60 BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
Section No. 7, A and, B — Oil asphalt, penetration method. — Section 
A continued distinctly more mosaic than B and required a little patch- 
ing. Section B had the aggregate exposed in numerous spots along 
the east half and needed somewhat heavy patching in the spring, to 
go through the season. The west half toward the trolley tracks was 
much better and less moisture appeared through the surface than near 
the gutter. 
Section No. 8 — Refined water-gas tar preparation, surface treat- 
ment. — During the past summer experiment No. 8 was re-treated with 
the same type of bituminous material as used in previous treatments, 
and the section appeared to be better than is usual in winter. The 
recent treatment, however, wore away in small areas, exposing the 
smooth surface of earlier treatments beneath. There were no breaks 
in the surface, and the wear since the last re-treatment has been uni- 
form with the surface, smooth and regular. This experiment indi- 
cated need of re- treatment in the summer. The cost of the re-treat- 
ment is given in table 65. 
Section No. 9 — Asphaltic petroleum, surface treatment; Section No. 
10 — Residual petroleum, surface treatment. — Section 9 was again 
re-treated during the past season. South of Kirke Street the east 
half of the section was wet and rough, but the rest of the section was 
better than is usual at the time of inspection, and presented a gener- 
ally smooth surface, except for waviness on the east one-third. 
It seemed probable that the section would require another treat- 
ment. Table 64 gives an analysis of the bituminous materials used in 
re-treating sections Nos. 9 and 10, and the cost of re-treatments appear 
in Table 65. 
Both ends of section No. 10 were rather better than usual at this 
season of the year but the middle one-third was bad, having developed 
the characteristic pot-holes at more or less regular intervals, owing 
apparently to the rhythmic impact of automobile traffic. 
Table 64. — Analysis of asphaltic petroleum used in retreatment of sections 9 and 10. 
Specific gravity 25°/25° C 0. 952 
Flash point (° C.) 18 
Burning point (° C.) 30 
Specific viscosity, Engler 50 c. c, 25° C 90. 9 
Loss at 163° C, 5 hours, 20 grams, percent 24.42 
Float test on residue, 50° C, seconds 118 
Per cent of total bitumen insoluble in 86° B . naphtha 10. 47 
Per cent fixed carbon 4. 50 
Bitumen soluble in CS 2 (total bitumen) 99. 92 
Organic matter insoluble 05 
Inorganic matter insoluble 03 
Total .- 100. 00 
