306 DESCRIPTIVE BOTANY. 



Turpentine is the product of this pine. It is obtained by cutting a pocket- 

 like cavity in the side of a tree. The wound tlius made discharges the fluid 

 into the pocket or box, which holds about three pints. These cavities fill in 

 about ten days ; the contents are then removed, two grooves are cut in the 

 bark above the pocket leading to the cavity, another filling takes place, and 

 the process is continued. The liquid is put into casks made on the spot, aud 

 hardens or becomes a semi-fluid, and forms the turpentine of commerce. 

 There are in the markets of the world several varieties obtained from other 

 coniferous trees. 



In America a single person attends to the emptying of 4,000 pockets, 

 which yield in a season sixteen barrels, Aveighing net 320 pounds to the' 

 barrel. The crude turpentine has a fixed resin dissolved in oil, with succinic 

 acid. 



Spirits of turpentine is procured by distilling crude turpentine and water ; 

 the water and spirits go over together, and are allowed to cool in a vat. The 

 mass will arrange itself into two layers, when the spirits may be drawn off 

 into vessels for market. 



Spirits of turpentine is largely used in the arts for dissolving gum resins, 

 for varnishes, aud for mixing paints, and before the discovery of petroleum 

 was used for illuminating purposes ; mixed with alcohol it formed the burning 

 fluid previously used for illuminating. As a medicine it is diaphoretic and 

 anthelmintic, acting directly upon the kidneys, and in large doses it is power- 

 fully cathartic. It is used by veterinary practitioners as a liniment. The 

 annual product in the United States is about 17,500,000 gallons. Rosin (or 

 colophony) is a residuum of distillation, after the volatile oil of turpentine has 

 gone over. 



Tar is obtained from the dead branches and trunks of trees that have been 

 exhausted by six or more years' tapping. The wood is cut into suitable 

 lengths and placed on end in a pyramidal stack upon a floor made of clay, 

 well pounded and concave, outside of which is a well, also lined with clay. In 

 arranging the wood a cavity is left in the center, and filled with combustibles, 

 such as dry cones, shavings, etc. ; the whole is then well covered with earth, a few 

 openings being left around the base. When all is ready fire is thrown down 

 among the combustibles in the center, and when well lighted the top is closed. 

 Great heat is produced, by which the tar is liquefied ; it then passes down into the 

 dish-like floor, whence it flows through an opening made for the purpose into 

 the well outside, from which it is ladled into barrels. It is interesting to note 

 that the Greeks obtained tar by a process precisely similar, centuries prior to 

 the beginning of the Christian era. The entire annual yield of tar in America 

 is about 100,000 barrels. It is also obtained in large quantities from Norway 

 and Sweden. 



Tar is largely used in the manufacture of naval cordage, as a paint, aud 

 otherwise, in naval architecture. As a medicine it was formerly used as a 

 diaphoretic, and as an ointment for scald head, and the vapor was inhaled for 

 lung affections. Tar water, that is, water which has for a time rested upon 

 tar, is also used for stomach disorders. 



Oil of tar is procured by distilling tar. 



Pitch is a solid black substance, the residuum of distilling tar for tar oil, 

 and is largely used in pavements, and for waterproof cements. 



Resin oil is a viscid whitish opalescent liqxaid obtained by the distillation of 

 resin, and was formerly used as a lubricating substance, and for the manufac- 

 ture of illuminating gas. 



