68 BULLETIN 407, IT. S. DEPARTMENT OF AGRICULTURE. 
been compacted by traffic, a surface treatment of light asphaltic oil 
was applied to the three sections. Section No. 3 is readily recognized 
by its smooth, even surface and well-preserved cross section. 
As these experiments are no longer comparable as types of bitumi- 
nous macadam pavement, their behavior will not be reported hereafter. 
SUPPLEMENTARY REPORT OF EXPERIMENTS AT YOUNGSTOWN, OHIO, 
1910. 
SLAG, SLAG AND LIME, SLAG AND WASTE SULPHITE LIQUOR PREPARATION, AND SLAG 
AND TAR. 
The original report of these experiments was published in Circular 
No. 92 and subsequent reports of anuual inspections are given in 
Circulars Nos. 94, 98, and 99, Office of Public Roads, and in U. S. 
Department of Agriculture Bulletins Nos. 105 and 257. The follow- 
ing is a report of the condition of the roadway on December 3, 1915. 
The sections are discussed in the order of their section numbers, 
beginning at Mahoning Avenue. With the exception of the tar-slag 
section, the road was covered with a thin sheet of snow at the time of 
the inspection, which concealed some of the surface details. 
Section No. 1. — Blast-Furnace Slag. 
The condition of this section has not changed appreciably during 
the past year. The surface is somewhat worn and pulverized in the 
middle of the road and wide, shallow ruts are noticeable in the wheel 
tracks. These ruts are not so pronounced as in the next two sections, 
however. Aside from these defects, the surface is smooth, uniformly 
worn, and free from large protruding stones. 
Section No. 2. — Blast- Furnace Slag and Lime. 
The general condition of this section is about the same as that of 
section No. 1. The ruts are somewhat more pronounced, particularly 
the one on the west side of the traveled way, and a depression, which 
was evidently due to wear, was noted about 50 feet from the north 
end of the section. 
Section No. 3. — Blast- Furnace Slag and Waste Sulphite Liquor Preparation. 
Little change has taken place in the condition of this section dur- 
ing the past year. About 100 feet from the north end two shallow 
depressions have formed in the wheel tracks, and for 200 feet from 
the north end the surface is worn and slightly depressed in the middle 
of the road. The ruts referred to in the two preceding sections 
extend to the top of the slight grade near the middle of this section. 
The south half of the section, which lies on the grade, is noticeably 
better than the north half and is one of the best preserved parts of 
the entire road. 
