379 
PARK AND CEMETERY. 
DUST SUPPRESSION AND MACADAM ROAD MAKING 
The thousands of experiments for the 
suppression of dust on macadam roads 
which have been made all over the coun- 
try during the past five years have now 
developed a vast amount of data on the 
subject. All kinds of promising com- 
pounds which make the dust sticky or 
heavy have been tried. 
Sometimes they have been of a char- 
acter that would permit of their being 
dissolved in water and used from an 
ordinary sprinkling cart, giving to the 
water a soapy or sticky character to de- 
lay evaporation. 
Several of these liquids have demon- 
strated their ability to keep the road 
dustless for a short period. None of 
them aim to, or have succeeded in pre- 
venting dust formation. 
Sea water has also been used in sea 
coast cities to some advantage, resulting 
in a considerable saving in sprinkling 
expense. 
Considerable areas have also been 
treated with oil of various grades and 
gravities, produced from either petro- 
leum or asphalt. Their effect upon the 
road has been considerably longer, and a 
good treatment with oil will keep the 
road dustless for weeks, inasmuch as it 
will not evaporate, but will disappear 
only by absorption into the roadway. 
The objection to the use of oil, however, 
has been the fact that it is obnoxious 
to pedestrians. Skirts and shoes are 
stained by it, and the automobilists and 
carriage owners complain of damage to 
their vehicles. 
Moreover, the oily dust which does 
arise from an oil treated road is espe- 
cially dirty and obnoxious, and property 
owners on oil treated roads have made 
complaint against the treatment. 
It has been generally recognized dur- 
ing the last year or two that all these 
methods are mere palliatives and do not 
strike at the source of the trouble, name- 
ly, the weakness .of the natural macadam 
binder. Under old style traffic a mac- 
adam road wore out very slowly ; but 
automobiles will destroy the finest sur- 
facing in a year, stripping the top dress- 
ing down to the number two stone. The 
water then finds ready access and does 
great damage. 
Many counties facing the problem of 
automobile wear, preferred to give up 
all attempt at maintaining a top dressing 
ot fine screened stone, and have admitted 
traffic directly upon the coarser stone, 
which constitutes the second layer. It 
was recognized that if this mosaic of 
number-two stone could only be made 
waterproof it would give tremendous 
durability, inasmuch as the abrasion on 
this surface as compared with a sur- 
face of fine screenings, was practically 
nil. The mosaic in fact, on an old road 
is practically non-dust-producing but is 
very susceptible to erosion by water and 
disruption by frost. 
It has been found that tarvia could 
be used to make the mosaic waterproof. 
This tar compound is applied to the 
road in a liquid condition and hardens 
among the fine interstices of the road- 
way somewhat like cement in concrete. 
The makers claim it to be absolutely wa- 
terproof and a road so treated will read- 
ily shed water. If the road happens 
to be imperfectly drained so as to leave 
puddles after a rain, the water in the 
puddles, it is claimed, will not be ab- 
sorbed by the road at all and will only 
disappear by the natural process of evap- 
oration. 
A single treatment with tarvia will 
give good results for a year, and will 
frequently show good effect much long- 
er. Sprinkling is unnecessary, and an 
occasional- cleaning is the only cure re- 
quired. A treatment with tarvia for such 
roads costs about $300 per mile and 
calls for no apparatus except an ordi- 
nary springling cart with a special ad- 
justable nozzle. 
It is pretty well established that the 
tarviated surface preserves the road so 
well as to more than save its cost in 
the renewal of the stone. Automobile 
traffic, instead of breaking it up, act- 
ually makes it smoother. 
It may be objected that the road made 
of exposed number-two stone must be 
rougher than one -with the usual top 
coat of fine screenings. This is correct, 
and this style of tarvia treatment would 
hardly be appropriate for city parks and 
boulevards, for instance. For village 
streets, however, and county thorough- 
fares, where the cost of maintenance is 
an important consideration, this process 
of road building can be used to great ad- 
vantage. The difference is principally 
a matter of appearance, the slight rough- 
ness of the surface not being great 
enough to affect tiie comfort of those 
who ride over it. 
The possibility of securing dustless 
roads at less than the cost of dusty ones 
makes it certain that this method of 
road construction will come rapidly into 
vogue. 
The illustration of the road in Oyster 
Bay, Long Island, shows the effect of 
tarvia on one of the principal streets of 
the village nine months after the applica- 
cation of the material. This village was 
one of the first to experiment with this 
style of road building, and its use in the 
vicinity is being rapidly extended as a 
consequence of the satisfactory outcome 
of the first experiment. 
STREET IN OYSTER BAY, L. I., N. Y., TREATED WITHTARVIA B. 
