247 
PARK AND CEMETERY. 
DUST SUPPRESSION ON THE BOSTON PARKWAYS 
We were so favorably impressed last 
year with our experience in the use of 
oil for laying dust on our parkways that 
we continued its use this season. From 
twelve miles of roadway treated with 
oil in 1906, we extended the treatment 
in 1907 over our whole system of roads 
— about forty-four miles. The results 
are most satisfactory. In point of effi- 
ciency there fs nothing to be desired, 
the dust being kept down perfectly, by 
night as well as by day. 
The oil treatment is cheaper than 
watering. Mr. C. E. Putnam, our en- 
gineer, a few years ago, after careful 
observation, computed the cost of wat- 
ering in Franklin Park at $489 per 
mile of 30 -foot roadway, watering be- 
ing done on 182 days. The cost for 
the same service on Commonwealth 
avenue, for 230 days, was $883 per mile 
of 30-foot roadway. Commonwealth 
avenue represents the most costly part 
of the system, and Franklin Park the 
least costly in point of dust laying. In 
view of the fact that cost of team hire 
is greater and hours of labor shorter 
than when the estimate was made, an 
average of $680 per mile per annum 
might be considered a low estimate of 
the present cost of dust suppression by 
the watered method. These estimates 
may seem a little high for watering: it 
must, however, be borne in mind that 
watering is done in the Park Depart- 
ment whenever the dust flies and the 
thermometer is not lower than 24 de- 
grees Fahrenheit. 
Oiling operations were commenced 
this year, 1907. on April 3d. since when 
to date, November 12, the total cost of 
oiling has been $352.67 per mile of 
road 30 feet wide, or at the rate of two 
cents per square yard; the amount of 
oil used being 1.49 pints per square 
yard. The dust season is not yet over; 
the result, however, will not be much 
affected, as we have considerable stock 
on hand, sufficient to run until Novem- 
ber 25. 
In addition to the effective laying of 
the dust, we find that the asphaltum in 
the oil has a binding effect on the sur- 
face of the road, and less surface repairs 
are necessary. We have been able in 
the middle of August this year to lay 
Paper Read by J» A. Pettigrew, Supt. of Parks, 
Boston, before the Massachusetts Highway 
Association. 
up our road rollers for the season, and, 
excepting for a portion of one of our 
parkways, which insufficient appropria- 
tion has prevented our repairing, the 
roadways are in good condition. The 
surface of the roads being better fixed, 
less washings result from rain, and less 
gutter scraping is necessary. It is even 
reported that the catch-basins on their 
fall cleaning up did not contain half so 
much material as usual. The softer 
footing on an oil-treated road is a 
benefit to horse. The cost of shoeing, 
too, we find to be reduced. 
We apply the oil in the form of an 
emulsion. The first application of the 
season contains about 16 per cent of oil, 
to form a basis; renewals contain from 
8 to 10 per cent of oil. Renewals are 
made in from ten to twenty-five days, 
according to location and the use to 
which the road may be subject. As 
for instance. Commonwealth avenue, 
between Arlington and Brookline ave- 
nues, requires renewals, or rather rein- 
forcements, at intervals of eight or ten 
days, while from Brookline avenue to 
the Newton line renewals are required 
only once in fourteen to sixteen days; 
Columbia Road, Arborway and Jamai- 
caway, with the Fens, fourteen to six- 
teen days, while Franklin Park, where 
automobiles are excluded, requires re- 
newals only at intervals of twenty to 
twenty-five days. 
In the manufacture of our emulsions 
we use steam pumps, which do the 
work of transference of materials and 
their emulsification by agitation. The 
formula is 10 to 15 pounds of soap dis- 
solved in 50 gallons of water, to each 
100 gallons of petroleum. The soap is 
placed in barrels of water and dissolved 
by steam heat, then pumped into the 
stock reservoirs, which are simply 
street sprinkling wagons. To, each bar- 
rel of soap and water, two barrels of 
petroleum are added. The pump is 
then attached to the tank of the sprink- 
ling wagon and the contents agitated 
until emulsified. This forms the stock, 
which contains 66 per cent of petro- 
leum. The stock is then run out to 
the work, and forms the supply for the 
sprinklers working on the drives, the 
transfer being m.ade by gravity flow, 
the stock wagons being set on slight 
elevations and large transferring hose 
being used. This method is crude; ex- 
periment might devise something bet- 
ter. Possibly compressed air could be 
used to advantage. Each stock tank 
will serve to fill four to six street 
sprinklers, according to the percentage 
of oil required in the application to the 
road. This we find to be from 16 per 
cent on the first application down to- 
5 to 8 per cent for renewals, as stated 
before. We find the ordinary street 
hydrant to be sufficient for the emul- 
sification of the stock with the added 
water in the sprinkling wagon. 
We are still in favor of a thin rolling 
cushion of coarse sand or fine screen- 
ings, saturated with oil. This is, how- 
ever, hard to maintain on curved roads, 
the swing of the wheels throwing it to 
the outer side of the curve. We believe 
that this loose, rolling cushion helps to 
release the air suction below the tire, 
which is so destructive to the road 
binder. Fine or dead sand of a yellow 
color makes a very pleasing surface, 
but must not be too heavily treated with 
oil, or a hard asphaltum surface will re- 
sult, which has a tendency to scale. 
I have not added the cost of the very 
slight cushion of sand, which we like 
to but do not always give to the surface 
of the road before oiling, for the reason 
that it more properly should come under 
the head of road repairs than that of 
dust suppression.. Under the water 
treatment we should have made, during 
the past season, not less than three or 
four applications of stone screenings, 
and rolled them into the surface. One 
application this year under the oil treat- 
ment has been sufficient. 
We find that cottonseed oil soap, at 
4^2 cents per pound, the best we have 
tried for the oil emulsion. The oil we 
use is Texas oil, for which we pay. net, 
6l4 cents per gallon. 
Small “pot holes,” formed by the 
water settling in small depressions of 
the roadway, and being forcibly ejected, 
along with road material, by the tires 
of the automobiles, are rarely found in 
our oil-treated roads. 
