﻿THE TERPEXE OILS OF MANILA ELEMI. 39 



this case the temperature recorded by the thermometer depended very 

 largely upon the rapidity of the distillation. The different fractions 

 were redistilled with the following results : 



(1) 170° to 180° almost completely; residue added to (2); 25 per cent 



to 200°. 



(2) 30 per cent from 200° to 260°; 40 per cent from 200° to 280°; residue 



added to (3). 



(3) 10 per cent below 200° beginning very low; 30 per cent from 200° to 



250°; 30 per cent from 250° to 300°; 15 per cent from 300° to 350°. 



The separations made in the above experiments are naturally incom- 

 plete, but they give an approximate idea of the composition of the crude 

 distillate. It will be seen that a product boiling below 300° constitutes 

 over one-half the weight of the original resin, which product may be 

 separated into about equal parts of low-boiling and high-boiling oils, the 

 point of separation being between 200° and 225° . A smaller portion of 

 a more viscous oil. having about the consistency of rosin oil, is also 

 obtained. The low-boiling oil resulting from the decomposition contains 

 a small proportion of very volatile constituents. All of the oils obtained 

 in these experiments were colored and, except the terpene oil removed 

 before decomposition of the resin had begun, possessed on offensive odor. 

 The colored products when redistilled are almost colorless, but change 

 again on standing. 



ELEMI OIL IX THE AGGREGATE. 



The combined results obtained by a careful examination of the oils 

 obtained from 21 individual samples of resin establish the true composi- 

 tion of elemi oil so far as these samples may be considered as representative 

 of the aggregate product. In several cases, notably in the last sample 

 examined, substances were obtained which were not encountered in any 

 other; it seems possible, therefore, that were the investigation continued, 

 still others would be found in which new constituents would appear, 

 although such cases would be rare and the substances themselves would 

 constitute so small a proportion of the aggregate oil that they would 

 scarcely need to be taken into account. 



It is obvious that in considering 'Mamla-elemi or the oil obtained there- 

 from as products of a species, we must deal with an aggregate sample of 

 these products; a sample derived from so great a number of individual 

 trees that the peculiarities of the individuals disappear. If the native 

 gatherer of resin untilizes a large number of trees and regularly removes 

 the resin from them in small portions, the product which he places 

 upon the market will be nearly homogeneous and a representative sample ; 

 but if he obtains his resin from a limited number of individuals his 

 product will not be representative and, if he utilizes resin which has 

 accumulated upon the trees in large quantity, it will not be homogeneous. 



