146 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1953 



the highest retention employed for the penta petroleum solution the cal- 

 culated net retention averaged 7.77 pounds of the penta solution per 

 cubic foot, or 0.382 pounds of pentachlorophenol per cubic foot; and 

 these figures represent, respectively, 40 miUigrams of pentachlorophenol 

 in the average block, or 6.2 milligrams per ec of block volume. Exact data 

 on treatment are discussed in the following paragraphs. The use of 

 carefully calculated gradient retentions in each case makes it possible 

 to detect any wide variation in the normal behavior of the blocks either 

 with respect to pickup during treatment or in the reaction of the test 

 fungus to the preservative. 



Data are included in Table I on average oven dry weight of the blocks. 



Table III — Full-Cell Treatments 

 Soil block tests; treating solution components, per cent by weight. (See 

 Table I). 



average density on an oven dry weight and volume basis, average pickup 

 of creosote or penta solution in pounds per cubic foot and in grams per 

 block, the concentration of the preservative materials in the toluene 

 preservative solution, and the average grams of preservative per cc of 

 block volume. All of the blocks in these two groups of charges were 

 chosen within a narrow density range. 



Block Density and Preservative Absorption 



It will be noted that in the charges in Table I there is a general trend 

 upward in the grams absorbed at treatment per cc of block volume, 

 as the specific gravity of the treating solution increases. This is, of 

 course, one of the results of increasing the concentration of creosote, for 

 example; and furthermore, as would be expected, the higher gravity 

 solutions represented by the creosote treatments show a higher pickup 

 in terms of total grams as well as in grams per cc. The make-up of the 



