DUST PREVENTION AND EOAD PRESERVATION. 43 
Section No. 4. — Blast-furnace slag and refined coke-oven tar. 
The surface of this section is distinctly mosaic and it is rather 
rough and uneven, particularly over the fill at the south end of the 
section. The surface is, as a whole, firm, and about 80 per cent of it 
is well bonded with tar which still shows considerable life. The 
section has worn much less than those adjoining it and is now from 1^- 
to 2 inches above them. 
Sections Nos. 5 and 6. — Blast-furnace slag. 
In general the surfaces of these two sections are about the same. 
They are slightly dusty, with the No. 1 stone showing frequently, and 
there were shallow ruts in the traveled way. In section No. 6 some 
very large pieces of slag, apparently from 4 to 5 inches in diameter, 
projected slightly above the surface and there were five shallow worn 
places on the east quarter. 
Section No. 7. — Blast-furnace slag and open-hearth slag. 
This section presented the same general surface as sections Nos. 5 
and 6. About 100 feet from the south end of the section the road has 
sunk from 3 to 4 inches over a tile cross drain. 
SUPPLEMENTARY REPORT OF EXPERIMENTS MADE AT NEWTON, MASS., 
1908. 
ASPHALTIC PREPARATIONS, TAR PREPARATIONS, RESIDUAL OIL, AND MOLASSES- OIL- 
LIME. 
The original report of these experiments was published in Circular 
No. 90, and reports of annual inspections were given in Circulars Nos. 
92, 94, 98, and 99. No repairs have been made during the past year 
and the following report covers an inspection made on December 13, 
1913. 
Experiments Nos. 1, 2, 3, 4, 5, 6, and 7. — Asphaltic preparation — Mixing 
METHOD. 
The surfacing of experiments Nos. 1 to 4, inclusive, was gradually 
disappearing, and the west half of experiment No. 5 had deteriorated 
seriously during the past year. There had been little change in the 
condition of experiments Nos. 6 and 7, excepting for the fact that 
the holes reported at the last inspection had slightly increased in 
area during the year. In experiment No. 7 two additional holes, 
each about 1 square foot in area, had developed. These are in the 
wheel tracks and will continue to enlarge. 
Experiment No. 8. — Residual petroleum — Mixing method. 
This section had not changed appreciably since it was inspected a 
year ago, excepting for the fact that eight small pits were developing. 
