A double eagle is a gold coin of the United States with a denomination of $20. The coins are made from a 90% gold and 10% copper alloy and have a weight of 1.0750 troy ounces. The eagle, half eagle, and quarter eagle were specifically given these names in the Act of Congress that originally authorized them, the double eagle was specifically created as such by name. The first double eagle was minted in 1849, coinciding with the California Gold Rush, in that year, the mint produced two pieces in proof. The first resides in the Smithsonian Institution in Washington, D. C, the second was presented to Treasury Secretary William M. Meredith and was sold as part of his estate—the present location of this coin remains unknown. In 1850, regular production began and continued until 1933, prior to 1850, eagles with a denomination of $10 were the largest denomination of US coin. The $10 eagles were produced beginning in 1795, just two years after the first U. S. mint opened, since the $20 gold piece had twice the value of the eagle, these coins were designated double eagles.
In 1866, the motto In God We Trust was added to the liberty coronet double eagle, in 1877, the coins denomination design on the reverse was changed from twenty D to twenty dollars creating a third and final subtype for the series. An 1879 pattern coin was made for the quintuple stella using a design combining features of the liberty head double eagle and stella pattern coin, however this coin was stolen in July 2008. The Saint-Gaudens double eagle is named for the designer, Augustus Saint-Gaudens, theodore Roosevelt imposed upon him in his last few years to redesign the nations coinage at the beginning of the 20th century. Saint-Gaudens work on the high-relief $20 gold piece is considered to be one of the most extraordinary pieces of art on any American coin. The mint eventually insisted on a version, as the high-relief coin took up to eleven strikes to bring up the details. Only 12,367 of these coins were struck in 1907 and these coins easily top the $10,000 price in circulated grades, but can reach nearly a half million dollars in the best states of preservation.
There were several changes in the years of this design. The first coins issued in 1907 design featured a date in Roman numerals, the motto In God We Trust was omitted from the initial design, as Roosevelt felt that putting the name of God on money that could be used for immoral purposes was inappropriate. By act of Congress, the motto was added in mid-1908, the design of the Saint-Gaudens coin was slightly changed once more when New Mexico and Arizona became states in 1912, and the number of stars along the rim was accordingly increased from 46 to 48. Double eagles were routinely minted through 1933, although few of the very last years coinages were released before the recall legislation of that year. Accordingly, these issues bring very high prices, the Saint-Gaudens obverse design was reused in the American eagle gold bullion coins that were instituted in 1986
Twenty-cent piece (United States coin)
The American twenty-cent piece is a coin struck from 1875 to 1878, but only for collectors in the final two years. Proposed by Nevada Senator John P. Jones, it proved a failure due to confusion with the quarter, in 1874, the newly elected Jones began pressing for a twenty-cent piece, which he stated would alleviate the shortage of small change in the far West. The bill passed Congress, and mint director Henry Linderman ordered pattern coins struck, Linderman eventually decided on an obverse and reverse similar to that of other silver coins. Although the coins have an edge, rather than reeded as with other silver coins, the new piece was close to the size of, and immediately confused with. Adding to the bewilderment, the obverse, or heads, sides of coins were almost identical. After the first year, in which over a million were minted, there was demand. At least a third of the mintage was melted by the government. Numismatist Mark Benvenuto called the twenty-cent piece a chapter of U. S. coinage history that closed almost before it began, a twenty-cent piece had been proposed as early as 1791, and again in 1806, but had been rejected.
The 1806 bill, introduced by Connecticut Senator Uriah Tracy, sought both a two-cent piece and a double dime, the bill passed the Senate twice, in 1806 and 1807, but did not pass the House of Representatives. Several factors converged to make possible a twenty-cent piece in the 1870s, the first was a shortage of small change in the far West, where base-metal coins did not circulate. Prices in the West were sometimes in bits, adding to the change problem, a second factor was the anxiety of Congress to see more silver made into coin. This was due to pressure from mining and other interests, the Coinage Act of 1873 ended the practice of allowing silver producers to have their bullion struck into silver dollars and returned to them. He quietly urged Congress to end the practice, which it did, within a year, silver prices had dropped, and producers tried vainly to deposit bullion at the mints for conversion into legal tender. Mining interests sought other means of selling silver to the government, the third was American interest in aligning its currency with the Latin Monetary Union and to bring its weights for coinage into the metric system.
Another purpose for an issue of silver coins, regardless of denomination, was to retire the fractional currency—low-value paper money or shinplasters. Congress passed legislation in 1875 and 1876 for large quantities of coins for this purpose. The father of the twenty-cent piece was Nevada Senator John P. Jones. Part-owner of the Crown Point Mine, he had elected to the Senate in 1873, on February 10,1874, he introduced a bill to authorize a twenty-cent piece
Turban Head eagle
The Turban Head eagle, known as the Capped Bust eagle, was a ten-dollar gold piece, or eagle, struck by the United States Mint from 1795 to 1804. The piece was designed by Robert Scot, and was the first in the eagle series, which continued until the Mint ceased striking gold coins for circulation in 1933. The common name is a misnomer, Liberty does not wear a turban but a cap, believed by some to be a pileus or Phrygian cap, the eagle was the largest denomination authorized by the Mint Act of 1792, which established the Bureau of the Mint. It was not struck until 1795, as the Mint at first struck copper and silver coins, the initial reverse, featuring an eagle with a wreath in its mouth, proved unpopular and was replaced by a heraldic eagle. Four 1804-dated eagles were struck in 1834 for inclusion in sets of US coins to be given to foreign potentates. These 1804 Plain 4 coins differ from the eagles actually struck in 1804 in the way the 4 in the date is styled, in 1791, Congress passed a resolution authorizing President George Washington to establish a mint.
Feeling that the resolution was inadequate, President Washington asked legislators to pass a law which would govern the new facility. The result was the Mint Act of 1792, which prescribed the specifications of the new US coins, the passage of the Mint Act was followed by the establishment in Philadelphia of the Mint, which by 1793 was striking cents and half cents. Coinage of precious metal pieces was delayed, Congress had required that the assayer and chief coiner each post a security bond of $10,000, a huge sum in those days. In 1794, Congress lowered the chief coiners bond to $5,000 and the assayers to $1,000, the first deposit of gold to be struck into coins was made at the Mint in February 1795, by Moses Brown of Boston. Around May 1795, the first Mint director, David Rittenhouse, Rittenhouse resigned in June, before the work came to fruition, and was replaced by Henry deSaussure. The new director took office on July 9,1795, deSaussure publicized that the Mint would be striking gold pieces, the new nations first, the first half eagles were struck 22 days later.
Dies for the coinage were prepared, most likely by Scot. The three designs for the Turban Head eagle—the obverse and the two reverses—are all by Scot and they are identical to designs used on other silver and gold coins of the period—the Mint did not yet put denominations on gold pieces. The origin of Scots obverse is uncertain and he contends that a bust should have drapery only if intended as part of a statue, Greco-Roman classicism has been misunderstood here. Breen disputes Vermeules contention that the cap is a pileus, the hat given to emancipated slaves as a symbol of their freedom, numismatic author David Lange contends the headgear is a mob cap, much in fashion at the time. The reverse that appeared on the eagle from 1795 to mid-1797 depicts an eagle clutching a victory wreath, perched on a branch, vermeule contends that the appearance of the bird is difficult to describe but that it has a healthy individuality and an almost-rustic charm. Breen suggests that the branch is from a tree, and that this is in tribute to deSaussure
Nickel (United States coin)
A nickel, in American usage, is a five-cent coin struck by the United States Mint. Composed of 75% copper and 25% nickel, the piece has been issued since 1866 and its diameter is.835 inches and its thickness is.077 inches. The silver half dime, equal to five cents, had issued since the 1790s. The American Civil War caused economic hardship, driving gold and silver from circulation, in response, in place of low-value coins, the government at first issued paper currency. In 1865, Congress abolished the five-cent fractional currency note after Spencer M. Clark, head of the Currency Bureau, the initial design of the Shield nickel was struck from 1866 until 1883, was replaced by the Liberty Head nickel. The Buffalo nickel was introduced in 1913 as part of a drive to increase the beauty of American coinage, in 1938, in 2004 and 2005, special designs in honor of the bicentennial of the Lewis and Clark Expedition were issued. In 2006, the Mint reverted to using Jefferson nickel designer Felix Schlags original reverse, although a new obverse, by Jamie Franki, was substituted.
As of the end of FY2013, it cost more than nine cents to produce a nickel, the silver half disme was one of the denominations prescribed by the Mint Act of 1792, its weight and fineness were set by law. By legend, President Washington supplied silverware from his home, Mount Vernon, in 1793, the newly established Philadelphia Mint began striking cents and half cents. Coinage of precious metal was delayed, Congress required the assayer and chief coiner to each post a security bond of $10,000, a huge sum in 1793. In 1794, Congress lowered the chief coiners bond to $5,000, silver coinage began that year. The half dime was struck to various designs by Mint Engraver Robert Scot from 1794 until 1805, though none were dated 1798,1799, in response, in 1804 the US stopped striking silver dollars, issuance of the half dime was discontinued from 1805 until 1829. Beginning in 1829, the silver five-cent piece was struck, beginning in 1837. In 1851, it ceased to be the smallest US silver coin as a three cent piece was issued by the Mint, although specie was hoarded or exported, the copper-nickel cent, the only base metal denomination being struck, vanished.
In 1864, Congress began the process of restoring coins to circulation by abolishing the three-cent note and authorizing bronze cents and two-cent pieces, with low intrinsic values and these new coins initially proved popular, though the two-cent piece soon faded from circulation. On March 3,1865, Congress passed legislation authorizing the Mint to strike three-cent pieces of 75% copper, in 1864, Congress authorized a third series of fractional currency notes. Clark kept his job only because of the intervention of Treasury Secretary Salmon P. Chase. In his 1865 report, Pollock wrote, From this nickel alloy, a coin for the denomination of five cents, only until the resumption of specie payments
Coins of the United States dollar
Coins of the United States dollar were first minted in 1792. New coins have been produced annually since and they make up an aspect of the United States currency system. Today, circulating coins exist in denominations of 1¢, 5¢, 10¢, 25¢, 50¢, minted are bullion and commemorative coins. All of these are produced by the United States Mint, the coins are sold to Federal Reserve Banks which in turn are responsible for putting coins into circulation and withdrawing them as demanded by the countrys economy. Today four mints operate in the United States producing billions of coins each year, the main mint is the Philadelphia Mint, which produces circulating coinage, mint sets and some commemorative coins. The Denver Mint produces circulating coinage, mint sets and commemoratives, the San Francisco Mint produces regular and silver proof coinage, and produced circulating coinage until the 1970s. The West Point Mint produces bullion coinage and Denver produce the dies used at all of the mints. The proof and mint sets are manufactured each year and contain examples of all of the circulating coins.
The producing mint of each coin may be identified, as most coins bear a mint mark. The identifying letter of the mint can be found on the front side of most coins, unmarked coins are issued by the Philadelphia mint. The mass and composition of the cent changed to the current copper plated zinc core in 1982, both types were minted in 1982 with no distinguishing mark. Cents minted in 1943 were struck on planchets punched from zinc coated steel which left the resulting edges uncoated and this caused many of these coins to rust. These steel pennies are not likely to be found in circulation today, the wheat cent was mainstream and common during its time. Some dates are rare, but many can still be found in circulation, nickels produced from mid-1942 through 1945 were manufactured from 56% copper, 35% silver and 9% manganese. This allowed the saved nickel metal to be shifted to production of military supplies during World War II. Few of these are found in circulation. Prior to 1965 and passage of the Coinage Act of 1965 the composition of the dime, half-dollar and dollar coins was 90% silver, the half-dollar continued to be minted in a 40% silver-clad composition between 1965 and 1970.
Dimes and quarters from before 1965 and half-dollars from before 1971 are generally not in circulation due to being removed for their silver content, in 1975 and 1976 bicentennial coinage was minted
The gold dollar or gold one-dollar piece is a gold coin that was struck as a regular issue by the United States Bureau of the Mint from 1849 to 1889. The coin had three types over its lifetime, all designed by Mint Chief Engraver James B, the Type 1 issue has the smallest diameter of any United States coin minted to date. A gold dollar coin had been proposed several times in the 1830s and 1840s, Congress was finally galvanized into action by the increased supply of bullion caused by the California gold rush, and in 1849 authorized a gold dollar. In its early years, silver coins were being hoarded or exported, Gold did not again circulate in most of the nation until 1879, once it did, the gold dollar did not regain its place. In its final years, it was struck in small numbers and it was in demand to be mounted in jewelry. The regular issue gold dollar was last struck in 1889, the following year, Congress followed Hamiltons recommendation only in part, authorizing a silver dollar, but no coin of that denomination in gold.
In 1831, the first gold dollar was minted, at the mint of Christopher Bechtler in North Carolina. Additional one-dollar pieces were struck by August Bechtler, Christophers son and he was opposed by the Mint Director, Robert M. Patterson. Woodbury persuaded President Andrew Jackson to have pattern coins struck, in response, Patterson had Mint Second Engraver Christian Gobrecht break off work on the new design for the silver one-dollar coin and work on a pattern for the gold dollar. Gobrechts design featured a Liberty cap surrounded by rays on one side, and a palm branch arranged in a circle with the denomination, consideration was given to including the gold dollar as an authorized denomination in the revisionary legislation that became the Mint Act of 1837. Nevertheless, after Mint Director Patterson appeared before a congressional committee, in January 1844, North Carolina Representative James Iver McKay, the chairman of the Committee on Ways and Means, solicited the views of Director Patterson on the gold dollar.
Patterson had more of Gobrechts pattern dollar struck to show to committee members and he told Treasury Secretary John C. Spencer that the gold coins of that size in commerce. This seemed to satisfy the committee as nothing more was done for the time, even before 1848, record amounts of gold were flowing to American mints to be struck into coin, but the California Gold Rush vastly increased these quantities. This renewed calls for a dollar, as well as for a higher denomination than the eagle. In January 1849, McKay introduced a bill for a gold dollar, there was much discussion in the press about the proposed coin, one newspaper published a proposal for an annular gold dollar, that is, with a hole in the middle to increase its small diameter. Nevertheless, Gobrechts successor as chief engraver, James B, prepared patterns, including some with a square hole in the middle. McKay introduced a version into the House on February 20, debate began the same day, McKay did not respond substantively, but stated that if no one wanted these denominations, they would not be called for at the Mint, and would not be coined
In science and engineering, the weight of an object is usually taken to be the force on the object due to gravity. Weight is a vector whose magnitude, often denoted by an italic letter W, is the product of the m of the object. The unit of measurement for weight is that of force, which in the International System of Units is the newton. For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, in this sense of weight, a body can be weightless only if it is far away from any other mass. Although weight and mass are scientifically distinct quantities, the terms are often confused with other in everyday use. There is a tradition within Newtonian physics and engineering which sees weight as that which is measured when one uses scales. There the weight is a measure of the magnitude of the force exerted on a body. Typically, in measuring an objects weight, the object is placed on scales at rest with respect to the earth, thus, in a state of free fall, the weight would be zero.
In this second sense of weight, terrestrial objects can be weightless, ignoring air resistance, the famous apple falling from the tree, on its way to meet the ground near Isaac Newton, is weightless. Further complications in elucidating the various concepts of weight have to do with the theory of relativity according to gravity is modelled as a consequence of the curvature of spacetime. In the teaching community, a debate has existed for over half a century on how to define weight for their students. The current situation is that a set of concepts co-exist. Discussion of the concepts of heaviness and lightness date back to the ancient Greek philosophers and these were typically viewed as inherent properties of objects. Plato described weight as the tendency of objects to seek their kin. To Aristotle weight and levity represented the tendency to restore the order of the basic elements, earth, fire. He ascribed absolute weight to earth and absolute levity to fire, archimedes saw weight as a quality opposed to buoyancy, with the conflict between the two determining if an object sinks or floats.
The first operational definition of weight was given by Euclid, who defined weight as, weight is the heaviness or lightness of one thing, compared to another, operational balances had, been around much longer. According to Aristotle, weight was the cause of the falling motion of an object
They made the first controlled, sustained flight of a powered, heavier-than-air aircraft on December 17,1903, four miles south of Kitty Hawk, North Carolina. In 1904–05 the brothers developed their flying machine into the first practical fixed-wing aircraft, although not the first to build and fly experimental aircraft, the Wright brothers were the first to invent aircraft controls that made fixed-wing powered flight possible. The brothers fundamental breakthrough was their invention of three-axis control, which enabled the pilot to steer the aircraft effectively and this method became and remains standard on fixed-wing aircraft of all kinds. From the beginning of their work, the Wright brothers focused on developing a reliable method of pilot control as the key to solving the flying problem. This approach differed significantly from other experimenters of the time who put emphasis on developing powerful engines. Using a small wind tunnel, the Wrights collected more accurate data than any before, enabling them to design and build wings.
Their first U. S. patent,821,393, did not claim invention of a machine, but rather. They gained the skills essential for their success by working for years in their shop with printing presses, motors. Their work with bicycles in particular influenced their belief that a vehicle like a flying machine could be controlled and balanced with practice. From 1900 until their first powered flights in late 1903, they conducted extensive tests that developed their skills as pilots. Their bicycle shop employee Charlie Taylor became an important part of the team, the Wright brothers status as inventors of the airplane has been subject to counter-claims by various parties. Much controversy persists over the competing claims of early aviators. The Wright brothers were two of seven born to Milton Wright, of English and Dutch ancestry, and Susan Catherine Koerner, of German. Wilbur was born near Millville, Indiana, in 1867, Orville in Dayton, the other Wright siblings were Reuchlin, Lorin and twins Otis and Ida.
In elementary school, Orville was given to mischief and was once expelled, the direct paternal ancestry goes back to a Samuel Wright who sailed to America and settled in Massachusetts in 1636. In 1878 their father, who traveled often as a bishop in the Church of the United Brethren in Christ, the device was based on an invention of French aeronautical pioneer Alphonse Pénaud. Made of paper and cork with a band to twirl its rotor. Wilbur and Orville played with it until it broke, and built their own, in years, they pointed to their experience with the toy as the spark of their interest in flying
The three-cent silver, known as the three-cent piece in silver or trime, was struck by the Mint of the United States for circulation from 1851 to 1872, and as a proof coin in 1873. Designed by the Mints chief engraver, James B, Longacre, it circulated well while other silver coinage was being hoarded and melted, but once that problem was addressed, became less used. It was abolished by Congress with the Coinage Act of 1873, after a massive importation of gold bullion during the California Gold Rush, silver could be traded for increasing amounts of gold, so U. S. silver coins were exported and melted for their metal. This, and the reduction of postage rates to three cents, prompted Congress in 1851 to authorize a coin of that made of.750 fine silver, rather than the conventional.900. The three-cent silver was the first American coin to contain metal valued significantly less than its value. The coin saw heavy use until Congress acted again in 1853, making silver coins lighter. Congress lightened the three-cent silver, and increased its fineness to 900 silver, a three-cent piece in copper-nickel was struck beginning in 1865, and the three-cent silver saw low mintages for its final decade before its abolition.
The series is not widely collected, and the pieces remain inexpensive relative to other U. S. coins of similar scarcity. Although the Mint of the United States had been striking silver coins since the 1790s, in 1834, for example, half dollars sold on the market at a premium of one percent. The U. S. was on a bimetallic standard, by early 1849, most of the silver coins in circulation were small coins of the Spanish colonial real, including the levy and fip. The levy and fip often passed for twelve and six cents respectively in the Eastern U. S, the mint accepted them as payment at a slightly lower figure, but even so, lost money on the transactions as many of the pieces were lightweight through wear. In the Western U. S. the levy and fip were accepted as the equivalent of the dime and half dime. Bullion from the California Gold Rush and other came to the Eastern U. S. in considerable quantities beginning in 1848. By the following year, the price of gold relative to silver had dropped, making it profitable to export American silver coins, sell them as bullion, early in 1849, Congress authorized a gold dollar to help bridge the gap.
Spanish silver coins were the bulk of what was left in commerce for small change, they were often heavily worn, reducing their intrinsic worth at a time when Americans expected coins to contain metal worth the value assigned to them. In 1850, New York Senator Daniel S. Dickinson introduced legislation for a three-cent piece in.750 fine silver, that is, three parts silver to one part copper. He proposed to offer it in exchange for the Spanish silver, the three-cent denomination was chosen as it coordinated well with the six and twelve cent values often assigned the fip and levy. No legislation passed in 1850, which saw continued export of Americas silver coinage, impetus for the passage of a three-cent coin came when Congress, in January 1851, considered reducing postage rates from five cents to three
An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by a metallic bonding character, an alloy may be a solid solution of metal elements or a mixture of metallic phases. Intermetallic compounds are alloys with a stoichiometry and crystal structure. Zintl phases are sometimes considered alloys depending on bond types. Alloys are used in a variety of applications. In some cases, a combination of metals may reduce the overall cost of the material while preserving important properties, in other cases, the combination of metals imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength. Examples of alloys are steel, brass, duralumin, the alloy constituents are usually measured by mass. Alloys are usually classified as substitutional or interstitial alloys, depending on the arrangement that forms the alloy. They can be classified as homogeneous, or heterogeneous or intermetallic. An alloy is a mixture of elements, which forms an impure substance that retains the characteristics of a metal.
Alloys are made by mixing two or more elements, at least one of which is a metal and this is usually called the primary metal or the base metal, and the name of this metal may be the name of the alloy. The other constituents may or may not be metals but, when mixed with the base, they will be soluble. The mechanical properties of alloys will often be different from those of its individual constituents. A metal that is very soft, such as aluminium, can be altered by alloying it with another soft metal. Although both metals are soft and ductile, the resulting aluminium alloy will have much greater strength. Adding a small amount of carbon to iron trades its great ductility for the greater strength of an alloy called steel. Due to its strength, but still substantial toughness, and its ability to be greatly altered by heat treatment, steel is one of the most useful. By adding chromium to steel, its resistance to corrosion can be enhanced, creating stainless steel, while adding silicon will alter its electrical characteristics, producing silicon steel
Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, ductile, highly unreactive and its name is derived from the Spanish term platina, translated into little silver. Platinum is a member of the group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes and it is one of the rarer elements in Earths crust with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some deposits, mostly in South Africa. Because of its scarcity in Earths crust, only a few hundred tonnes are produced annually, Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the sands of various rivers. Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry.
Being a heavy metal, it leads to health issues upon exposure to its salts, compounds containing platinum, such as cisplatin and carboplatin, are applied in chemotherapy against certain types of cancer. Pure platinum is a lustrous and malleable, silver-white metal, Platinum is more ductile than gold, silver or copper, thus being the most ductile of pure metals, but it is less malleable than gold. The metal has excellent resistance to corrosion, is stable at temperatures and has stable electrical properties. Platinum reacts with oxygen slowly at high temperatures. It reacts vigorously with fluorine at 500 °C to form platinum tetrafluoride and it is attacked by chlorine, bromine and sulfur. Platinum is insoluble in hydrochloric and nitric acid, but dissolves in hot aqua regia to form chloroplatinic acid and its physical characteristics and chemical stability make it useful for industrial applications. Its resistance to wear and tarnish is well suited to use in fine jewelry, the most common oxidation states of platinum are +2 and +4.
The +1 and +3 oxidation states are common, and are often stabilized by metal bonding in bimetallic species. As is expected, tetracoordinate platinum compounds tend to adopt 16-electron square planar geometries, Platinum has six naturally occurring isotopes, 190Pt, 192Pt, 194Pt, 195Pt, 196Pt, and 198Pt
A grain is a unit of measurement of mass, for the troy grain, equal to exactly 7001647989100000000♠64.79891 milligrams. It is nominally based upon the mass of a seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat, expressions such as thirty-two grains of wheat, taken from the middle of the ear appear to have been ritualistic formulas, essentially the premodern equivalent of legal boilerplate. Another book states that Captain Henry Kater, of the British Standards Commission, the grain was the legal foundation of traditional English weight systems, and is the only unit that is equal throughout the troy and apothecaries systems of mass. The unit was based on the weight of a grain of barley. The fundamental unit of the pre-1527 English weight system known as Tower weights, was a different sort of known as the wheat grain. The Tower wheat grain was defined as exactly 45⁄64 of a troy grain.79891 milligrams, 7000100000000000000♠1 gram is approximately 7001154323600000000♠15.43236 grains.
The unit formerly used by jewellers to measure pearls, diamonds, or other stones, called the jewellers grain or pearl grain, is equal to 1⁄4 of a carat. The grain was the name of a traditional French unit equal to 6995531150000000000♠53.115 mg. In both British Imperial and U. S. customary units, there are precisely 7,000 grains per avoirdupois pound, the grain is commonly used to measure the mass of bullets and propellants. The term refers to a particle of gunpowder, the size of which varies according to requirements. In archery, the grain is the unit used to weigh arrows. In dentistry, gold foil, used as a material to restore teeth, is measured in grains, in North America, the hardness of water is often measured in grains per US gallon of calcium carbonate equivalents. Otherwise, water hardness is measured in the metric unit parts per million, one grain per US gallon is approximately 6995171000000000000♠17.1 ppm. Soft water contains 1–4 gpg of calcium carbonate equivalents, while hard water contains 11–20 gpg, though no longer recommended, grains are still used occasionally in medicine as part of the apothecaries system, especially in prescriptions for older medicines such as aspirin or phenobarbital.
For example, the dosage of a standard 6996325000000000000♠325 mg tablet of aspirin is sometimes given as 7000500000000000000♠5 grains, in that example the grain is approximated to 6995650000000000000♠65 mg, though the grain can be approximated to 6995600000000000000♠60 mg, depending on the medication and manufacturer. The apothecaries system has its own system of notation, in which the symbol or abbreviation is followed by the quantity in lower case Roman numerals. For amounts less than one, the quantity is written as a fraction, or for one half, therefore, a prescription for tablets containing 325 mg of aspirin and 30 mg of codeine can be written ASA gr