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



Plate X. 



/■''"-.'•. 



Penetration in Paving Blocks. 



No. 1 blocks treated with creosote No. 4. No. 2 blocks treated with 75 per cent creosote No. 4 and 

 25 per cent tar No. 5. No. 3 blocks treated with 50 per cent creosote No. 4 and 50 per cent tar 

 No. 5. No. 4 blocks treated with 25 per cent creosote No. 4 and 75 per cent tar No. 5. 



