﻿40 GLOVER. 



The great variation which I found at different times in the oil obtained 

 from commercial ehmi is readily explained. It is plain what the com- 

 position of elemi oil is when considered as an aggregate product; it 

 should be remembered that to the lasvo-limonene which accompanies 

 phellandrene should be added an equal amount of dextro-limonene and 

 the whole considered as dipentene. 



Granted that we have a representative sample of resin, the composition 

 of the oil will also be influenced by the following factors : 



( 1 ) The age of the resin. 



(2) The temperature of the distillation. This factor will largely 

 determine the proportion of the high-boiling part of the oil and will 

 influence the composition of the terpene portion, because some of the 

 terpenes suffer a change at higher temperatures. 



(3) The length of time used in the distillation. This factor will 

 influence only the proportion of high-boiling oil. 



Yield of oil. — In the first seven samples examined considerable dif- 

 ference was found in the oil content. While there may be a certain 

 amount of variation shown by the individual samples in this respect, 

 it is thought that the differences found are more directly connected with 

 the age of the resin. As previously noted, Schimmel & Co. state that the 

 yield of oil is from 15 to 30 per cent. In several cases where I have 

 examined samples of fresh, soft, resin purchased in Manila, I have always 

 found the total yield to be from 25 to 30 per cent of the weight of the 

 resin. 



