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 
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Cu. Ft. —Millions 
Fig. 1.— Total material treated (1) 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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