidity (pH) of solutions.  In industry demanding purity (food, pharmaceutical, drinking water), high-quality hydrochloric acid is used to control the pH of process water streams. In less-demanding industry, technical quality hydrochloric acid suffices for neutralizing waste streams and swimming pool pH control.

Regeneration of ion exchangers.

High-quality hydrochloric acid is used in the regeneration of ion exchange resins. Cation exchange is widely used to remove ions such as Na and Ca from aqueous solutions, producing demineralized water. The acid is used to rinse the cations from the resins. Na is replaced with H and Ca with 2 H.  Ion exchangers and demineralized water are used in all chemical industries, drinking water production, and many food industries.

Other.

Hydrochloric acid is used for a large number of small-scale applications, such as leather processing, purification of common salt, household cleaning, and building construction. Oil production may be stimulated by injecting hydrochloric acid into the rock formation of an oil well, dissolving a portion of the rock, and creating a large-pore structure. Oil well acidizing is a common process in the North Sea oil production industry.  Hydrochloric acid has been used for dissolving calcium carbonate, i.e. such things as de-scaling kettles and for cleaning mortar off brickwork, but it is a hazardous liquid which must be used with care. When used on brickwork the reaction with the mortar only continues until the acid has all been converted, producing calcium chloride, carbon dioxide, and water:  Many chemical reactions involving hydrochloric acid are applied in the production of food, food ingredients, and food additives. Typical products include aspartame, fructose, citric acid, lysine, hydrolyzed vegetable protein as food enhancer, and in gelatin production. Food-grade (extra-pure) hydrochloric acid can be applied when needed for the final product.

Presence in living organisms.

Gastric acid is one of the main secretions of the stomach. It consists mainly of hydrochloric acid and acidifies the stomach content to a pH of 1 to 2.  Chloride (Cl) and hydrogen (H) ions are secreted separately in the stomach fundus region at the top of the stomach by parietal cells of the gastric mucosa into a secretory network called canaliculi before it enters the stomach lumen.  Gastric acid acts as a barrier against microorganisms to prevent infections and is important for the digestion of food. Its low pH denatures proteins and thereby makes them susceptible to degradation by digestive enzymes such as pepsin. The low pH also activates the enzyme precursor pepsinogen into the active enzyme pepsin by self-cleavage. After leaving the stomach, the hydrochloric acid of the chyme is neutralized in the duodenum by sodium bicarbonate.  The stomach itself is protected from the strong acid by the secretion of a thick mucus layer, and by secretin induced buffering with sodium bicarbonate. Heartburn or peptic ulcers can develop when these mechanisms fail. Drugs of the antihistaminic and proton pump inhibitor classes can inhibit the production of acid in the stomach, and antacids are used to neutralize excessive existing acid.

Safety.

Concentrated hydrochloric acid (fuming hydrochloric acid) forms acidic mists. Both the mist and the solution have a corrosive effect on human tissue, with the potential to damage respiratory organs, eyes, skin, and intestines irreversibly. Upon mixing hydrochloric acid with common oxidizing chemicals, such as sodium hypochlorite (bleach, NaClO) or potassium permanganate (KMnO), the toxic gas chlorine is produced.  Personal protective equipment such as latex gloves, protective eye goggles, and chemical-resistant clothing and shoes will minimize risks when handling hydrochloric acid. The United States Environmental Protection Agency rates and regulates hydrochloric acid as a toxic substance.  The UN number or DOT number is 1789. This number will be displayed on a placard on the container.

Hydrochloric acid or muriatic acid is a colorless inorganic chemical system with the formula. Hydrochloric acid has a distinctive pungent smell. It is classified as strongly acidic and can attack the skin over a wide composition range, since the hydrogen chloride completely dissociates in an aqueous solution.

Kyselina chlorovodíková (též kyselina solná, latinsky "acidum hydrochloricum") je velmi silná kyselina, jedna z lidstvu nejdéle známých a nejvíce využívaných. Jde o vodný roztok plynného chlorovodíku (HCl).