486 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



had been weathered twelve weeks; and the 10.0 blocks would have been 

 attacked at the end of five weeks w^eathering; while the 8-pound blocks 

 would have been attacked after three weeks and about two weeks in the 

 case of Creosote I and II, respectively. Under all these assumptions the 

 treatment threshold for creosote in these block tests would probably 

 have been set at above 8 pounds, and possibly around 9 pounds or more 

 per cubic foot, in 1934; which would agree very well with the evidence 

 obtained from soil-block tests, ?^-inch stake tests, and test posts that 

 has been presented in this paper. 



Older records show very substantial quantities of the fraction below 

 355°C remaining in well treated wood after long service. Alleman's 1907 

 paper^ is a classic. Writing of the increasing use of creosoted wood he 

 states: "Recent reports . . . have clearly shown that, while proper treat- 

 ment gives remarkably good results, much of this timber was not prop- 

 erly treated and has not lasted as it should". All of which in his opinion 

 *^ . . makes it imperative that we should know, as completely as pos- 

 sible, just what constitutes efficient creosote treatment. The different 

 sorts of oils are believed to have different preservative values w^hen 

 mjected into timber, but there is, unfortunately, a lack of uniformity 

 in opinion". 



AUeman chose, as the best method for finding some of the answers, 

 an extraction of oils from treated timber that had given good service. 

 As solvents he used absolute alcohol and subsequently anhydrous ben- 

 zene. He fractionated the extracted creosotes with a view to determining 

 the character of the oils, deciding to make his cuts so as to collect the 

 distillate as follows: I to 170°C; II 170-205°C; III 205-245°C, which 

 he regarded as the naphthalene fraction; IV 245-270^C; V 270-320°C; 

 VI 320-420°C; and VII the residue above 420°C. 



The wood from which he extracted the creosotes consisted of ties, 

 mostly British, piles from England and the United States, paving blocks, 

 and a section of creosoted wood duct removed in perfect condition after 

 fourteen years service in Bell Telephone plant in Philadelphia. The 

 EngUsh piles had been in service forty-three years, the other old samples 

 all averaged a little over twenty years. Alleman's extractions showed — • 

 after all these years in use — that there were on the average over 9 

 pounds per cubic foot of oil remaining in the ties and English piles; 

 nearly 9 pounds remaining in the conduit; and about 16 pounds remain- 

 ing in the American piles and the paving blocks. 



The writer has calculated the residue above 355°C in these extracted 

 oils to have varied from about 23 to about 42 per cent ; and the pounds 

 per cubic foot of oil distilling below 355°C remaining in the treated wood 



