Unalaska is the chief center of population in the Aleutian Islands. The city is in the Aleutians West Census Area, a regional component of the Unorganized Borough in the U. S. state of Alaska. Unalaska is located on Unalaska Island and neighboring Amaknak Island in the Aleutian Islands off mainland Alaska; the population was 4,376 at the 2010 census, 79% of the entire Aleutians West Census Area. Unalaska is the second largest city behind Bethel; the Aleut or Unangan people have lived on Unalaska Island for thousands of years. The Unangan, who were the first to inhabit the island of Unalaska, named it "Ounalashka", meaning "near the peninsula"; the regional native corporation has adopted this moniker, is known as the Ounalashka Corporation. The Russian fur trade reached Unalaska when Stepan Glotov and his crew arrived on August 1, 1759. Natives and their descendants comprised most of the community's population until the mid-20th century, when the involvement of the United States in World War II led to a large-scale influx of people and construction of buildings all along the strategically located Aleutians.
All of the community's port facilities are on Amaknak Island, better known as Dutch Harbor or just "Dutch". It is the largest fisheries port in the U. S. by volume caught. It includes Dutch Harbor Naval Operating Base and Fort Mears, U. S. Army, a U. S. National Historic Landmark. Dutch Harbor is connected to Unalaska by a bridge. Amaknak Island is home to 59 percent of the city's population, although it has less than 3 percent of its land area; the island of Unalaska was first inhabited by the Aleut people, who named it "Ounalashka", meaning: "Near the Peninsula". They developed an intricate and complex society long before their first contact with the Russian fur traders who would document their existence. Unalaska and Amaknak Islands contained 24 settlements with more than 1,000 Aleut inhabitants in 1759, when the first Russian group under Stepan Glotov came and started trading for three years on Umnak and Unalaska. Between 1763 and 1766, a conflict between the Russian fur traders and the Unalaska Natives occurred.
Solov'ev returned to Unalaska and directed the massacre of many Natives. In the 1760s, Unalaska was temporarily used as a Russian fur trading post; the post was permanently established in 1774, was incorporated into the Russian-American Company. It was there that Captain James Cook encountered the navigator Gerasim Izmailov in 1778. In 1788 the Spanish made contact with the Russians in Alaska for the first time. An expedition by Esteban José Martínez and Gonzalo López de Haro visited several Russian settlements, their westernmost visit was to Unalaska. On August 5, 1788, they claimed Unalaska for Spain. Alexander Andreyevich Baranov was shipwrecked here in 1790. In 1825, the Russian Orthodox Church of the Holy Ascension was built in Unalaska; the founding priest, Ivan Veniaminov canonized as Saint Innocent of Alaska, composed the first Aleut writing system with local assistance, translated scripture into Aleut. Between 1836 and 1840, chicken-pox and whooping-cough epidemics drastically reduced the population.
On October 18, 1867, the United States purchased Alaska, making Unalaska part of the U. S. territory. In 1880, the Methodist Church opened a clinic for orphans in Unalaska. Between 1899 and 1905, the Gold Rush brought many ships through Dutch Harbor where the North American Commercial Company had a coaling station. During the first half of the century, the island was touched by numerous epidemics, first in 1900, in 1919 the Spanish flu touched the island: these contributed to a dramatic decrease of the population in Unalaska; the United States started fortifying Dutch Harbor in 1940, resulting in the construction of the Dutch Harbor Naval Operating Base and Fort Mears. On June 3, 1942, the town was attacked by Japanese forces in the Battle of Dutch Harbor, part of the Aleutian Islands campaign. After the attack and the Japanese occupation of Attu all of the native residents of the island were arrested. Many were held, in camps in Southeast Alaska for the duration of the war. Beginning in the 1950s, Unalaska became a center of the Alaskan king crab fishing industry.
A 1982 crash in king crab harvests decimated the industry, the mid-1980s saw a transition to bottom fishing. The city has struggled with problems like alcoholism and unemployment in the past and still does, although the situation has improved in recent years. One example is the Elbow Room, a bar which locally, abroad, became infamous for its raucousness, it was closed in 2005. Since 2005, the Discovery Channel's documentary show Deadliest Catch has focused on fishermen who are based in Dutch Harbor. According to the U. S. Census Bureau, the city has a total area of 212.3 square miles, of which 111.0 square miles is land and 101.3 square miles of it is water. Makushin Volcano is located on the island. By climbing one of the smaller hills in the area, such as Pyramid Peak or Mount Newhall, it is possible to get a good look at the snow-covered cone. A major find was announced in 2015 after scientists examined a group of giant, quadruped, marine mammal fossils; the speci
A sail is a tensile structure—made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, windsurfers, ice boats, sail-powered land vehicles. Sails may be made from a combination of woven materials—including canvas or polyester cloth, laminated membranes or bonded filaments—usually in a three- or four-sided shape. A sail provides propulsive force via a combination of lift and drag, depending on its angle of attack—its angle with respect to the apparent wind. Apparent wind is the air velocity experienced on the moving craft and is the combined effect of the true wind velocity with the velocity of the sailing craft. Angle of attack is constrained by the sailing craft's orientation to the wind or point of sail. On points of sail where it is possible to align the leading edge of the sail with the apparent wind, the sail may act as an airfoil, generating propulsive force as air passes along its surface—just as an airplane wing generates lift—which predominates over aerodynamic drag retarding forward motion.
The more that the angle of attack diverges from the apparent wind as a sailing craft turns downwind, the more drag increases and lift decreases as propulsive forces, until a sail going downwind is predominated by drag forces. Sails are unable to generate propulsive force if they are aligned too to the wind. Sails may be attached to a mast, boom or other spar or may be attached to a wire, suspended by a mast, they are raised by a line, called a halyard, their angle with respect to the wind is controlled by a line, called a sheet. In use, they may be designed to be curved in both directions along their surface as a result of their curved edges. Battens may be used to extend the trailing edge of a sail beyond the line of its attachment points. Other non-rotating airfoils that power sailing craft include wingsails, which are rigid wing-like structures, kites that power kite-rigged vessels, but do not employ a mast to support the airfoil and are beyond the scope of this article. Sailing craft employ two types of the square rig and the fore-and-aft rig.
The square rig carries the primary driving sails are carried on horizontal spars, which are perpendicular or square, to the keel of the vessel and to the masts. These spars are called yards and their tips, beyond the last stay, are called the yardarms. A ship so rigged is called a square-rigger; the square rig is aerodynamically most efficient. A fore-and-aft rig consists of sails that are set along the line of the keel rather than perpendicular to it. Vessels so rigged. Archaeological studies of the Cucuteni-Trypillian culture ceramics show use of sailing boats from the sixth millennium BCE onwards. Excavations of the Ubaid period in Mesopotamia provides direct evidence of sailing boats. Sails from ancient Egypt are depicted around 3200 BCE, where reed boats sailed upstream against the River Nile's current. Ancient Sumerians used square rigged sailing boats at about the same time, it is believed they established sea trading routes as far away as the Indus valley; the proto-Austronesian words for sail and other rigging parts date to about 3000 BCE when this group began their Pacific expansion.
Greeks and Phoenicians began trading by ship by around 1200 BCE. Triangular fore-and-aft rigs were invented in the Mediterranean as single-yarded lateen sails and independently in the Pacific as the more efficient bi-sparred crab claw sail, continue to be used throughout the world. During the 16th-19th centuries other fore-and-aft sails were developed in Europe, such as the spritsail, gaff rig, genoa and Bermuda rig mainsail, improving the upwind sailing ability of European vessels; the fore-and-aft rig began as a convention of southern Europe and the Mediterranean Sea: the gentle climate made its use practical, in Italy a few centuries before the Renaissance it began to replace the square rig which had dominated all of Europe since the dawn of sea travel. Northern Europeans were resistant to adopting the fore-and-aft rig, despite having seen its use in the course of trade and during the Crusades; the Renaissance changed this: beginning in 1475, their use increased and within a hundred years the fore-and-aft rig was in common use on rivers and in estuaries in Britain, northern France, the Low Countries, though the square rig remained standard for the harsher conditions of the open North Sea as well as for trans-Atlantic sailing.
The lateen sail proved to have better upwind performance for smaller vessels. Aerodynamic forces on sails depend on wind speed and direction and the speed and direction of the craft; the direction that the craft is traveling with respect to the true wind is called the "point of sail". The speed of the craft at a given point of sail contributes to the apparent wind —the wind speed and direction as measured on the moving craft; the apparent wind on the sail creates a total aerodynamic force, which may be resolved into drag—the force component in the direction of the apparent wind—and lift—the force component normal to the apparent wind. Depending on the alignment of the sail with the apparent wind, lift or drag may be the predominant propulsive component. Total aerodynamic force resolves into a forward, driving force—resisted by the medium through or over which the craft is passing —and a lateral force, resisted by the underwater foils, ice runners, or wheels of the sailing craft. For apparent wind angles aligned with the entry point of the sail, the sail acts as an airfoil and lift is the predominant component of propulsion.
Russian America was the name of the Russian colonial possessions in North America from 1733 to 1867. Its capital was Novo-Archangelsk, now Sitka, Alaska, USA. Settlements spanned parts of what are now the U. S. states of California and two ports in Hawaii. Formal incorporation of the possessions by Russia did not take place until the Ukase of 1799 which established a monopoly for the Russian–American Company and granted the Russian Orthodox Church certain rights in the new possessions. Many of its possessions were abandoned in the 19th century. In 1867, Russia sold its last remaining possessions to the United States of America for $7.2 million. The earliest written accounts indicate. In 1648 Semyon Dezhnev sailed from the mouth of the Kolyma River through the Arctic Ocean and around the eastern tip of Asia to the Anadyr River. One legend holds that some of his boats were reached Alaska. However, no evidence of settlement survives. Dezhnev's discovery was never forwarded to the central government, leaving open the question of whether or not Siberia was connected to North America.
In 1725, Tsar Peter the Great called for another expedition. As a part of the 1733 -- 1743 Second Kamchatka the Sv. Petr under the Dane Vitus Bering and the Sv. Pavel under the Russian Alexei Chirikov set sail from the Kamchatkan port of Petropavlovsk in June 1741, they were soon separated. On 15 July, Chirikov sighted land the west side of Prince of Wales Island in southeast Alaska, he sent a group of men ashore in a longboat, making them the first Europeans to land on the northwestern coast of North America. On 16 July and the crew of Sv. Petr sighted Mount Saint Elias on the Alaskan mainland. Meanwhile and the Sv. Pavel headed back to Russia in October with news of the land. In November Bering's ship was wrecked on Bering Island. There Bering fell ill and died, high winds dashed the Sv. Petr to pieces. After the stranded crew wintered on the island, the survivors built a boat from the wreckage and set sail for Russia in August 1742. Bering's crew reached the shore of Kamchatka in 1742; the high quality of the sea-otter pelts.
From 1743 small associations of fur traders began to sail from the shores of the Russian Pacific coast to the Aleutian islands. As the runs from Asiatic Russia to America became longer expeditions, the crews established hunting and trading posts. By the late 1790s, some of these had become permanent settlements. Half of the fur traders were from the various European parts of the Russian Empire, while the others were Siberian or of mixed origins. Rather than hunting the marine life, the Russians forced the Aleuts to do the work for them by taking hostage family members in exchange for hunted seal furs; as word spread of the riches in furs to be had, competition among Russian companies increased and the Aleuts were enslaved. Catherine the Great, who became Empress in 1763, proclaimed goodwill toward the Aleuts and urged her subjects to treat them fairly. On some islands and parts of the Alaska Peninsula, groups of traders had been capable of peaceful coexistence with the local inhabitants. Other groups could not manage the committed acts of violence.
Hostages were taken, families were split up, individuals were forced to leave their villages and settle elsewhere. The growing competition between the trading companies, merging into fewer and more powerful corporations, created conflicts that aggravated the relations with the indigenous populations. Over the years, the situation became catastrophic; as the animal populations declined, the Aleuts too dependent on the new barter economy created by the Russian fur-trade, were coerced into taking greater and greater risks in the dangerous waters of the North Pacific to hunt for more otter. As the Shelekhov-Golikov Company developed a monopoly, it used skirmishes and violent incidents turned into systematic violence as a tool of colonial exploitation of the indigenous people; when the Aleuts revolted and won some victories, the Russians retaliated, killing many and destroying their boats and hunting gear, leaving them no means of survival. The most devastating effects were from disease: during the first two generations of Russian contact, 80 percent of the Aleut population died from Eurasian infectious diseases.
Though the Alaskan colony was never profitable because of the costs of transportation, most Russian traders were determined to keep the land for themselves. In 1784, Grigory Ivanovich Shelekhov, who would set up the Russian-Alaska Company that became the Alaskan colonial administration, arrived in Three Saints Bay on Kodiak Island with two ships, the Three Saints and the St. Simon; the Koniag Alaska Natives harassed the Russian party and Shelekhov responded by killing hundreds and taking hostages to enforce the obedience of the rest. Having established his authority on Kodiak Island, Shelekhov founded the second permanent Russian settlement in Alaska on the island's Three Saints Bay. In 1790, back in Russia, hired Alexander Andreyevich Baranov to manage his Alaskan fur enterprise. Baranov moved the colony to the northeast end of Kodiak Island; the site developed as
Cook Inlet stretches 180 miles from the Gulf of Alaska to Anchorage in south-central Alaska. Cook Inlet branches into the Knik Arm and Turnagain Arm at its northern end surrounding Anchorage. On its south end merges with Shelikof Strait, Stevenson Entrance, Kennedy Entrance and Chugach Passage; the watershed covers about 100,000 km² of southern Alaska, east of the Aleutian Range and east of the Alaska Range, receiving water from its tributaries the Knik River, the Little Susitna River, the Susitna and Matanuska rivers. The watershed includes the drainage areas of Denali. Within the watershed there are several national parks and the active volcano Mount Redoubt, along with three other active volcanoes. Cook Inlet provides navigable access to the port of Anchorage at the northern end, to the smaller Homer port further south. Before the growth of Anchorage, Knik was the destination for most marine traffic in upper Cook Inlet. 400,000 people live within the Cook Inlet watershed. The Cook Inlet region contains active volcanoes, including Mount Redoubt.
Volcanic eruptions in the region have been associated with earthquakes and tsunamis, debris avalanches have resulted in tsunamis also. There was an earthquake of the magnitude of 7.1 on December 31, 1901 generated by an eruption that caused several tsunamis. In 2009 a lahar from Mt. Redoubt threatened the Drift River oil terminal; the inlet was first settled by Dena'ina people. In the 18th century, Russian fur hunters were among the first European visitors; the Lebedev Lastochkin Company leader Stepan Zaikov established a post at the mouth of the Kenai River, Fort Nikolaev, in 1786. These fur trappers used Siberian Native and Alaska Native people Aleuts from the Aleutian Islands and Koniag natives from Kodiak, to hunt for sea otters and other marine mammal species for trade with China via Russia's then-exclusive inland port of trade at Kiakhta. Other Europeans to visit Cook Inlet include the 1778 expedition of James Cook, its namesake, who sailed into it while searching for the Northwest Passage.
Cook received maps of Alaska, the Aleutians, Kamchatka during a visit with Russian fur trader Gerasim Izmailov in Unalaska, combined these maps with those of his expedition to create the first Mercator projection of the North Pacific. The inlet was named after Cook in 1794 by George Vancouver, who had served under Cook in 1778. Turnagain Arm was named by William Bligh of HMS Bounty fame. Bligh served as Cook's Sailing Master on his 3rd and final voyage, the aim of, discovery of the Northwest Passage. Upon reaching the head of Cook Inlet, Bligh was of the opinion that both Knik Arm and Turnagain Arm were the mouths of rivers and not the opening to the Northwest Passage. Under Cook's orders Bligh organized a party to travel up Knik Arm, which returned to report Knik Arm indeed led only to a river. Afterwards a second party was dispatched up Turnagain Arm and it too returned to report only a river lay ahead; as a result of this frustration the second body of water was given the disingenuous name "Turn Again".
Early maps label Turnagain Arm as the "Turnagain River". The S. S. Farallon was a wooden Alaskan Steamship Company liner that struck Black Reef in the Cook Inlet on January 5, 1910. All thirty-eight men on board survived, were rescued twenty-nine days later. Few white people visited upper Cook Inlet until construction of the Alaska Railroad along the eastern shores of Turnagain Arm and Knik Arm of Cook Inlet around 1915; the natives of the Eklutna village are the descendants of the residents of eight native villages around upper Cook Inlet. During the 1964 Alaska earthquake, areas around the head of Turnagain Arm near Girdwood and Portage dropped as much as 8 feet by subsidence and subsequent tidal action. Both hamlets were destroyed. Girdwood was relocated inland and Portage was abandoned. About 20 miles of the Seward Highway sank below the high-water mark of Turnagain Arm. Most of Alaska's population surrounds Cook Inlet, concentrated in the Anchorage, Alaska area and in communities on the Kenai Peninsula.
The more remote west side of the inlet is not connected to the road system, is home to the village of Tyonek, a number of oil camps. The Cook Inlet Basin contains large gas deposits including several offshore fields; as of 2005 there were 16 platforms in Cook Inlet, the oldest of, the XTO A platform first installed by Shell in 1964, newest of, the Osprey platform installed by Forest Oil in 2000. Most of the platforms are operated by Union Oil, acquired by Chevron in 2005. There are numerous oil and gas pipelines running around and under the Cook Inlet; the main destinations of the gas pipelines are to Kenai where the gas is used to fuel commercial fertilizer production and a liquified natural gas plant and to Anchorage where the gas is consumed for domestic uses. Alaska has half the known coal reserves in the U. S. For decades, there has been a proposal to build a large coal mine on the west side of Cook Inlet near the Chuitna River, the native village of Tyonek, Alaska. American Rivers has placed the Chuitna River on its list of the 10 most endangered rivers for 2007, based on the threat of this mine.
Turnagain Arm is one of only about 60 bodies of water worldwide to exhibit a tidal bore. The bore may be more than six feet high and travel at 15 miles per hour on high spring tides and opposing winds. Turnagain Arm sees the largest tidal range in United States, with a mean of 30 feet, the fourth highest in th
A kayak is a small, narrow watercraft, propelled by means of a double-bladed paddle. The word kayak originates from the Greenlandic word qajaq; the traditional kayak has one or more cockpits, each seating one paddler. The cockpit is sometimes covered by a spray deck that prevents the entry of water from waves or spray, differentiating the craft from a canoe; the spray deck makes it possible for suitably skilled kayakers to roll the kayak: that is, to capsize and right it without it filling with water or ejecting the paddler. Some modern boats vary from a traditional design but still claim the title "kayak", for instance in eliminating the cockpit by seating the paddler on top of the boat. Kayaks are being sailed, as well as propelled by means of small electric motors, by outboard gas engines; the kayak was first used by the indigenous Aleut, Inuit and Ainu hunters in subarctic regions of the world. Kayaks were developed by the Inuit, Yup'ik, Aleut, they used the boats to hunt on inland lakes and coastal waters of the Arctic Ocean, North Atlantic, Bering Sea and North Pacific oceans.
These first kayaks were constructed from stitched seal or other animal skins stretched over a wood or whalebone-skeleton frame.. Kayaks are believed to be at least 4,000 years old; the oldest existing kayaks are exhibited in the North America department of the State Museum of Ethnology in Munich, with the oldest dating from 1577. Native people made many types of boat for different purposes; the Aleut baidarka was made in double or triple cockpit designs, for hunting and transporting passengers or goods. An umiak is a large open sea canoe, ranging from 17 to 30 feet, made with wood, it is considered a kayak although it was paddled with single-bladed paddles, had more than one paddler. Native builders designed and built their boats based on their own experience and that of the generations before them, passed on through oral tradition; the word "kayak" means "man's boat" or "hunter's boat", native kayaks were a personal craft, each built by the man who used it—with assistance from his wife, who sewed the skins—and fitting his size for maximum maneuverability.
The paddler wore a tuilik, a garment, stretched over the rim of the kayak coaming, sealed with drawstrings at the coaming and hood edges. This enabled the "eskimo roll" and rescue to become the preferred methods of recovery after capsizing as few Inuit could swim. Instead of a tuilik, most traditional kayakers today use a spray deck made of waterproof synthetic material stretchy enough to fit around the cockpit rim and body of the kayaker, which can be released from the cockpit to permit easy exit. Inuit kayak builders had specific measurements for their boats; the length was three times the span of his outstretched arms. The width at the cockpit was the width of the builder's hips plus two fists; the typical depth was his fist plus the outstretched thumb. Thus typical dimensions were about 17 feet long by 20–22 inches wide by 7 inches deep; this measurement system confounded early European explorers who tried to duplicate the kayak, because each kayak was a little different. Traditional kayaks encompass three types: Baidarkas, from the Bering sea & Aleutian islands, the oldest design, whose rounded shape and numerous chines give them an Blimp-like appearance.
Most of the Aleut people in the Aleutian Islands eastward to Greenland Inuit relied on the kayak for hunting a variety of prey—primarily seals, though whales and caribou were important in some areas. Skin-on-frame kayaks are still being used for hunting by Inuit people in Greenland, because the smooth and flexible skin glides silently through the waves. In other parts of the world home builders are continuing the tradition of skin on frame kayaks with modern skins of canvas or synthetic fabric, such as sc. ballistic nylon. Contemporary traditional-style kayaks trace their origins to the native boats of Alaska, northern Canada, Southwest Greenland. Wooden kayaks and fabric kayaks on wooden frames dominated the market up until the 1950s, when fiberglass boats were first introduced in the US, inflatable rubberized fabric boats were first introduced in Europe. Rotomolded plastic kayaks first appeared in 1973, most kayaks today are made from roto-molded polyethylene resins; the development of plastic and rubberized inflatable kayaks arguably initiated the development of freestyle kayaking as we see it today, since these boats could be made smaller and more resilient than fiberglass boats.
Kayak design is a matter of trade-offs: directional stability vs maneuverability. Multihull kayaks face a different set of trade-offs; the paddler's body shap
Port and starboard
Port and starboard are nautical and aeronautical terms of orientation that deal unambiguously with the structure of vessels and aircraft. Their structures are bilaterally symmetrical, meaning they have mirror-image left and right halves if divided long-ways down the middle. One asymmetric feature is that on aircraft and ships where access is at the side, this access is only provided on the port side. To understand, which, when a person is on board and facing the bow on a vessel or aircraft, that is, facing forward towards the direction the vehicle is heading when underway, the port side is the left-hand side and the starboard side is the right-hand side; however and starboard never change. The term starboard derives from the Old English steorbord, meaning the side on which the ship is steered. Before ships had rudders on their centrelines, they were steered with a steering oar at the stern of the ship on the right hand side of the ship, because more people are right-handed. Since the steering oar was on the right side of the boat, it would tie up at the wharf on the other side.
Hence the left side was called port. The Oxford English Dictionary cites port in this usage since 1543. Larboard was used instead of port; this is from Middle English ladebord and the term lade is related to the modern load. Larboard sounds similar to starboard and in 1844 the Royal Navy ordered that port be used instead; the United States Navy followed suit in 1846. Larboard continued to be used well into the 1850s by whalers. An Anglo-Saxon record of a voyage by Ohthere of Hålogaland used the word "bæcbord" for the left side of a ship; the navigational treaty convention, the International Regulations for Preventing Collisions at Sea—for instance, as appears in the UK's Merchant Shipping Regulations 1996 —sets forth requirements for maritime vessels to avoid collisions, whether by sail or powered, whether a vessel is overtaking, approaching head-on, or crossing. To set forth these navigational rules, the terms starboard and port are essential, to aid in in situ decision-making, the two sides of each vessel are marked, dusk to dawn, by navigation lights, the vessel's starboard side by green and its port side by red.
Aircraft are lit in the same way. Anatomical terms of location, another example of terms of directionality that do not depend on the location of the observer for things that are bilaterally symmetrical Direction Glossary of nautical terms Handedness Laterality Proper right and proper left Reflection symmetry Sinistral and dextral
A mattress is a large, rectangular pad for supporting the reclining body, designed to be used as a bed or on a bed frame, as part of a bed. Mattresses may consist of a quilted or fastened case of heavy cloth, that contains materials such as hair, cotton, foam rubber, or a framework of metal springs. Mattresses may be filled with air or water. Mattresses are placed on top of a bed base which may be solid, as in the case of a platform bed, or elastic, such as an upholstered wood and wire box spring or a slatted foundation. Popular in Europe, a divan incorporates both mattress and foundation in a single upholstered, footed unit. Divans have at least one innerspring layer as well as cushioning materials, they may be supplied with a secondary mattress and/or a removable "topper." Mattresses may be filled with air or water, or a variety of natural fibers, such as in futons. Kapok is a common mattress material in Southeast Asia, coir in South Asia; the word mattress derives from the Arabic مَطْرَحٌ which means "something thrown down" or "place where something is thrown down" and hence "mat, cushion".
During the Crusades Europeans adopted the Arabic method of sleeping on cushions on the floor, the word materas descended into Middle English through the Romance languages. The oldest known mattress dates to around 77,000 years ago. Early mattresses contained a variety of natural materials including feathers or horse hair. In the first half of the 20th century, a typical mattress sold in North America had an innerspring core and cotton batting or fiberfill. Modern mattresses contain either an inner spring core or materials such as latex, viscoelastic or other flexible polyurethane foams. Other fill components include insulator pads over the coils that prevent the bed's upholstery layers from cupping down into the innerspring, as well as polyester fiberfill in the bed's top upholstery layers. In 1899 James Marshall introduced the first individually wrapped pocketed spring coil mattress now known as Marshall coils. In North America the typical mattress sold. In Europe, polyurethane foam cores and latex cores have long been popular and make up a much larger proportion of the mattresses sold.
A conventional mattress consists of two primary sections – a core or "support layer" and the upholstery or "comfort layer" – wrapped in a thick fabric called the ticking. Upholstery layers provide cushioning and comfort; the upholstery layer consists of three parts: the insulator, the middle upholstery, the quilt. Mattresses are made to conform to bed sizing standards that vary by market. Innerspring mattresses consist of just the spring core, the top and bottom upholstery layers; the core of the mattress supports the sleeper’s body. Modern spring mattress cores called "innersprings" are made up of steel coil springs, or "coils"; the gauge of the coils is another factor which determines support. Coils are measured in quarter increments; the lower the number, the thicker the spring. In general, higher-quality mattress coils have a 14-gauge diameter. Coils of 14 to 15.5-gauge give more under pressure, while a 12.5-gauge coil, the thickest available, feels quite firm. Connections between the coils help the mattress retain its shape.
Most coils are connected by interconnecting wires. There are four types of mattress coils: Bonnell coils are the oldest and most common. First adapted from buggy seat springs of the 19th century, they are still prevalent in mid-priced mattresses. Bonnell springs are a round-top, hourglass-shaped steel wire coil; when laced together with cross wire helicals, these coils form the simplest innerspring unit referred to as a Bonnell unit. Offset coils are an hourglass type coil on which portions of the top and bottom convolutions have been flattened. In assembling the innerspring unit, these flat segments of wire are hinged together with helical wires; the hinging effect of the unit is designed to conform to body shape. LFK coils are an unknotted offset coil with a columnar shape. Continuous coils is an innerspring configuration in which the rows of coils are formed from a single piece of wire, they work in a hinging effect similar to that of offset coils. Marshall coils known as wrapped or encased coils or pocket springs, are thin-gauge, barrel-shaped, knot-less coils individually encased in fabric pockets—normally a fabric from man-made, non-woven fiber.
Some manufacturers pre-compress these coils, which makes the mattress firmer and allows for motion separation between the sides of the bed. As the springs are not wired together, they work more or less independently: the weight on one spring does not affect its neighbors. More than half the consumers who participated in a survey had chosen to buy pocket spring mattresses. Upholstery layers provide cushioning and comfort; some manufacturers call the mattress core the "support layer" and the upholstery layer the "comfort layer". The upholstery layer consists of three parts: the insulator, the middle upholstery, the quilt; the insulator separates the mattress core from the middle upholstery. It is made of fiber or mesh and is intended to keep the middle upholstery in place; the middle upholstery comprises all the material between the quilt. It is made from materials which are intended t