498 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



the Laboratories' controlled weathering procedure will provide a means 

 for determining truly effective threshold retentions for oil-type and salt- 

 type preservatives for comparable service requirements. 



6. These threshold determinations are supplying data that would have 

 been most valuable in planning retention gradients in small stake and 

 pole diameter post tests in test plots; and, in general, the bioassay tests 

 explain and confirm the unequivocal results of experience. 



7. Through the soil-block test a ready method is available for use in 

 the quality control of a wood treater's current product at plants where 

 large supplies of preservatives are received from one or more constant 

 sources and are stored in bulk. No present method of bioassay control is 

 sufficiently rapid to be effective or practicable on mixed samples taken 

 at treating plants receiving preservatives at frequent intervals in small 

 lots from varied sources. 



8. The soil-block development may soon make it possible to reach 

 approximately the ideal in which the long-time service tests of treated 

 material in fine will confirm the Laboratories' rapid test results with 

 respect to preservative requirements. Coupled with results- type require- 

 ments (wherein the end product — not the steps of manufacture and 

 treatment — are defined) viz., (a) retention in the wood, (b) penetration, 

 and (c) cleanliness, there will then be even better assurance than at the 

 present of the quality performance always expected under Bell System 

 specifications. 



ACKNOWLEDGEMENTS 



It is hoped that the preceding pages will be accepted by the reader for 

 what they are — condensed results of teamwork over the years — into 

 which have been woven some individual ideas, opinions and interpreta- 

 tions. The writer is responsible for the literature review and for the 

 selection of the items discussed. In one way or another various members 

 of the Timber Products Group of Bell Telephone Laboratories have 

 contributed to the collection and analysis of the supporting data. Thanks 

 are due especially for help on the soil-block section to J. Leutritz, Jr., 

 L. R. Snoke and Ruth Ann MacAUister; on the %-inch stake section to 

 J. Leutritz, Jr. ; on the text post and pole line sections to G. Q. Lumsden 

 and A. H. Hearn; on the review and editing of the manuscript to R. J. 

 Nossaman, F. F. Famsworth and G. Q. Lumsden; on the zealous check- 

 ing and assembly of test, tables and figures to Jean E. Perry; and on the 

 correlation of the Madison cooperative test data to Catherine G. Duncan. 

 Dorothy Storm's untiring efforts as a secretarial task force are deeply 



