348 



The World's Commercial Products 



Mixtures of essential oil and 

 resin. These are usually vis- 

 cous liquids or semi-solids. 

 Examples : " Balsam of 

 Copaiba," wood oil, elemi, 

 Canada balsam. 3. Balsams 

 and balsamic resins. These 

 may be either liquids such as 

 " balsam of Peru " or solids 

 such as " benzoin." They 

 contain either benzoic or 

 cinnamic acid, and the pres- 

 ence of one or both of these 

 acids or their compounds 

 confers on them their peculiar 

 " balsamic " odour. These 

 true " balsams " should be 

 distinguished from such pro- 

 ducts as copaiba and Canada 

 " balsams," which are really 

 oleo-resins. 4. Gum-resins. 

 These are mixtures of true 

 gums with resins and may 

 also contain some essential 

 oil. Examples : Myrrh and 

 asafoetida. 



Copals 



The copals are a class of 

 hard resins used in the pre- 

 paration of elastic varnishes 

 suitable for outdoor use, as, 

 for example, on railway 

 carriages. 



They are derived from 

 many different trees and are procured from several countries. They are always very hard, 

 melt with difficulty, are usually insoluble in all solvents and are only convertible into 

 varnishes by a preliminary process' of destructive "distillation. 



In all the localities in which, copal is produced, three qualities are generally put on the 

 market : — 1. Fossil Copal, found in the ground usually in districts from which copal trees 

 have entirely disappeared. 2. Semi-fossilised Copal, collected from the soil in the neighbour- 

 hood vof living', copal trees. 3. Fresh Copal, found on • living trees either as the result of 

 exudation through natural fissures'* or from "artificial incisions. Of these three kinds the first 

 is of most value, " fresh copal " being of little value in European markets. 



East African Copals. These are also known in English commerce as " animi resins or 

 gums." They are found "in a fossil condition in Zanzibar, Madagascar, and along the East 

 African coast from the third to the tenth parallelof latitude. 



American Copals. These are collected in South America and probably originated from 

 Hymenaea Courbaril, a tree closely related to that supposed to have produced the East African 

 copals, which they resemble in character, though they are somewhat softer. 



Kauri or Cowrie Copal. This variety is produced wholly in New Zealand, whence enormous 



By permission of 



Zealand GoveriinuiU 



A KAURI 



TREE 



