38 BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
Table 41. — Analysis of asphaltic petroleum 1 used in re-treatment of experiment Xo. 1. 
Specific gravity 25°/25° C 0. 956 
Flash point (° C) 28 
Burning point (° C.) 50 
Specific viscosity, Engler, 25° C, 50 c. c 187. 5 
Loss at 163° C, 5 hours, 20 grams (per cent) 28. 23 
Float test on residue, 2 50° C. (seconds) 188 
Per cent of total bitumen insoluble in 86° B . naphtha 16. 5S 
Fixed carbon (per cent) 9. 04 
Total bitumen (soluble in CS 2 ) per cent . . 99. 95 
Organic matter insoluble per cent . . .05 
Inorganic matter insoluble per cent. . . 00 
100. 00 
Experiment No. 2 — Residual asphaltic petroleum, hot application, 
corresponding to experiment No. 5, on the BockviUe Pike. — This section 
was in generally good condition. There was a slight tendency to 
crumble, especially at the edges, but little or no mud formed. It 
was thought very early in 1916 that this section would require re- 
treatment during the summer, but it bled profusely and had to be 
dressed heavily until about the middle of the summer. The section 
appeared to be somewhat better than section No. 5 of the Koekville 
Pike. 
Experiment No. 3 — Goal-tar preparation, cold application. — The 
original application on this section never produced a close, intact 
mat and in the summer of 1916 had to be patched frequently where 
the macadam had become exposed and in November was retreated 
with the same bituminous material as applied originally. The char- 
acteristics of the bituminous material appear in Table 42, and cost 
data and quantities in Table 43. At the time of inspection the ex- 
periment was in excellent condition, with no signs of further disinte- 
gration or unusual wear. 
Table 42. — Analysis of coal-tar preparation 3 used in retreatment of experiment No. 3. 
Specific gravity 25°/25° C 1. 149 
Specific viscosity. Engler 50 c. c. at 40° C 12. 1 
Per cent free carbon ^insoluble in CS 2 ) 6. 19 
Per cent Per cent 
Distillation : by volume, by weight. 
Water 0.0 0.0 
First light oils 4 (to 110° C.) 1.8 1.1 
Second light oils 4 (110° to 170° C.) 1.5 .8 
Heavy oils 5 (170° to 270° C.) 19. 8 17. 1 
Heavy oils 4 (270° to 300° C.) 9. 7. S 
Pitch residue 67. 9 73. 2 
Total 100. 100. 
1 Fairlv viscous stickv fluid. * Clear. 
2 Very viscous stickv fluid. 6 One-half solid. 
3 Faiflv thin fluid. 
