34 The Forest Products Laboratory 



In connection with the investigations into the fundamentals of 

 the chemical pulping processes, attention has been directed to the im- 

 provement of the processes in their various details. Typical of the 

 improvements worked out is the impregnation of the chips with cook- 

 ing liquor before starting the cook. This is applicable to the sulphate 

 and soda processes and produces more uniform cooking and increased 

 yields of pulp, at the same time reducing the cooking period and the 

 steam consummation. The commercial trials of this improvement were 

 successfully completed shortly before the declaration of war. 



There are many problems in the specialty fields which could be 

 solved if time and funds were available. On some of these the labora- 

 tory has worked as occasion arose. In connection with the utilization 

 of waste hemlock bark from j^ulpwood, a new use for spent tanbark 

 presented itself, and experiments were undertaken to determine its 

 commercial value. 



As a direct result of this work, a number of companies began the 

 use of a certain percentage of spent tanbark in the manufacture of 

 roofing felts, in place of cotton rag stock. This produced a new market 

 and exercised a stabilizing effect upon the cotton rag market, which 

 had begun to skyrocket. 



In the Derived Products of Wood 



The hardwood distillation industry is one of the older wood- 

 utihzing industries, and has gradually developed to its present state 

 largely without the aid of organized research. The laboratory under- 

 took a series of experiments to determine the fundamentals of the 

 process and found that proper control of the temperature in the re- 

 torts during distillation produced decided increases in the yield of 

 valuable products without increasing the time required. This im- 

 provement has been rapidly adopted by the industry. 



Beech, birch, and maple have always been considered the standard 

 woods for distillation, and only a very small percentage of other woods 

 was used. As part of its distillation studies, the laboratory deter- 

 mined the value of a number of other hardwoods such as oaks and 

 chestnut, and demonstrated that the yields from several were sufficient 

 to warrant commercial exploitation. Several plants have recently 

 been erected to distill these substitute MOods exclusivelv. 



