Turpentine as met with in commerce is mainly derived from _Pinus maritima_, yielding French turpentine, and _Pinus australis_, furnishing most of the American turpentine. The latter is obtained from North and South Carolina, Georgia and Alabama. In Hanbury and Fluckiger's Pharmacographia there is a full description of the manner in which the trees are wounded to obtain the turpentine. Besides these there are Venice turpentine from the larch, _Pinus Larix_, Strassburg turpentine from _Abies pectinata_, and Canada balsam from _Pinus balsamea_. The crude American turpentine is a viscid liquid of about the consistence of honey, but varying to a soft solid, known as gum, thus, according to the amount of exposure which it has undergone, it contains about 10 to 25 per cent. of "spirits," to which the name of turpentine is commonly given, the rest being resin, or as it is usually called, rosin. In Liverpool almost all the spirits of turpentine comes from America, so that it is almost impossible to get a sample of French. The terpene from American turpentine is called austraterebenthene. It possesses dextro-rotatory polarization of +21.5. Its density is 0.864. Boiling point 156 deg. C. In taking the boiling point of a commercial sample of spirits it is necessary to wait until the thermometer becomes steady. Not more than 5 per cent. should pass over before this takes place, and then there is not more than two or three degrees of rise until almost all is distilled over. The liquids of lower boiling point do not appear to have been much studied. In French spirits they seem to be of the same composition as the main product, but with more action on polarized light. French spirits of turpentine is mainly composed of terebenthene. The boiling point and sp. gr. are the same as those of the austraterebenthene, but the polarization is left handed and amounts to -40.5. Isomeric modifications. Heated to 300 deg. C. in a sealed tube for two hours, it becomes an isomeric compound, boiling at 175 deg. C., while the density is lowered, being only 0.8586 at 0 deg. C. The rotatory power is only -9 deg.. It oxidizes much more rapidly. It is called isoterebenthene and has a smell of essential oil of lemons. By the action of a small quantity of sulphuric acid, among other products terebene is formed. It has the same boiling point and sp. gr. as terebenthene, but is without action on polarized light. Austraterebenthene forms similar if not identical bodies. Polymers. One part of boron fluoride BF3 instantly converts 160 parts of terebenthene into polymers boiling above 300 deg. C., and optically inactive. H2 SO4 does the same on heating and forms diterebene C20 H32. Terchloride of antimony does the same, and also produces tetraterebene C40H64, a solid brittle compound formed by the union of four molecules of C10 H16. It does not boil below 350 deg. C. and decomposes on heating.