Bui. 606, U. S. Dept. of Agriculture. 
Plate V 
Penetration in White Ash— Heartwood (Fraxinus lanceolata). 
1, piece No. 86 treated 30 minutes; 2, piece No. 67 treated 60 minutes; 3, piece No. 68 treated 120 
minutes. The thin-walled tyloses allowed the creosote to penetrate the vessels to some extent 
in addition to the penetration obtained in the wood prosenchvma. Spots on the untreated 
areas are points to which the creosote penetrated through the vessels. 
