Encyclopædia Britannica, Ninth Edition/Turpentine
TURPENTINE consists of the oleo-resins which exude from certain trees, especially from some conifers and from the terebinth tree, Pistacia Terebinthus, L. It was to the product of the latter, now known as Chian turpentine, that the term was first applied. The terebinth tree (τέρμινθοσ of Theophrastus) and its resin (ῤητίνη τερμίνθινη) were well known and highly prized from the earliest times. The tree is a native of the islands and shores of the Mediterranean, passing eastward into Central Asia; but the resinous exudation found in commerce is collected in the island of Scio. Chian turpentine is a tenacious semi-fluid transparent body, yellow to dull brown in colour, with an agreeable resinous odour and little taste. On exposure to the air it becomes dry, hard, and brittle. In their general characters, turpentines are soft solids or semi-fluid bodies, consisting of a mixture of one or more resins with essential oils, which, although differing in physical properties, have a composition corresponding to the formula C10H16. They also contain minute quantities of oxygenated oils. Formerly they had considerable reputation in medicine, and they still continue to be employed in plasters and ointments; but their great use is in the arts, for which they are separated by distillation into rosin or colophony (see Rosin, vol. xx. p. 852.) and oil or spirit of turpentine.
Crude or common turpentine is the commercial name which embraces the oleo-resin yielded by several coniferous trees, both European and American. The principal European product, sometimes distinguished as Bordeaux turpentine, is obtained from the sea pine, Pinus maritima, in the Landes department of France. Crude turpentine is further yielded by the Scotch fir, P. sylvestris, throughout northern Europe, and by the Corsican pine, P. Laricio, in Austria and Corsica. In the United States the turpentine-yielding pines are the swamp pine, P. palustris, and the loblolly, P. Tæda, both inhabiting North and South Carolina, Georgia, and Alabama. Venice turpentine is yielded by the larch tree, Larix europæa, from which it is collected principally in Tyrol. Strasburg turpentine is obtained from the bark of the silver fir; but it is collected only in small quantities. Less known turpentines are obtained from the mountain pine, P. Pumilio, the stone pine, P. Cembra, the Aleppo pine, P. halepensis, &c. The so-called Canada balsam, from Abies balsamea (see Balsam, vol. iii. p. 293.), is also a true turpentine.
Oil of turpentine as a commercial product is obtained from all or any of these oleo-resins, but on a large scale only from crude or common turpentine. The essential oil is rectified by redistillation with water and alkaline carbonates, and the water which the oil carries over with it is removed by a further distillation over calcium chloride. Oil of turpentine is a colourless liquid of oily consistence, with a strong characteristic odour and a hot disagreeable taste. Its boiling point ranges from 152° to 172° C. at ordinary temperature; its sp. gr. is between 0·856 and 0·870; and in optical properties it rotates the plane of polarized light both to right and left in varying degrees according to its sources. It is soluble in alcohol, ether, benzol, other essential oils, and the fixed oils, and itself is a solvent of resins and caoutchouc. On exposure to the air it dries to a solid resin, and when oxidized in the presence of water gives off peroxide of hydrogen—a reaction utilized in the preparation of a disinfectant called "sanitas." Oil of turpentine is largely used in the preparation of varnishes, and as a medium by painters in their "flat" colours.