24 BULLETIN 586, U. S. DEPARTMENT OF AGRICULTURE. 
TaBLE 28.—Analysis of residual asphaltic petroleum + used on experiment No. 2. 
SPECtiCieraNs hy, 2om/2ernO okies any elec a ean Ne paei faye mA OY RUN To, Sa 0. 995 
Specitie viscosity, Hmeler WOO li . S0leL el tact ees ach. aU en ean keene ily) 
Mloatitest,p0" (Os(Seconds) heer te ESTs Ne Vere so Ae One Me vee eeee 36 
Loss wG3c C20 hours. Olorams, (pet Cent): sacs sec eee ee ieee en eee 13. 56 
Float test on residue, 50° C. (seconds)...............-------- pa a aaa 232 
Per cent of total bitumen insoluble in 86° B naphtha......................- 20. 12 
Bixed i carbor (per Cent) sueee ut se diem ie AS wee Ne eae MME ESR an 10. 79 
SolupleimiGS, (totalibitumien per cent)es 2 oes wae eee eee eee eee a 99. 87 
Orsanicmattenansoluble (per cent). Fee 2 ee ee snl 
Imorganie matter msoluble(pericent): 3252 -). a0) 222k ee ee . 02 
TOtalen ME SEEN oa se dees oak he so) RY eS ee od aed 2 Ad 100. 00 
The first tank car of oil delivered at Alexandria was found to be 
low in viscosity and was rejected as not conforming to the specifica- 
tion. This rejection occasioned a delay of about two weeks in secur- 
ing the oil for experiment No. 2, during which time experiment No. 3 
was completed. When the contractor was ready to resume work on 
experiment No. 2, bad weather had set in and further delay was 
occasioned. Finally, it was deemed expedient to complete the experi- 
ment, although the weather conditions were not altogether favorable, 
because it was feared that long-continued bad weather might make 
it necessary to postpone the work until the next season. The oil 
accordingly was applied on the first warm day, regardless of the fact 
that the road surface was damp. The oil was applied 0.53 gallon 
per square yard, while the rate for gravel top-dressmg was the same 
as in experiment No. 1, or 78 square yards to 1 cubic yard. No 
lack of uniformity in the distribution of either the oil or the gravel 
was noticed. Where successive distributor loads of oil jomed, care 
was exercised to prevent overlapping, and there was no unevenness 
at any of the jomts. From station 85+00 to 85+45, however, 
the gravel surface on the east side of the road was man very well 
bonded when the work was done. 
Experiment No. 3.—SuRFACcE TREATMENT Usina Two APPLICATIONS OF TAR. 
_First application of coal-tar preparation applied cold; second application refined 
coal tar, applied hot. 
Location, station 85+-45 to 109-+00. 
Total length, 2,355 feet. 
Total area, 4,187 square yards. 
Both kinds of tar for this experiment were hauled in the distributor 
from Washington, about 15 miles, to the road. The first applica- 
tion was of the same material as used on experiment No. 1, analysis 
of which is shown in Table 27. This application was made in a 
1 Viscous, sticky fluid. 
