DUST PREVENTION AND ROAD PRESERVATION, 1915. 69 
Section No. 4. — Blast-Furnace Slag and Refined Coke-Oven Tar. 
The greater portion of this section was constructed over a deep 
fill and, as noted in previous inspection reports, initial failure was 
due to unequal settlement. The surface over the fill and the short 
stretch to the north has disintegrated and numerous holes and depres- 
sions have formed, ranging from a square foot to a square yard in 
area. The south 50 feet of the section, which has not suffered from 
settlement, remains practically intact and presents a smooth, true 
surface. The wearing surface was cut through with great difficulty 
and it was necessary to use a sharp pick in order to remove a small 
section for examination. 
Section No. 5. — Blast-Furnace Slag. 
As noted in former inspection reports, this section is lower at its 
junction with section No. 4 by about 1£ inches. The ruts in the 
portion lying in the damp cut remain. The south one-third of the 
section, which at the last inspection was in very satisfactory condi- 
tion, has developed two depressions at 165 feet and 135 feet, respec- 
tively, from the south end. Both were about 2 J inches in depth 
and showed signs of raveling. 
Section No. 6. — Blast- Furnace Slag. 
This section has not changed materially during the past year. The 
ruts are wide and more pronounced than in the preceding sections, 
but there is less loose pulverized material in the middle of the road. 
There are two rather deep depressions in the traveled way near the 
middle of the section and three long, deep ones in the east rut in the 
north 100 feet of the section. However, there was no evidence of 
raveling in any of these depressions. 
Section No. 7. — Blast-Furnace and Open-Hearth Slag. 
The condition of this section has not changed appreciably in the 
past 12 months. The surface as a whole is firm and well bound and 
noticeably harder than any of the other sections, except that portion 
of No. 4 which still remains intact. 
Several years ago the fill near the south end of the section settled 
irregularly and a deep hole was formed. This has not been repaired 
and continues to be a menace to traffic. 
SUPPLEMENTARY REPORT OF EXPERIMENTS AT GARDEN CITY, BUCK- 
LIN, FORD, AND DODGE CITY, KANS., 1908. 
SAND-CLAY. 
The original report of these experiments is contained in circular 
No. 90, and reports of subsequent annual inspections are published 
in Circulars Nos. 92, 94, 98, and 99, Office of Public Roads, and in 
