EVALUATION OF WOOD PRESERVATIVES 121 



Block Density and Preservative Absorption 146 



Weathering 150 



Conditioning 162 



Sterilization 152 



Flow Chart for the Bioassay Test 152 



Some Madison Test Results 154 



Check Tests at the Murray Hill Laboratories 159 



Across the Threshold 160 



The Significance of the Results of Laboratory Soil-Block Tests on Oil- 

 Type Preservatives 160 



Bibliography 163 



Subjects to be Covered in Part II 



Evaluation by Treated % Inch Southern Pine Sap wood Stakes in Test Plots 



Rating the Condition of the Stakes 



Depreciation Curves for % Inch Stakes 



Estimating Threshold Retentions and Average Life 

 Evaluation b}^ Treated Pole-Diameter Posts in Test Plots 

 Evaluation by Pole Test Lines and by Line Experience; Service Tests 

 Discussion 



Density and Growth Rate 



Size and Shape of the Test Blocks 



Toluene as a Diluent for Creosote Treating Solutions 



The Distribution of the Preservative in the Block 



Heat Sterilization of the Treated Blocks 



The Weathering of Creosote and Creosoted Wood 



General Considerations; Creosote Fractions 



Creosote Losses 



Creosote Losses from Treated Blocks 



Creosote Losses from Impregnated Filter Paper 



An Interpretation of Creosote Losses 



The Gross Characteristics of the Residual Creosotes in Soil-Block Tests of 

 Weathered Blocks 



The Evaluation of Greensalt 



The Evaluation of Pentachlorophenol 



Swedish Creosote Evaluation Tests 



Shortening the Bioassay Test 



Toughness or Impact Tests for Determining Preservative Effectiveness 

 Other Accelerated Bioassay Tests 

 Other Observations 

 Conclusions 

 Acknowledgments 



INTRODUCTION 



In discussing the problems involved in the evaluation of wood pre- 

 servatives over the years, it has generally been found necessary to onent 

 the audience — in this case the readers of this Journal — in the field of 

 biology, and particularly m the field of biological tests involving wood- 



