Frostburg mining journal. [volume] (Frostburg, Md.) 1871-1913, 1906-10-20

THIRTY MILES AN HOUR.
of road. Several motor cars of differ
ent types and weights are in rcadi-
ness The photographers and the men
with stop watches are duly placed at
their appointed stations. WhooSh, OF
goes Il machine at Il rapid rate, fol
lowed closely by another. in the front
of which. WSh the chauffeur, sits
man whD operates II camera. The
dust flies upward in a cloud, partly
obSCuring the automobile in front but
that Is what is wanted to show by
photography how much dust is thus
thrown up from the roadbcd, to be
carried off by the breeze. and SO, in
considerable part, lost.
To say that dust is the life of road
is not putting the fact too strongly.
1t Is the cementing material of the road
surface, which, combining with the
moisture contributed hy rain, holds to-
gethcr the stony PARTICLES composing
that surface. shedding storm water
and preventing the particles from un-
dergoing diSintcgration. Thus it may
be said that dust is to n road what
shingles are to IL house. If 1t is taken
away the roalbed goes to pieces. The
amount of dust thrown up by the au-
tomohlc is in proportion to the speed
at which it goes. But, in order to oh
tain exact figures on this point. the
government experts take Il series of
photographs of each motor car, tray
cling over the same stretch of road, at
ten miles. twenty miles, thirty miles
and so on up to seventy miles an hour.
\ stretch of road with Il fairly sharp
turn is chosen by preference, in order
that photographers posted at the bend
may. with safety to themselves, snap
shoot each motor car from directly
in front. as it approaches, and also
directly from behind after it has
passed by. Now, it is not merely for
theoretical purposes that the road bu-
reau is making these experiments. 1t
Is trying to find a remedy for the mis-
chicf-a practical part of the inquiry
which Is being carried on Simultanc-
ouSly with the automobile tests above
described. Something must be found.
obviously, to keep the dust from being
carried Off the roads. and the pre-
vcntive seems to be either tar or oil.
For some months past the experts
have been applying tar and crude pc
troleum to different sections of roads,
and they have found that either
Though the tar seems to be preferred
accomplShes the purpose admirably.
1t appears that an application Of tar
costs less than cents Il square yard,
including labor, and ii will last for a
year or so, though Just how long can
not he stated exactly as yet The cost
Of oil is even less. The tar Is trans
ported for the purpose in tank cars
and heated in the car hy Introducing n
coil of steam pipe into it and furnish
ing the requisite heat from an engine
on wheels which is run up alongside
In this way the material Is made fluid,
SO rs to he easily spread hy men with
brOOmS or otherwise over the surface
of tie roA1bcd that is to be treated.
The tar gives Il hard and smooth coat
Ing, rcSrltbliug asphalt. 1t pcnetrates
to Il depth OF one or two inches, ana in
the ease of macadam forms Il sort OF
matriX into which the stones of the top
layer are set. \ tarrcd street is dust
less in the same sense that an asphalt
street is dustleSs.