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
Claviharp Claviharp The claviharp is a 19th-century musical instrument that combined a harp with a keyboard. J. C. Dietz invented the instrument in 1813 CE. His grandfather was one of the first upright piano manufacturers. Struck by what he saw as difficulties and defects of the harp, in 1810, he built an "instrument à cordes pincées à clavier", which connected a keyboard to the harp strings. He made the instrument to address limitations of the harp—susceptibility of catgut strings to atmospheric change, inconsistency of sound as finger motion varies, limited diatonic scale (without pedals), and lack of dampers. The claviharp's keyboard