Bui. 607, U. S. Dept. of Agriculture. 



Plate I. 







• ; f ~ 



A Thin Film of a Mixture of Equal Parts, by Volume, of Creosote and 

 Normal By-Product Coke-Oven Tar No. 1 (Normal Amount of Free Car- 

 bon in Tar, 6 Per Cent, by Weight). 



Magnification, about 400 diameters. 



