34 BULLETIN 105, U. S. DEPARTMENT OF AGRICULTURE. 
product originally used and was then covered with, a layer of clean 
limestone screenings which, would pass a 1-inch screen. The surface 
was first swept by hand push brooms, and the oil was applied by 
allowing- it to run from the bungs of the barrels and distributing it 
with brooms. The surface was not rolled. A torrential rain inter- 
rupted the work when the south half of the section had been com- 
pleted. Some of the oil was washed into the gutters and this is no 
doubt responsible for the fact that the southern end of the section 
now presents a rougher appearance than the north half. 
Table 33 shows the characteristics of the bituminous material used. 
Table 33. — Analysis of asphaltic petroleum 1 used in second surface treatment of section 
No. 9. 
Specific gravity 25°/25° C 0. 959 
Flash point ° C 38 
Burning point ° C 80 
Viscosity, Engler, 25° C, 50 c. c. specific 1.33. 3 
Per cent of loss at 163° C, 5 hours (20 grams) 25. 05 
Float test of residue (50° C) 2 1'29" 
Per cent of total bitumen insoluble in 86° B. naphtha 7. 84 
Per cent of fixed carbon 4. 96 
Per cent soluble in CS 2 (total bitumen) 99. 92 
Per cent of organic matter insoluble 08 
Per cent of inorganic matter insoluble 00 
Total , 100.00 
The materials and cost data for the second surface treatment of 
sections Nos. 8 and 9 are given in Table 34 , as follows: 
Table 34. — Materials and cost data for second treatment of sections Nos. 8 and 9. 
Section 8. 
Section 9. 
1,447 
761 
.25 
.204 
.012 
.012 
( 3 ) 
.210 
2.25 
1.426 
( 3 ) 
.364 
2.54 
2.G84 
.37 
.526 
.30 
5.45 
5.210 
Area treated (square yards) jl, 44 
Materials per square yard: 
Bitumen (gallons) 
Screenings (cubic yards) 
Cost data (cents per square yard): 
Sweeping and cleaning 
Bitumen 
Application of bitumen 
Screenings 
Spreading screenings : 
Rolling 
Total cost. 
Section No. 10. — Residual petroleum — Surface treatment. 
As had been anticipated, this section began to bleed excessively 
with the advent of warm weather and required the application of 
approximately 4 cubic yards of limestone screenings to prevent the 
surface from picidng up. The surface also began to wave badly, 
i Thin, fluid, with strong naphtha odor. 
2 Soft, sticky, with slight flow. 
3 Automobile distributor used; cost charged in price of bitumen. 
