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BELL SYSTEM TECHNICAL JOURNAL 



is equally clear that if early failures in line and consequent replacement 

 charges are to be reduced to a practical minimum it is essential to 

 inspect the treated poles closely and to eliminate the poorly treated 

 ones before they are shipped to the Telephone Companies. 



The Inspected Lines 

 The selection of the lines to be inspected was based largely on 

 geographical location without prior knowledge of the condition of 

 the poles. An attempt was made to get as wide a distribution as 

 possible. The lines were located in Florida; in the Piedmont section 

 of North Carolina and South Carolina; in the Appalachian foothills 

 and mountains of Tennessee, North Carolina and Virginia; in the 

 Lake States region in Illinois, Wisconsin and Michigan ; and in northern 

 New Jersey. Sections of the chosen lines contained from 100 to 200 

 or more poles that had been set consecutively in one year. Old records, 

 plus identifying marks placed on these poles when they were treated, 

 made it possible to determine the supplier of the poles and the type 

 of creosote used in treatment. 



Method of Inspection 



External decay is relatively rare in creosoted southern pine poles, 



so the inspection methods employed were directed particularly at 



finding internal decay. The latter occurs as a result of infection by 



water or air-borne spores that probably enter through checks or cracks 



■^^^tC.' 



Fig. 1 — Cross-sections of poles which failed because of decay that developed in the 

 internal untreated sapwood. 



