DUST PREVENTION AND ROAD PRESERVATION, 1916. 43 
had received no maintenance since its original construction in 
April, 1915, but was in fair condition. The surface had the general 
appearance of a road over sandy loam, except that the ruts of from 
14 to 2 inches were shallower than is usual with road surfaces of 
loam. The ruts in the natural sand road adjacent to the experi- 
ment were from 5 to 7 inches deep. Since the inspection of Decem- 
ber 10, 1915, which was mentioned in the original report of this 
experiment, the coat of loose material on the surface had decreased 
in thickness to a minimum of about one-fourth of an inch and a 
maximum of about 1 inch. The path worn by horses in the center 
of the road was hardly noticeable. Instead of following the center 
line of the road, travel had followed a curved path, and near the 
center of the section the track was extremely close to the north edge 
of the surfacing. This no doubt was responsible for failure of the 
surfacing in several spots along the north rut, though some of the 
weak spots could not be explained in this way. The following is 
a list of the spots where partial or total failure has occurred, and 
which need immediate attention: 
18 feet from east end of experiment, hole in center of road. 
24 to 30 feet from east end of experiment, north one-half of road. 
39 feet from the east end of experiment, center. 
45 feet from east end of experiment, north rut. 
66 feet from the east end of experiment, north rut. 
71 feet from the east end of experiment, center and north rut. 
84 feet from the east end of experiment, center. 
100 feet from the east end of experiment, center and north rut. 
The county officials at the time of inspection were preparing to 
treat the surface with asphaltic oil which was used extensively in 
construction of coralline-rock roads at the time. It was expected 
that such a surface treatment would check the disintegration at the 
points noted above, as well as prevent other defects from developing, 
WEST PALM BEACH, FLA., 1915. 
BITUMINOUS SAND. 
In continuation of experiments Nos. 1 to 7 a section of sand- 
asphalt or bituminous sand surfacing was built in January, 1915, 
as experiment No. 8. Its construction is described in Bulletin 407, 
U. S. Department of Agriculture. This section was inspected on 
December 11, 1916, and its condition was as follows: 
Experiment No. 8—Bituminous sand.—The surface showed waves 
at quite regular intervals. The sheet was intact, tough and very 
slightly calk-marked and pitted. No failure was apparent at any 
point and no difference in behavior of surface appearance was notice- 
able in the various parts of the experiment. 
