NECESSARY TO TREAT THE TAR 47 



dangerous principles can be eliminated from the 

 tar from which the pitch is made. We have 

 already tried washing the pitch, and one of the 

 Patent Fuel Companies very kindly did this on 

 a large scale washing several tons but unfor- 

 tunately the process injured the " binding " quality 

 of it. Hence it will be necessary to experiment 

 with the tar. 



