434 COMPOUND PRODUCTS. CHAP. I. 



From the resinous juices of the Fir, the substances 

 known by the name of pitch and tar are also ma- 

 nufactured. The trunk is cut or cleft into pieces 

 of a convenient size, which are piled together in 

 heaps and covered with turf. They are then set on 

 fire, and the resinous juice which is thus extricated, 

 being prevented from escaping in a volatile state 

 by means of the turf, is precipitated and collected 

 in a vessel beneath. It is partly converted into an 

 empyreumatic oil, and is now tar, which by being 

 further inspissated is converted into pitch. 



Mastich. This resin is extracted from the 

 Pistacea Lentiscus, a tree which grows plentifully 

 in the island of Chios. It exudes in a fluid state 

 from incisions made in the stem, and concretes into 

 brittle grains somewhat yellowish and semi-trans- 

 parent. In this state it is sold under the name of 

 mastich. It has scarcely any taste, but when 

 heated it melts and exhales a fragrant odour. It is 

 sometimes employed as a varnish. 



Sandarach. This resin is obtained from the 

 Juniperus communis or common Juniper, by spon- 

 taneous exudation. It concretes in the form of 

 small round tears somewhat brownish and semi- 

 transparent, resembling mastich. It is used also 

 as a varnish. 



Elemi. This resin is extracted from the Amyris 

 Elemifera, a tree which grows in North America. 

 It exudes from incisions made in the bark during 

 dry weather, and is left to harden in the sun. It 



