50 
BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
Table 51. — Analysis of refined tars used in re-treatment of experiments Nos. 1 and 2, 
Rockville Pike. 
Experiment No. 1. 
Experiment No. 2. 
Bit umin ous material. 
Characteristics 
Specific gravity 25725° C 
Float test 32° C. , seconds 
Specific viscosity, Engler 50 c. c, 50° C. 
Per cent free carbon 
Coal tar refined... 
Viscous, sticky... 
1.209 
135 
13.56... 
Water-gas tar re- 
fined. 
Viscous, sticky. 
1. 140. 
19.4. 
2.91. 
Per cent 
by 
volume. 
Distillation: 
First fight oils (to 110° C.) 
Second light oils (110° to 170° C). 
Heavy oils (170° to 270° C.) 
Heavy oils (270° to 300° C.) 
Pitch residue 
U3.4 
27.8 
78.8 
Total. 
100.0 
Per cent 
by 
weight. 
Per cent 
by 
volume. 
11.0 
6.5 
82.5 
3 0.20 
3.10 
2 22.08 
12.04 
65.58 
100.0 
100.0 
Per cent 
by 
weight. 
0.14 
.08 
19.81 
10.82 
68.82 
99.67 
Solid. 
Clear. 
3 Cloudy. 
Experiment No. 3 — Asphaltic petroleum, cold application. — The ac- 
tion of this experiment is so well known that little description is 
necessary. Its conduct during the winters of 1915 and 1916 was 
thoroughly characteristic, and in June, 1916, it became necessary to 
re-treat as usual. The work was done by hand, as described in the 
last report, using the same bituminous material originally applied 
with torpedo sand as top-dressing. Table 52 shows the character- 
istics of the bituminous material and cost data will be found in 
Table 53. 
All bottoms and all but the better drained slopes were thoroughly 
wet ; one or two breaks had occurred near the top of the hill 600 feet 
from the south end of the experiment. The necessity for patching 
and re-treating during the following summer was evident. 
Table 52. — Analysis of asphaltic petroleums used in re-treatment of experiments Nos. 8 
and 7, Rockville Pike. 
Experi- 
Experi- 
ment 
ment 
No. 3. 
No. 7. 
0.945 
0.952 
37 
18 
93 
30 
97.5 
90.9 
26.09 
24.42 
101 
118 
14.67 
10.47 
8.5 
4.50 
99.85 
99.92 
.15 
.05 
.00 
.03 
Specific gravity 25725 ° C 
Flash point (° C.) 
Burning point (°C.) 
Specific viscosity, Engler, 50 c. c.,25°C 
Loss at 163° C. , 5 hours, 20 grams, per cent 
Float test on residue, 50° C. , seconds 
Per cent of total bitumen insoluble in 86° B. naphtha 
Per cent fixed carbon 
Bitumen soluble in CS 2 (total bitumen), per cent 
Organic matter insoluble , 
Inorganic matter insoluble 
Total 
100.00 
100.00 
