The solid lubricants, such as graphite, soapstone, etc., usually have but a limited field of use. A certain form of graphite lately introduced, however, has been shown in experimental laboratory tests, to have great lubricating value with a low coefficient of friction. The great value of this new form of graphite is due to the fact that crystals of graphite appear as minute scales or plates, which present a very good sliding surface and thus serve as a lubricant,