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A golf ball is a special ball designed to be used in the game of golf. Under the rules of golf, a golf ball has a mass no more than 1.620 oz (45.93 grams), has a diameter not less than 1.680 in (42.67 mm), and performs within specified velocity, distance, and symmetry limits. Like golf clubs, golf balls are subject to testing and approval by the R&A (formerly part of the Royal and Ancient Golf Club of St Andrews) and the United States Golf Association, and those that do not conform with regulations may not be used in competitions ''(Rule 5–1)''. ==History== It is commonly believed that hard wooden, round balls were the first balls used for golf between the 14th through the 17th centuries. Though they were undoubtedly used for other similar contemporary stick and ball games, made from hardwoods such as beech and box trees, there is no definite evidence that they were used in golf in Scotland. It is equally, if not more likely, that leather balls filled with cows' hair were used, imported from The Netherlands from at least 1486 onwards.〔(Golf Ball History from Hairy to Haskell 2014 )〕 Then or later, the ''featherie'' ball was developed and introduced. A featherie, or feathery, is a hand-sewn round leather pouch stuffed with chicken or goose feathers and coated with paint, usually white in color. The volume measurement for the feathers was a gentleman's top hat full of feathers. The feathers were boiled and softened before they were stuffed into the leather pouch. Making a featherie was a tedious and time-consuming process. An experienced ball maker could only make a few balls in one day, and so they were expensive. A single ball would cost between 2 shillings and 5 shillings, which is the equivalent of 10 to 20 US dollars today.〔(Feature Interview with Kevin Cook May, 2007 ). golfclubatlas.com〕 There were a few drawbacks to the featherie. First, it was hard to make a perfectly round, spherical ball, and because of this, the featherie often flew irregularly. Also, when the featherie became too wet, its distance would be reduced, and there was a possibility of its splitting open upon impact when hit or when hitting the ground or other hard surface. Despite these, the featherie was still a dramatic improvement over the wooden ball, and remained the standard golf ball well into the 19th century. In 1848, the Rev. Dr. Robert Adams Paterson (sometimes spelled Patterson) invented the gutta-percha ball (or ''guttie'', ''gutty'').〔(【引用サイトリンク】title=Timeline of the history of golf )〕 The guttie was made from dried sap of the Malaysian sapodilla tree. The sap had a rubber-like feel and could be made round by heating and shaping it in a round mold. Because gutties were cheaper to produce, could be re-formed if they became out-of-round or damaged, and had improved aerodynamic qualities, they soon became the preferred ball for use.〔(【引用サイトリンク】title=gutta percha golf balls )〕 Accidentally, it was discovered that nicks in the guttie from normal use actually provided a ball with a more consistent ball flight than a guttie with a perfectly smooth surface. Thus, makers began intentionally making indentations into the surface of new balls using either a knife or hammer and chisel, giving the guttie a textured surface. Many patterns were tried and used. These new gutties, with protruding nubs left by carving patterned paths across the ball's surface, became known as "brambles" due to their resemblance to bramble fruit. The next breakthrough in golf ball development came in 1898. Coburn Haskell of Cleveland, Ohio had driven to nearby Akron, Ohio for a golf date with Bertram Work, the superintendent of the B.F. Goodrich Company. While he waited in the plant for Work, Haskell picked up some rubber thread and wound it into a ball. When he bounced the ball, it flew almost to the ceiling. Work suggested Haskell put a cover on the creation, and that was the birth of the 20th century wound golf ball that would soon replace the guttie bramble ball. The new design became known as the rubber Haskell golf ball. For decades, the wound rubber ball consisted of a liquid-filled or solid round core that was wound with a layer of rubber thread into a larger round inner core and then covered with a thin outer shell made of balata sap. The balata is a tree native to Central and South America and the Caribbean. The tree is tapped and the soft, viscous fluid released is a rubber-like material similar to gutta-percha, which was found to make an ideal cover for a golf ball. Balata, however, is relatively soft. If the leading edge of a highly lofted short iron contacts a balata-covered ball in a location other than the bottom of the ball a cut or "smile" will often be the result, rendering the ball unfit for play in most instances. In the early 1900s, it was also found that inverting the dimples to be concave in look and feel provided even more control of the ball's trajectory, flight, and spin than did the raised or protruding-dimpled guttie bramble balls (a patent was taken out by David Stanley Froy, James McHardy and Peter G. Fernie in 1897 for a ball with indentations with David Stanley Froy playing in The Open in 1900 at the Old Course at St. Andrews with the first prototype).〔(Espacenet - Bibliographic data )〕 Players were able to put additional backspin on the new wound, inverted-dimpled, balls when using more lofted clubs, thus inducing the ball to stop more quickly on the green. Manufacturers soon began designing, making, and selling various types of golf balls with various dimple patterns to improve the length, trajectory, spin, and overall "feel" characteristics of the new wound golf balls. Wound, balata-covered golf balls would be used for decades well into the late 20th century.〔("Hot, new solid-core balls have nearly KO'd their wound-ball rivals" ), ''Golf Digest'', June 2001.〕 In the mid-1960s, a new synthetic resin, an ionomer of ethylene acid named "Surlyn," was introduced (by E. I. du Pont de Nemours and Company), as were new urethane blends for golf ball covers, and these new materials soon displaced balata as they proved more durable and more resistant to cutting.〔(DuPont™ Surlyn® golf ball applications ). dupont.com (2005-12-02). Retrieved on 2013-11-03.〕 Along with various other materials that came into use to replace the rubber-wound internal sphere, golf balls came to be classified as either two-piece, three-piece, or four-piece balls according to the number of layered components. These basic materials continue to be used in modern balls, with further advances in technology creating balls that can be customized to a player's strengths and weaknesses, and even allowing for the combination of characteristics that were formerly mutually-exclusive. Liquid cores were commonly used in golf balls as early as 1917. The liquid cores in many of the early balls contained a caustic liquid, typically an alkali, causing eye injuries to children who happened to dissect a golf ball out of curiosity. By the 1920s, golf ball manufacturers had stopped using caustic liquids, but into the 1970s and 1980s golf balls were still at times exploding when dissected and were causing injuries due to the presence of crushed crystalline material present in the liquid cores. In 1967, Spalding purchased a patent for a solid golf ball from Jim Bartsch. The original patent proposed a ball void of the former layered approach seen in earlier designs, but Bartsch's patent lacked the chemical properties needed in its manufacturing. Under Spalding, and its chemical engineering team, the development of a chemical resin eliminated the need for the former layered components entirely. Since this time, the majority of non-professional golfers have transitioned to using solid core (or "2-piece") golf balls.〔 The specifications for the golf ball continue to be governed by the ruling bodies of the game; namely, The Royal & Ancient (The R&A), formerly part of the Royal and Ancient Golf Club of St Andrews, and the United States Golf Association (USGA). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Golf ball」の詳細全文を読む スポンサード リンク
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