Strings (tennis) be more durable than many other types of strings due to its outstanding tension retention. This may help to offset the high initial cost. The use of a dense string pattern also generally improves the longevity of natural gut. Natural gut is produced by drying fibers extracted from a part of the cow intestine called the serous membrane, or serosa, which contains collagen designed to withstand the stretching and contraction of the intestine. It is this elasticity that makes the fibers useful for tennis string. Sheep intestines have also been used for racquet strings in the past. The first natural
Musical instrument classification percussion instruments made of wood or metal ("Ghana vadya", "solid instruments"); and percussion instruments with skin heads, or drums ("avanaddha vadya", "covered instruments"). Victor-Charles Mahillon later adopted a system very similar to this. He was the curator of the musical instrument collection of the conservatoire in Brussels, and for the 1888 catalogue of the collection divided instruments into four groups: strings, winds, drums, and other percussion. This scheme was later taken up by Erich von Hornbostel and Curt Sachs who published an extensive new scheme for classication in "Zeitschrift für Ethnologie" in 1914. Their scheme is widely used today, and