GUM JUNIPER. 



249 



Gum Juniper^ or Gum Sandarach. — This Gum is pro- 

 duced by Callitris quadrivalvis, called the Arar-tree in 

 Barbary (Nat. Ord. Conifem), 



It is from the wood of this tree that the Turks form the 

 ceilings and floors of their mosques^ it being considered by 

 them almost indestructible. The gum is in long thin tears, 

 rarely exceeding half an inch in length, and one-sixteenth 

 of an. inch in thickness; it is not unlike mastic, but is 

 whiter, and has a more resinous and less agreeable odour. 

 It is used for making fine varnishes, and formerly was much 

 used in manufacturing pounce for writing, which was merely 

 powdered sandarach; the invention of blotting-paper has 

 however rendered it useless for this purpose. The imports 

 are about twelve to fifteen tons annually. 



Turpentine. — An oleo-resin (combination of resin and 

 oil) which flows from incisions made in the stems of various 

 trees belonging to the Coniferous order. The principal 

 are Pimts palustris (Plate XIX. fig. 97) and Finns Tceda, 



These trees furnish the North American turpentine, which 

 is now almost the only kind imported. They are found in 

 the forests of North Carolina and Yirginia, where amazing 

 quantities of turpentine are collected and exported to all 

 parts of the world. It reaches us in barrels holding from 



