76 BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
Roads and Rural Engineering, United States Department of Agri- 
culture, in 1914 Kansas alone had more than 750 miles of road sur- 
faced with sand-clay, which was almost three-fourths of the total 
mileage of improved roads in the State. It seems, therefore, that 
these experiments have served their purpose entirely, and they will 
not be reported on again. 
BOWLING GREEN, KY., 1907. 
KENTUCKY ROCK ASPHALT. 
The original report of this experiment was published in Circular No. 
89 and reports of subsequent inspections in Circulars Nos. 90, 92, 94, 
98, and 99, and Bulletins Nos. 105, 257, and 407 United States Depart- 
ment of Agriculture. The following report relates to the condition of 
the pavement on January 6, 1917. This work had not been repaired 
or cared for in any way since its construction. The failure of the 
surface was most marked in the west 150 feet. On the north side of 
this section the surface failed for one-third the width of the road and 
the remaining area was covered with holes. The next 150 feet had 
several large worn areas and numerous pot holes. The surface 
of the remaining portion still was intact and where the binder had not 
failed the surface was smooth and hard. Generally speaking, the 
condition of this experimental road would not warrant any repairs 
in the future. 
Resume of Previous Reports. 
A series of experimental road sections were constructed in 1907, for 
the purpose of determining the fitness of Kentucky rock asphalt and 
crude Kentucky oil on binders in macadam construction and also to 
determine the comparative value of a residuum oil preparation and 
crude oil as dust preventives. The following table indicates the 
method of construction and shows the condition of experimental 
sections at the time of several inspections. The tabulation has been 
prepared from reports of inspections made by this office, published 
in Circulars Nos. 89, 90, 92, 94, 98, 99, and in Bulletins Nos. 105, 257, 
and 407, United States Department of Agriculture. 
