EVALUATION OF WOOD PRESERVATIVES 449 



EVALUATION BY POLE TEST LINES AND BY LINE EXPERIENCE; SERVICE 

 TESTS 



In 1932 a condensed reporf^ of American Telephone and Telegraph 

 Company experience with creosoted pole test lines, including brush, 

 open-tank and pressure treatments, and covering northern (eastern) cedar, 

 southern white cedar, chestnut and southern pine poles, ends with the 

 following conclusions, among other generalizations: 



"Because of the fact that many of the test specimens are still in 

 service, conclusions can be reached only in the case of some of the less 

 important problems whose solution has been sought. The possibility of 

 extending the life of poles through preservative treatment is abundantly 

 demonstrated, but the capabilities of the more effective processes of 

 treatment (studies) can as yet only be estimated. 



"... the indications are that in the cases not already affected, the 

 beginning of decay attack will mainly be dependent upon changes in the 

 quantity and the composition of the preservative retained in the individ- 

 ual poles." 



This was only twenty years ago. Even in 1932 this service test report 

 was more valuable as history than as a technical base for treatment 

 specifications. The report reconfirmed the common knowledge that dur- 

 able timbers like northern cedar and chestnut were better line units if 

 properly butt-treated with creosote, and that adequate penetration and 

 absorption of creosote were essential factors in the economy of pressure 

 treatment of non-durable southern pine poles. However, by 1932 



(a) The type of creosote used for treating the relatively large heart 

 and small sapwood southern pine poles for the famous Washington-Nor- 

 folk and Montgomery-New Orleans lines was no longer available com- 

 mercially; 



(b) The type of virgin pine timber used was becoming scarcer and 

 scarcer; 



(c) The supply of commercial chestnut pole timber was just about 

 completely exhausted; 



(d) New and improved methods of butt treatment involving the use 

 of machines for incising the ground section were being applied to northern 

 cedar and to western cedar poles, and besides, the use of northern cedar 

 was gradually shrinking to limited areas in telephone plant in the North- 

 eastern and Lake States; and 



(e) Because of vastly increased competition in the pole treating in- 

 dustry, and because the chestnut supply had failed, and because the 

 excessive bleeding of creosote from the old style "12-pound" full-cell 



