DUST PKEVENTION AND ROAD PKESERVATION, 1915. 11 
Immediately after the mixture was cooled sufficiently to avoid 
" waving ; " it was rolled with an 8-ton tandem roller. A seal coat of 
approximately one-half gallon of fluxed native asphalt A to the square 
yard was then applied by hand pouring pots, as described in experi- 
ments Nos. 1 and 2. Sandstone chips approximately free from dust, 
as indicated in the mechanical analysis of Table 7, were then spread 
uniformly in sufficient quantity to fill the superficial voids, and broomed 
with rattan brooms while the roller worked. A slight excess of chips 
was applied, which soon broke up into fine particles under traffic. 
Experiment No. 4. — Bituminous Macadam (Mixing Method); Sandstone with 
Oil-Asphalt X. 
Location: Station 28+10 to station 38+10. 
Total length: 1,000 feet. 
Total area: 1,924 square yards. 
This experiment was exactly similar to experiment No. 3, except 
that oil-asphalt X of properties shown in Table 8 was used instead of 
fluxed native asphalt. The maximum grade on this section is 4.92 
per cent. 
Experiment No. 5. — Bituminous Macadam (Penetration Method); Gneiss 
with Fluxed Native Asphalt A. 
Location: Station 38+10 to station 50+45. 
Total length: 1,235 feet. 
Total area: 2,196.6 square yards. 
This experiment was exactly similar to experiment No. 1, except 
that u li-inch" gneiss was used instead of sandstone. The mechan- 
ical analysis of the crushed gneiss is shown in Table 5 and the phys- 
ical properties of the stone in Table 4. The mechanical analysis of 
the chips used is shown in Table 7. The chips broke up into fine 
particles under traffic. 
Experiment No. 6. — Bituminous Macadam (Penetration Method); Gneiss 
with Oil-Asphalt X. 
Location: Station 50+45 to station 58+45. 
Total length: 800 feet. 
Total area: 1,422.2 square yards. 
This experiment was exactly similar to experiment No. 5, except 
that oil-asphalt X was used instead of fluxed native asphalt. 
