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 , has a diameter not less than , 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 Early Balls It is commonly believed that hard wooden, round balls, made from hardwoods such as beech and box, were the first balls used for golf between the 14th through the 17th centuries. Though wooden balls were no doubt used for other similar contemporary stick and ball games, there is no definite evidence that they were actually 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 onward. The Featherie 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. A standard featherie used 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, so they were expensive. A single ball would cost , which is equivalent to US$10–20 today. There were a few drawbacks to the featherie. First, it was difficult to make a perfectly spherical ball, so the featherie often flew irregularly. Second, when the featherie became too wet, its distance would be reduced, and there was a possibility of its splitting open upon impact, both when hit or when contacting the ground or another hard surface. Despite these drawbacks, the featherie was a dramatic improvement over the wooden ball, and remained the standard golf ball well into the 19th century. The Guttie In 1848, the Rev. Dr. Robert Adams Paterson (sometimes spelled Patterson) invented the gutta-percha ball (or guttie, gutty). The guttie was made from dried sap of the Malaysian sapodilla tree. The sap had