28 BULLETIN 407, IT. S. DEPAETMENT OF AGRICULTURE. 
the plant was still slightly warm from the refining process. The 
distance from the plant to the near end of the section was about 12 
miles. 
Experiment' No. 5. — Refined Coal Tar, Hot Application, Similar to Experi- 
ment No. 1, on Rockvtlle Pike. 
Location: Station 226+20 to station 295+00. 
Length: 5,880 feet. 
Total area: 9,800 square yards. 
Date of application: September 13, 14, 15, and 16. 
Temperature of tar: 180° F. 
Table 29. — Analysis of refined coal tar used on experiment No. 5. 
Specific gravity, 25°/25° C 1. 181 
Float test at 32° C. (time) V 45" 
Free carbon (insoluble in CS 2 ), per cent 9. 39 
._. .„ ,. Percent Percent 
Distillation: by volume, by weight. 
Water 0. 0. 
First light oils (to 110° C) .0 
Second light oils (110° to 170° C.) .0 
Heavy oils (170° to 270° C.) 13. 5 11. 4 
Heavy oils (270° to 315° C.) 13. 2 11. 3 
Pitch residue 73. 3 77. 8 
Total 100. 100. 5 
The surface of section No. 5 was also in excellent condition, and 
the experiment was conducted similarly to experiments Nos. 3 and 
4. The bitumen was prepared in a local plant and was hauled to 
the work in the distributors ready for application. The haul from 
the plant to the near end of the section was about 11 miles. 
The cost data given in Table 30 are based upon the following unit 
prices for labor and materials. 
Foreman, per 8-hour day $4. 00 
Distributor operator, per 8-hour day 2. 50 
Roller operator, per 8-hour day 3. 00 
Motor-truck driver, per 8-hour day 2. 50 
Teams, per 8-hour day 4. 00 
Laborers, per 8-hour day 1. 60-2. 00 
Gravel on siding, per ton 1. 65 
Asphaltic petroleum on siding, per gallon l . 05 
Residual asphaltic petroleum on siding, per gallon \ 07£ 
Coal-tar preparation on siding, per gallon *. 09£ 
Refined water-gas tar at plant, per gallon *• 08£ 
Refined coal tar at plant, per gallon 1 - 08 
i Estimated. 
