36 BULLETIX 1Q5 ? U. S, DEPARTMENT OF AGBICULTUBE. 
thus trimming off the hump.:, and filling depressions the general con- 
tour of the road was greatly improved. In December all bare places 
were covered with a light application of the water-gas tar preparation 
No. 1 the analysis of which is given in Table 2, and screenings. 
The total cost of maintaining and repairing the surface during the 
year was $40.41, or 1.19 cents per square yard for the entire area. 
SUPPLEMENTARY REPORT OF EXPERIMENTS MADE AT JAMAICA, N. Y., 
1911. 
OIL-CEMENT CONCRETE, OIL ASPHALT, TAR, AND FLUXED NATIVE ASPHALT. 
The original report of these experiments was published in Circular 
]STo. 98, and the report of an inspection made December 19, 1912, with 
repairs to date, was given in Circular Xo. 99. The experiments were 
again inspected and repaired in June, 1913, and the following report 
covers the work done at that time and the condition of the sections 
when again inspected on December 16, 1913. 
EXPERIMEXT Xo. 1. — OlL-CEAIEXT COXCRETE. 
When inspected in June it was found that practically all of the vari- 
ous carpet coats which were applied to this section in 1912 were gone 
with the exception of the refined coal-tar section. About 75 per cent 
of the carpet coat on this section was in fair condition. 
The surface of the pavement showed the effect of the wear of traffic 
and contained many shallow depressions among which the following 
were so deep as to be practically through the concrete: Station + 98, 
4 feet by 5 feet, against the south side of the pavement; station + 
75, 2 J feet by 3 feet, 8 feet from the south edge of the pavement; sta- 
tion + 77, 1 foot by 1J feet, 13 feet from the south edge of the pave- 
ment; station + 77, 1 J feet by 1J feet, 16 feet from the south edge of 
the pavement; station + 03, 2 J feet by 4 feet, IS feet from the south 
edge of the pavement. 
The expansion joint at station + 97 was in perfect condition and 
had completely protected the abutting ends o*f the concrete. 
Repairs were made as follows: The entire section was gone over 
and all the old flush coat that could be loosened readily with pick and 
shovel was removed. The shallow depressions, 1 to 1J inches in 
depth, were filled to grade with f-inch stone. The deep depressions 
were cut out to the subgrade to the size above stated and filled with 
1^-inch stone, the voids of which were filled with sand and refined 
coal tar. The depression at station + 03 was repaired with paving 
brick. The entire section was then surface-treated with bituminous 
materials as follows: From station + 00 to station + 57, refined 
coal tar, 0.30 gallon per square yard; from station + 57 to station 
+ 97, water-gas tar preparation Xo. 1, 0.44 gallon per square yard; 
and from station + 97 to the east end of the section, water-gas 
