EVALUATION OF WOOD PRESERVATIVES 



155 



Table VIII — Continued 

 Test fungus, Lenzites trabea, Mad. 617 



Preservative 



* R = retention at treatment in Ib/cu ft. 



t Preservatives 6, 7, 8 and 11 are the numbered coop, creosotes (12). 



A = BTL 5340 creosote, 



B = 5 per cent penta in petroleum, 



E = 50/50 by volume mixture of A and B. 

 All preservatives were applied in a toluene solution. The heavy lines represent 

 approximate threshold levels. 



carefully following the soil-block technique. The data, representing the 

 writer's interpretation of the relation between average weight loss and 

 average treatment retention, are shown in Table VIII and represented 

 by the graphs in Figs. 10, 11 and 12. The preservatives in Figs. 11 and 

 12 labeled (A), (B) and (E) on the graphs, were respectively a domestic 

 creosote (BTL No. 5340, Table II) ; a 5 per cent solution of pentachloro- 

 phenol in Standard Oil Company of New Jersey No. 2105 Process oil, 

 and a 50/50 by volume mixture of these two.^^ Fig. 11 represents the 

 results obtained with cooperative creosotes Nos. 6, 7, 8 and 11 and 

 with BTL No. 5340. 



In all three figures there are weight losses that can evidently be classed 

 as operational losses, that is, losses by evaporation of some of the volatile 

 materials still remaining in the blocks during the time they were in test 

 and in the subsequent conditioning period.'' The general areas in which 

 the amount of preservative with which the blocks were treated failed to 

 protect the wood against attack by the different fungi are shown by the 

 rise in the weight loss lines. Perhaps the most interesting set of compara- 

 tive results are revealed by Fig. 10. The test fungus was Lentinus kpideus, 

 Mad. 534. From these graphs the threshold for creosote for this organism 



