UNITED STATES DEPARTMENT OF AGRICULTURE 



_ BULLETIN No. 607 





Contribution from the Forest Service 

 HENRY S. GRAVES, Forester 



J&p<$ m ru 



Washington, D. C. 



PROFESSIONAL PAPER 



June 7, 1918 



TESTS OF THE ABSORPTION AND PENETRATION OF COAL 

 TAR AND CREOSOTE IN LONGLEAF PINE. 



By Clyde H. Teesdale, in charge, Section of Wood Preservation, and J. D. MacLean, 

 Assistant Engineer in Forest Products. 



CONTENTS. 



Introduction 1 



Materials used 2 



Effect on penetration of differences in the pre- 

 servative 5 



Page. 

 Tests of the effect of varying time, pressure, 



and temperature 12 



Summary 21 



Appendix 23 



INTRODUCTION. 



One of the most important questions in the preservative treat- 

 ment of wood is the cost of the preservative. Particularly is this 

 true when creosote is used, and anything which will tend to reduce 

 the cost of this preservative without decreasing its efficiency will 

 be a direct aid to the industry. The use of tar and creosote mix- 

 tures in the preservative treatment of wood has increased rapidly in 

 recent years, particularly in the treatment of wood paving blocks. 

 This is due largely to the fact that the tar and creosote mixtures 

 can be produced more cheaply than can creosote containing no tar. 

 There are two other factors, however, aside from cost which must be 

 considered as affecting the use of tar and creosote mixtures. A 

 preservative treatment, to be effective, should show good absorption 

 and penetration and the preservative must be toxic to wood-destroy- 

 ing fungi. 1 



This paper reports the results of an investigation into the effect 

 of tar in creosote upon absorption and penetration of the preservative. 

 The study was made at the Forest Products Laboratory, maintained 

 by the Forest Service, United States Department of Agriculture, in 

 cooperation with the University of Wisconsin at Madison, Wis. 2 



1 In general the toxicity of tar and creosote mixtures is sufficient to warrant their use in preserva- 

 tives. Toxicity of wood preservatives is discussed in Bulletins 155 and 227 of the Department of 

 Agriculture. 



2 Acknowledgments are made to Mr. F. M. Bond, formerly of the Forest Service, under whose 

 direction a portion of this work was done. 



11917"— 18— Bull. 607 1 



