448 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



1.0 



0.4 



2 3 4 3 2 



DISTANCE FROM SURFACE IN INCHES 



100 



80 



60 



oc 

 40 3 



h- 

 (0 



o 



5 



^ Fig. 29 — Schematic diagram of a longitudinal section of a creosoted southern 

 pine test post, showing average distribution of creosote in Ib/cu ft; average 

 density (oven-dry weight and volume as tested) ; average moisture content, oven- 

 dry wood basis; and the retention levels in the outer inch of sound, decaying and 

 failed specimens. See text. 



representing a longitudinal section of an 8 inch diameter southern pine 

 test post. The sound, decaying and failed retention levels calculated for 

 the outer one inch (Table XVII) of such a diagrammatic post are also 

 shown. When one considers all the variations in the wood itself and in 

 the treatment, the site and environmental conditions where the pole is 

 used, and the probability of the incidence of decay, the above general 

 conclusions with respect to necessary retention seem reasonable and 

 practicable. To refine and narrow the conclusions by repeating the post 

 tests with the same creosotes — if one could get them — would certainly 

 require the use of at least some posts with higher retentions and an 

 obligatory assay of all of the treated specimens to be sure that the re- 

 quired retentions were actually in the wood in the right places. Appar- 

 ently practical answers to questions about such required retentions can 

 be answered very much more quickly by repeated series of soil-block 

 tests in which many of the variables can be controlled. 



