112 OUR NATIONAL FORESTS 



varies greatly and many of them have been shown 

 to have very small value. 



Studies in wood distillation seek to find new 

 woods which can be used for this industry, new 

 and more efficient methods which can be employed, 

 and new uses for wood waste and stumps. Char- 

 coal, wood alcohol, acetate of lime, and tar are 

 derived from the distillation of such woods as 

 beech, birch, and maple, to which tar oils and tur- 

 pentine are added for the pines and other resinous 

 woods. These by-products of wood distillation 

 have many uses, as well as the many products which 

 are, in turn, made from these by-products. Char- 

 coal is used in the manufacture of black powder, 

 acetic acid is used in the manufacture of explosives, 

 and wood alcohol is converted into formaldehyde 

 for disinfection against contagious diseases. By 

 means of temperature control methods developed at 

 the Laboratory in the destructive distillation of 

 hardwoods, the net gain per annum of one com- 

 pany's plant was over $17,000. About one-half of 

 the plants of the country have adopted the new 

 method developed by the Forest Products Labora- 

 tory. 



Experiments have been conducted by the Labor- 



