naf'tha or nap'tha, a colorless liquid obtained in the distillation of petroleum. It evaporates readily. It is used as a substitute for turpentine in the manufacture of paints and varnishes. Naphtha takes up grease readily and is used in cleaning gloves, the collars of soiled clothing, etc. It is also used as fuel to furnish heat or to produce steam, especially in naphtha launches and for some purposes as a substitute for gasoline. Crude petroleum yields from six to twelve per cent of its own weight of naphtha. Naphtha contains no oxygen, and is therefore used by chemists to preserve potassium and other metals which have a strong affinity for oxygen. It is volatile and inflammable; great care must be exercised to prevent its vapor catching fire on approach of a flame of any kind. The principal kinds of naphtha in commercial use are native naphtha, coal naphtha, paraffine oil, shale naphtha, and naphtha from caoutchouc. Bitumen and asphaltum are closely allied substances in a solid form. See PETROLEUM.