250 POPULAR ECONOMIC BOTANY. 



two to two and a half hundredweights, and has the consis- 

 tency and appearance of honey, sometimes white and some- 

 times yellow in colour, generally much mixed with im- 

 purities, such as fragments of bark, small twigs, etc. When 

 distilled the turpentine of commerce yields from 14 to 16 

 per cent, of a fine colourless essential oil, usually called 

 Spirits of Turpentine ; the residue is the Rosin or Resin of 

 the shops. The economic purposes to which these two pro- 

 ducts are applied are very various : the former is essential 

 to the manufacture of paint, and the latter is much em- 

 ployed in the manufacture of common soap, in caulking 

 ships, making the common kinds of sealing-wax, and many 

 other uses. Rosin is of two kinds, yellow and brown or 

 block ; the latter has been called Colophony : the difference 

 depends upon the duration of the process of distillation, the 

 resin getting darker the longer the heat is continued. The 

 quantity of turpentine imported in 1851 was 21,731 tons, 

 besides 12,000 gallons of the distilled oil, and 1900 tons 

 of rosin. 



There are two or three other products, which are either 

 oleo-resins or products of them. — 



Thus, or Frankincense, much used in pharmacy for 

 making plaisters, — a turpentine from which most of the 



