70 Report of Schimmel § Co. April/October 1917. 



Experiments have further given proof of the fact that a careful treatment of the 

 trees, especially care in chipping, has decided advantages and leads to a better yield 

 of turpentine. 



One disadvantage of the cup-method is caused thereby that frequently very thin 

 trees are worked, which was not the case in the box-system. The following con- 

 siderations are a warning against this practice: 1. Possible damage to, or destruction 

 of, the trees. 2. Such processes being unremunerative.' 



It has been definitely proposed to substitute the distillation on a small scale of 

 the individual turpentine-farms by a distillation on a large scale at a suitable place, 

 where the crude turpentine can be brought to in a tank-waggon. The future must 

 indicate if such a proposal is feasible in practice. 



Further particulars about the qualities of the turpentine or oil of turpentine con- 

 tained in coniferous wood are to be found in a publication by C. G. Schwalbe 1 ) on 

 the resin of pine trees and especially of Scotch pines. The voluminous literature on 

 the resin content of coniferous trees treats principally of the so-called "pathological" 

 resin which exudes or is formed when a tree is injured. Only a small part of these 

 investigations refers to the normal resin of the living tree or to the resin contained 

 in wood that has been felled. 



In Schwalbe's paper experiments are mentioned in detail which had the object, 

 by a close investigation of the resin in fresh and mature wood, of obtaining information 

 as to its qualities and composition. 



The attempt to determine the quantity of turpentine obtained in the alcohol and 

 ether-extracts lead to a most surprising result. One is accustomed to regard the crude 

 resin of coniferous trees as a mixture of turpentine oil and of special resinic acids, 

 especially with regard to those kinds of resin which exude from the trees on being 

 injured. This notion concerning the turpentine yield of crude resins has also been 

 transferred to the resin in the undamaged wood substance of coniferous trees. 



In order now to determine the real yield of turpentine 2 ) in resin-fat mixtures in 

 the first instance from mature wood, an attempt was made to drive off the oil of 

 turpentine by the aid of steam. Contrary to all expectations, no trace of oil of turpentine 

 could be found in the distillate as a separate oil layer. As possibly other volatile 

 components of the crude resin might have facilitated the solubility of the oil of 

 turpentine in water, the distillate was extracted with ether, the latter evaporated, and 

 the remainder concentrated at a moderate temperature, but even then no residue was 

 obtainable ! 



This result was all the more surprising as it is notorious that quite considerable 

 quantities of oil of turpentine are obtainable as a by-product of the soda-cellulose 

 manufacture from wood that has been stored for several years. Possibly the presence 

 of turpentine or turpentine oil might be caused in this case by the portion of the 

 wood which chanced to be examined having lost its (oil of?) turpentine content during 

 the protracted storage period, had it not been for the fact that the examination of the 

 resin-fat extract from quite freshly felled wood lead to exactly the same result, namely 

 total absence of (oil of ?) turpentine. If, however, such freshly felled wood was subjected 

 to a treatment with caustic soda solution under pressure and heating up to 170°, oil 

 of turpentine was easily detected in the current of steam that was blown off. 



*) Zeitscltr. f. Forst- u. Jagdivesen 47 (1915), 92. — 2 ) In this paper the terms turpentine and oil of 

 turpentine are perpetually mixed up. Unfortunately, the text does not always allow one to form an opinion 

 if the oil or the gum is referred to. Comp. page 78, footnote 1. 



