H. S. SACKETT 

 Chief, Office of Wood Utilization. United Stales Forest Service, .Chicago, Illinois 



The second group of sections may 

 properly be called the physical group, 

 and contains the sections of wood pres- 

 ervation, pathology, and wood physics. 

 Wood preservation covers the study of 

 the treatment of wood by substances to 

 improve its durability or appearance. 

 The treatment of wood to improve its 

 durability is rapidly becoming an im- 

 portant industry, and in the future it 

 will work a great reduction in the waste 

 which takes place in use because of de- 

 cay, insects, and marine borers. Many 

 of its fundamental problems are yet to 

 be solved, however, and on these the 

 laboratory will work. Closely allied 

 with wood preservation is the section 

 of pathology, which studies the dis- 

 eases which prey upon woods. By an 



advantageous cooperative arrangement 

 part of its work. The section of wood 

 physics will investigate the microscopic 

 the Bureau of Plant Industry will man 

 this section and supervise the technical 

 structure of wood and the relation be- 

 tween structure and physical properties 

 such as strength, toughness, and pene- 

 trability to liquids. 



The third group contains two sec- 

 tions, which rest substantially on me- 

 chanical engineering. It may, there- 

 fore, be called the engineering group. 

 The first of these is timber testing, 

 which aims to build up, through me- 

 chanical tests, a rating table for the 

 properties of our commercial woods. 

 By means of the figures, when secured, 

 we may classify woods according to 



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