84 VEGETABLE SUBSTANCES. 



of pine; and, having covered them with turf, they 

 were suffered to burn in the same smothered manner; 

 while the tar, melting, fell to the bottom of the stack, 

 and ran out by a small channel cut for the purpose." 



From the larch is obtained what is called Venice 

 turpentine : it is procured by incision into the tree ; 

 and from it the transparent oil of turpentine is dis- 

 tilled. The larch yields a gum and a manna; and a 

 species of fungus that grows upon it in Siberia has a 

 rind which the natives make use of in dyeing red; 

 while the body of the fungus is used as a soap. The 

 common, or Strasburgh turpentine is obtained chiefly 

 from the silver fir; Burgundy pitch from the spruce; 

 and Canada balsam, the purest of all the pine tur- 

 pentines, from the balm of Gilead fir. Turpentine of 

 highly aromatic flavour, called in commerce Chian 

 turpentine, is also derived from the turpentine-tree, 

 (Pistacia terebinthus ,) a native of Barbary and the 

 south of Europe, which is a tree belonging to ano- 

 ther family, and quite different in appearance from 

 the pines. 



Turpentine, from what species soever of the pine it 

 is derived, can be dissolved in rectified spirit or pure 

 alcohol; and, by distillation, they all give similar 

 oils, which, from their being distilled, (and not from 

 any resemblance to alcohol, or spirits properly so 

 called,) are vulgalarly termed spirits of turpentine. If 

 the distillation be performed with water, the product 

 is an essential oil, the common spirit of turpentine; 

 and, if the distillation be carried on in a retort, without 

 water, the product is more volatile and pungent 

 a concentrated oil as it were, and is called the 

 etherial spirit of turpentine. The residuum that is 

 left, in both cases, is a brownish resinous mass, 

 brittle, capable of being melted, highly inflammable, 

 insoluble in water, but mixing freely with oils: it is 

 the common rosin of commerce. 



Beside producing these resins and oils, there are 



