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113-615: The word "saddle" originates from the Old English word sadol which in turn comes from the Proto-Germanic language * sathulaz , with cognates in various other Indo-European languages , including the Latin sella . Some saddles also include: There is evidence, though disputed, that humans first began riding the horse not long after domestication , possibly as early as 4000 BC. The earliest saddle known thus far

226-553: A manometer . Depending on where the inlet holes are located on the probe, it can measure static pressures or stagnation pressures. There is a two-dimensional analog of pressure – the lateral force per unit length applied on a line perpendicular to the force. Surface pressure is denoted by π: π = F l {\displaystyle \pi ={\frac {F}{l}}} and shares many similar properties with three-dimensional pressure. Properties of surface chemicals can be investigated by measuring pressure/area isotherms, as

339-421: A saddle blanket or pad in order to provide a comfortable fit for the horse. It also has sturdier stirrups and uses a cinch rather than a girth . Its most distinctive feature is the horn on the front of the saddle, originally used to dally a lariat when roping cattle. Other nations such as Australia and Argentina have stock saddles that usually do not have a horn, but have other features commonly seen in

452-730: A sword , spare horse shoes and other equipment. In the US, the McClellan saddle was introduced in the 1850s by George B. McClellan for use by the United States Cavalry , and the core design was used continuously, with some improvements, until the 1940s. Today, the McClellan saddle continues to be used by ceremonial mounted units in the U.S. Army. The basic design that inspired McClellan saw use by military units in several other nations, including Rhodesia and Mexico, and even to

565-534: A V-shaped arrangement of strap billets on the sideboards for the attachment of the girth. This girthing system could be moved forward or back to obtain an optimum fit on a wide range of horses. From 1902 the Universal Military Saddle was manufactured with a fixed tree, broad panels to spread the load, and initially a front arch in three sizes. The advantage of this saddle was its lightness, ease of repair and comfort for horse and rider. From 1912

678-488: A base of wood with a thin leather covering that frequently has a lacquer finish. Central Asian saddles have no pad and must be ridden with a saddle blanket. The horn comes in particular good use during the rough horseback sport of buskashi , played throughout Central Asia, which involves two teams of riders wrestling over a decapitated goat's carcass. In the Near East, a saddle large enough to carry more than one person

791-667: A common history of pre-Proto-Germanic speakers throughout the Nordic Bronze Age . The Proto-Germanic language developed in southern Scandinavia (Denmark, south Sweden and southern Norway) and the northern-most part of Germany in Schleswig Holstein and northern Lower Saxony, the Urheimat (original home) of the Germanic tribes. It is possible that Indo-European speakers first arrived in southern Scandinavia with

904-706: A degree by the British in the Boer War . Military saddles are still produced and are now used in exhibitions, parades and other events. Saddles in Asia date to the time of the Scythians and Cimmerians . Modern Asian saddles can be divided into two groups: those from nomadic Eurasia, which have a prominent horn and leather covering, and those from East Asia, which have a high pommel and cantle. Central Asian saddles are noted for their wide seats and high horns. The saddle has

1017-432: A dialect of Proto-Indo-European that had lost its laryngeals and had five long and six short vowels as well as one or two overlong vowels. The consonant system was still that of PIE minus palatovelars and laryngeals, but the loss of syllabic resonants already made the language markedly different from PIE proper. Mutual intelligibility might have still existed with other descendants of PIE, but it would have been strained, and

1130-467: A girth or surcingle that included breast straps and cruppers . From the earliest depictions, saddles became status symbols . To show off an individual's wealth and status, embellishments were added to saddles, including elaborate sewing and leather work, precious metals such as gold, carvings of wood and horn, and other ornamentation. The Scythians also developed an early saddle that included padding and decorative embellishments. Though they had neither

1243-400: A gravitational well such as a planet, otherwise known as atmospheric pressure . In the case of planetary atmospheres , the pressure-gradient force of the gas pushing outwards from higher pressure, lower altitudes to lower pressure, higher altitudes is balanced by the gravitational force , preventing the gas from diffusing into outer space and maintaining hydrostatic equilibrium . In

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1356-423: A higher stagnation pressure when forced to a standstill. Static pressure and stagnation pressure are related by: p 0 = 1 2 ρ v 2 + p {\displaystyle p_{0}={\frac {1}{2}}\rho v^{2}+p} where The pressure of a moving fluid can be measured using a Pitot tube , or one of its variations such as a Kiel probe or Cobra probe , connected to

1469-475: A larger scope of linguistic developments, spanning the Nordic Bronze Age and Pre-Roman Iron Age in Northern Europe (second to first millennia BC) to include "Pre-Germanic" (PreGmc), "Early Proto-Germanic" (EPGmc) and "Late Proto-Germanic" (LPGmc). While Proto-Germanic refers only to the reconstruction of the most recent common ancestor of Germanic languages, the Germanic parent language refers to

1582-555: A late stage. The early stage includes the stress fixation and resulting "spontaneous vowel-shifts" while the late stage is defined by ten complex rules governing changes of both vowels and consonants. By 250 BC Proto-Germanic had branched into five groups of Germanic: two each in the West and the North and one in the East. The following changes are known or presumed to have occurred in

1695-618: A leather covering. Japanese saddles are classified as Chinese-style ( karagura ) or Japanese-style ( yamatogura ). In the Nara period the Chinese style was adopted. Gradually the Japanese changed the saddle to suit their needs, and in the Heian period , the saddle typically associated with the samurai class was developed. These saddles, known as kura , were lacquered as protection from

1808-520: A measured, rather than defined, quantity. These manometric units are still encountered in many fields. Blood pressure is measured in millimetres (or centimetres) of mercury in most of the world, and lung pressures in centimetres of water are still common. Underwater divers use the metre sea water (msw or MSW) and foot sea water (fsw or FSW) units of pressure, and these are the units for pressure gauges used to measure pressure exposure in diving chambers and personal decompression computers . A msw

1921-411: A more complex dependence on the variables of state. Vapour pressure is the pressure of a vapour in thermodynamic equilibrium with its condensed phases in a closed system. All liquids and solids have a tendency to evaporate into a gaseous form, and all gases have a tendency to condense back to their liquid or solid form. The atmospheric pressure boiling point of a liquid (also known as

2034-424: A physical container, the pressure of the gas originates from the molecules colliding with the walls of the container. The walls of the container can be anywhere inside the gas, and the force per unit area (the pressure) is the same. If the "container" is shrunk down to a very small point (becoming less true as the atomic scale is approached), the pressure will still have a single value at that point. Therefore, pressure

2147-417: A problem, as shorter trees are most often on saddles made for children, though a short tree with an unbalanced adult rider may create abnormal pressure points. While a horse's back can be measured for size and shape, the saddle must be tried on the individual animal to assure proper fit. Saddle blankets or pads can provide assistance to correct minor fit problems, as well as provide comfort and protection to

2260-510: A properly conditioned horse and rider. British Universal Pattern military saddles were used by the mounted forces from Australia, Britain, Canada, New Zealand and South Africa . The Steel Arch Universal Pattern Mark I was issued in 1891. This was found to irritate riders and in 1893 it was discontinued in favour of the Mark II . In 1898, the Mark III appeared, which had the addition of

2373-420: A scalar, has no direction. The force given by the previous relationship to the quantity has a direction, but the pressure does not. If we change the orientation of the surface element, the direction of the normal force changes accordingly, but the pressure remains the same. Pressure is distributed to solid boundaries or across arbitrary sections of fluid normal to these boundaries or sections at every point. It

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2486-529: A solid tree nor stirrups, these early treeless saddles and pads provided protection and comfort to the rider, with a slight increase in security. The Sarmatians also used a padded treeless early saddle, possibly as early as the seventh century BC and ancient Greek artworks of Alexander the Great of Macedon depict a saddle cloth. The Greeks called the saddlecloth or pad, ephippium (ἐφίππιον or ἐφίππειον). Early solid-treed saddles were made of felt that covered

2599-495: A suffix of "a", to avoid confusion, for example "kPaa", "psia". However, the US National Institute of Standards and Technology recommends that, to avoid confusion, any modifiers be instead applied to the quantity being measured rather than the unit of measure. For example, " p g = 100 psi" rather than " p = 100 psig" . Differential pressure is expressed in units with "d" appended; this type of measurement

2712-448: A unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m ); similarly, the pound-force per square inch ( psi , symbol lbf/in ) is the traditional unit of pressure in the imperial and US customary systems. Pressure may also be expressed in terms of standard atmospheric pressure ; the unit atmosphere (atm)

2825-408: A western saddle, including a deep seat, high cantle, and heavier leather. The tree of a western saddle is the most critical component, defining the size and shape of the finished product. The tree determines both the width and length of the saddle as it sits on the back of the horse, as well as the length of the seat for the rider, width of the swells (pommel), height of cantle, and, usually, shape of

2938-760: A wooden frame. Chinese saddles are depicted among the cavalry horses in the Terracotta Army of the Qin dynasty , completed by 206 BC. Asian designs proliferated during China 's Han dynasty around approximately 200 BC. One of the earliest solid-treed saddles in the Western world was the "four horn" design, first used by the Romans as early as the 1st century BC. Neither design had stirrups. Recent archeological finds in Mongolia (e.g. Urd Ulaan Uneet site) suggest that

3051-424: Is "p" or P . The IUPAC recommendation for pressure is a lower-case p . However, upper-case P is widely used. The usage of P vs p depends upon the field in which one is working, on the nearby presence of other symbols for quantities such as power and momentum , and on writing style. Mathematically: p = F A , {\displaystyle p={\frac {F}{A}},} where: Pressure

3164-453: Is 100 kPa (15 psi), a gas (such as helium) at 200 kPa (29 psi) (gauge) (300 kPa or 44 psi [absolute]) is 50% denser than the same gas at 100 kPa (15 psi) (gauge) (200 kPa or 29 psi [absolute]). Focusing on gauge values, one might erroneously conclude the first sample had twice the density of the second one. In a static gas , the gas as a whole does not appear to move. The individual molecules of

3277-463: Is a scalar quantity. It relates the vector area element (a vector normal to the surface) with the normal force acting on it. The pressure is the scalar proportionality constant that relates the two normal vectors: d F n = − p d A = − p n d A . {\displaystyle d\mathbf {F} _{n}=-p\,d\mathbf {A} =-p\,\mathbf {n} \,dA.} The minus sign comes from

3390-490: Is a fundamental parameter in thermodynamics , and it is conjugate to volume . The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m , or kg·m ·s ). This name for the unit was added in 1971; before that, pressure in SI was expressed in newtons per square metre. Other units of pressure, such as pounds per square inch (lbf/in ) and bar , are also in common use. The CGS unit of pressure

3503-416: Is a scalar quantity, not a vector quantity. It has magnitude but no direction sense associated with it. Pressure force acts in all directions at a point inside a gas. At the surface of a gas, the pressure force acts perpendicular (at right angle) to the surface. A closely related quantity is the stress tensor σ , which relates the vector force F {\displaystyle \mathbf {F} } to

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3616-434: Is a vital rule for fitting that no damage should occur to the horse's skin and no injury should be presented to any muscular or neural tissues beneath the saddle. Width of the saddle is the primary means by which a saddle is measured and fitted to a horse, though length of the tree and proper balance must also be considered. The gullet of a saddle must clear the withers of the horse, but yet must not be so narrow as to pinch

3729-409: Is an art and in ideal circumstances is performed by a professional saddle maker or saddle fitter. Custom-made saddles designed for an individual horse and rider will fit the best, but are also the most expensive. However, many manufactured saddles provide a decent fit if properly selected, and some minor adjustments can be made. The definition of a fitting saddle is still controversial; however, there

3842-449: Is an established constant. It is approximately equal to typical air pressure at Earth mean sea level and is defined as 101 325  Pa . Because pressure is commonly measured by its ability to displace a column of liquid in a manometer , pressures are often expressed as a depth of a particular fluid (e.g., centimetres of water , millimetres of mercury or inches of mercury ). The most common choices are mercury (Hg) and water; water

3955-458: Is called a howdah which is fitted on elephants. Some of the largest examples of a saddle, elaborate howdah were used in warfare outfitted with weaponry, and alternatively for monarchs, maharajahs, and sultans. Saddles from East Asia differ from Central Asian saddles by their high pommel and cantle and lack of a horn. East Asian saddles can be divided into several types that are associated with certain nationalities and ethnic groups. Saddles used by

4068-509: Is considerable friction across the center line of a horse's back. The stirrup was one of the milestones in saddle development. The first stirrup-like object was invented in India in the 2nd century BC, and consisted of a simple leather strap in which the rider's toe was placed. It offered very little support, however. Mongolic Rouran tribes in Mongolia are thought to have been the inventors of

4181-485: Is defined as 0.1 bar (= 10,000 Pa), is not the same as a linear metre of depth. 33.066 fsw = 1 atm (1 atm = 101,325 Pa / 33.066 = 3,064.326 Pa). The pressure conversion from msw to fsw is different from the length conversion: 10 msw = 32.6336 fsw, while 10 m = 32.8083 ft. Gauge pressure is often given in units with "g" appended, e.g. "kPag", "barg" or "psig", and units for measurements of absolute pressure are sometimes given

4294-407: Is equal to this pressure, and the torr is defined as 1 ⁄ 760 of this. Manometric units such as the centimetre of water , millimetre of mercury , and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer. Pressure is the amount of force applied perpendicular to the surface of an object per unit area. The symbol for it

4407-454: Is its flatter appearance, the lack of a horn, and the self-padding design of the panels : a pair of pads attached to the underside of the seat and filled with wool, foam, or air. However, the length and angle of the flaps, the depth of the seat and height of the cantle all play a role in the use for which a particular saddle is intended. The "tree" that underlies the saddle is usually one of the defining features of saddle quality. Traditionally,

4520-807: Is largely a matter of convention. The first coherent text recorded in a Germanic language is the Gothic Bible , written in the later fourth century in the East Germanic variety of the Thervingi Gothic Christians , who had escaped persecution by moving from Scythia to Moesia in 348. Early West Germanic text is available from the fifth century, beginning with the Frankish Bergakker runic inscription . The evolution of Proto-Germanic from its ancestral forms, beginning with its ancestor Proto-Indo-European , began with

4633-421: Is limited, such as on pressure gauges , name plates , graph labels, and table headings, the use of a modifier in parentheses, such as "kPa (gauge)" or "kPa (absolute)", is permitted. In non- SI technical work, a gauge pressure of 32 psi (220 kPa) is sometimes written as "32 psig", and an absolute pressure as "32 psia", though the other methods explained above that avoid attaching characters to

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4746-426: Is most often the compressive stress at some point within a fluid . (The term fluid refers to both liquids and gases – for more information specifically about liquid pressure, see section below .) Fluid pressure occurs in one of two situations: Pressure in open conditions usually can be approximated as the pressure in "static" or non-moving conditions (even in the ocean where there are waves and currents), because

4859-409: Is no friction, it is inviscid (zero viscosity ). The equation for all points of a system filled with a constant-density fluid is p γ + v 2 2 g + z = c o n s t , {\displaystyle {\frac {p}{\gamma }}+{\frac {v^{2}}{2g}}+z=\mathrm {const} ,} where: Explosion or deflagration pressures are

4972-437: Is nontoxic and readily available, while mercury's high density allows a shorter column (and so a smaller manometer) to be used to measure a given pressure. The pressure exerted by a column of liquid of height h and density ρ is given by the hydrostatic pressure equation p = ρgh , where g is the gravitational acceleration . Fluid density and local gravity can vary from one reading to another depending on local factors, so

5085-584: Is related to energy density and may be expressed in units such as joules per cubic metre (J/m , which is equal to Pa). Mathematically: p = F ⋅ distance A ⋅ distance = Work Volume = Energy (J) Volume  ( m 3 ) . {\displaystyle p={\frac {F\cdot {\text{distance}}}{A\cdot {\text{distance}}}}={\frac {\text{Work}}{\text{Volume}}}={\frac {\text{Energy (J)}}{{\text{Volume }}({\text{m}}^{3})}}.} Some meteorologists prefer

5198-413: Is termed Pre-Proto-Germanic . Whether it is to be included under a wider meaning of Proto-Germanic is a matter of usage. Winfred P. Lehmann regarded Jacob Grimm 's "First Germanic Sound Shift", or Grimm's law, and Verner's law , (which pertained mainly to consonants and were considered for many decades to have generated Proto-Germanic) as pre-Proto-Germanic and held that the "upper boundary" (that is,

5311-463: Is the barye (Ba), equal to 1 dyn·cm , or 0.1 Pa. Pressure is sometimes expressed in grams-force or kilograms-force per square centimetre ("g/cm " or "kg/cm ") and the like without properly identifying the force units. But using the names kilogram, gram, kilogram-force, or gram-force (or their symbols) as units of force is deprecated in SI. The technical atmosphere (symbol: at) is 1 kgf/cm (98.0665 kPa, or 14.223 psi). Pressure

5424-695: Is the reconstructed proto-language of the Germanic branch of the Indo-European languages . Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic branches during the fifth century BC to fifth century AD: West Germanic , East Germanic and North Germanic . The latter of these remained in contact with the others over a considerable time, especially with the Ingvaeonic languages (including English ), which arose from West Germanic dialects, and had remained in contact with

5537-434: Is the air pressure in an automobile tire , which might be said to be "220  kPa (32 psi)", but is actually 220 kPa (32 psi) above atmospheric pressure. Since atmospheric pressure at sea level is about 100 kPa (14.7 psi), the absolute pressure in the tire is therefore about 320 kPa (46 psi). In technical work, this is written "a gauge pressure of 220 kPa (32 psi)". Where space

5650-564: Is the question of what specific tree, in the tree model of language evolution, best explains the paths of descent of all the members of a language family from a common language, or proto-language (at the root of the tree) to the attested languages (at the leaves of the tree). The Germanic languages form a tree with Proto-Germanic at its root that is a branch of the Indo-European tree, which in turn has Proto-Indo-European at its root. Borrowing of lexical items from contact languages makes

5763-548: Is typical not of Germanic but Celtic languages. Another is * walhaz 'foreigner; Celt' from the Celtic tribal name Volcae with k → h and o → a . Other likely Celtic loans include * ambahtaz 'servant', * brunjǭ 'mailshirt', * gīslaz 'hostage', * īsarną 'iron', * lēkijaz 'healer', * laudą 'lead', * Rīnaz 'Rhine', and * tūnaz, tūną 'fortified enclosure'. These loans would likely have been borrowed during

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5876-401: Is useful when considering sealing performance or whether a valve will open or close. Presently or formerly popular pressure units include the following: As an example of varying pressures, a finger can be pressed against a wall without making any lasting impression; however, the same finger pushing a thumbtack can easily damage the wall. Although the force applied to the surface is the same,

5989-401: The vector area A {\displaystyle \mathbf {A} } via the linear relation F = σ A {\displaystyle \mathbf {F} =\sigma \mathbf {A} } . This tensor may be expressed as the sum of the viscous stress tensor minus the hydrostatic pressure. The negative of the stress tensor is sometimes called the pressure tensor, but in

6102-790: The Australian stock saddle . In Asia and throughout the world, there are numerous saddles of unique designs used by various nationalities and ethnic groups. English saddles are used for English riding throughout the world, not just in England or English-speaking countries. They are the saddles used in all of the Olympic equestrian disciplines. The term English saddle encompasses several different styles of saddle, including those used for eventing , show jumping and hunt seat , dressage , saddle seat , horse racing , horse surfing and polo . The major distinguishing feature of an English saddle

6215-677: The Corded Ware culture in the mid-3rd millennium BC, developing into the Nordic Bronze Age cultures by the early second millennium BC. According to Mallory, Germanicists "generally agree" that the Urheimat ('original homeland') of the Proto-Germanic language, the ancestral idiom of all attested Germanic dialects, was primarily situated in an area corresponding to the extent of the Jastorf culture . Early Germanic expansion in

6328-503: The Funnelbeaker culture , but the sound change in the Germanic languages known as Grimm's law points to a non-substratic development away from other branches of Indo-European. Proto-Germanic itself was likely spoken after c. 500 BC, and Proto-Norse , from the second century AD and later, is still quite close to reconstructed Proto-Germanic, but other common innovations separating Germanic from Proto-Indo-European suggest

6441-685: The Han Chinese are noted by their use of inlay work for ornamentation. Tibetan saddles typically employ iron covers inlaid with precious metals on the pommel and cantle and universally come with padding. Mongolian saddles are similar to the Tibetan style except that they are typically smaller and the seat has a high ridge. Saddles from ethnic minority groups in China's southwest, such as in Sichuan and Yunnan provinces, have colorful lacquer work over

6554-637: The Norse . A defining feature of Proto-Germanic is the completion of the process described by Grimm's law , a set of sound changes that occurred between its status as a dialect of Proto-Indo-European and its gradual divergence into a separate language. The end of the Common Germanic period is reached with the beginning of the Migration Period in the fourth century AD. The alternative term " Germanic parent language " may be used to include

6667-602: The Pazyryk culture , where later saddles were found. Eurasian and Northern Asian nomads on the Mongolian plateau developed an early form of saddle with a rudimentary frame, which included two parallel leather cushions, with girth attached to them, a pommel and cantle with detachable bone/horn/hardened leather facings, leather thongs, a crupper , breastplate , and a felt shabrack adorned with animal motifs. These were located in Pazyryk burials finds. These saddles, found in

6780-681: The Pre-Roman Iron Age (fifth to first centuries BC) placed Proto-Germanic speakers in contact with the Continental Celtic La Tène horizon . A number of Celtic loanwords in Proto-Germanic have been identified. By the first century AD, Germanic expansion reached the Danube and the Upper Rhine in the south and the Germanic peoples first entered the historical record . At about the same time, extending east of

6893-541: The Ukok Plateau , Siberia were dated to 500-400 BC. Iconographic evidence of a predecessor to the modern saddle has been found in the art of the ancient Armenians , Assyrians , and steppe nomads depicted on the Assyrian stone relief carvings from the time of Ashurnasirpal II . Some of the earliest saddle-like equipment were fringed cloths or pads used by Assyrian cavalry around 700 BC. These were held on with

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7006-621: The Vistula ( Oksywie culture , Przeworsk culture ), Germanic speakers came into contact with early Slavic cultures, as reflected in early Germanic loans in Proto-Slavic . By the third century, Late Proto-Germanic speakers had expanded over significant distance, from the Rhine to the Dniepr spanning about 1,200 km (700 mi). The period marks the breakup of Late Proto-Germanic and

7119-424: The normal boiling point ) is the temperature at which the vapor pressure equals the ambient atmospheric pressure. With any incremental increase in that temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure and lift the liquid to form vapour bubbles inside the bulk of the substance. Bubble formation deeper in the liquid requires a higher pressure, and therefore higher temperature, because

7232-484: The "lower boundary" was the dropping of final -a or -e in unstressed syllables; for example, post-PIE * wóyd-e > Gothic wait , 'knows'. Elmer H. Antonsen agreed with Lehmann about the upper boundary but later found runic evidence that the -a was not dropped: ékwakraz … wraita , 'I, Wakraz, … wrote (this)'. He says: "We must therefore search for a new lower boundary for Proto-Germanic." Antonsen's own scheme divides Proto-Germanic into an early stage and

7345-409: The 18th century, fox hunting became increasingly popular in England. The high-cantle, high-pommel design of earlier saddles became a hindrance, unsafe and uncomfortable for riders as they jumped. Due to this fact, Guérinière's saddle design which included a low pommel and cantle and allowed for more freedom of movement for both horse and rider, became increasingly popular throughout northern Europe. In

7458-556: The 2nd century CE, as well as the non-runic Negau helmet inscription, dated to the 2nd century BCE), and in Roman Empire -era transcriptions of individual words (notably in Tacitus ' Germania , c. AD 90 ). Proto-Germanic developed out of pre-Proto-Germanic during the Pre-Roman Iron Age of Northern Europe. According to the Germanic substrate hypothesis , it may have been influenced by non-Indo-European cultures, such as

7571-606: The Celtic Hallstatt and early La Tène cultures when the Celts dominated central Europe, although the period spanned several centuries. Pressure Pressure (symbol: p or P ) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled gage pressure) is the pressure relative to the ambient pressure. Various units are used to express pressure. Some of these derive from

7684-429: The Germanic subfamily exhibited a less treelike behaviour, as some of its characteristics were acquired from neighbours early in its evolution rather than from its direct ancestors. The internal diversification of West Germanic developed in an especially non-treelike manner. Proto-Germanic is generally agreed to have begun about 500 BC. Its hypothetical ancestor between the end of Proto-Indo-European and 500 BC

7797-628: The Mongolic Rouran tribes had sophisticated, wooden frame saddles as early as the 3rd century AD. The wooden frame saddle found at the Urd Ulaan Uneet site in Mongolia is one of the earliest examples found in Central and East Asia. The development of the solid saddle tree was significant; it raised the rider above the horse's back, and distributed the rider's weight on either side of the animal's spine instead of pinpointing pressure at

7910-688: The air. The strikes against the saddle's horn compress the pelvic ring, which can lead to further complications such as pubic symphysis or injury to the sacroiliac joint . Proto-Germanic language Pontic Steppe Caucasus East Asia Eastern Europe Northern Europe Pontic Steppe Northern/Eastern Steppe Europe South Asia Steppe Europe Caucasus India Indo-Aryans Iranians East Asia Europe East Asia Europe Indo-Aryan Iranian Indo-Aryan Iranian Others European Proto-Germanic (abbreviated PGmc ; also called Common Germanic )

8023-489: The beginning of the (historiographically recorded) Germanic migrations . The earliest available complete sentences in a Germanic language are variably dated to the 2nd century AD, around 300 AD or the first century AD in runic inscriptions (such as the Tune Runestone ). The language of these sentences is known as Proto-Norse , although the delineation of Late Common Germanic from Proto-Norse at about that time

8136-447: The convention that the force is considered towards the surface element, while the normal vector points outward. The equation has meaning in that, for any surface S in contact with the fluid, the total force exerted by the fluid on that surface is the surface integral over S of the right-hand side of the above equation. It is incorrect (although rather usual) to say "the pressure is directed in such or such direction". The pressure, as

8249-498: The dates of borrowings and sound laws are not precisely known, it is not possible to use loans to establish absolute or calendar chronology. Most loans from Celtic appear to have been made before or during the Germanic Sound Shift . For instance, one specimen * rīks 'ruler' was borrowed from Celtic * rīxs 'king' (stem * rīg- ), with g → k . It is clearly not native because PIE * ē → ī

8362-414: The development of a separate common way of speech among some geographically nearby speakers of a prior language and ended with the dispersion of the proto-language speakers into distinct populations with mostly independent speech habits. Between the two points, many sound changes occurred. Phylogeny as applied to historical linguistics involves the evolutionary descent of languages. The phylogeny problem

8475-432: The earlier boundary) was the fixing of the accent, or stress, on the root syllable of a word, typically on the first syllable. Proto-Indo-European had featured a moveable pitch-accent consisting of "an alternation of high and low tones" as well as stress of position determined by a set of rules based on the lengths of a word's syllables. The fixation of the stress led to sound changes in unstressed syllables. For Lehmann,

8588-686: The early 20th century, Captain Frederico Caprilli revolutionized the jumping saddle by placing the flap at an angle that allowed a rider to achieve the forward seat necessary for jumping high fences and traveling rapidly across rugged terrain. The modern Western saddle was developed from the Spanish saddles that were brought by the Spanish Conquistadors when they came to the Americas . These saddles were adapted to suit

8701-480: The entire journey that the dialect of Proto-Indo-European that would become Proto-Germanic underwent through the millennia. The Proto-Germanic language is not directly attested by any complete surviving texts; it has been reconstructed using the comparative method . However, there is fragmentary direct attestation of (late) Proto-Germanic in early runic inscriptions (specifically the Vimose inscriptions , dated to

8814-496: The erosion of unstressed syllables, which would continue in its descendants. The final stage of the language included the remaining development until the breakup into dialects and, most notably, featured the development of nasal vowels and the start of umlaut , another characteristic Germanic feature. Loans into Proto-Germanic from other (known) languages or from Proto-Germanic into other languages can be dated relative to each other by which Germanic sound laws have acted on them. Since

8927-480: The flat edge is used, force is distributed over a larger surface area resulting in less pressure, and it will not cut. Whereas using the sharp edge, which has less surface area, results in greater pressure, and so the knife cuts smoothly. This is one example of a practical application of pressure For gases, pressure is sometimes measured not as an absolute pressure , but relative to atmospheric pressure ; such measurements are called gauge pressure . An example of this

9040-404: The fluid pressure increases above the atmospheric pressure as the depth increases. The vapor pressure that a single component in a mixture contributes to the total pressure in the system is called partial vapor pressure . When a person swims under the water, water pressure is felt acting on the person's eardrums. The deeper that person swims, the greater the pressure. The pressure felt is due to

9153-419: The following, the term "pressure" will refer only to the scalar pressure. According to the theory of general relativity , pressure increases the strength of a gravitational field (see stress–energy tensor ) and so adds to the mass-energy cause of gravity . This effect is unnoticeable at everyday pressures but is significant in neutron stars , although it has not been experimentally tested. Fluid pressure

9266-425: The gas, however, are in constant random motion . Because there are an extremely large number of molecules and because the motion of the individual molecules is random in every direction, no motion is detected. When the gas is at least partially confined (that is, not free to expand rapidly), the gas will exhibit a hydrostatic pressure. This confinement can be achieved with either a physical container of some sort, or in

9379-548: The hectopascal (hPa) for atmospheric air pressure, which is equivalent to the older unit millibar (mbar). Similar pressures are given in kilopascals (kPa) in most other fields, except aviation where the hecto- prefix is commonly used. The inch of mercury is still used in the United States. Oceanographers usually measure underwater pressure in decibars (dbar) because pressure in the ocean increases by approximately one decibar per metre depth. The standard atmosphere (atm)

9492-412: The height of a fluid column does not define pressure precisely. When millimetres of mercury (or inches of mercury) are quoted today, these units are not based on a physical column of mercury; rather, they have been given precise definitions that can be expressed in terms of SI units. One millimetre of mercury is approximately equal to one torr . The water-based units still depend on the density of water,

9605-545: The history of Proto-Germanic in the wider sense from the end of Proto-Indo-European up to the point that Proto-Germanic began to break into mutually unintelligible dialects. The changes are listed roughly in chronological order, with changes that operate on the outcome of earlier ones appearing later in the list. The stages distinguished and the changes associated with each stage rely heavily on Ringe 2006 , Chapter 3, "The development of Proto-Germanic". Ringe in turn summarizes standard concepts and terminology. This stage began with

9718-437: The horn. Traditional trees were made of wood or wood laminate covered with rawhide and this style is still manufactured today, though modern synthetic materials are also used. The rawhide is stretched and molded around the tree, with minimal padding between the tree and the exterior leather, usually a bit of relatively thin padding on the seat, and a sheepskin cover on the underside of the skirts to prevent chafing and rubbing on

9831-405: The horse's back, but no amount of padding can compensate for a poor-fitting saddle. For example, saddles that are either too wide or too narrow for the horse will cause change in pressure points and ultimately muscle atrophy in the epaxial muscles . The common problems associated with saddle fitting problems are: bridging, ill-fitting headplates and incorrect stuffing of the panels. Depending on

9944-441: The horse's back. The tree must be positioned so that the tree points (English) or bars (Western) do not interfere with the movement of the horse's shoulder. The seat of the saddle must be positioned so that the rider, when riding correctly, is placed over the horse's center of balance . The bars of the saddle must not be so long that they place pressure beyond the last rib of the horse. A too-short tree alone does not usually create

10057-421: The horse. Though a western saddle is often considerably heavier than an English saddle, the tree is designed to spread out the weight of the rider and any equipment the rider may be carrying so that there are fewer pounds per square inch on the horse's back and, when properly fitted, few if any pressure points. Thus, the design, in spite of its weight, can be used for many hours with relatively little discomfort to

10170-450: The integrated spring steel and gullet plate, some without). Synthetic materials vary widely in quality. Polyurethane trees are often very well-made, but some cheap saddles are made with fiberglass trees of limited durability. Synthetic trees are often lighter, more durable, and easier to customize. Some designs are intended to be more flexible and move with the horse. Several companies offer flexible trees or adjustable gullets that allow

10283-457: The modern English and Western saddles. One variant of the English saddle was developed by François Robinchon de la Guérinière , a French riding master and author of "Ecole de Cavalerie" who made major contributions to what today is known as classical dressage . He put great emphasis on the proper development of a "three point" seat that is still used today by many dressage riders. In

10396-514: The modern stirrup, but the first dependable representation of a rider with paired stirrups was found in China in a Jin Dynasty tomb of about 302 AD. The stirrup appeared to be in widespread use across China by 477 AD, and later spread to Europe. This invention gave great support for the rider, and was essential in later warfare . Accounts of the cavalry system of the Mali Empire describe

10509-454: The motions create only negligible changes in the pressure. Such conditions conform with principles of fluid statics . The pressure at any given point of a non-moving (static) fluid is called the hydrostatic pressure . Closed bodies of fluid are either "static", when the fluid is not moving, or "dynamic", when the fluid can move as in either a pipe or by compressing an air gap in a closed container. The pressure in closed conditions conforms with

10622-497: The needs of vaqueros and cowboys of Mexico, Texas and California , including the addition of a horn that allowed a lariat to be tied or dallied for the purpose of holding cattle and other livestock. In the Western world there are two basic types of saddles used today for horseback riding , usually called the English saddle and the "stock" saddle. The best known stock saddle is the American western saddle , followed by

10735-413: The period marked the definitive break of Germanic from the other Indo-European languages and the beginning of Germanic proper, containing most of the sound changes that are now held to define this branch distinctively. This stage contained various consonant and vowel shifts, the loss of the contrastive accent inherited from PIE for a uniform accent on the first syllable of the word root, and the beginnings of

10848-415: The principles of fluid dynamics . The concepts of fluid pressure are predominantly attributed to the discoveries of Blaise Pascal and Daniel Bernoulli . Bernoulli's equation can be used in almost any situation to determine the pressure at any point in a fluid. The equation makes some assumptions about the fluid, such as the fluid being ideal and incompressible. An ideal fluid is a fluid in which there

10961-552: The reduction of the resulting unstressed syllables. By this stage, Germanic had emerged as a distinctive branch and had undergone many of the sound changes that would make its later descendants recognisable as Germanic languages. It had shifted its consonant inventory from a system that was rich in plosives to one containing primarily fricatives, had lost the PIE mobile pitch accent for a predictable stress accent, and had merged two of its vowels. The stress accent had already begun to cause

11074-539: The relative position of the Germanic branch within Indo-European less clear than the positions of the other branches of Indo-European. In the course of the development of historical linguistics, various solutions have been proposed, none certain and all debatable. In the evolutionary history of a language family, philologists consider a genetic "tree model" appropriate only if communities do not remain in effective contact as their languages diverge. Early Indo-European had limited contact between distinct lineages, and, uniquely,

11187-428: The result of the ignition of explosive gases , mists, dust/air suspensions, in unconfined and confined spaces. While pressures are, in general, positive, there are several situations in which negative pressures may be encountered: Stagnation pressure is the pressure a fluid exerts when it is forced to stop moving. Consequently, although a fluid moving at higher speed will have a lower static pressure , it may have

11300-511: The rider's seat bones, reducing the pressure (force per unit area) on any one part of the horse's back, thus greatly increasing the comfort of the horse and prolonging its useful life. The invention of the solid saddle tree also allowed development of the true stirrup as it is known today. Without a solid tree, the rider's weight in the stirrups creates abnormal pressure points and makes the horse's back sore. Thermography studies on "treeless" and flexible tree saddle designs have found that there

11413-409: The rider, the saddle may need to be adjusted or replaced entirely to ensure proper fitment. Riding a saddle that doesn't properly secure and balance the rider can cause pain in the hips and back, as well as saddle sores under the bones that make contact with the saddle during riding. On horseback, a rider's pelvis may receive a saddle-horn injury due to falling onto the saddle after being bounced into

11526-423: The saddle was built on an adjustable tree and consequently only one size was needed. Its advantage over the fixed tree 1902 pattern was its ability to maintain a better fit on the horse's back as the horse gained or lost weight. This saddle was made using traditional methods and featured a seat blocked from sole leather, which maintained its shape well. Military saddles were fitted with metal staples and dees to carry

11639-432: The same saddle to be used on different sizes of horses. Western saddles are saddles originally designed to be used on horses on working cattle ranches in the United States. Used today in a wide variety of western riding activities, they are the "cowboy saddles" familiar to movie viewers, rodeo fans, and those who have gone on tourist trail rides. The Western saddle has minimal padding of its own, and must be used with

11752-511: The separation of a distinct speech, perhaps while it was still forming part of the Proto-Indo-European dialect continuum. It contained many innovations that were shared with other Indo-European branches to various degrees, probably through areal contacts, and mutual intelligibility with other dialects would have remained for some time. It was nevertheless on its own path, whether dialect or language. This stage began its evolution as

11865-399: The thumbtack applies more pressure because the point concentrates that force into a smaller area. Pressure is transmitted to solid boundaries or across arbitrary sections of fluid normal to these boundaries or sections at every point. Unlike stress , pressure is defined as a scalar quantity . The negative gradient of pressure is called the force density . Another example is a knife. If

11978-410: The tree of an English saddle is built of laminated layers of high quality wood reinforced with spring steel along its length, with a riveted gullet plate. These trees are semi-adjustable and are considered "spring trees". They have some give, but a minimum amount of flexibility. More recently, saddle manufacturers are using various materials to replace wood and create a synthetic molded tree (some with

12091-537: The two-dimensional analog of Boyle's law , πA = k , at constant temperature. Surface tension is another example of surface pressure, but with a reversed sign, because "tension" is the opposite to "pressure". In an ideal gas , molecules have no volume and do not interact. According to the ideal gas law , pressure varies linearly with temperature and quantity, and inversely with volume: p = n R T V , {\displaystyle p={\frac {nRT}{V}},} where: Real gases exhibit

12204-416: The unit of pressure are preferred. Gauge pressure is the relevant measure of pressure wherever one is interested in the stress on storage vessels and the plumbing components of fluidics systems. However, whenever equation-of-state properties, such as densities or changes in densities, must be calculated, pressures must be expressed in terms of their absolute values. For instance, if the atmospheric pressure

12317-462: The use of stirrups and saddles in the cavalry. Stirrups and saddles brought about innovation in new tactics, such as mass charges with thrusting spears and swords. Saddles were improved upon during the Middle Ages , as knights needed saddles that were stronger and offered more support. The resulting saddle had a higher cantle and pommel (to prevent the rider from being unseated in warfare) and

12430-528: The weather. Early samurai warfare was conducted primarily on horseback and the kura provided a rugged, stable, comfortable platform for shooting arrows, but it was not well suited for speed or distance. In the Edo period horses were no longer needed for warfare and Japanese saddles became quite elaborate and were decorated with mother of pearl inlays, gold leaf, and designs in colored lacquer. A saddle, regardless of type, must fit both horse and rider. Saddle fitting

12543-463: The weight of the water above the person. As someone swims deeper, there is more water above the person and therefore greater pressure. The pressure a liquid exerts depends on its depth. Liquid pressure also depends on the density of the liquid. If someone was submerged in a liquid more dense than water, the pressure would be correspondingly greater. Thus, we can say that the depth, density and liquid pressure are directly proportionate. The pressure due to

12656-593: Was built on a wooden tree that supported more weight from a rider with armor and weapons. This saddle, a predecessor to the modern Western saddle , was originally padded with wool or horsehair and covered in leather or textiles. It was later modified for cattle tending and bullfighting in addition to the continual development for use in war. Other saddles, derived from earlier, treeless designs, sometimes added solid trees to support stirrups, but were kept light for use by messengers and for horse racing . The saddle eventually branched off into different designs that became

12769-602: Was discovered inside a woman's tomb in the Turpan basin , in what is now Xinjiang , China , dating to between 727–396 BC. The saddle is made of cushioned cow hide, and shows signs of usage and repair. The tomb is associated with the Subeixi Culture, which is associated with the Jushi Kingdom described in later Chinese sources. The Subeixi people had contact with Scythians, and share a similar material culture with

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