TURNSOLE, or TOUltNSOLE. (Allem; COLOURING MATTERS.] TURPENTINE. The well-known liquid to which the word turpen tine is now so commonly applied, is only the volatile portion of tur n 11 pentine properly so called. Trite turpentine is really an oleo-reain, a liquid of about the consistence of honey. It flows naturally, or by incision, from the wood of most coniferous trees, such as pine, larch, fir, pistachio, &a, and by distillation yields spirit, essence, or volatile oil of turpentine, the non-volatile portion being common resin, or cute pAony. (!testes.] Oil of turpentine is very largely used in the prepa ration of painta and varnishes, and also, when rectified, for burning in lamps under the name of ciusaphin. The derivation of the word tur pentine is not very evident. It was known and described by 31arcus Graces in the eighth century.
The turpentine met with in English commerce is nearly all imported from the States of America, North Carolina and Virginia supplying the greater part-. It is the produce of Pisna palmitin., P. Veda, and P. atria. French or Bordeaux turpentine is mainly obtained from Pietas otaritinto, a treo growing abundantly on the coasts of Southern Europe.
The method of procuring turpentine is very simple. An incision, or hole, is mule in the bark of the tree, or a small piece of the bark is removed, in the spring of the year. From this wound the turpentine slowly exudes, and is collected either in a little trough attached to the stem, in a hollow made at the foot of the tree, or by some similar con trivance. It is from time to time transferred to casks made to hold about 2 cwt. The first gathering is sometimes called riryin turpentine, and contains about 20 per cent of oil ; that collected towards the end of the season, in October, has a more solid but still soft consistence, and is not so rich in oil. As might be expected, the crude turpentine frequently contains portions of twigs, chips, and leaves ; these are sometimes separated by straining the melted turpentine, and the latter is then termed refined. Venice turpentine is the variety produced from the larch tree (Larix Europa-a); Canadian turpentine, or Canada balsam, exudes from the Allure balsantea ; and Chian turpentine is obtained from the Pistacia terebinthrts.
Turpentine slowly hardens when exposed to the aIr. This is partly duo to evaporation of the more liquid portion, and partly to resinifica tion of the fluid part by oxidation. It is probable that in the tissues
of the plant turpentine is simply a mobile juice, and that in the ordi nary state of oleo-reein it is a product rather than a simple vegetable educt. It softens and liquifies when heated, readily takes fire in the air, and burns with a Benumb:it smoky flume. It is completely dis solved by alcohol or ether, and by distillation with water yields oil of turpentine.
Oil of turpentine (C„, II.). As already indicated, this Is obtained by distilling turpentine with water ; it then forms the upper layer of the condensed product. For most purposes it is re-distilled with Caustic alkali, acid matters and traces of resin being thereby removed.
Oil of turpentine is a colourless mobile liquid, of characteristic odour and hut pungent taste. It should be neutral to test-paper, of specific gravity 0.86, boiling-point about 320° Fahr., and a vapour density of 4-76. It rotates a ray of polarised light, to the left or right according to origin. It is very soluble in ether and absolute alcohol, less so in ordinary (hydrated) alcohol, and is not miscible with water. It is a good solvent of resins, oils, sulphur, phosphorus, and caoutehonc. Pure turpentine, as obtained by re-distillation in vacuo, has constant, well-defined, la-vo-rotation. BertheIot distinguishes it as tercbenthen.
Nodifirations and Deriratires of Oil of Turpentine. Under the influ ence of heat, or of chemical re agents, or of both combined, oil of tur pentine yields several Interesting substances. hotercbenthen is one of the products into which oil of turpentine is resolved on heating, in a closed vessel, to about 470' Fehr. It is a colourless liquid, having an odour of stale lemons, sp. gr. 0.843 at 71° Fehr., boiling-point 350° Fehr, possesses hcvo-rotation of varying intensity on polarised light, yields a solid hydrate and hydrochlorate. Mcfateretenthen, like isotere bentheu, has the mine composition as oil of turpentine ; it is formed under the same circumstances aa isoterebenthen, but remains in the retort after the heat has been raised to 000' Fehr. It distils, however, at a temperature slightly higher than 600°, and then forms a yellowish, very viscid liquid of sp. gr. 0.913 at 03* Fehr. It has a disagreeable odour, and exerts hevo-rotation on polarised light.