Is it farther or further?
castor oil cas·tor oil (kās'tər)
A colorless or pale yellowish oil extracted from the seeds of the castor-oil plant, used pharmaceutically as a laxative and skin softener and industrially as a lubricant.
nonvolatile fatty oil obtained from the seeds of the castor bean, Ricinus communis, of the spurge family (Euphorbiaceae). It is used in the production of synthetic resins, plastics, fibres, paints, varnishes, and various chemicals including drying oils and plasticizers. Castor oil is viscous, has a clear and colourless to amber or greenish appearance, a faint characteristic odour, and a bland but slightly acrid taste, with a usually nauseating aftertaste.