:S99 
PARK AND CEMETERY. 
sorted’ to. When a surface of this character 
begins to show wear, it is best to apply an- 
other coat of material before the holes ap- 
pear in large numbers. When tar is used, 
especially of a high, melting point, consider- 
able care must be exercised in cleaning the 
old pavement and thoroughly rolling and 
dressing the new layer while hot in order 
to prevent peeling. The patching of holes 
in a surface treated road is usually unsat- 
isfactory. and where the pavement is badly 
worn it is better, as a rule, to scarify and 
resurface as before. 
By following this method of maintenance, 
however, a large amount of machinery is of 
necessity kept upon the boulevards during a 
sea’son when it is most objectionable and 
thereby causes considerable and well-founded 
criticism by citizens and taxpayers. Where- 
as this treatment is undoubtedly the best 
and perhaps the only practical treatment 
which can be carried on in suburban parks, 
which are used infrequently during the 
Winter, for a metropolitan park system, 
which has miles of boulevards, subject to 
well-nigh constant traffic during the winter 
and summer months alike, there seems but 
ALONG MINNEHAHA PARKWAY. 
one solution of the question, and that is by 
the adoption of permanent pavements. 
Inasmuch as the sole object of park sys- 
tems is for pleasure, recreation and com- 
fort, the boulevards should be made as con- 
ducive to these requirements as any other 
part of the system. If^ the macadam road 
must go, consequent to modern uses and 
conditions, its substitute should embody as 
many of its good qualities as possible. Al- 
though there is no question as to the per- 
manency of the motor, either in its pres- 
ent or an improved form, yet the continued 
fluctuation in the popularity of driving, 
makes it reasonable to believe that the horse 
will never be entirely superseded by any 
mechanical contrivance; therefore, a pave- 
ment should be designed to meet the re- 
quirements of the horse as well as that of 
the motor. In this connection, nearly all of 
the standard pavements fall short, and it is 
toward the production of one of more ideal 
type that some engineers and park men are 
now wmrking. Such a pavement should 
present an easy riding, malleable, and slight- 
ly elastic surface of a color which will be 
restful to the eyes, and which will not draw 
the heat, as in the case of the black as- 
phalt pavements. It should emit no dis- 
agreeable odor, should not crack or chip in 
cold weather, nor become sticky or wavy 
under summer use. It must be easily cleaned, 
sanitary and dustless. It should present a 
surface rough enough to prevent skidding 
or slipping, yet it should be sufficiently 
smooth to present a good appearance, and to 
cause no vibration while being traversed. 
Inasmuch as nearly all park systems have 
at present well constructed macadam roads 
which may serve as foundations, it is but 
necessary to secure a wearing coat of from 
one inch to two inches in thickness which 
will be able to wUhstand traffic for several 
years. ^To secure such a wearing coat, 
which shall embody the qualities mentioned 
is now the object of some experimentation. 
At present the principal binding materials 
available are the various forms of tar and 
asphalt, the latter being by far the most 
important, and containing the two princi- 
pal components, asphaltine and petroline. In 
most forms of asphalt pavements, an excess- 
ive amount of asphaltine is used, with the 
result that the pavement is hard and re- 
sistant. Petroline, which may be said to be 
the life of asphalt, and which gives to it its 
elasticity, and cementeous properties, can be 
used to advantage in larger proportions in 
park pavements. The mixing of coal tar 
with asphalt is resorted to in some cases, 
and probably is not detrimental if used in 
small quantities. Its low range of ductility, 
and its tendency to become brittle, due to 
the loss of its volatile oils, however, should 
limit its use. EScperimental roads are now 
being constructed by first obtaining a binder 
melting at from one hundred and sixty de- 
grees to two hundred and twenty degrees 
Fahrenheit, and which seems to fulfill 
the qualities demanded. This binder is in- 
corporated with the road metal in various 
ways. In one instance it was heated up to 
three hundred and fifteen degrees, and 
poured into the interstices of the macadam 
composed of limestone three inches in diam- 
eter, after it had been thoroughly compact- 
ed by rolling. Before the binder could have 
a chance to cool, heated sand was spread 
upon the surface and rolled. One applica- 
tion of oil emulsion was then made to the 
surface in order to soften up a part of the 
binder so that it would work through the 
sand finish. Two pieces of road constructed 
in this way are now presenting an unusually 
good appearance. In another case, the bind- 
er is being mixed by machinery with care- 
fully graded road material ranging from 
fine sand to three-quarter-inch stone, and is 
rolled upon a previously prepared surface in 
a two-inch layer; a flush coat of asphalt is 
then applied and spread in place with rub- 
ber squeegees, after which a coat of coarse 
sand is applied, and rolled thoroughly into 
the flush coat. 
Surfacings of the kinds mentioned can be 
laid at a cost of from forty cents to sixty 
cents per square j'ard. In experimental 
work of this kind, where special results are 
looked for, everything depends upon a suit- 
able binder. As a rule, park superintendents 
and engineers are greatly deficient in the 
knowledge of the theory and practice of 
road construction where bitumen is em- 
ployed as a filler, and it w’ill be only by con- 
tinued and systematic experiments that suc- 
cess will be achieved. It is necessary in 
carrying on a series of experiments of this 
kind that each binder sha‘ll be subjected to 
a thorough physical and chemical test. By 
employing the same person in all cases to 
make such tests, and by carefully tabulating 
and comparing records, good pieces of work 
can be duplicated by means of rigid specifi- 
cations in the purchase of material. This 
is a point which should be given careful 
consideration in all road work where bitu- 
mens are employed, whether for mere sur- 
facing or for work of a more permanent 
character. 
An animated discussion of this para- 
fnount subject followed and Superin- 
tendent Wirth, of Minneapolis, wanted 
