PART I. TARS AND THE PRODUCTION OF CREOSOTES FROM 



TARS. 



CHAPTER I. INTRODUCTION AND DEFINITIONS. 



The preservative treatment of wood is widely recognized to be of 

 great importance, not only in its bearing upon the conservation of our 

 forest resources, but also because it is a large factor in reducing the 

 annual expense for upkeep in those industries that use large amounts 

 of timber under conditions in which it is particularly liable to destruc- 

 tion by the lower forms of organized life. The importance of the 



O /O ZO JO 40 ^O 60 70 eo 90 /OO //O /ZO /JO /40 /SO /60 



Co. f^T —Millions 



Fig. 1. — Total material treated (0 by wood preservatives. 



wood-preserving industry is indicated by the diagram (fig. 1), which 

 shows the total amount of timber annually treated with preserva- 

 tives in this country for the years 1909 to 1919, inclusive. 



DEFINITIONS. 



The term '' creosote," or " creosote oil," has such a wide variation in 



meaning that all statistics include, in all probability, not only the 



product obtained from the distillation of coal tar, but also mixtures 



of the distillates with crude, refined, or filtered tar, mixtures of 



water-gas tar distillates, and mixtures of coal-tar distillates and 



water-gas tar. It is, therefore, advisable to define the terms that will 



be used in this bulletin. 



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