PARK AND CEMETERY. 
PAVIT.IOX OVERLOOKING LAKE HARRIET, MINNEAPOLIS PARK SYSTEM. 
pavements. I have come to the belief that 
too much stress has been laid to the dam- 
age done to road surfaces by chains, spuds, 
etc. Assuming that the damage is caused 
by the release of a vacuum formed by a 
flattened tire under great tveight, and by the 
slipping of the tire under the great tractive 
force exerted by the rear wheels, it is ob- 
vious that any device which would tend to 
prevent this vacuum, or to prevent the 
shearing stress from being exerted . on the 
surface would help in a degree to maintain 
the road rather than the reverse. However, 
the.^e effects are exerted to a more or less 
degree even when chains are employed, and 
I mention this point only to observe that it 
does not seem justifiable to enact rules pro- 
hibiting the use of devices by which the 
safety of individuals is guarded, when by so 
doing only a questionable harm to public 
property is as'erted. 
Finding that our experiments in laying 
unprotected macadam proved on the whole 
unsatisfactory, inasmuch as it was impos- 
sible to ma.ke any particular piece of pave- 
ment remain in condition more than one 
year, we abandoned the project, and returned 
to the method of treating the road sur- 
faces with various materials in order to lay 
the dust at night as well as during the day, 
and to give the road surfaces resisting qual- 
ities other than that due to the natural 
binding properties of the stone. 
Calcium chloride as well as sodium chlo- 
ride has been given a fair trial, but neither 
of these chemicals has demonstrated its 
ability to more than lay the dust at a cost 
slightly under that of sprinkling with water, 
wherc'us no beneficial effects relative to the 
lasting qualities of the road have been 
shown. 
• Careful experiments have been carried on 
in the use of oils, both of asphaltic and par- 
affin bases, and ranging from fifteen to 
twenty-seven degrees specific gravity, ap- 
plied both hot and cold upon pavements 
constructed in various ways and of different 
types of rock. Various oils, asphalts and 
tars have been made into solutions or emul- 
sions with water by chemical and mechani- 
cal means, and to some extent the various 
I)atented fluids offered by the trade for the 
suppression of dust have been tested. Up to 
date, the most satisfactory and economical 
surface treatment employed has been that 
of oil emulsions. Considerable experimenta- 
tion was necessary before the proper for- 
mula was adopted. At present, we have in 
the neighborhood of 200, OOu square yards of 
surface treated with emulsions at a cost of, 
about one-tenth that of sprinkling with 
water. The roadways are kept absolutely 
dustless at all hours of the day. No odor 
can be detected, and the roads are open for 
traffic continually. The roads are not made 
slippery under ordinary conditions, and the 
treatment is popular with both drivers and 
property owners. Last season some trouble 
was experienced by the drying out of the 
stone, due to a watershed caused by a thin 
asphaltic film on the surface. This film 
when once broken quickly ravelled away, 
allowing the stone to pick up. This year 
little trouble has been experienced on this 
account, due to different method of manu- 
facture and of applying the material; a 
larger percentage of light oil is used, and 
after three applications of the emulsion, a 
scout wagon is sent over the road, sprinkling 
only the weak looking places. In this way, 
comparatively little oil is used, and one 
wagon is capable of covering a large amount 
of territory. 
The emulsion is made in a specially pre- 
pared plant, fitted out wUb a series of tanks 
connected with each other, and with a me- 
dium sized steam pump. The oils are mixed 
in the proportion of one part residuum of 
about nineteen degrees specific gravity with 
three parts paraffin base fuel oil. One part 
of the mixed oils is then incorporated with 
nine parts of hot water, to which naphtha 
soap is added, in the proportion of fifteen 
pounds to five hundred gallons of water. 
Roads treated with five applications of emul- 
sion came through the Winter in goo<l con- 
dition, with the exception of some of the 
main boulevards, which were subjected to 
unusually heavy automobile traffic. Luring 
the early Spring a number of heavy snow- 
storms occurred, and the automobile.^ taking 
the beaten track, rapidly cut through the 
surface, scattering the macadam in all di- 
rections. In some cases, it was only neces- 
sary this Spring to repair the four parallel 
tracks to put the road once more in con- 
dition. In using heavy residuum oils from 
California, Texas and Kainsas on the road 
surfaces, the best results have been obtained 
by first scarifying the road, and after shap- 
ing, rolling thoroughly with a heavy roller, 
at the same time applying watc‘r. No bin«l- 
er is used other than that found in the 
old road material. After drying, the surface 
presents a rough but firm, appearance, which 
affords excellent penetration to the binding- 
fluid. The hot asphalts are then applied by 
driving three or four tank wagons abreast 
with the outlet valves partially open. Men 
follow l-)ehind with road brooms, spread the 
material, and brush it into the interstices. 
A layer of torpedo sand or screenings is th€*n 
applied and rolled thoroughly. In api>lying- 
tar it was found more expedient to draw the 
material from the heating wagons into ordi- 
nary five-gallon sprinkling cans, the per- 
forations in the nozzles having been previ- 
ously enlarged. Resurfacing of this kind 
can be carried on at a cost of from se\'en 
cents to fifteen cents per square yard, as- 
suming the cost of oil or tar to be from four 
cents to ten cents jier gallon where n'» 
stone has to be added to the rnadhe<l. 
R()ads treate<l in this manner can ])e count- 
ed on to give fairly good satisfaction umlor 
extreme wear foi' twelve to eighteen montlis. 
Inasmuch as no water sprinkling is neces- 
sary the cost (*r maintenance per year is 
considerably less than when tlu' <]rivewa>s 
were sprinkled with ^\afeI•. am! when patch- 
ing of the liolt-s had t-. hr continually r<-- 
