PARK AND CEMETERY. 
293 
to employ means which will not help, but 
rather defeat, at least to a certain extent, 
the intent for which you wish to use 
them. Now, you come to Minneapolis on 
your way to Denver, and I will convince 
you, or you will convince me. We cannot 
both be right — one of us is wrong. Who 
is? Theodore Wirth. 
OIL AS A DUST-LAYER 
By H. S. Richards, Asst. Supt. South Park 
System, Chicago. 
In this age of automobiling the necessity 
of eliminating the dust nuisance from pub- 
lic highways, especially in municipalities, is 
rapidly becoming an important one. The 
work of good road congresses, the experi- 
ments of highway engineers, and of the 
office of public roads of our National De- 
partment of Agriculture, and proposed 
legislation tending towards this end, shows 
that a national interest in the work has 
been aroused. 
Most of the pavements being laid now- 
adays contain asphalt in the mixture used 
for paving, and are of a kind that will not 
only stand the wear and tear of automo- 
bile traffic, but will also be practically free 
from dust. The South Park Commission- 
ers of Chicago have secured their best re- 
sults in this line by surfacing driveways 
with a mixture called asphaltic concrete, 
which is laid in various thicknesses, de- 
pending on the amount of traffic, upon a 
crushed stone macadam base. This kind 
of pavement is not only very wear resist- 
ant to automobile traffic, but has the ad- 
ditional advantage of being practically 
dustless. 
The building of good pavements is a 
slow and costly proposition. In the mean- 
time, while such pavements are being con- 
structed, the many miles of macadam and 
unimproved driveways need much atten- 
tion for laying the dust, which under the 
enormous pleasure traffic of a city like 
Chicago, and also of many public high- 
ways, becomes an intolerable nuisance, as 
well as a menace to health, not only to the 
traveling public, but also to the people 
whose residences or stores line the drive- 
ways. 
In the past, water has been relied upon 
to keep down the dust, but it had to be 
applied almost constantly in dry weather 
to accomplish the purpose, and then the 
dust was kept down only in the day time, 
and care had to be taken not to apply too 
much at any one time, lest the roadways 
become muddy. 
The first experiments by the South Park 
Commissioners with anything other than 
pure water for laying dust was with a so- 
lution of rock-salt in water during dry 
and cold, wintry weather, about ten years 
ago. Clouds of dust were being raised by 
the wind from the bare roadways. Sprink- 
ling the drives during the very cold 
weather which was occurring at the time 
with water was impracticable and danger- 
ous, as the water froze almost immediately 
after its application, surfacing the drive- 
ways with a coating of ice. It was found 
that by dissolving rock-salt in water, in 
the proportion of one gallon of the salt to 
eighty gallons of water, a solution was ob- 
tained which did not freeze during cold 
weather. Whenever necessary, during a 
period of four or five winters, to lay the 
dust, the above named solution was used 
for this purpose, and very 'good results 
were secured. 
Calcium chloride, crude oil and various 
forms of bituminous compounds, such as 
“Westrumite,” road tar and heavy as- 
phaltic oils, have been used in the effort to 
find a satisfactory dust-laying material. 
The using of heavy “black oil” seems to 
be a costly one if we consider the damage 
done to household goods and to vehicles. 
It is disagreeable to the traveling public 
for some days after its application, on ac- 
count of its slow absorption into the road- 
bed if it is not properly applied, and my 
observation has been that this has not 
been done in the great majority of cases. 
The tar-like oil is tracked into the houses, 
where rugs, clothing and other household 
goods are damaged, and passing vehicles 
become spattered with it, making them 
greasy and unsightly. To apply this “black 
oil” in a manner that will eliminate these 
objectionable features means additional 
cost, in that all loose material must be 
cleaned from the surface of the road be- 
fore the oil is applied, and then a thin cov- 
ering of screenings, coarse sand or other 
material of that kind must be spread on 
top of the oil after its application to ab- 
sorb the excess. 
A more satisfactory dust-laying agent 
has been found in the so-called “light road 
oil.” This material is a petroleum dis- 
tillate, a clear, straw-colored liquid, look- 
ing much like water when first applied to a 
roadway or other surface, but becoming 
darker from exposure to the weather and 
wear of traffic on surfaces treated with it. 
It was brought to my attention in the 
summer of 1911. During August of that 
year a tank car (about 7,000 gallons) of 
it was applied to a macadam driveway at 
the rate of about one-fourth gallon per 
square yard. Although a heavy downpour 
of rain the next day after its application 
washed some of the oil into the sewers, 
yet no dust was noticed on this driveway 
for the rest of the season. It must here 
be stated that the drive was thoroughly 
cleaned with a street-sweeping machine to 
remove all loose material before the oil 
was applied. 
The results' were so satisfactory on that 
driveway that this year, 1912, 145,900 gal- 
lons of “light road oil” were purchased 
for dust-laying purposes throughout the 
South Park system. This kind of oil was 
so free from objectionable features that it 
was decided to try a light application of 
it on a large torpedo-gravel covered ball- 
field which had been sprinkled with water 
in previous years to keep dowu the dust. 
The oil not only laid the dust satisfactorily, 
but also killed the weeds which grew on 
the ballfield before and the removal of 
which had previously been a source of ex- 
pense. This treatment was extended to 
every ballfield, children’s playground and 
outdoor men’s and women’s gymnasiums 
in the South parks. The gravel walks in 
all of the small parks were also treated 
with this oil with very good results. 
In all there were treated over half a 
million (511,368) square yards of surface, 
of which 62,474 square yards of drive were 
given two applications. These areas in- 
cluded : 
Sq. Yds. 
Driveways (62,474 square yards were 
oiled twice) 141,251 
Gravel walks 87,652 
Playgrounds 269,844 
Clay tennis courts 12,621 
Total 511,368 
On most of the drives the dust was ef- 
fectually kept down all of the time. In 
one or two instances, where drives were 
oiled in sections, the results were not of 
the best, because traffic tracked the dust 
and loose material from the unoiled sec- 
tions over upon the oiled sections, and 
caused the latter to become dusty for some 
distance from the division lines. The walks 
and playgrounds, however, proved gener- 
ally satisfactory throughout the season, be- 
ing free from dust, and the playgrounds 
also free from little clumps of weeds and 
grass which previously grew upon them. 
In the case of the clay tennis courts, it 
seems that the best results in making them 
compact and dustless can be obtained only 
when the clay is thoroughly saturated with 
oil to make it waterproof. The oil should 
be applied to the courts repeatedly in light 
applications of not more than one-fourth 
gallon per square yard at any one time, 
and it is probable that the clay will ab- 
sorb one-half to one gallon per square 
yard. 
Wherever possible the oil was applied 
from ordinary water-sprinkling wagons 
drawn by two horses each. Where the 
teams could not be used, hand sprinkling 
carts or sprinkling cans were used. There 
are several good oil-spreading machines on 
the market by the use of which the amount 
of oil applied per square yard can be 
nicely regulated. 
We have found the use of oil cheaper 
than water for dust-laying purposes, with 
the additional advantage of laying the dust 
twenty-four hours daily throughout the 
year. If it is scientifically applied similar » 
results can undoubtedly be secured else- 
where. 
