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. 
Bituminouspmatentale: eres ee =n eeise eo /eiserese Sea sigsee ee aweergs .---| Water-gas tar re- 
fined. 
CWHATACETISHICS Bee Ney folate e cps rei ota ote nie in are Meters tear ieaet a ae ee 5 MED sticky. 
Specificierayity25°/25°1C se ee ae aes eae ee 1. 209 1.140. 
Rloatitestia29 Crsseconds-2 3 ie oes ee ie ke a A ee 5 
Specific viscosity, Engler 50 c. c., 50° C 19. 4, 
IPencentired CaLbOlssaeceeercssceeeeceee eee ee ere e eee eee " 2.91. 
Per cent | Per cent Hee cent re cent 
by by y Dy 
volume. | weight. | volume. | weight. 
Distillation: 
Hirst light Onsi(to LION eee a eee ee ee een onene seen Se leeaoener ee pee ao eee 30. 20 0.14 
Second light oils Sepeal to WONG) pots 333 5 ee SEES ase | (RES eer [Pp eye 3.10 -08 
Heavy ous d0sto2 702 Ch) ecereseeeneeeser asc nee aceon ecies 113.4 11.0 222.08 19. 81 
HeaviyOlls (270ctoe0ONCs) ee - Sia! ee eee eee 27.8 6.5 12.04 10. 82 
Pitch residue. . ove Rae ee wale vos be Seen ee ciet oem meee ee 78.8 82.5 65. 58 68. 82 
Tota eee sincere) iersthom ite sere ates ome win seem iersnimetnen aries 100.0 100.0 100.0 99. 67 
1 Solid. 2 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. 3 
and 7, Rockville Pike. 
Experi- Experi- 
men 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 
Bitumen soluble in CS, (total bitumen), per cent................--.------------- 99. 85 99. 92 
Organic matterinsaliblel 2.3) Fee hoo. Vee hr ee ey, eae) eee etl 15 -05 
Inorganicimatterinsolublos esas eee oie Ae in 2 Ue he Re aces oe .00 -03 
Hy ar LR a SUA GS a A UES Pd SRP ee ee 1 Se cae ae 100. 00 100. 00 
