14 FOREST PRODUCTS LABORATORY. 



and humidity to obtain best results in drying, and they will cover the 

 entire range from an absolutely green condition to absolute dryness. A 

 number of drying schedules have already been published. This class 

 of work has direct application throughout the wood-using industries. 



STEAM BENDING. 



The proper steam bending of heavy wooden parts, such as artillery 

 \vheel rims, presents a number of problems on which the Laboratory has 

 done a limited amount of work and on which it plans to do much more 

 in the near future. The proper moisture condition of the stock, the 

 length and temperature of steaming or other preliminary treatment, and 

 the mechanical details of the actual bending must all be worked out 

 before present high losses in this process can be overcome. 



IDENTIFICATION. 



The accurate identification of woods is important not only in the in- 

 vestigative work of the Laboratory, where it is essential that the kind of 

 wood under test be definitely knowTi, but to wood users generally. 

 There is a steadily increasing demand in the various industries for serv- 

 ice of this character, and several thousand specimens of wood are an- 

 nually identified for outside concerns. Microscopic slides and photo- 

 micrographs made from the slides have been prepared for practically all 

 American woods of importance and are available for study. Authentic 

 specimens of most species are also available. 



WOOD PRESERVATION. 



PRESERVATIVES. 



The amount of wood in the form of railroad ties, mine timbers, posts, 

 poles, and other products which is destroyed each year by decay is 

 estimated at from one-half to three-quarters of a billion cubic feet. 

 It is therefore important to devise methods of treating wood with pre- 

 servatives that will reduce this waste to a .minimum. 



